WorldWideScience

Sample records for based optoelectronic tweezers

  1. Single-sided lateral-field and phototransistor-based optoelectronic tweezers

    Science.gov (United States)

    Ohta, Aaron (Inventor); Chiou, Pei-Yu (Inventor); Hsu, Hsan-Yin (Inventor); Jamshidi, Arash (Inventor); Wu, Ming-Chiang (Inventor); Neale, Steven L. (Inventor)

    2011-01-01

    Described herein are single-sided lateral-field optoelectronic tweezers (LOET) devices which use photosensitive electrode arrays to create optically-induced dielectrophoretic forces in an electric field that is parallel to the plane of the device. In addition, phototransistor-based optoelectronic tweezers (PhOET) devices are described that allow for optoelectronic tweezers (OET) operation in high-conductivity physiological buffer and cell culture media.

  2. Optoelectronic tweezers for medical diagnostics

    Science.gov (United States)

    Kremer, Clemens; Neale, Steven; Menachery, Anoop; Barrett, Mike; Cooper, Jonathan M.

    2012-01-01

    Optoelectronic tweezers (OET) allows the spatial patterning of electric fields through selected illumination of a photoconductive surface. This enables the manipulation of micro particles and cells by creating non-uniform electrical fields that then produce dielectrophoretic (DEP) forces. The DEP responses of cells differ and can produce negative or positive (repelled or attracted to areas of high electric field) forces. Therefore OET can be used to manipulate individual cells and separate different cell types from each other. Thus OET has many applications for medical diagnostics, demonstrated here with work towards diagnosing Human African Trypanosomiasis, also known as sleeping sickness.

  3. Electrodes for Microfluidic Integrated Optoelectronic Tweezers

    OpenAIRE

    Kuo-Wei Huang; Sabbir Sattar; Zhong, Jiang F.; Cheng-Hsu Chou; Hsiung-Kuang Tsai; Pei-Yu Chiou

    2011-01-01

    We report on two types of electrodes that enable the integration of optoelectronic tweezers (OETs) with multilayer poly(dimethylsilane)- (PDMS-) based microfluidic devices. Both types of electrodes, Au-mesh and single-walled carbon nanotube- (SWNT-) embedded PDMS thin film, are optically transparent, electrically conductive, and can be mechanically deformed and provide interfaces to form strong covalent bonding between an OET device and PDMS through standard oxygen plasma treatment. Au-mesh ...

  4. Manipulation of microparticles and red blood cells using optoelectronic tweezers

    Indian Academy of Sciences (India)

    R S Verma; R Dasgupta; N Kumar; S Ahlawat; A Uppal; P K Gupta

    2014-02-01

    We report the development of an optoelectronic tweezers set-up which works by lightinduced dielectrophoresis mechanism to manipulate microparticles. We used thermal evaporation technique for coating the organic polymer, titanium oxide phthalocyanine (TiOPc), as a photoconductive layer on ITO-coated glass slide. Compare to the conventional optical tweezers, the technique requires optical power in W range and provides a manipulation area of a few mm2. The set-up was used to manipulate the polystyrene microspheres and red blood cells (RBCs). The RBCs could be attracted or repelled by varying the frequency of the applied AC bias.

  5. Continuous cell lysis in microfluidics through acoustic and optoelectronic tweezers

    OpenAIRE

    Witte, C.; Kremer, C; Cooper, J.M.; Neale, S.L.

    2013-01-01

    A versatile platform for efficient cell lysis using a combination of acoustic and electric fields in a microchannel is presented. Cell membrane disruption is triggered by electric fields inducing electroporation and then lysis. The principle of optoelectronic tweezers (OET) is applied to control the electric field strength and a surface acoustic wave transducer is attached to an OET chip to implement acoustic tweezing (AT). The system is characterized in terms of spatial contro...

  6. Biaxial crystal-based optical tweezers

    DEFF Research Database (Denmark)

    Angelsky, Oleg V.; Maksimyak, Andrew P.; Maksimyak, Peter P.;

    2010-01-01

    We suggest an optical tweezer setup based on an optically biaxial crystal. To control movements of opaque particles, we use shifts. The results of experimental studies are reported which are concerned with this laser tweezer setup. We demonstrate a movement of microparticles of toner using a sing...... singular-optical trap, rotation of particles due to orbital angular momentum of the field, and converging or diverging of two different traps when changing transmission plane of polariser at the input of our polarisation interferometer....

  7. In Situ Raman Spectroscopy of COOH-Functionalized SWCNTs Trapped with Optoelectronic Tweezers

    Directory of Open Access Journals (Sweden)

    Peter J. Pauzauskie

    2012-01-01

    Full Text Available Optoelectronic tweezers (OETs were used to trap and deposit aqueous dispersions of carboxylic-acid-functionalized single-walled carbon nanotube bundles. Dark-field video microscopy was used to visualize the dynamics of the bundles both with and without virtual electrodes, showing rapid accumulation of carbon nanotubes when optical virtual electrodes are actuated. Raman microscopy was used to probe SWCNT materials following deposition onto metallic fiducial markers as well as during trapping. The local carbon nanotube concentration was observed to increase rapidly during trapping by more than an order of magnitude in less than one second due to localized optical dielectrophoresis forces. This combination of enrichment and spectroscopy with a single laser spot suggests a broad range of applications in physical, chemical, and biological sciences.

  8. Self-Locking Optoelectronic Tweezers for Single-Cell and Microparticle Manipulation across a Large Area in High Conductivity Media

    Science.gov (United States)

    Yang, Yajia; Mao, Yufei; Shin, Kyeong-Sik; Chui, Chi On; Chiou, Pei-Yu

    2016-03-01

    Optoelectronic tweezers (OET) has advanced within the past decade to become a promising tool for cell and microparticle manipulation. Its incompatibility with high conductivity media and limited throughput remain two major technical challenges. Here a novel manipulation concept and corresponding platform called Self-Locking Optoelectronic Tweezers (SLOT) are proposed and demonstrated to tackle these challenges concurrently. The SLOT platform comprises a periodic array of optically tunable phototransistor traps above which randomly dispersed single cells and microparticles are self-aligned to and retained without light illumination. Light beam illumination on a phototransistor turns off the trap and releases the trapped cell, which is then transported downstream via a background flow. The cell trapping and releasing functions in SLOT are decoupled, which is a unique feature that enables SLOT’s stepper-mode function to overcome the small field-of-view issue that all prior OET technologies encountered in manipulation with single-cell resolution across a large area. Massively parallel trapping of more than 100,000 microparticles has been demonstrated in high conductivity media. Even larger scale trapping and manipulation can be achieved by linearly scaling up the number of phototransistors and device area. Cells after manipulation on the SLOT platform maintain high cell viability and normal multi-day divisibility.

  9. Silicon photomultiplier-based optoelectronic mixing

    Science.gov (United States)

    Yishuo, Song; Xiaoping, Du; Zhaoyang, Zeng; Shengjun, Wang

    2013-09-01

    Silicon photomultiplier (SiPM)-based optoelectronic mixing (OEM) is studied for the first time. The validity of SiPM-based OEM is experimentally verified. Compared with the avalanche photodiodes-based OEM, the SiPM-based OEM is less noisy and easy to realize for its low voltage operation and high responsivity.

  10. Optoelectronic Oscillator Based on Polarization Modulation

    Science.gov (United States)

    Pan, Shilong; Zhou, Pei; Tang, Zhenzhou; Zhang, Yamei; Zhang, Fangzheng; Zhu, Dan

    2015-07-01

    A polarization modulator together with a polarizer can implement phase modulation, intensity modulation with tunable chirp, and frequency-doubling intensity modulation. If an optical filter is incorporated, frequency-quadrupling and frequency-sextupling intensity modulations and a microwave photonic phase shifter can also be realized. By using a polarization modulator to replace the intensity modulator in an optoelectronic oscillator, various new features are enabled. In this article, an analytical model for the polarization modulator-based systems is established. The recent development in employing polarization modulators for constructing optoelectronic oscillators is discussed. The emerging applications enabled by the polarization modulator-based optoelectronic oscillators and the possible future development are also discussed.

  11. YBCO based multilayers for optoelectronic devices

    International Nuclear Information System (INIS)

    YBCO based multilayers have been deposited independently by three techniques: laser ablation, inverted cylindrical target sputtering (ICM) and on-axis planar D.C. Magnetron Sputtering. The last technique is used to cover uniformly R-plane sapphire and LaAlO3 2 inch wafers with YBCO or multilayers to achieve optoelectronic devices such as infrared detectors. Very thin (- 3 nm) YSZ and MgO dielectric films have been studied as tunnel barriers for making such high Tc tunnel junctions. 14 refs., 11 figs

  12. Optoelectronic date acquisition system based on FPGA

    Science.gov (United States)

    Li, Xin; Liu, Chunyang; Song, De; Tong, Zhiguo; Liu, Xiangqing

    2015-11-01

    An optoelectronic date acquisition system is designed based on FPGA. FPGA chip that is EP1C3T144C8 of Cyclone devices from Altera corporation is used as the centre of logic control, XTP2046 chip is used as A/D converter, host computer that communicates with the date acquisition system through RS-232 serial communication interface are used as display device and photo resistance is used as photo sensor. We use Verilog HDL to write logic control code about FPGA. It is proved that timing sequence is correct through the simulation of ModelSim. Test results indicate that this system meets the design requirement, has fast response and stable operation by actual hardware circuit test.

  13. Static and dynamic response of carbon nano tube-based nano-tweezers

    International Nuclear Information System (INIS)

    In this paper static and dynamic responses of a nano-tweezer composed of two carbon nano-tube arms are investigated. Taking into account a continuum model and considering the electrostatic actuation as well as the presence of the van der Waals forces, the static nonlinear equations are solved by a step by step linearization and Galerkin projection method. Simulating the closing dynamics of the nano-tweezer, the specified effective diameters of the nano tubes compared to existing experimental data. Then by imposing a step DC voltage and taking into account the inertia effects, the dynamic responses and pull-in conditions of the nano-tweezer are studied. In the static and dynamic analysis, the effects of various parameters such as initial gap, length and diameter of the nano tubes on the pull-in conditions are investigated. Also the effect of damping and asymmetric stiffness of the arms on the pull-in voltages of the nano-tweezer is reported. Comparison of the results with the published experimental data shows that the use of continuum model and employing the Galerkin based step by step linearization method could effectively simulate the response of nano-tweezers.

  14. GaAs-based optoelectronic neurons

    Science.gov (United States)

    Lin, Steven H. (Inventor); Kim, Jae H. (Inventor); Psaltis, Demetri (Inventor)

    1993-01-01

    An integrated, optoelectronic, variable thresholding neuron implemented monolithically in GaAs integrated circuit and exhibiting high differential optical gain and low power consumption is presented. Two alternative embodiments each comprise an LED monolithically integrated with a detector and two transistors. One of the transistors is responsive to a bias voltage applied to its gate for varying the threshold of the neuron. One embodiment is implemented as an LED monolithically integrated with a double heterojunction bipolar phototransistor (detector) and two metal semiconductor field effect transistors (MESFET's) on a single GaAs substrate and another embodiment is implemented as an LED monolithically integrated with three MESFET's (one of which is an optical FET detector) on a single GaAs substrate. The first noted embodiment exhibits a differential optical gain of 6 and an optical switching energy of 10 pJ. The second embodiment has a differential optical gain of 80 and an optical switching energy of 38 pJ. Power consumption is 2.4 and 1.8 mW, respectively. Input 'light' power needed to turn on the LED is 2 micro-W and 54 nW, respectively. In both embodiments the detector is in series with a biasing MESFET and saturates the other MESFET upon detecting light above a threshold level. The saturated MESFET turns on the LED. Voltage applied to the biasing MESFET gate controls the threshold.

  15. Design and optimization of arrays of neodymium iron boron-based magnets for magnetic tweezers applications

    International Nuclear Information System (INIS)

    We present the design methodology for arrays of neodymium iron boron (NdFeB)-based magnets for use in magnetic tweezers devices. Using finite element analysis (FEA), we optimized the geometry of the NdFeB magnet as well as the geometry of iron yokes designed to focus the magnetic fields toward the sample plane. Together, the magnets and yokes form a magnetic array which is the basis of the magnetic tweezers device. By systematically varying 15 distinct shape parameters, we determined those features that maximize the magnitude of the magnetic field gradient as well as the length scale over which the magnetic force operates. Additionally, we demonstrated that magnetic saturation of the yoke material leads to intrinsic limitations in any geometric design. Using this approach, we generated a compact and light-weight magnetic tweezers device that produces a high field gradient at the image plane in order to apply large forces to magnetic beads. We then fabricated the optimized yoke and validated the FEA by experimentally mapping the magnetic field of the device. The optimization data and iterative FEA approach outlined here will enable the streamlined design and construction of specialized instrumentation for force-sensitive microscopy

  16. Design and optimization of arrays of neodymium iron boron-based magnets for magnetic tweezers applications.

    Science.gov (United States)

    Zacchia, Nicholas A; Valentine, Megan T

    2015-05-01

    We present the design methodology for arrays of neodymium iron boron (NdFeB)-based magnets for use in magnetic tweezers devices. Using finite element analysis (FEA), we optimized the geometry of the NdFeB magnet as well as the geometry of iron yokes designed to focus the magnetic fields toward the sample plane. Together, the magnets and yokes form a magnetic array which is the basis of the magnetic tweezers device. By systematically varying 15 distinct shape parameters, we determined those features that maximize the magnitude of the magnetic field gradient as well as the length scale over which the magnetic force operates. Additionally, we demonstrated that magnetic saturation of the yoke material leads to intrinsic limitations in any geometric design. Using this approach, we generated a compact and light-weight magnetic tweezers device that produces a high field gradient at the image plane in order to apply large forces to magnetic beads. We then fabricated the optimized yoke and validated the FEA by experimentally mapping the magnetic field of the device. The optimization data and iterative FEA approach outlined here will enable the streamlined design and construction of specialized instrumentation for force-sensitive microscopy. PMID:26026529

  17. Design and Synthesis of Chiral Molecular Tweezers Based on Deoxycholic Acid

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of new chiral molecular tweezers have been designed and synthesized by using deoxycholic acid as spacer and aromatic amines as arms.Instead of using toxic phosgene,the triphosgene was employed in synthesis of the molecular tweezers receptors.These chiral molecular tweezers showed good enantioselectivity for D-amino acid methyl esters.

  18. Optical tweezers and non-ratiometric fluorescent-dye-based studies of respiration in sperm mitochondria

    International Nuclear Information System (INIS)

    The purpose of this study is to investigate how the mitochondrial membrane potential affects sperm motility using laser tweezers and a non-ratiometric fluorescent probe, DiOC6(3). A 1064 nm Nd:YVO4 continuous wave laser was used to trap motile sperm at a power of 450 mW in the trap spot. Using customized tracking software, the curvilinear velocity (VCL) and the escape force from the laser tweezers were measured. Human (Homo sapiens), dog (Canis lupis familiaris) and drill (Mandrillus leucophaeus) sperm were treated with DiOC6(3) to measure the membrane potential in the mitochondria-rich sperm midpieces. Sperm from all three species exhibited an increase in fluorescence when treated with the DiOC6(3). When a cyanide inhibitor (CCCP) of aerobic respiration was applied, sperm of all three species exhibited a reduction in fluorescence to pre-dye levels. With respect to VCL and escape force, the CCCP had no effect on dog or human sperm, suggesting a major reliance upon anaerobic respiration (glycolysis) for ATP in these two species. Based on the preliminary study on drill sperm, CCCP caused a drop in the VCL, suggesting potential reliance on both glycolysis and aerobic respiration for motility. The results demonstrate that optical trapping in combination with DiOC6(3) is an effective way to study sperm motility and energetics

  19. Counter-propagating dual-trap optical tweezers based on linear momentum conservation

    Energy Technology Data Exchange (ETDEWEB)

    Ribezzi-Crivellari, M.; Huguet, J. M. [Small Biosystems Lab, Dept. de Fisica Fonamental, Universitat de Barcelona, Avda. Diagonal 647, 08028 Barcelona (Spain); Ritort, F. [Small Biosystems Lab, Dept. de Fisica Fonamental, Universitat de Barcelona, Avda. Diagonal 647, 08028 Barcelona (Spain); Ciber-BBN de Bioingenieria, Biomateriales y Nanomedicina, Instituto de Salud Carlos III, Madrid (Spain)

    2013-04-15

    We present a dual-trap optical tweezers setup which directly measures forces using linear momentum conservation. The setup uses a counter-propagating geometry, which allows momentum measurement on each beam separately. The experimental advantages of this setup include low drift due to all-optical manipulation, and a robust calibration (independent of the features of the trapped object or buffer medium) due to the force measurement method. Although this design does not attain the high-resolution of some co-propagating setups, we show that it can be used to perform different single molecule measurements: fluctuation-based molecular stiffness characterization at different forces and hopping experiments on molecular hairpins. Remarkably, in our setup it is possible to manipulate very short tethers (such as molecular hairpins with short handles) down to the limit where beads are almost in contact. The setup is used to illustrate a novel method for measuring the stiffness of optical traps and tethers on the basis of equilibrium force fluctuations, i.e., without the need of measuring the force vs molecular extension curve. This method is of general interest for dual trap optical tweezers setups and can be extended to setups which do not directly measure forces.

  20. Frequency-doubling optoelectronic oscillator based on destructive interference

    Science.gov (United States)

    Jiang, Jun; Chen, Fushen; Fan, Mengqiu; Li, Chengxin; Dong, Qimeng

    2015-12-01

    A frequency-doubling optoelectronic oscillator (OEO) using two cascaded modulators based on destructive interference is proposed and experimentally demonstrated. In the proposed system, we utilize a cascaded modulator including a phase modulator and an intensity modulator, which implements a carrier-suppressed double-sideband modulation based on destructive interference to generate a frequency-doubled microwave signal. Meanwhile, the phase modulator is connected by a chirp fiber Bragg grating in the loop, which forms a microwave photonic filter to select the fundamental frequency signal in the OEO loop. As a result, a frequency-doubled microwave signal at 17.9 and 20.5 GHz is generated, respectively. The phase noises and the long-term stability of the generated microwave signals are also investigated.

  1. Opto-electronic transport properties of graphene oxide based devices

    International Nuclear Information System (INIS)

    Large area, solution-processed, graphene oxide (GO)nanocomposite based photo FET has been successfully fabricated. The device exhibits p-type charge transport characteristics in dark condition. Our measurements indicate that the transport characteristics are gate dependent and extremely sensitive to solar light. Photo current decay mechanism of GO is well explained and is associated with two phenomena: a) fast response process and b) slow response process. Slow response photo decay can be considered as the intrinsic phenomena which are present for both GO and reduced GO (r-GO), whereas the first response photo decay is controlled by the surface defect states. Demonstration of photo FET performance of GO thin film is a significant step forward in integrating these devices in various optoelectronic circuits

  2. Self-assembly characteristics of a multipolar donor-acceptor-based bis-pyrene integrated molecular tweezer

    Indian Academy of Sciences (India)

    Deepak Asthana; Geeta Hundal; Pritam Mukhopadhyay

    2014-09-01

    A modular design of a molecular tweezer is presented that integrates a multipolar D--A [D: Donor, A: Acceptor] scaffold, 1-aminopyrene-based fluorophore units and L-alanine-based linkers. The synthesis of the molecule is based on two-fold aromatic nucleophilic reactions (ArSN) and coupling reactions of the acid and amino functionalities. This molecule crystallizes in a non-centrosymmteric (P21) space group.We present its rich self-assembly characteristics that involves an array of -stacking interactions. In addition, the molecular tweezer within its cleft forms H-bonding with two dimethylformamide molecules. Such multipolar D--A systems containing chiral and fluorophore units are potential candidatesfor a number of electronic and photonic applications.

  3. Guest-responsive structural adaptation of a rationally-designed molecular tweezer based on Tröger’s base

    Indian Academy of Sciences (India)

    Ishita Neogi; Alankriti Bajpai; Jarugu Narasimha Moorthy

    2014-09-01

    We have designed and synthesized a modified Tröger’s base TB in which the sterically-rigidified aryl rings that protrude into its groove were envisaged to preclude self-inclusion. From a limited preliminary experimentation, TB has been found to exhibit guest inclusion. The X-ray determined structures of the crystals of guest-free TB and its inclusion compounds with acetonitrile and -dichlorobenzene reveal remarkable adaptability of the TB core to undergo subtle structural changes in response to the guest that is included. The structural analyses demonstrate the fact that TB behaves like a molecular tweezer.

  4. Optical tweezers based measurement of PLGA-NP interaction with prostate cancer cells

    Science.gov (United States)

    Blesener, Thea; Mondal, Argha; Menon, Jyothi U.; Nguyen, Kytai T.; Mohanty, Samarendra

    2013-02-01

    In order to quantify the binding capacities of polymeric, biodegradable and biocompatible poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), conjugated with either R11 peptides or Folic Acid, the strength by detach from prostate cancer cells (PCCs) was measured via optical tweezers based measurements. Specific nanoparticle drug delivery eliminates the previously used diffuse, full-body application of potent cancer drugs by localizing drug delivery to malignant cells. Precise monitoring of NP position in the trap near the PCC membrane using a fluorescence imaging based method enabled calibration of the trap stiffness and subsequent force measurements. By defining the force with which the many diverse conjugates and coatings of different types of NPs bind the vast array of cancer cell types, chemotherapeutic drugs can be delivered in a specific manner with the optimal particle and corresponding conjugates. Further, and most significantly, the rupture force measurements will reveal whether or not targeted nanoparticles can overcome the force of blood attempting to pull the particle from designated cells. Our preliminary study revealed that the binding between PLGA-NPs and prostate cancer cells is enhanced by coating with folic acid or R11 peptides. These conjugates increase the force required to detach the particle thus allowing particles to overcome drag force of the blood in prostate capillary systems.

  5. MOF-based electronic and opto-electronic devices.

    Science.gov (United States)

    Stavila, V; Talin, A A; Allendorf, M D

    2014-08-21

    Metal-organic frameworks (MOFs) are a class of hybrid materials with unique optical and electronic properties arising from rational self-assembly of the organic linkers and metal ions/clusters, yielding myriads of possible structural motifs. The combination of order and chemical tunability, coupled with good environmental stability of MOFs, are prompting many research groups to explore the possibility of incorporating these materials as active components in devices such as solar cells, photodetectors, radiation detectors, and chemical sensors. Although this field is only in its incipiency, many new fundamental insights relevant to integrating MOFs with such devices have already been gained. In this review, we focus our attention on the basic requirements and structural elements needed to fabricate MOF-based devices and summarize the current state of MOF research in the area of electronic, opto-electronic and sensor devices. We summarize various approaches to designing active MOFs, creation of hybrid material systems combining MOFs with other materials, and assembly and integration of MOFs with device hardware. Critical directions of future research are identified, with emphasis on achieving the desired MOF functionality in a device and establishing the structure-property relationships to identify and rationalize the factors that impact device performance. PMID:24802763

  6. Novel thiopene-based polymers and copolymers for optoelectronic

    Czech Academy of Sciences Publication Activity Database

    Cimrová, Věra; Výprachtický, Drahomír; Kmínek, Ivan; Pavlačková, Petra

    Kuala Lumpur : Universiti Teknologi Mara, 2008. s. 96. [International Conference on Functional Materials and Devices /2./. 16.06.2008-19.06.2008, Kuala Lumpur ] R&D Projects: GA MŠk(CZ) 1M06031; GA AV ČR IAA4050409 Institutional research plan: CEZ:AV0Z40500505 Keywords : fluorene-thiophene copolymers * optoelectronics * photophysics Subject RIV: CD - Macromolecular Chemistry

  7. Optical tweezers and surface plasmon resonance combination system based on the high numerical aperture lens

    Science.gov (United States)

    Shan, Xuchen; Zhang, Bei; Lan, Guoqiang; Wang, Yiqiao; Liu, Shugang

    2015-11-01

    Biology and medicine sample measurement takes an important role in the microscopic optical technology. Optical tweezer has the advantage of accurate capture and non-pollution of the sample. The SPR(surface plasmon resonance) sensor has so many advantages include high sensitivity, fast measurement, less consumption of sample and label-free detection of biological sample that the SPR sensing technique has been used for surface topography, analysis of biochemical and immune, drug screening and environmental monitoring. If they combine, they will play an important role in the biological, chemical and other subjects. The system we propose use the multi-axis cage system, by using the methods of reflection and transmiss ion to improve the space utilization. The SPR system and optical tweezer were builtup and combined in one system. The cage of multi-axis system gives full play to its accuracy, simplicity and flexibility. The size of the system is 20 * 15 * 40 cm3 and thus the sample can be replaced to switch between the optical tweezers system and the SPR system in the small space. It means that we get the refractive index of the sample and control the particle in the same system. In order to control the revolving stage, get the picture and achieve the data stored automatically, we write a LabVIEW procedure. Then according to the data from the back focal plane calculate the refractive index of the sample. By changing the slide we can trap the particle as optical tweezer, which makes us measurement and trap the sample at the same time.

  8. Synthesis, structure, and opto-electronic properties of organic-based nanoscale heterojunctions

    OpenAIRE

    Cimrová Vĕra; Rezek Bohuslav; Čermák Jan; Kromka Alexander; Ledinský Martin; Hubík Pavel; Mareš Jiří; Purkrt Adam; Fejfar Antonín; Kočka Jan

    2011-01-01

    Abstract Enormous research effort has been put into optimizing organic-based opto-electronic systems for efficient generation of free charge carriers. This optimization is mainly due to typically high dissociation energy (0.1-1 eV) and short diffusion length (10 nm) of excitons in organic materials. Inherently, interplay of microscopic structural, chemical, and opto-electronic properties plays crucial role. We show that employing and combining advanced scanning probe techniques can provide us...

  9. Single molecule measurements of DNA helicase activity with magnetic tweezers and t-test based step-finding analysis.

    Science.gov (United States)

    Seol, Yeonee; Strub, Marie-Paule; Neuman, Keir C

    2016-08-01

    Magnetic tweezers is a versatile and easy to implement single-molecule technique that has become increasingly prevalent in the study of nucleic acid based molecular motors. Here, we provide a description of the magnetic tweezers instrument and guidelines for measuring and analyzing DNA helicase activity. Along with experimental methods, we describe a robust method of single-molecule trajectory analysis based on the Student's t-test that accommodates continuous transitions in addition to the discrete transitions assumed in most widely employed analysis routines. To illustrate the single-molecule unwinding assay and the analysis routine, we provide DNA unwinding measurements of Escherichia coli RecQ helicase under a variety of conditions (Na+, ATP, temperature, and DNA substrate geometry). These examples reveal that DNA unwinding measurements under various conditions can aid in elucidating the unwinding mechanism of DNA helicase but also emphasize that environmental effects on DNA helicase activity must be considered in relation to in vivo activity and mechanism. PMID:27131595

  10. Standard Cell-Based Implementation of a Digital Optoelectronic Neural-Network Hardware

    Science.gov (United States)

    Maier, Klaus D.; Beckstein, Clemens; Blickhan, Reinhard; Erhard, Werner

    2001-03-01

    A standard cell-based implementation of a digital optoelectronic neural-network architecture is presented. The overall structure of the multilayer perceptron network that was used, the optoelectronic interconnection system between the layers, and all components required in each layer are defined. The design process from VHDL-based modeling from synthesis and partly automatic placing and routing to the final editing of one layer of the circuit of the multilayer perceptrons are described. A suitable approach for the standard cell-based design of optoelectronic systems is presented, and shortcomings of the design tool that was used are pointed out. The layout for the microelectronic circuit of one layer in a multilayer perceptron neural network with a performance potential 1 magnitude higher than neural networks that are purely electronic based has been successfully designed.

  11. An optical tweezer-based study of antimicrobial activity of silver nanoparticles

    Indian Academy of Sciences (India)

    Yogesha; Sarbari Bhattacharya; M K Rabinal; Sharath Ananthamurthy

    2012-08-01

    Understanding and characterizing microbial activity reduction in the presence of antimicrobial agents can help in the design and manufacture of antimicrobial drugs. We demonstrate the use of an optical tweezer setup in recording the changes in bacterial activity with time, induced by the presence of foreign bodies in a bacterial suspension. This is achieved by monitoring the fluctuations of an optically trapped polystyrene bead immersed in it. Examining the changes in the fluctuation pattern of the bead with time provides an accurate characterization of the reduction in the microbial activity. Here, we report on the effect of addition of silver nanoparticles on bacterial cultures of Pseudomonas aeroginosa, Escherichia coli and Bacillus subtilis. We observe a decrease in the bacterial activity with time for the investigated bacterial samples. This method in our opinion, enables one to track changes in bacterial activity levels as a function of time of contact with the antibacterial agent with greater efficacy than traditional cell counting methods.

  12. Micro-particle manipulation by single beam acoustic tweezers based on hydrothermal PZT thick film

    Directory of Open Access Journals (Sweden)

    Benpeng Zhu

    2016-03-01

    Full Text Available Single-beam acoustic tweezers (SBAT, used in laboratory-on-a-chip (LOC device has promising implications for an individual micro-particle contactless manipulation. In this study, a freestanding hydrothermal PZT thick film with excellent piezoelectric property (d33 = 270pC/N and kt = 0.51 was employed for SBAT applications and a press-focusing technology was introduced. The obtained SBAT, acting at an operational frequency of 50MHz, a low f-number (∼0.9, demonstrated the capability to trap and manipulate a micro-particle sized 10μm in the distilled water. These results suggest that such a device has great potential as a manipulator for a wide range of biomedical and chemical science applications.

  13. Synthesis of a New Optoelectronic Material Based on Oriented Adsorption of Dyes to Nanoparticles Surface

    Institute of Scientific and Technical Information of China (English)

    LI Gui-an; SONG Jian-ping; LI Xiu

    2005-01-01

    Synthesis of the optoelectronic storage material with structure for coating by nanosized metal and azo-dye was reported. The characterization of composites was made by using transmission electron microscope (TEM), ultraviolet-visible spectrometer (UV-Vis) and thermogravity analyzer (TGA). It is found that, due to the specific structure, in which azo-dye molecules are oriented and adsorbed on the spherical surface of nanosized metal, the absorption maximum of azo-dye methyl orange shift towards shorter wavelength band. The experimental results show that the proposed technique here would offer a promising way to synthesize short wavelength optoelectronic storage material by doping of metal nanoparticles coated with dyes in polymer. Furthermore, the composites based on the structure can present excellent thermal properties suitable for the requirements of optical storage. This new type of material is capable of matching semiconductor laser (GaN) in optoelectronic storage technology.

  14. Construction of optical data processing systems based on optoelectronic liquid crystal elements

    Science.gov (United States)

    Tolstik, Alexei; Melnikova, Elena

    2005-11-01

    The methods for the optical signal conversion based on the optoelectronic system "relief grating - liquid crystal" and liquid-crystal (LC) cells using S- or twist-effect have been presented. New schemes forming the basis for realization of bistable LC devices, optoelectronic logic elements and systems of electrically-coupled LC elements intended for the production of laser oscillations at the constant input intensity have been proposed. It has been demonstrated that with the use of varying parameters of optoelectronic feedback one is enabled to set up both regular and chaotic intensity oscillations, to control the frequency and form of these oscillations, to realize functional changes of logic elements. The developed LC systems have been introduced into the educational practice of students mastering modem information techniques.

  15. Quantitative modeling of forces in electromagnetic tweezers

    OpenAIRE

    Bijamov, Alex; Shubitidze, Fridon; Oliver, Piercen M.; Vezenov, Dmitri V.

    2010-01-01

    This paper discusses numerical simulations of the magnetic field produced by an electromagnet for generation of forces on superparamagnetic microspheres used in manipulation of single molecules or cells. Single molecule force spectroscopy based on magnetic tweezers can be used in applications that require parallel readout of biopolymer stretching or biomolecular binding. The magnetic tweezers exert forces on the surface-immobilized macromolecule by pulling a magnetic bead attached to the free...

  16. Optoelectronic studies on heterocyclic bases of deoxyribonucleic acid for DNA photonics.

    Science.gov (United States)

    El-Diasty, Fouad; Abdel-Wahab, Fathy

    2015-10-01

    The optoelectronics study of large molecules, particularly π-stacking molecules, such as DNA is really an extremely difficult task. We perform first electronic structure calculations on the heterocyclic bases of 2'-deoxyribonucleic acid based on Lorentz-Fresnel dispersion theory. In the UV-VIS range of spectrum, many of the optoelectronic parameters for DNA four bases namely adenine, guanine, cytosine and thymine are calculated and discussed. The results demonstrate that adenine has the highest hyperpolarizability, whereas thymine has the lowest hyperpolarizability. Cytosine has the lower average oscillator energy and the higher lattice energy. Thymine infers the most stable nucleic base with the lower phonon energy. Thymine also has the highest average oscillator energy and the lower lattice energy. Moreover, the four nucleic acid bases have large band gap energies less than 5 eV with a semiconducting behavior. Guanine shows the smallest band gap and the highest Fermi level energy, whereas adenine elucidates the highest band gap energy. PMID:26117785

  17. Effect of annealing over optoelectronic properties of graphene based transparent electrodes

    Science.gov (United States)

    Yadav, Shriniwas; Kaur, Inderpreet

    2016-04-01

    Graphene, an atom-thick two dimensional graphitic material have led various fundamental breakthroughs in the field of science and technology. Due to their exceptional optical, physical and electrical properties, graphene based transparent electrodes have shown several applications in organic light emitting diodes, solar cells and thin film transistors. Here, we are presenting effect of annealing over optoelectronic properties of graphene based transparent electrodes. Graphene based transparent electrodes have been prepared by wet chemical approach over glass substrates. After fabrication, these electrodes tested for optical transmittance in visible region. Sheet resistance was measured using four probe method. Effect of thermal annealing at 200 °C was studied over optical and electrical performance of these electrodes. Optoelectronic performance was judged from ratio of direct current conductivity to optical conductivity (σdc/σopt) as a figure of merit for transparent conductors. The fabricated electrodes display good optical and electrical properties. Such electrodes can be alternatives for doped metal oxide based transparent electrodes.

  18. Optoelectronic studies on heterocyclic bases of deoxyribonucleic acid for DNA photonics

    Energy Technology Data Exchange (ETDEWEB)

    El-Diasty, Fouad, E-mail: fdiasty@yahoo.com; Abdel-Wahab, Fathy

    2015-10-01

    The optoelectronics study of large molecules, particularly π-stacking molecules, such as DNA is really an extremely difficult task. We perform first electronic structure calculations on the heterocyclic bases of 2′-deoxyribonucleic acid based on Lorentz–Fresnel dispersion theory. In the UV–VIS range of spectrum, many of the optoelectronic parameters for DNA four bases namely adenine, guanine, cytosine and thymine are calculated and discussed. The results demonstrate that adenine has the highest hyperpolarizability, whereas thymine has the lowest hyperpolarizability. Cytosine has the lower average oscillator energy and the higher lattice energy. Thymine infers the most stable nucleic base with the lower phonon energy. Thymine also has the highest average oscillator energy and the lower lattice energy. Moreover, the four nucleic acid bases have large band gap energies less than 5 eV with a semiconducting behavior. Guanine shows the smallest band gap and the highest Fermi level energy, whereas adenine elucidates the highest band gap energy. - Highlights: • Optical constants of the four DNA bases are determined. • Band gap energy, Fermi level, average oscillator energy, oscillator strength and lattice energy are calculated and analyzed. • Results provide some useful references for the potential application of the DNA bases in optoelectronic devices.

  19. Optoelectronic studies on heterocyclic bases of deoxyribonucleic acid for DNA photonics

    International Nuclear Information System (INIS)

    The optoelectronics study of large molecules, particularly π-stacking molecules, such as DNA is really an extremely difficult task. We perform first electronic structure calculations on the heterocyclic bases of 2′-deoxyribonucleic acid based on Lorentz–Fresnel dispersion theory. In the UV–VIS range of spectrum, many of the optoelectronic parameters for DNA four bases namely adenine, guanine, cytosine and thymine are calculated and discussed. The results demonstrate that adenine has the highest hyperpolarizability, whereas thymine has the lowest hyperpolarizability. Cytosine has the lower average oscillator energy and the higher lattice energy. Thymine infers the most stable nucleic base with the lower phonon energy. Thymine also has the highest average oscillator energy and the lower lattice energy. Moreover, the four nucleic acid bases have large band gap energies less than 5 eV with a semiconducting behavior. Guanine shows the smallest band gap and the highest Fermi level energy, whereas adenine elucidates the highest band gap energy. - Highlights: • Optical constants of the four DNA bases are determined. • Band gap energy, Fermi level, average oscillator energy, oscillator strength and lattice energy are calculated and analyzed. • Results provide some useful references for the potential application of the DNA bases in optoelectronic devices

  20. Fachtagung 'carbon-nanophysics': carbon based organic optoelectronic devices

    International Nuclear Information System (INIS)

    Full text: Recent developments on carbon based organic light emitting diodes (OLEDs), photovoltaic diodes (OPVs) and photoactive organic field effect transistors (photOFETs) are discussed. The photophysics of such devices is based on the photoinduced charge and/or energy transfer interactions between donor type semiconducting conjugated materials and acceptor type conjugated molecules such as Buckminster-fullerene, C60. Furthermore, organic/inorganic nanoparticle based 'hybrid' devices will be discussed. This talk gives an overview of materials' aspect, charge-transport, and device physics of organic diodes and field-effect transistors. Due to the compatibility of carbon/ hydrogen based organic semiconductors with organic biomolecules and living cells there can be a great opportunity to integrate such organic semiconductor devices (biOFETs) with the living organisms. In general, bio/life sciences and information technology can be bridged in an advanced cybernetic approach using organic semiconductor devices embedded in bio-life sciences. This field of bio-organic electronic devices is proposed to be an important mission of organic semiconductor devices. (author)

  1. Silicon-based optoelectronics: Monolithic integration for WDM

    Science.gov (United States)

    Pearson, Matthew Richard T.

    2000-10-01

    This thesis details the development of enabling technologies required for inexpensive, monolithic integration of Si-based wavelength division multiplexing (WDM) components and photodetectors. The work involves the design and fabrication of arrayed waveguide grating demultiplexers in silicon-on-insulator (SOI), the development of advanced SiGe photodetectors capable of photodetection at 1.55 mum wavelengths, and the development of a low cost fabrication technique that enables the high volume production of Si-based photonic components. Arrayed waveguide grating (AWG) demultiplexers were designed and fabricated in SOI. The fabrication of AWGs in SOI has been reported in the literature, however there are a number of design issues specific to the SOI material system that can have a large effect on device performance and design, and have not been theoretically examined in earlier work. The SOI AWGs presented in this thesis are the smallest devices of this type reported, and they exhibit performance acceptable for commercial applications. The SiGe photodetectors reported in the literature exhibit extremely low responsivities at wavelengths near 1.55 mum. We present the first use of three dimensional growth modes to enhance the photoresponse of SiGe at 1.55 mum wavelengths. Metal semiconductor-metal (MSM) photodetectors were fabricated using this undulating quantum well structure, and demonstrate the highest responsivities yet reported for a SiGe-based photodetector at 1.55 mum. These detectors were monolithically integrated with low-loss SOI waveguides, enabling integration with nearly any Si-based passive WDM component. The pursuit of inexpensive Si-based photonic components also requires the development of new manufacturing techniques that are more suitable for high volume production. This thesis presents the development of a low cost fabrication technique based on the local oxidation of silicon (LOCOS), a standard processing technique used for Si integrated circuits

  2. Ge-Photodetectors for Si-Based Optoelectronic Integration

    Directory of Open Access Journals (Sweden)

    Sungjoo Lee

    2011-01-01

    Full Text Available High speed photodetectors are a key building block, which allow a large wavelength range of detection from 850 nm to telecommunication standards at optical fiber band passes of 1.3–1.55 µm. Such devices are key components in several applications such as local area networks, board to board, chip to chip and intrachip interconnects. Recent technological achievements in growth of high quality SiGe/Ge films on Si wafers have opened up the possibility of low cost Ge-based photodetectors for near infrared communication bands and high resolution spectral imaging with high quantum efficiencies. In this review article, the recent progress in the development and integration of Ge-photodetectors on Si-based photonics will be comprehensively reviewed, along with remaining technological issues to be overcome and future research trends.

  3. Study of a thiophene-based polymer for optoelectronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Cheylan, S. [ICFO, Institut de Ciencies Fotoniques, Edificio NEXUS II, c. Jordi Girona 29, 08034 Barcelona (Spain)]. E-mail: Stephanie.cheylan@icfo.es; Fraleoni-Morgera, A. [Department of Industrial and Materials Chemistry, University of Bologna, V. Risorgimento 4, 40136 Bologna (Italy); Puigdollers, J. [Departamento de Ingenieria Electronica, Universidad Politecnica de Cataluna, UPC, Campus Nord Edifici C4, c/ Jordi Girona 1-3, 08034 Barcelona (Spain); Voz, C. [Departamento de Ingenieria Electronica, Universidad Politecnica de Cataluna, UPC, Campus Nord Edifici C4, c/ Jordi Girona 1-3, 08034 Barcelona (Spain); Setti, L. [Department of Industrial and Materials Chemistry, University of Bologna, V. Risorgimento 4, 40136 Bologna (Italy); Alcubilla, R. [Departamento de Ingenieria Electronica, Universidad Politecnica de Cataluna, UPC, Campus Nord Edifici C4, c/ Jordi Girona 1-3, 08034 Barcelona (Spain); Badenes, G. [ICFO, Institut de Ciencies Fotoniques, Edificio NEXUS II, c. Jordi Girona 29, 08034 Barcelona (Spain); Costa-Bizzarri, P. [Department of Industrial and Materials Chemistry, University of Bologna, V. Risorgimento 4, 40136 Bologna (Italy); Lanzi, M. [Department of Industrial and Materials Chemistry, University of Bologna, V. Risorgimento 4, 40136 Bologna (Italy)

    2006-02-21

    A thiophene-based conjugated polymer bearing a cyano group (-CN) as a side chain substituent was successfully synthesized. The polymer evidences an excellent film ability from various organic solvents as well as an enhanced photoluminescence. The polymer has been characterized optically (Fourier Transformed Infrared spectroscopy, absorption and photoluminescence) in solution and in film, while X-ray diffraction measurements (XRD) of thin films were performed to investigate its bulk morphological features. From the absorption edge of the spectrum of a thin polymer film, the optical band gap of the polymer is estimated to be 2.0 eV, which corresponds to orange emission. Furthermore, a single layer light emitting diode (LED) was fabricated. The device produced bright stable electroluminescence at room temperature. All of the results indicate that this polymer is a promising emissive material for application in polymeric LEDs.

  4. Study of a thiophene-based polymer for optoelectronic applications

    International Nuclear Information System (INIS)

    A thiophene-based conjugated polymer bearing a cyano group (-CN) as a side chain substituent was successfully synthesized. The polymer evidences an excellent film ability from various organic solvents as well as an enhanced photoluminescence. The polymer has been characterized optically (Fourier Transformed Infrared spectroscopy, absorption and photoluminescence) in solution and in film, while X-ray diffraction measurements (XRD) of thin films were performed to investigate its bulk morphological features. From the absorption edge of the spectrum of a thin polymer film, the optical band gap of the polymer is estimated to be 2.0 eV, which corresponds to orange emission. Furthermore, a single layer light emitting diode (LED) was fabricated. The device produced bright stable electroluminescence at room temperature. All of the results indicate that this polymer is a promising emissive material for application in polymeric LEDs

  5. Tracking technology for optoelectronic imaging platform of tethered balloon based on DGPS/INS

    Science.gov (United States)

    Wang, Y. W.; Wang, Z. Y.; Zhou, W. H.; Han, X. Q.

    2011-06-01

    In this paper, a tracking method for optoelectronic imaging platform of tethered balloon based on difference global positioning system/inertial navigation system is presented in detail. The location and attitude information of optoelectronic imaging platform, the azimuth and elevation angles of camera's line of sight are used by this method to locate the ground target at the centre point of the camera's field of view through corresponding coordinate transformation. And then, the method makes use of the update position and attitude information to solve the theoretical point of camera's line of sight inversely. Finally, an angle control commend will be sent to the inertially-stabilized turntable on the optoelectronic imaging platform, which will adjust its azimuth and elevation angle to make the camera's line of sight to the ground target. A lot of experiments are conducted, and the results show that the initial ground target is always in the centre of camera's field of view no matter how the balloon's position and attitude change, and the new location data of ground target has little difference with the initial location data, while the difference between them is close to 0.

  6. Fast physical and pseudo random number generation based on a nonlinear optoelectronic oscillator

    Science.gov (United States)

    Mu, Penghua; Pan, Wei; Xiang, Shuiying; Li, Nianqiang; Liu, Xinkai; Zou, Xihua

    2015-08-01

    High speed random number generation (RNG) utilizing a nonlinear optoelectronic oscillator (OEO) is explored experimentally. It has been found that by simply adjusting either the injected optical power or the gain of the modulator driver, low complexity dynamics such as square wave, and more complex dynamics including fully developed chaos can be experimentally achieved. More importantly, physical RNG based on high-speed-oscilloscope measurements and pseudo RNG based on post-processing are implemented in this paper. The generated bit sequences pass all the standard statistical random tests, indicating that fast physical and pseudo RNG could be achieved based on the same OEO entropy source. Our results could provide further insight into the implementation of RNG based on chaotic optical systems.

  7. Synthesis, structure, and opto-electronic properties of organic-based nanoscale heterojunctions

    Directory of Open Access Journals (Sweden)

    Cimrová Vĕra

    2011-01-01

    Full Text Available Abstract Enormous research effort has been put into optimizing organic-based opto-electronic systems for efficient generation of free charge carriers. This optimization is mainly due to typically high dissociation energy (0.1-1 eV and short diffusion length (10 nm of excitons in organic materials. Inherently, interplay of microscopic structural, chemical, and opto-electronic properties plays crucial role. We show that employing and combining advanced scanning probe techniques can provide us significant insight into the correlation of these properties. By adjusting parameters of contact- and tapping-mode atomic force microscopy (AFM, we perform morphologic and mechanical characterizations (nanoshaving of organic layers, measure their electrical conductivity by current-sensing AFM, and deduce work functions and surface photovoltage (SPV effects by Kelvin force microscopy using high spatial resolution. These data are further correlated with local material composition detected using micro-Raman spectroscopy and with other electronic transport data. We demonstrate benefits of this multi-dimensional characterizations on (i bulk heterojunction of fully organic composite films, indicating differences in blend quality and component segregation leading to local shunts of photovoltaic cell, and (ii thin-film heterojunction of polypyrrole (PPy electropolymerized on hydrogen-terminated diamond, indicating covalent bonding and transfer of charge carriers from PPy to diamond.

  8. Synthesis, structure, and opto-electronic properties of organic-based nanoscale heterojunctions

    Science.gov (United States)

    Rezek, Bohuslav; Čermák, Jan; Kromka, Alexander; Ledinský, Martin; Hubík, Pavel; Mareš, Jiří J.; Purkrt, Adam; Cimrová, Vĕra; Fejfar, Antonín; Kočka, Jan

    2011-12-01

    Enormous research effort has been put into optimizing organic-based opto-electronic systems for efficient generation of free charge carriers. This optimization is mainly due to typically high dissociation energy (0.1-1 eV) and short diffusion length (10 nm) of excitons in organic materials. Inherently, interplay of microscopic structural, chemical, and opto-electronic properties plays crucial role. We show that employing and combining advanced scanning probe techniques can provide us significant insight into the correlation of these properties. By adjusting parameters of contact- and tapping-mode atomic force microscopy (AFM), we perform morphologic and mechanical characterizations (nanoshaving) of organic layers, measure their electrical conductivity by current-sensing AFM, and deduce work functions and surface photovoltage (SPV) effects by Kelvin force microscopy using high spatial resolution. These data are further correlated with local material composition detected using micro-Raman spectroscopy and with other electronic transport data. We demonstrate benefits of this multi-dimensional characterizations on (i) bulk heterojunction of fully organic composite films, indicating differences in blend quality and component segregation leading to local shunts of photovoltaic cell, and (ii) thin-film heterojunction of polypyrrole (PPy) electropolymerized on hydrogen-terminated diamond, indicating covalent bonding and transfer of charge carriers from PPy to diamond.

  9. Thickness dependence on the optoelectronic properties of multilayered GaSe based photodetector.

    Science.gov (United States)

    Ko, Pil Ju; Abderrahmane, Abdelkader; Takamura, Tsukasa; Kim, Nam-Hoon; Sandhu, Adarsh

    2016-08-12

    Two-dimensional (2D) layered materials exhibit unique optoelectronic properties at atomic thicknesses. In this paper, we fabricated metal-semiconductor-metal based photodetectors using layered gallium selenide (GaSe) with different thicknesses. The electrical and optoelectronic properties of the photodetectors were studied, and these devices showed good electrical characteristics down to GaSe flake thicknesses of 30 nm. A photograting effect was observed in the absence of a gate voltage, thereby implying a relatively high photoresponsivity. Higher values of the photoresponsivity occurred for thicker layers of GaSe with a maximum value 0.57 AW(-1) and external quantum efficiency of of 132.8%, and decreased with decreasing GaSe flake thickness. The detectivity was 4.05 × 10(10) cm Hz(1/2) W(-1) at 532 nm laser wavelength, underscoring that GaSe is a promising p-type 2D material for photodetection applications in the visible spectrum. PMID:27354428

  10. Fluorescence Detection of H5N1 Virus Gene Sequences Based on Optical Tweezers with Two-Photon Excitation Using a Single Near Infrared Nanosecond Pulse Laser.

    Science.gov (United States)

    Li, Cheng-Yu; Cao, Di; Kang, Ya-Feng; Lin, Yi; Cui, Ran; Pang, Dai-Wen; Tang, Hong-Wu

    2016-04-19

    We present an analytical platform by combining near-infrared optical tweezers with two-photon excitation for fluorescence detection of H5N1 virus gene sequences. A heterogeneous enrichment strategy, which involved polystyrene (PS) microsphere and quantum dots (QDs), was adopted. The final hybrid-conjugate microspheres were prepared by a facile one-step hybridization procedure by using PS microspheres capturing target DNA and QDs tagging, respectively. Quantitative detection was achieved by the optical tweezers setup with a low-cost 1064 nm nanosecond pulse laser for both optical trapping and two-photon excitation for the same hybrid-conjugate microsphere. The detection limits for both neuraminidase (NA) gene sequences and hemagglutinin (HA) gene sequences are 16-19 pM with good selectivity for one-base mismatch, which is approximately 1 order of magnitude lower than the most existing fluorescence-based analysis method. Besides, because of the fact that only signal from the trapped particle is detected upon two-photon excitation, this approach showed extremely low background in fluorescence detection and was successfully applied to directly detect target DNA in human whole serum without any separation steps and the corresponding results are very close to that in buffer solution, indicating the strong anti-interference ability of this method. Therefore, it can be expected to be an emerging alternative for straightforward detecting target species in complex samples with a simple procedure and high-throughput. PMID:27023254

  11. Quantum computation architecture using optical tweezers

    DEFF Research Database (Denmark)

    Weitenberg, Christof; Kuhr, Stefan; Mølmer, Klaus;

    2011-01-01

    We present a complete architecture for scalable quantum computation with ultracold atoms in optical lattices using optical tweezers focused to the size of a lattice spacing. We discuss three different two-qubit gates based on local collisional interactions. The gates between arbitrary qubits...... quantum computing....

  12. Predicting the optoelectronic properties of nanowire films based on control of length polydispersity

    Science.gov (United States)

    Large, Matthew J.; Burn, Jake; King, Alice A.; Ogilvie, Sean P.; Jurewicz, Izabela; Dalton, Alan B.

    2016-05-01

    We demonstrate that the optoelectronic properties of percolating thin films of silver nanowires (AgNWs) are predominantly dependent upon the length distribution of the constituent AgNWs. A generalized expression is derived to describe the dependence of both sheet resistance and optical transmission on this distribution. We experimentally validate the relationship using ultrasonication to controllably vary the length distribution. These results have major implications where nanowire-based films are a desirable material for transparent conductor applications; in particular when application-specific performance criteria must be met. It is of particular interest to have a simple method to generalize the properties of bulk films from an understanding of the base material, as this will speed up the optimisation process. It is anticipated that these results may aid in the adoption of nanowire films in industry, for applications such as touch sensors or photovoltaic electrode structures.

  13. Brownian motion properties of optoelectronic random bit generators based on laser chaos.

    Science.gov (United States)

    Li, Pu; Yi, Xiaogang; Liu, Xianglian; Wang, Yuncai; Wang, Yongge

    2016-07-11

    The nondeterministic property of the optoelectronic random bit generator (RBG) based on laser chaos are experimentally analyzed from two aspects of the central limit theorem and law of iterated logarithm. The random bits are extracted from an optical feedback chaotic laser diode using a multi-bit extraction technique in the electrical domain. Our experimental results demonstrate that the generated random bits have no statistical distance from the Brownian motion, besides that they can pass the state-of-the-art industry-benchmark statistical test suite (NIST SP800-22). All of them give a mathematically provable evidence that the ultrafast random bit generator based on laser chaos can be used as a nondeterministic random bit source. PMID:27410852

  14. A Novel Optoelectronic Device Based on Correlated Two-Dimensional Fermions

    Science.gov (United States)

    Dianat, Pouya

    Conventional metallic contacts can be replicated by quantum two dimensional charge (of Fermion) systems (2DFS). Unlike metals, the particle concentration of these "unconventional" systems can be accurately controlled in an extensive range and by means of external electronic or optical stimuli. A 2DFS can, hence, transition from a high-density kinetic liquid into a dilute-but highly correlated-gas state, in which inter-particle Coulombic interactions are significant. Such interactions contribute negatively, by so-called exchange-correlation energies, to the overall energetics of the system, and are manifested as a series negative quantum capacitance. This dissertation investigates the capacitive performance of a class of unconventional devices based on a planar metal-semiconductor-metal structure with an embedded 2DFS. They constitute an opto-electronically controlled variable capacitor, with record breaking figures-of-merit in capacitance tuning ranges of up to 7000 and voltage sensitivities as large as 400. Internal eld manipulations by localized depletion of a dense 2DFS account for the enlarged maximum and reduced minimum capacitances. The capacitance-voltage characteristics of these devices incur an anomalous "Batman" shape capacitance enhancement (CE) of up to 200% that may be triggered optically. The CE is attributed to the release and storage of exchange-correlation energies; from the "unconventional" plate and in the dielectric, respectively. This process is enforced by density manipulation of the 2DFS by a hybrid of an external eld and light-generated carriers. Under moderate optical powers, the capacitance becomes 43 times greater than the dark value; thus a new capacitance-based photodetection method is offered. This new capacitance based photodetection method has a range of applications in optoelectronics, particularly in the next generation of photonic integrated systems.

  15. Phase noise analysis of clock recovery based on an optoelectronic phase-locked loop

    DEFF Research Database (Denmark)

    Zibar, Darko; Mørk, Jesper; Oxenløwe, Leif Katsuo; Clausen, Anders

    2007-01-01

    A detailed theoretical analysis of a clock-recovery (CR) scheme based on an optoelectronic phase-locked loop is presented. The analysis emphasizes the phase noise performance, taking into account the noise of the input data signal, the local voltage-controlled oscillator (VCO), and the laser....... It is shown that a large loop length results in a higher timing jitter of the recovered clock signal. The impact of the loop length on the clock signal jitter can be reduced by using a low-noise VCO and a low loop filter bandwidth. Using the model, the timing jitter of the recovered optical and...... electrical clock signal can be evaluated. We numerically investigate the timing jitter requirements for combined electrical/optical local oscillators, in order for the recovered clock signal to have less jitter than that of the input signal. The timing jitter requirements for the free-running laser and the...

  16. Nanocellulose-based Translucent Diffuser for Optoelectronic Device Applications with Dramatic Improvement of Light Coupling.

    Science.gov (United States)

    Wu, Wei; Tassi, Nancy G; Zhu, Hongli; Fang, Zhiqiang; Hu, Liangbing

    2015-12-01

    Nanocellulose is a biogenerated and biorenewable organic material. Using a process based on 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)/NaClO/NaBr system, a highly translucent and light-diffusive film consisting of many layers of nanocellulose fibers and wood pulp microfibers was made. The film demonstrates a combination of large optical transmittance of ∼90% and tunable diffuse transmission of up to ∼78% across the visible and near-infrared spectra. The detailed characterizations of the film indicate the combination of high optical transmittance and haze is due to the film's large packing density and microstructured surface. The superior optical properties make the film a translucent light diffuser and applicable for improving the efficiencies of optoelectronic devices such as thin-film silicon solar cells and organic light-emitting devices. PMID:26572592

  17. Compact laser tweezers

    Czech Academy of Sciences Publication Activity Database

    Šerý, Mojmír; Lošťák, Z.; Kalman, M.; Jákl, Petr; Zemánek, Pavel

    Bellingham: SPIE, 2007, 6609:1-7. ISBN 978-0-8194-6748-5. ISSN 0277-786X. [Czech-Polish-Slovak Conference Wave and Quantum Aspects of Contemporary Optics /15./. Liberec (CZ), 11.09.2006-15.09.2006] R&D Projects: GA MPO FT-TA2/059 Institutional research plan: CEZ:AV0Z20650511 Keywords : laser tweezers * laser diode * optical manipulation Subject RIV: BH - Optics, Masers, Lasers

  18. Organic optoelectronics

    CERN Document Server

    Hu, Wenping; Gong, Xiong; Zhan, Xiaowei; Fu, Hongbing; Bjornholm, Thomas

    2012-01-01

    Written by internationally recognized experts in the field with academic as well as industrial experience, this book concisely yet systematically covers all aspects of the topic.The monograph focuses on the optoelectronic behavior of organic solids and their application in new optoelectronic devices. It covers organic electroluminescent materials and devices, organic photonics, materials and devices, as well as organic solids in photo absorption and energy conversion. Much emphasis is laid on the preparation of functional materials and the fabrication of devices, from materials synthesis a

  19. Plasmon enhanced optical tweezers with gold-coated black silicon

    CERN Document Server

    Kotsifaki, Domna G; Lagoudakis, Pavlos G

    2016-01-01

    Plasmonic optical tweezers are a ubiquitous tool for the precise manipulation of nanoparticles and biomolecules at low photon flux, while femtosecond-laser optical tweezers can probe the nonlinear optical properties of the trapped species with applications in biological diagnostics. In order to adopt plasmonic optical tweezers in real-world applications, it is essential to develop large-scale fabrication processes without compromising the trapping efficiency. Here, we develop a novel platform for continuous wave (CW) and femtosecond plasmonic optical tweezers, based on gold-coated black silicon. In contrast with traditional lithographic methods, the fabrication method relies on simple, single-step, maskless tabletop laser processing of silicon in water that facilitates scalability. Gold-coated black silicon supports repeatable trapping efficiencies comparable to the highest ones reported to date. From a more fundamental aspect, a plasmon-mediated efficiency enhancement is a resonant effect, and therefore, dep...

  20. An optically tunable wideband optoelectronic oscillator based on a bandpass microwave photonic filter.

    Science.gov (United States)

    Jiang, Fan; Wong, Jia Haur; Lam, Huy Quoc; Zhou, Junqiang; Aditya, Sheel; Lim, Peng Huei; Lee, Kenneth Eng Kian; Shum, Perry Ping; Zhang, Xinliang

    2013-07-15

    An optoelectronic oscillator (OEO) with wideband frequency tunability and stable output based on a bandpass microwave photonic filter (MPF) has been proposed and experimentally demonstrated. Realized by cascading a finite impulse response (FIR) filter and an infinite impulse response (IIR) filter together, the tunable bandpass MPF successfully replaces the narrowband electrical bandpass filter in a conventional single-loop OEO and serves as the oscillating frequency selector. The FIR filter is based on a tunable multi-wavelength laser and dispersion compensation fiber (DCF) while the IIR filter is simply based on an optical loop. Utilizing a long length of DCF as the dispersion medium for the FIR filter also provides a long delay line for the OEO feedback cavity and as a result, optical tuning over a wide frequency range can be achieved without sacrificing the quality of the generated signal. By tuning the wavelength spacing of the multi-wavelength laser, the oscillation frequency can be tuned from 6.88 GHz to 12.79 GHz with an average step-size of 0.128 GHz. The maximum frequency drift of the generated 10 GHz signal is observed to be 1.923 kHz over 1 hour and its phase noise reaches the -112 dBc/Hz limit of our measuring equipment at 10 kHz offset frequency. PMID:23938489

  1. Electrical performances of commercial GaN and GaAs based optoelectronics under neutron irradiation

    International Nuclear Information System (INIS)

    This paper aims to demonstrate the effects of displacement damage caused by high energetic neutron particle towards the electrical performances of gallium arsenide (GaAs) and gallium nitride (GaN) p-n based diodes. The investigations are carried out through current-voltage (I-V) and capacitance-voltage (C-V) measurements using Keithley 4200 SCS. Two different commercial optoelectronics diodes; GaN on SiC light emitting diode (LED) and GaAs infrared emitting diode (IRED) were radiated with neutron using pneumatic transfer system (PTS) in the PUSPATI TRIGA Mark II research reactor under total neutron flux of 1×1012 neutron/cm2.s. Following the neutron exposure for 1, 3 and 5 minutes, the I-V forward bias and reverse bias leakage current increase for GaAs IREDs, but minimal changes were observed in the GaN LEDs. The C-V measurements revealed that the capacitance and carrier concentration of GaAs IREDs decrease with increasing radiation flux

  2. Electrical performances of commercial GaN and GaAs based optoelectronics under neutron irradiation

    Science.gov (United States)

    Fauzi, D. Ahmad; Rashid, N. K. A. Md; Karim, J. Abdul; Zin, M. R. Mohamed; Hasbullah, N. F.; Sheik Fareed, O. A.

    2013-12-01

    This paper aims to demonstrate the effects of displacement damage caused by high energetic neutron particle towards the electrical performances of gallium arsenide (GaAs) and gallium nitride (GaN) p-n based diodes. The investigations are carried out through current-voltage (I-V) and capacitance-voltage (C-V) measurements using Keithley 4200 SCS. Two different commercial optoelectronics diodes; GaN on SiC light emitting diode (LED) and GaAs infrared emitting diode (IRED) were radiated with neutron using pneumatic transfer system (PTS) in the PUSPATI TRIGA Mark II research reactor under total neutron flux of 1×1012 neutron/cm2.s. Following the neutron exposure for 1, 3 and 5 minutes, the I-V forward bias and reverse bias leakage current increase for GaAs IREDs, but minimal changes were observed in the GaN LEDs. The C-V measurements revealed that the capacitance and carrier concentration of GaAs IREDs decrease with increasing radiation flux.

  3. Optical tweezers absolute calibration

    CERN Document Server

    Dutra, R S; Neto, P A Maia; Nussenzveig, H M

    2014-01-01

    Optical tweezers are highly versatile laser traps for neutral microparticles, with fundamental applications in physics and in single molecule cell biology. Force measurements are performed by converting the stiffness response to displacement of trapped transparent microspheres, employed as force transducers. Usually, calibration is indirect, by comparison with fluid drag forces. This can lead to discrepancies by sizable factors. Progress achieved in a program aiming at absolute calibration, conducted over the past fifteen years, is briefly reviewed. Here we overcome its last major obstacle, a theoretical overestimation of the peak stiffness, within the most employed range for applications, and we perform experimental validation. The discrepancy is traced to the effect of primary aberrations of the optical system, which are now included in the theory. All required experimental parameters are readily accessible. Astigmatism, the dominant effect, is measured by analyzing reflected images of the focused laser spo...

  4. Steps towards silicon optoelectronics

    CERN Document Server

    Starovoytov, A

    1999-01-01

    nanostructure fabrication. Thus, this thesis makes a dual contribution to the chosen field: it summarises the present knowledge on the possibility of utilising optical properties of nanocrystalline silicon in silicon-based electronics, and it reports new results within the framework of the subject. The main conclusion is that due to its promising optoelectronic properties nanocrystalline silicon remains a prospective competitor for the cheapest and fastest microelectronics of the next century. This thesis addresses the issue of a potential future microelectronics technology, namely the possibility of utilising the optical properties of nanocrystalline silicon for optoelectronic circuits. The subject is subdivided into three chapters. Chapter 1 is an introduction. It formulates the oncoming problem for microelectronic development, explains the basics of Integrated Optoelectronics, introduces porous silicon as a new light-emitting material and gives a brief review of other competing light-emitting material syst...

  5. A hybrid lightwave transmission system based on light injection/optoelectronic feedback techniques and fiber-VLLC integration

    Science.gov (United States)

    Tsai, Wen-Shing; Lu, Hai-Han; Li, Chung-Yi; Chen, Bo-Rui; Lin, Hung-Hsien; Lin, Dai-Hua

    2016-04-01

    A hybrid lightwave transmission system based on light injection/optoelectronic feedback techniques and fiber-visible laser light communication (VLLC) integration is proposed and experimentally demonstrated. To be the first one of its kind in employing light injection and optoelectronic feedback techniques in a fiber-VLLC integration lightwave transmission system, the light is successfully directly modulated with Community Access Television (CATV), 16-QAM, and 16-QAM-OFDM signals. Over a 40 km SMF and a 10 m free-space VLLC transport, good performances of carrier-to-noise ratio (CNR)/composite second-order (CSO)/composite triple-beat (CTB)/bit error rate (BER) are achieved for CATV/16-QAM/16-QAM-OFDM signals transmission. Such a hybrid lightwave transmission system would be very useful since it can provide broadband integrated services including CATV, Internet, and telecommunication services over both distribute fiber and in-building networks.

  6. Continuous Monitoring of Specific mRNA Expression Responses with a Fluorescence Resonance Energy Transfer-Based DNA Nano-tweezer Technique That Does Not Require Gene Recombination.

    Science.gov (United States)

    Shigeto, Hajime; Nakatsuka, Keisuke; Ikeda, Takeshi; Hirota, Ryuichi; Kuroda, Akio; Funabashi, Hisakage

    2016-08-16

    This letter discusses the feasibility of continuously monitoring specific mRNA expression responses in a living cell with a probe structured as a fluorescence resonance energy transfer (FRET)-based DNA nano-tweezer (DNA-NT). The FRET-based DNA-NT, self-assembled from three single-stranded DNAs, alters its structure from an open state to a closed state in recognition of a target mRNA, resulting in the closing of the distal relation of previously modified FRET-paired fluorescent dyes and generating a FRET signal. The expressions of glucose transporters (GLUT) 1 and 4 in a mouse hepato-carcinoma (Hepa 1-6 cells) were selected as the target model. Live-cell imaging analysis of Hepa 1-6 cells with both FRET-based DNA-NTs indicated that the behaviors of the FRET signals integrated in each individual cell were similar to those measured with the conventional mass analysis technique of semiquantitative real-time (RT) polymerase chain reaction (PCR). From these results, it is concluded that continuous monitoring of gene expression response without gene recombination is feasible with a FRET-based DNA-NT, even in a single cell manner. PMID:27458920

  7. Nanowire Optoelectronics

    Science.gov (United States)

    Wang, Zhihuan; Nabet, Bahram

    2015-12-01

    Semiconductor nanowires have been used in a variety of passive and active optoelectronic devices including waveguides, photodetectors, solar cells, light-emitting diodes (LEDs), lasers, sensors, and optical antennas. We review the optical properties of these nanowires in terms of absorption, guiding, and radiation of light, which may be termed light management. Analysis of the interaction of light with long cylindrical/hexagonal structures with subwavelength diameters identifies radial resonant modes, such as Leaky Mode Resonances, or Whispering Gallery modes. The two-dimensional treatment should incorporate axial variations in "volumetric modes,"which have so far been presented in terms of Fabry-Perot (FP), and helical resonance modes. We report on finite-difference timedomain (FDTD) simulations with the aim of identifying the dependence of these modes on geometry (length, width), tapering, shape (cylindrical, hexagonal), core-shell versus core-only, and dielectric cores with semiconductor shells. This demonstrates how nanowires (NWs) form excellent optical cavities without the need for top and bottommirrors. However, optically equivalent structures such as hexagonal and cylindrical wires can have very different optoelectronic properties meaning that light management alone does not sufficiently describe the observed enhancement in upward (absorption) and downward transitions (emission) of light inNWs; rather, the electronic transition rates should be considered. We discuss this "rate management" scheme showing its strong dimensional dependence, making a case for photonic integrated circuits (PICs) that can take advantage of the confluence of the desirable optical and electronic properties of these nanostructures.

  8. Optical and optoelectronic properties of nanostructures based on wide-bandgap semiconductors

    International Nuclear Information System (INIS)

    Recently, more and more research is done on nitride nanostructures in order to control the electrical and optical properties in a more sophisticated manner for optimized light-matter-interaction and extraction efficiency. In this context, the work presented in this thesis has been carried out, concentrating on two main topics. One aspect is the characterization of InGaN quantum dots (QDs). QDs possess a unique atom-like density of states for electrons, allowing for generation and manipulation of discrete electronic states. This thesis contains the analysis of QDs embedded in optoelectronic devices such as LEDs. Measurements of the electroluminescence (EL) of QD ensembles as well as single QDs are presented. Especially QD EL obtained at higher temperatures up to 150 K is a main achievement of this work. Furthermore, the photoluminescence (PL) of QD multilayer structures has been examined and discussed in detail. Experiments on the optical amplification in these multilayers have been carried out for the first time, yielding a maximum optical gain of g(max)/(mod)=50/cm. Another main aspect of solid state lighting is the efficient light extraction from light sources. For this purpose, pillar microcavities based on nitrides have been investigated. This type of optical resonator possesses a discrete optical mode structure due to the three-dimensional optical confinement in these structures. For optimal light-matter coupling conditions, this leads to an enhanced extraction efficiency. In this context, studies on QD pillar microcavities (MCs) processed by focused ion beam milling from planar MC structures are presented. After a detailed analysis of the photonic properties of these pillar MCs, a temperature-variation method to tune the cavity in resonance with QD emission is demonstrated, yielding a five-fold enhancement of the extraction efficiency. These experiments were carried out on selenide-based structures which possess a very high structural quality. An alternative

  9. 光热效应用于光纤光镊焦点位置的研究%Focus Location Measurement of Fiber Optic Tweezer Based on the Photothermal Effect

    Institute of Scientific and Technical Information of China (English)

    李新宇; 梁姗姗; 孙长森

    2012-01-01

    光镊是利用光穿过处于系统焦点的物体时产生的动量变化对其施加力的作用,因此确定光镊系统焦点位置是极其重要的.但目前缺少有效确定光镊焦点的方法.本文提出利用测量皮安培量级电流的膜片钳技术,基于光在溶液中产生的光热效应来确定光纤端面出射光斑的焦点.基于水的吸收光谱,选用波长为980 nm、845 nm和功率为100mW的激光作为光源.由于光热效应引起溶液电导的改变,影响流过玻璃微电极的电流,再用标准温度引起电流变化对膜片器放大器记录的电流标定,将电流值转换成温度值,获得微电极尖端点的温升值.用三维微操纵器控制玻璃微电极的空间位置,获得温度空间分布,从而确定该光斑焦点位置.%Fiber optic tweezer is an effective method in biomedical applications that can be used to operate the objective in a microscale. It employs the moment changes when the photon passes through a small particle to generate a weak force on the particle. So the accurate control of the focus is the most important thing for the application of the tweezer. However, the tweezer is usually used in liquid environment. So the focus location measurement becomes extremely important and this cannot be easily obtained through the common CCD technology. In order to solve this problem, the Patch Clamp technology is employed, which has been successfully used in the electrophysiology field. In this technique, a micro pipette filled with the extracellular solution bearing a mega Ohm resistance, can give rise to a microampere current measuring accuracy. Based on the optical characteristics of the pure water and the FTIR result proves that the optical characteristics extracellular solution are quite close to pure water, 845 nm and 980 nm wavelength are chosen as the operating wavelength. The photothermal effect is generated by the solution absorbed the optical energy, and this effect can also cause the

  10. Ultrafast Phase Comparator for Phase-Locked Loop-Based Optoelectronic Clock Recovery Systems

    DEFF Research Database (Denmark)

    Gomez-Agis, F.; Oxenløwe, Leif Katsuo; Kurimura, S.;

    2009-01-01

    The authors report on a novel application of a chi((2)) nonlinear optical device as an ultrafast phase comparator, an essential element that allows an optoelectronic phase-locked loop to perform clock recovery of ultrahigh-speed optical time-division multiplexed (OTDM) signals. Particular interes...... is devoted to a quasi-phase-matching adhered-ridge-waveguide periodically poled lithium niobate (PPLN) device, which shows a sufficient high temporal resolution to resolve a 640 Gbits OTDM signal.......The authors report on a novel application of a chi((2)) nonlinear optical device as an ultrafast phase comparator, an essential element that allows an optoelectronic phase-locked loop to perform clock recovery of ultrahigh-speed optical time-division multiplexed (OTDM) signals. Particular interest...

  11. FIBER RING RESONATOR BASED OPTO-ELECTRONIC OSCILLATOR - PHASE NOISE OPTIMISATION AND THERMAL STABILITY STUDY

    OpenAIRE

    Saleh, Khaldoun; Bouchier, Aude; Merrer, Pierre-Henri; Llopis, Olivier; Cibiel, Gilles

    2011-01-01

    In the microwave domain and among many other advantages, optics represents an elegant solution to increase the quality Q factor in a system. Different types of optical resonators lead to Q factors above 109, and these resonators can be used as an alternative to optical delay lines to set up the frequency in optoelectronic oscillators (OEO). However, microwave-optics is also a complex field, and if the use of optical resonators in high spectral purity frequency generation systems like OEO has ...

  12. Nanowire Optoelectronics

    Directory of Open Access Journals (Sweden)

    Wang Zhihuan

    2015-12-01

    Full Text Available Semiconductor nanowires have been used in a variety of passive and active optoelectronic devices including waveguides, photodetectors, solar cells, light-emitting diodes (LEDs, lasers, sensors, and optical antennas. We review the optical properties of these nanowires in terms of absorption, guiding, and radiation of light, which may be termed light management. Analysis of the interaction of light with long cylindrical/hexagonal structures with subwavelength diameters identifies radial resonant modes, such as Leaky Mode Resonances, or Whispering Gallery modes. The two-dimensional treatment should incorporate axial variations in “volumetric modes,”which have so far been presented in terms of Fabry–Perot (FP, and helical resonance modes. We report on finite-difference timedomain (FDTD simulations with the aim of identifying the dependence of these modes on geometry (length, width, tapering, shape (cylindrical, hexagonal, core–shell versus core-only, and dielectric cores with semiconductor shells. This demonstrates how nanowires (NWs form excellent optical cavities without the need for top and bottommirrors. However, optically equivalent structures such as hexagonal and cylindrical wires can have very different optoelectronic properties meaning that light management alone does not sufficiently describe the observed enhancement in upward (absorption and downward transitions (emission of light inNWs; rather, the electronic transition rates should be considered. We discuss this “rate management” scheme showing its strong dimensional dependence, making a case for photonic integrated circuits (PICs that can take advantage of the confluence of the desirable optical and electronic properties of these nanostructures.

  13. Optical tweezers principles and applications

    CERN Document Server

    Jones, Philip; Volpe, Giovanni

    2015-01-01

    Combining state-of-the-art research with a strong pedagogic approach, this text provides a detailed and complete guide to the theory, practice and applications of optical tweezers. In-depth derivation of the theory of optical trapping and numerical modelling of optical forces are supported by a complete step-by-step design and construction guide for building optical tweezers, with detailed tutorials on collecting and analysing data. Also included are comprehensive reviews of optical tweezers research in fields ranging from cell biology to quantum physics. Featuring numerous exercises and problems throughout, this is an ideal self-contained learning package for advanced lecture and laboratory courses, and an invaluable guide to practitioners wanting to enter the field of optical manipulation. The text is supplemented by www.opticaltweezers.org, a forum for discussion and a source of additional material including free-to-download, customisable research-grade software (OTS) for calculation of optical forces, dig...

  14. Coaxial Atomic Force Microscope Tweezers

    CERN Document Server

    Brown, K A; Westervelt, R M

    2010-01-01

    We demonstrate coaxial atomic force microscope (AFM) tweezers that can trap and place small objects using dielectrophoresis (DEP). An attractive force is generated at the tip of a coaxial AFM probe by applying a radio frequency voltage between the center conductor and a grounded shield; the origin of the force is found to be DEP by measuring the pull-off force vs. applied voltage. We show that the coaxial AFM tweezers (CAT) can perform three dimensional assembly by picking up a specified silica microsphere, imaging with the microsphere at the end of the tip, and placing it at a target destination.

  15. Coaxial atomic force microscope tweezers

    Science.gov (United States)

    Brown, K. A.; Aguilar, J. A.; Westervelt, R. M.

    2010-03-01

    We demonstrate coaxial atomic force microscope (AFM) tweezers that can trap and place small objects using dielectrophoresis (DEP). An attractive force is generated at the tip of a coaxial AFM probe by applying a radio frequency voltage between the center conductor and a grounded shield; the origin of the force is found to be DEP by measuring the pull-off force versus applied voltage. We show that the coaxial AFM tweezers can perform three-dimensional assembly by picking up a specified silica microsphere, imaging with the microsphere at the end of the tip, and placing it at a target destination.

  16. Telemedicine optoelectronic biomedical data processing system

    Science.gov (United States)

    Prosolovska, Vita V.

    2010-08-01

    The telemedicine optoelectronic biomedical data processing system is created to share medical information for the control of health rights and timely and rapid response to crisis. The system includes the main blocks: bioprocessor, analog-digital converter biomedical images, optoelectronic module for image processing, optoelectronic module for parallel recording and storage of biomedical imaging and matrix screen display of biomedical images. Rated temporal characteristics of the blocks defined by a particular triggering optoelectronic couple in analog-digital converters and time imaging for matrix screen. The element base for hardware implementation of the developed matrix screen is integrated optoelectronic couples produced by selective epitaxy.

  17. HoloHands: Kinect Control of Optical Tweezers

    CERN Document Server

    McDonald, Craig; McDougall, Craig; McGloin, David

    2012-01-01

    The increasing number of applications for holographic manipulation techniques has sparked the development of more accessible control interfaces. Here, we describe a holographic optical tweezers experiment that is controlled by gestures which are detected by a Microsoft Kinect. We demonstrate that this technique can be used to calibrate the tweezers using the Stokes Drag method and compare this to automated calibrations. We also show that multiple particle manipulation can be handled. This is a promising new line of research for gesture-based control that could find applications in a wide variety of experimental situations.

  18. Marker-free cell discrimination by holographic optical tweezers

    Science.gov (United States)

    Schaal, F.; Warber, M.; Zwick, S.; van der Kuip, H.; Haist, T.; Osten, W.

    2009-06-01

    We introduce a method for marker-free cell discrimination based on optical tweezers. Cancerous, non-cancerous, and drug-treated cells could be distinguished by measuring the trapping forces using holographic optical tweezers. We present trapping force measurements on different cell lines: normal pre-B lymphocyte cells (BaF3; "normal cells"), their Bcr-Abl transformed counterparts (BaF3-p185; "cancer cells") as a model for chronic myeloid leukaemia (CML) and Imatinib treated BaF3-p185 cells. The results are compared with reference measurements obtained by a commercial flow cytometry system.

  19. Reconfigurable Integrated Optoelectronics

    OpenAIRE

    Richard Soref

    2011-01-01

    Integrated optics today is based upon chips of Si and InP. The future of this chip industry is probably contained in the thrust towards optoelectronic integrated circuits (OEICs) and photonic integrated circuits (PICs) manufactured in a high-volume foundry. We believe that reconfigurable OEICs and PICs, known as ROEICs and RPICs, constitute the ultimate embodiment of integrated photonics. This paper shows that any ROEIC-on-a-chip can be decomposed into photonic modules, some of them fixed and...

  20. Multi-Beam Optical Tweezers

    DEFF Research Database (Denmark)

    2003-01-01

    A set of multi-beam electromagnetic tweezers is provided comprising a multi-beam generator for emission of a plurality of electromagnetic beams, at least some of the electromagnetic beams intersecting each other, or, having an individually controlled polarization whereby the position and/or angul...

  1. Surface coatings based on polysilsesquioxanes: solution-processible smooth hole-injection layers for optoelectronic applications.

    Science.gov (United States)

    Kessler, Daniel; Lechmann, Maria C; Noh, Seunguk; Berger, Rüdiger; Lee, Changhee; Gutmann, Jochen S; Theato, Patrick

    2009-07-16

    Optoelectronic devices usually consist of a transparent conductive oxide (TCO) as one electrode. Interfacial engineering between the TCO electrode and the overlying organic layers is an important method for tuning device performance. We introduce poly(methylsilsesquioxane)-poly(N,N-di-4-methylphenylamino styrene) (PMSSQ-PTPA) as a potential hole-injection layer forming material. Spin-coating and thermally induced crosslinking resulted in an effective planarization of the anode interface. HOMO level (-5.6 eV) and hole mobility (1 × 10(-6)  cm(2)  · Vs(-1) ) of the film on ITO substrates were measured by cyclovoltammetry and time-of-flight measurement demonstrating the hole injection capability of the layer. Adhesion and stability for further multilayer built-up could be demonstrated. Contact angle measurements and tape tests after several solvent treatments proved the outstanding film stability. PMID:21638376

  2. Single-molecule phenyl-acetylene-macrocycle-based optoelectronic switch functioning as a quantum-interference-effect transistor.

    Science.gov (United States)

    Hsu, Liang-Yan; Rabitz, Herschel

    2012-11-01

    This work proposes a new type of optoelectronic switch, the phenyl-acetylene-macrocycle-based single-molecule transistor, which utilizes photon-assisted tunneling and destructive quantum interference. The analysis uses single-particle Green's functions along with Floquet theory. Without the optical field, phenyl-acetylene-macrocycle exhibits a wide range of strong antiresonance between its frontier orbitals. The simulations show large on-off ratios (over 10(4)) and measurable currents (~10(-11) A) enabled by photon-assisted tunneling in a weak optical field (~2 × 10(5) V/cm) and at a small source-drain voltage (~0.05 V). Field amplitude power scaling laws and a range of field intensities are given for operating one- and two-photon assisted tunneling in phenyl-acetylene-macrocycle-based single-molecule transistors. This development opens up a new direction for creating molecular switches. PMID:23215309

  3. Design and simulation of programmable relational optoelectronic time-pulse coded processors as base elements for sorting neural networks

    Science.gov (United States)

    Krasilenko, Vladimir G.; Nikolsky, Alexander I.; Lazarev, Alexander A.; Lazareva, Maria V.

    2010-05-01

    In the paper we show that the biologically motivated conception of time-pulse encoding usage gives a set of advantages (single methodological basis, universality, tuning simplicity, learning and programming et al) at creation and design of sensor systems with parallel input-output and processing for 2D structures hybrid and next generations neuro-fuzzy neurocomputers. We show design principles of programmable relational optoelectronic time-pulse encoded processors on the base of continuous logic, order logic and temporal waves processes. We consider a structure that execute analog signal extraction, analog and time-pulse coded variables sorting. We offer optoelectronic realization of such base relational order logic element, that consists of time-pulse coded photoconverters (pulse-width and pulse-phase modulators) with direct and complementary outputs, sorting network on logical elements and programmable commutation blocks. We make technical parameters estimations of devices and processors on such base elements by simulation and experimental research: optical input signals power 0.2 - 20 uW, processing time 1 - 10 us, supply voltage 1 - 3 V, consumption power 10 - 100 uW, extended functional possibilities, learning possibilities. We discuss some aspects of possible rules and principles of learning and programmable tuning on required function, relational operation and realization of hardware blocks for modifications of such processors. We show that it is possible to create sorting machines, neural networks and hybrid data-processing systems with untraditional numerical systems and pictures operands on the basis of such quasiuniversal hardware simple blocks with flexible programmable tuning.

  4. High-speed optical packet processing technologies based on novel optoelectronic devices

    Science.gov (United States)

    Takenouchi, Hirokazu; Takahashi, Ryo; Takahata, Kiyoto; Nakahara, Tatsushi; Suzuki, Hiroyuki

    2004-10-01

    To cope with the explosive growth of IP traffic, we must increase both the link capacity between nodes and the node throughput. These requirements have stimulated research on photonic networks that use optical technologies. Optical packet switching (OPS) is an attractive solution because it maximizes the use of the network bandwidth. The key functions in achieving such networks include synchronization, label processing, compression/decompression, regeneration, and buffering for high-speed asynchronous optical packets. However, it is impractical to implement such functions by using all-optical approaches. We have proposed a new optoelectronic system composed of a packet-by-packet optical clock-pulse generator (OCG), an all-optical serial-to-parallel converter (SPC), a photonic parallel-to-serial converter (PSC), and CMOS circuitry. The OCG provides a single optical pulse synchronized with the incoming packet, and the SPC carries out a parallel conversion of the incoming packet. The parallel converted data are processed in the smart CMOS circuit, and reconstructed into an optical packet by the photonic PSC. Our system makes it possible to carry out various functions for high-speed asynchronous optical packets. This paper reviews our recent work on high-speed optical packet processing technologies such as buffering, packet compression/decompression, and label swapping, which are key technologies for constructing future OPS networks.

  5. Aligned silver nanowire-based transparent electrodes for engineering polarisation-selective optoelectronics

    Science.gov (United States)

    Park, Byoungchoo; Bae, In-Gon; Huh, Yoon Ho

    2016-01-01

    We herein report on a remarkably simple, fast, and economic way of fabricating homogeneous and well oriented silver nanowires (AgNWs) that exhibit strong in-plane electrical and optical anisotropies. Using a small quantity of AgNW suspension, the horizontal-dip (H-dip) coating method was applied, in which highly oriented AgNWs were deposited unidirectionally along the direction of coating over centimetre-scale lengths very rapidly. In applying the H-dip-coating method, we adjusted the shear strain rate of the capillary flow in the Landau-Levich meniscus of the AgNW suspension, which induced a high degree of uniaxial orientational ordering (0.37-0.43) of the AgNWs, comparable with the ordering seen in archetypal nematic liquid crystal (LC) materials. These AgNWs could be used to fabricate not only transparent electrodes, but also LC-alignment electrodes for LC devices and/or polarising electrodes for organic photovoltaic devices, having the potential to revolutionise the architectures of a number of polarisation-selective opto-electronic devices for use in printed/organic electronics.

  6. Frequency- and phase-tunable optoelectronic oscillator based on a DPMZM and SBS effect

    Science.gov (United States)

    Wu, Beilei; Wang, Muguang; Sun, Jian; Yin, Bin; Chen, Hongyao; Li, Tangjun; Jian, Shuisheng

    2016-03-01

    A novel approach to the optoelectronic oscillator (OEO) for the generation of a microwave signal with simultaneously frequency and phase tunability is proposed and experimentally demonstrated. In the proposed OEO, a carrier phase-shifted double-sideband modulated optical signal generated using a dual-parallel Mach-Zehnder modulator (DPMZM) is split into two parts. For one part, the signal is injected into a photodetector (PD) after passing through a section of high nonlinear fiber and then fed back into the DPMZM to form an OEO loop. The stimulated Brillouin scattering effect is used to select the oscillation frequency which equals to the Brillouin frequency shift. For the other part, a carrier phase-shifted single-sideband modulated signal is achieved by a tunable filter, and then converts to a microwave signal by a second PD. The tunable phase of the generated microwave signal is achieved by controlling the bias voltage of the DPMZM to change the phase difference between the optical carrier and the sideband. Thanks to the wavelength-dependent effect of the Brillouin frequency shift, the tunable frequency is realized by tuning the frequency of the laser source. Microwave signals with a tunable frequency from 8.950 to 9.351 GHz and a tunable phase from 0° to 360° are experimentally generated.

  7. Novel heterocyclic based blue and green emissive materials for opto-electronics

    Science.gov (United States)

    Ramkumar, V.; Kannan, P.

    2015-08-01

    Two different novel heterocyclic compounds namely 2,5-bis(1,3-diphenyl-4,5-dihydro-1H-pyrazol-5-yl)thiophene (Material I) and 2,5-bis(3-(naphthalen-1-yl)-1-phenyl-4,5-dihydro-1H-pyrazol-5-yl)thiophene (Material II) were designed, synthesized and characterized by spectral methods. The synthesized materials were confirmed by standard techniques such as FT-IR, 1H NMR and elemental analysis. Physical properties include thermal, surface morphology of the materials were explained from TGA, DSC and SEM analysis. Optical properties such as absorption, emission, solvent effect have been investigated by UV-Visible and fluorescence spectrophotometers. The blue and green emission of the materials was confirmed by using UV light as well as fluorescence spectrophotometers. Bandgap energies of these materials were obtained by both experimental and theoretical calculation from of cyclic voltammetry, UV-Visible spectrophotometer and DFT calculation. I-V characteristic analysis used to determine the threshold voltage (Von) of the two materials. The obtained results of the materials have promising to be applicable for opto-electronic applications.

  8. A reconfigurable optoelectronic oscillator based on cascaded coherence-controllable recirculating delay lines.

    Science.gov (United States)

    Liu, Xinkai; Pan, Wei; Zou, Xihua; Luo, Bin; Yan, Lianshan; Lu, Bing

    2012-06-01

    A novel optoelectronic oscillator (OEO) using cascaded recirculating delay lines (RDLs) is proposed and experimentally demonstrated. In the proposed OEO, instead of the use of an electronic microwave ðlter, two infinite impulse response (IIR) photonic microwave ðlters (PMFs) formed by two RDLs are employed to select oscillation frequencies. Specifically, an amplified spontaneous emission (ASE) source is adopted to avoid self-interference of each RDL, and two approximately equal gain RDLs are employed to reduce the influence of mutual interference between the two RDLs. Therefore, a stable microwave signal can be generated from the OEO loop. In the experiment, by tuning the lengths of RDLs, microwave signals at different frequencies, such as 194.1MHz, 648.5MHz and 2.99GHz, have been generated. The phase noise performance of the generated microwave signal is also investigated. The proposed approach has the potential for the generation of microwave signals up to tens of GHz with the use of integrated micro-ring devices. PMID:22714357

  9. Nano-light-emitting-diodes based on InGaN mesoscopic structures for energy saving optoelectronics

    Science.gov (United States)

    Mikulics, M.; Winden, A.; Marso, M.; Moonshiram, A.; Lüth, H.; Grützmacher, D.; Hardtdegen, H.

    2016-07-01

    Vertically integrated III-nitride based nano-LEDs (light emitting diodes) were designed and fabricated for operation in the telecommunication wavelength range in the (p-GaN/InGaN/n-GaN/sapphire) material system. The band edge luminescence energy of the nano-LEDs could be engineered by tuning the composition and size of the InGaN mesoscopic structures. Narrow band edge photoluminescence and electroluminescence were observed. Our mesoscopic InGaN structures (depending on diameter) feature a very low power consumption in the range between 2 nW and 30 nW. The suitability of the technological process for the long-term operation of LEDs is demonstrated by reliability measurements. The optical and electrical characterization presented show strong potential for future low energy consumption optoelectronics.

  10. Optical tweezers technique and its applications

    Science.gov (United States)

    Guo, HongLian; Li, ZhiYuan

    2013-12-01

    Since their advent in the 1980s, optical tweezers have attracted more and more attention due to their unique non-contact and non-invasion characteristics and their wide applications in physics, biology, chemistry, medical science and nanoscience. In this paper, we introduce the basic principle, the history and typical applications of optical tweezers and review our recent experimental works on the development and application of optical tweezers technique. We will discuss in detail several technological issues, including high precision displacement and force measurement in single-trap and dual-trap optical tweezers, multi-trap optical tweezers with each trap independently and freely controlled by means of space light modulator, and incorporation of cylindrical vector optical beams to build diversified optical tweezers beyond the conventional Gaussian-beam optical tweezers. We will address the application of these optical tweezers techniques to study biophysical problems such as mechanical deformation of cell membrane and binding energy between plant microtubule and microtubule associated proteins. Finally we present application of the optical tweezers technique for trapping, transporting, and patterning of metallic nanoparticles, which can be harnessed to manipulate surface plasmon resonance properties of these nanoparticles.

  11. Optical tweezers calibration with Bayesian inference

    Science.gov (United States)

    Türkcan, Silvan; Richly, Maximilian U.; Le Gall, Antoine; Fiszman, Nicolas; Masson, Jean-Baptiste; Westbrook, Nathalie; Perronet, Karen; Alexandrou, Antigoni

    2014-09-01

    We present a new method for calibrating an optical-tweezer setup that is based on Bayesian inference1. This method employs an algorithm previously used to analyze the confined trajectories of receptors within lipid rafts2,3. The main advantages of this method are that it does not require input parameters and is insensitive to systematic errors like the drift of the setup. Additionally, it exploits a much larger amount of the information stored in the recorded bead trajectory than standard calibration approaches. The additional information can be used to detect deviations from the perfect harmonic potential or detect environmental influences on the bead. The algorithm infers the diffusion coefficient and the potential felt by a trapped bead, and only requires the bead trajectory as input. We demonstrate that this method outperforms the equipartition method and the power-spectrum method in input information required (bead radius and trajectory length) and in output accuracy. Furthermore, by inferring a higher order potential our method can reveal deviations from the assumed second-order potential. More generally, this method can also be used for magnetic-tweezer calibration.

  12. Photonic Nanojet in Optical Tweezers

    CERN Document Server

    Neves, Antonio Alvaro Ranha

    2015-01-01

    Photonic nanojets has been brought into attention ten years ago for potential application as ultramicroscopy technique, using its sub-wavelength resolution to enhance detection and interaction with matter. For these novel applications under development, optically trapping a sphere, acts as an ideal framework to employ these nanojets. In this case, the nanojet is generated by a highly focused incident beam contrary to the traditional plane wave. It inherits the advantage from optical trapping, with the microsphere in equilibrium on the beam propagation axis, and be positioned arbitrarily in space, especially for intracellular applications. Moreover, due to optical scattering forces, when in equilibrium, there is a shift of the sphere centre with respect to the beam focus. However, within the stable equilibrium of an optical tweezers configuration, it does not allow the formation of a photonic nanojet. To overcome this, a double optical tweezers, in an unorthodox configuration of two collinearly and co-propagat...

  13. Plasmon enhanced optical tweezers with gold-coated black silicon

    Science.gov (United States)

    Kotsifaki, D. G.; Kandyla, M.; Lagoudakis, P. G.

    2016-05-01

    Plasmonic optical tweezers are a ubiquitous tool for the precise manipulation of nanoparticles and biomolecules at low photon flux, while femtosecond-laser optical tweezers can probe the nonlinear optical properties of the trapped species with applications in biological diagnostics. In order to adopt plasmonic optical tweezers in real-world applications, it is essential to develop large-scale fabrication processes without compromising the trapping efficiency. Here, we develop a novel platform for continuous wave (CW) and femtosecond plasmonic optical tweezers, based on gold-coated black silicon. In contrast with traditional lithographic methods, the fabrication method relies on simple, single-step, maskless tabletop laser processing of silicon in water that facilitates scalability. Gold-coated black silicon supports repeatable trapping efficiencies comparable to the highest ones reported to date. From a more fundamental aspect, a plasmon-mediated efficiency enhancement is a resonant effect, and therefore, dependent on the wavelength of the trapping beam. Surprisingly, a wavelength characterization of plasmon-enhanced trapping efficiencies has evaded the literature. Here, we exploit the repeatability of the recorded trapping efficiency, offered by the gold-coated black silicon platform, and perform a wavelength-dependent characterization of the trapping process, revealing the resonant character of the trapping efficiency maxima. Gold-coated black silicon is a promising platform for large-scale parallel trapping applications that will broaden the range of optical manipulation in nanoengineering, biology, and the study of collective biophotonic effects.

  14. Plasmon enhanced optical tweezers with gold-coated black silicon.

    Science.gov (United States)

    Kotsifaki, D G; Kandyla, M; Lagoudakis, P G

    2016-01-01

    Plasmonic optical tweezers are a ubiquitous tool for the precise manipulation of nanoparticles and biomolecules at low photon flux, while femtosecond-laser optical tweezers can probe the nonlinear optical properties of the trapped species with applications in biological diagnostics. In order to adopt plasmonic optical tweezers in real-world applications, it is essential to develop large-scale fabrication processes without compromising the trapping efficiency. Here, we develop a novel platform for continuous wave (CW) and femtosecond plasmonic optical tweezers, based on gold-coated black silicon. In contrast with traditional lithographic methods, the fabrication method relies on simple, single-step, maskless tabletop laser processing of silicon in water that facilitates scalability. Gold-coated black silicon supports repeatable trapping efficiencies comparable to the highest ones reported to date. From a more fundamental aspect, a plasmon-mediated efficiency enhancement is a resonant effect, and therefore, dependent on the wavelength of the trapping beam. Surprisingly, a wavelength characterization of plasmon-enhanced trapping efficiencies has evaded the literature. Here, we exploit the repeatability of the recorded trapping efficiency, offered by the gold-coated black silicon platform, and perform a wavelength-dependent characterization of the trapping process, revealing the resonant character of the trapping efficiency maxima. Gold-coated black silicon is a promising platform for large-scale parallel trapping applications that will broaden the range of optical manipulation in nanoengineering, biology, and the study of collective biophotonic effects. PMID:27195446

  15. Transparent oxide optoelectronics

    Directory of Open Access Journals (Sweden)

    Hiromichi Ohta

    2004-06-01

    Full Text Available This article reviews transparent oxide optoelectronic devices based on our efforts focusing on transparent thin-film transistors fabricated from single-crystalline films of InGaO3(ZnO5 with a natural superlattice structure, near-ultraviolet (UV emitting diodes composed of heteroepitaxially grown p-type SrCu2O2 and n-type ZnO, and single-crystalline NiO and ZnO pn-heterojunction diode UV detectors.

  16. Local electric field measurements by optical tweezers

    Directory of Open Access Journals (Sweden)

    G. Pesce

    2011-09-01

    Full Text Available We report a new technique to measure direction and amplitude of electric fields generated by microelectrodes embedded in polar liquid environment, as often used in microfluidic devices. The method is based on optical tweezers which act as sensitive force transducer while a trapped charged microsphere behaves as a probe. When an electric field is applied the particles moves from its equilibrium position and finishes in a new equilibrium position where electric and optical forces are balanced. A trapped bead is moved to explore the electric field in a wide region around the microelectrodes. In such way maps of electric fields with high spatial resolution can be reconstructed even for complex electrode geometries where numerical simulation approaches can fail. Experimental results are compared with calculations based on finite element analysis simulation.

  17. iTweezers: optical micromanipulation controlled by an Apple iPad

    Science.gov (United States)

    Bowman, R. W.; Gibson, G.; Carberry, D.; Picco, L.; Miles, M.; Padgett, M. J.

    2011-04-01

    The 3D interactive manipulation of multiple particles with holographic optical tweezers is often hampered by the control system. We use a multi-touch interface implemented on an Apple iPad to overcome many of the limitations of mouse-based control, and demonstrate an elegant and intuitive interface to multi-particle manipulation. This interface connects to the tweezers system hardware over a wireless network, allowing it to function as a remote monitor and control device.

  18. Dynamical stabilisation in optical tweezers

    Science.gov (United States)

    Jones, Philip H.; Richards, Christopher J.; Smart, Thomas J.; Cubero, David

    2015-03-01

    We present a study of dynamical stabilisation of an overdamped, microscopic pendulum realised using optical tweezers. We first derive an analytical expression for the equilibrium dynamically stabilised pendulum position in a regime of high damping and high modulation frequency of the pendulum pivot. This model implies a threshold behavior for stabilisation to occur, and a continuous evolution of the angular position which, unlike the underdamped case, does not reach the fully inverted position. We then test the theoretical predictions using an optically trapped microparticle subject to fluid drag force, finding reasonable agreement with the threshold and equilibrium behavior at high modulation amplitude. Analytical theory and experiments are complemented by Brownian motion simulations.

  19. Optoelectronic structure and related transport properties of BiCuSeO-based oxychalcogenides: First principle calculations

    Science.gov (United States)

    Khan, Wilayat; Azam, Sikander; Kanoun, Mohammed Benali; Goumri-Said, Souraya

    2016-08-01

    Recent experiments have revealed that the p-type BiCuSeO-based oxychalcogenides compounds exhibit a high thermoelectric figures of merit due to their very low lattice thermal conductivities and moderate Seebeck coefficient in the medium temperature range. In the present work, we reported on the optoelectronic and thermoelectric properties using the full potential linear augmented plane wave method and modified Becke-Johnson potential with spin-orbit coupling. The properties show that the BiCuSeO-based oxychalcogenides exhibit a semiconductor behavior with band gap values of 0.51, 0.45 and 0.41 eV for BiCuSO, BiCuSeO, and BiCuTeO, respectively. Due to their prominent role for thermoelectric applications, we combined Boltzmann transport theory to DFT results to compute the transport properties, mainly electronic conductivity, thermal conductivity, Seebeck coefficient and power factor. The present results show the dominance of BiCuTeO for thermoelectric application compared to the BiCuSO and BiCuSeO.

  20. Current trends in integrated optoelectronics

    CERN Document Server

    Lee, TP

    1994-01-01

    This compilation of review articles by leading experts presents clearly the trend in future optoelectronic devices. It is clear that optoelectronic and photonic integration help to further improve high-speed system capabilities and increase the total systems and network capacities with WDM technology. The foundation of the integration technology is based on quantum well materials, and advanced epitaxial growth and device processing techniques. The integrated laser/ modulators, multi-wavelength laser arrays, and OEIC receivers have demonstrated the feasibility of this technology, but much work

  1. An introduction to optoelectronic sensors

    CERN Document Server

    Tajani, Antonella; Cutolo, Antonello

    2009-01-01

    This invaluable book offers a comprehensive overview of the technologies and applications of optoelectronic sensors. Based on the R&D experience of more than 70 engineers and scientists, highly representative of the Italian academic and industrial community in this area, this book provides a broad and accurate description of the state-of-the-art optoelectronic technologies for sensing. The most innovative approaches, such as the use of photonic crystals, squeezed states of light and microresonators for sensing, are considered. Application areas range from environment to medicine and healthcare

  2. Photonic nanojets in optical tweezers

    International Nuclear Information System (INIS)

    Photonic nanojets have been brought into attention ten years ago for potential application in ultramicroscopy, because of its sub-wavelength resolution that can enhance detection and interaction with matter. For these novel applications under development, the optical trapping of a sphere acts as an ideal framework to employ photonic nanojets. In the present study, we generated nanojets by using a highly focused incident beam, in contrast to traditional plane waves. The method inherits the advantage of optical trapping, especially for intracellular applications, with the microsphere in equilibrium on the beam propagation axis and positioned arbitrarily in space. Moreover, owing to optical scattering forces, when the sphere is in equilibrium, its center shifts with respect to the focal point of the incident beam. However, when the system is in stable equilibrium with a configuration involving optical tweezers, photonic nanojets cannot be formed. To overcome this issue, we employed double optical tweezers in an unorthodox configuration involving two collinear and co-propagating beams, the precise positioning of which would turn on/off the photonic nanojets, thereby improving the applicability of photonic nanojets. - Highlights: • Photonic nanojets from an optically trapped microsphere are presented. • Electromagnetic beams are described by using beam shape coefficients. • Beam shape coefficients are determined by generalized Lorenz–Mie theory. • Scheme to turn on and off a photonic nanojet is described

  3. Influence of TiO2 Nanoparticles on Enhancement of Optoelectronic Properties of PFO-Based Light Emitting Diode

    Directory of Open Access Journals (Sweden)

    Bandar Ali Al-Asbahi

    2013-01-01

    Full Text Available Improvement on optoelectronic properties of poly (9,9′-di-n-octylfluorenyl-2.7-diyl- (PFO- based light emitting diode upon incorporation of TiO2 nanoparticles (NPs is demonstrated. The PFO/TiO2 nanocomposites with different weight ratios between 5 and 35 wt.% were prepared using solution blending method before they were spin coated onto Indium Tin Oxide substrate. Then a thin Al layer was deposited onto the nanocomposite layer to act as top electrode. The nanocomposites were tested as emissive layer in organic light emitting diodes (OLEDs. The TiO2 NPs played the most crucial role in facilitating charge transport and electrical injection and thus improved device performance in terms of turn-on voltage, electroluminescence spectra (EL, luminance, and luminance efficiency. The best composition was OLED with 5 wt.% TiO2 NPs content having moderate surface roughness and well distribution of NPs. The device performance was reduced at higher TiO2 NPs content due to higher surface roughness and agglomeration of TiO2 NPs. This work demonstrated the importance of optimum TiO2 NPs content with uniform distribution and controlled surface roughness of the emissive layer for better device performance.

  4. Timing Jitter Analysis for Clock recovery Circuits Based on an Optoelectronic Phase-Locked Loop (OPLL)

    DEFF Research Database (Denmark)

    Zibar, Darko; Mørk, Jesper; Oxenløwe, Leif Katsuo; Galili, Michael; Clausen, Anders

    2005-01-01

    Timing jitter of an OPLL based clock recovery is investigated. We demonstrate how loop gain, input and VCO signal jitter, loop filter bandwidth and a loop time delay influence jitter of the extracted clock signal......Timing jitter of an OPLL based clock recovery is investigated. We demonstrate how loop gain, input and VCO signal jitter, loop filter bandwidth and a loop time delay influence jitter of the extracted clock signal...

  5. Enhanced multi-hop operation using hybrid optoelectronic router with time-to-live-based selective forward error correction.

    Science.gov (United States)

    Nakahara, Tatsushi; Suzaki, Yasumasa; Urata, Ryohei; Segawa, Toru; Ishikawa, Hiroshi; Takahashi, Ryo

    2011-12-12

    Multi-hop operation is demonstrated with a prototype hybrid optoelectronic router for optical packet switched networks. The router is realized by combining key optical/optoelectronic device/sub-system technologies and complementary metal-oxide-semiconductor electronics. Using the hop count monitored via the time-to-live field in the packet label, the optoelectronic buffer of the router performs buffering with forward error correction selectively for packets degraded due to multiple hopping every N hops. Experimental results for 10-Gb/s optical packets confirm that the scheme can expand the number of hops while keeping the bit error rate low without the need for optical 3R regenerators at each node. PMID:22274034

  6. Optical tweezers and manipulation of PMMA beads in various conditions

    Science.gov (United States)

    Kotsifaki, D. G.; Makropoulou, M.; Serafetinides, A. A.

    2009-07-01

    Laser optical trapping and micromanipulation of microparticles or cells and subcellular structures have gained remarkable interest in biomedical research and applications. Several laser sources are employed for the combination of a laser scalpel with an optical tweezers device, under microscopic control. However, although the principles and the mechanisms of pulsed laser ablation have been well described for macroscopic interventions, the microbeam operation, under microscopic guidance, necessitates further experiments and investigations. We present experimental results of controlled micro-ablation of PMMA beads of 3-8 μm diameters, trapped by laser tweezers in various media e.g. solutes of different index of refraction. An optical tweezers system, based on a continuous wave He-Ne laser emitting at 632.8 nm, was tested on beads and, despite the low power of the He-Ne laser, the optical trap was stable. Another optical system, based on a cw Nd:YAG laser emitting at 1.06 μm, was tested on microspheres too. Successful beads ablation was carried out by irradiation with multiple, or even a single nitrogen laser pulse of 7 ns pulse duration at a wavelength of 337 nm. The ablative perforation of the microspheres was estimated by controlling the laser fluence. Moreover, shape deformations of PMMA microspheres were observed. The experimentally obtained results are theoretically explained via the spatial intensity distribution based on Mie light scattering theory. Furthermore, the appearance of laser ablation holes in the back side of microspheres is explained by the ablation triggered shock waves propagation. The role of the stretching forces action is also discussed. Additionally, we report experimental results on measuring the optical trap force of PMMA beads. A powerful optical tweezers system based on a continuous wave Nd:YAG laser was used in order to estimate the trapping efficiency for several beads diameter.

  7. Probing DNA with micro- and nanocapillaries and optical tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Steinbock, L J; Otto, O; Skarstam, D R; Jahn, S; Chimerel, C; Gornall, J L; Keyser, U F, E-mail: ufk20@cam.ac.u [Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

    2010-11-17

    We combine for the first time optical tweezer experiments with the resistive pulse technique based on capillaries. Quartz glass capillaries are pulled into a conical shape with tip diameters as small as 27 nm. Here, we discuss the translocation of {lambda}-phage DNA which is driven by an electrophoretic force through the nanocapillary. The resulting change in ionic current indicates the folding state of single {lambda}-phage DNA molecules. Our flow cell design allows for the straightforward incorporation of optical tweezers. We show that a DNA molecule attached to an optically trapped colloid is pulled into a capillary by electrophoretic forces. The detected electrophoretic force is in good agreement with measurements in solid-state nanopores.

  8. PbSe-Based Colloidal Core/Shell Heterostructures for Optoelectronic Applications

    Directory of Open Access Journals (Sweden)

    Gary Zaiats

    2014-10-01

    Full Text Available Lead-based (IV–VI colloidal quantum dots (QDs are of widespread scientific and technological interest owing to their size-tunable band-gap energy in the near-infrared optical region. This article reviews the synthesis of PbSe-based heterostructures and their structural and optical investigations at various temperatures. The review focuses on the structures consisting of a PbSe core coated with a PbSexS1–x (0 ≤ x ≤ 1 or CdSe shell. The former-type shells were epitaxially grown on the PbSe core, while the latter-type shells were synthesized using partial cation-exchange. The influence of the QD composition and the ambient conditions, i.e., exposure to oxygen, on the QD optical properties, such as radiative lifetime, Stokes shift, and other temperature-dependent characteristics, was investigated. The study revealed unique properties of core/shell heterostructures of various compositions, which offer the opportunity of fine-tuning the QD electronic structure by changing their architecture. A theoretical model of the QD electronic band structure was developed and correlated with the results of the optical studies. The review also outlines the challenges related to potential applications of colloidal PbSe-based heterostructures.

  9. Characterising Conical Refraction Optical Tweezers

    CERN Document Server

    McDonald, Craig; Rafailov, Edik; McGloin, David

    2014-01-01

    Conical refraction occurs when a beam of light travels through an appropriately cut biaxial crystal. By focussing the conically refracted beam through a high numerical aperture microscope objective, conical refraction optical tweezers can be created, allowing for particle manipulation in both Raman spots and in the Lloyd/Poggendorff rings. We present a thorough quantification of the trapping properties of such a beam, focussing on the trap stiffness and how this varies with trap power and trapped particle location. We show that the lower Raman spot can be thought of as a single-beam optical gradient force trap, while radiation pressure dominates in the upper Raman spot, leading to optical levitation rather than trapping. Particles in the Lloyd/Poggendorff rings experience a lower trap stiffness than particles in the lower Raman spot but benefit from rotational control.

  10. Simulation of superresolution holography for optical tweezers

    OpenAIRE

    Thomson, L. C.; Boissel, Y.; Whyte, G; Yao, E; Courtial, J.

    2008-01-01

    Optical tweezers manipulate microscopic particles using foci of light beams. Their performance is therefore limited by diffraction. Using computer simulations of a model system, we investigate the application of superresolution holography for two-dimensional (2D) light shaping in optical tweezers, which can beat the diffraction limit. We use the direct-search and Gerchberg algorithms to shape the center of a light beam into one or two bright spots; we do not constrain the remainder of the bea...

  11. Novel Erbium(III) and Ytterbium(III)-based materials for Optoelectronic and Telecommunication Applications

    OpenAIRE

    Martín Ramos, Pablo

    2013-01-01

    Esta Tesis Doctoral se enmarca en el área de la Ingeniería de Materiales con aplicaciones en Ingenierías Electrónica y de Telecomunicación. Es relativa al diseño molecular, síntesis, elucidación estructural, absorción-óptica, excitación y fotoluminescencia de 44 nuevos complejos de erbio(III) e iterbio(III) octacoordinados por 6 oxígenos de tres ligandos β-dicetonato y 2 nitrógenos de una base de Lewis, que exhiben emisión a longitudes de onda críticas en el infrarrojo, comportamiento óptico-...

  12. Nano-scale electronic and optoelectronic devices based on 2D crystals

    Science.gov (United States)

    Zhu, Wenjuan

    In the last few years, the research community has been rapidly growing interests in two-dimensional (2D) crystals and their applications. The properties of these 2D crystals are diverse -- ranging from semi-metal such as graphene, semiconductors such as MoS2, to insulator such as boron nitride. These 2D crystals have many unique properties as compared to their bulk counterparts due to their reduced dimensionality and symmetry. A key difference is the band structures, which lead to distinct electronic and photonic properties. The 2D nature of the material also plays an important role in defining their exceptional properties of mechanical strength, surface sensitivity, thermal conductivity, tunable band-gap and their interaction with light. These unique properties of 2D crystals open up a broad territory of applications in computing, communication, energy, and medicine. In this talk, I will present our work on understanding the electrical properties of graphene and MoS2, in particular current transport and band-gap engineering in graphene, interface between gate dielectrics and graphene, and gap states in MoS2. I will also present our work on the nano-scale electronic devices (RF and logic devices) and photonic devices (plasmonic devices and photo-detectors) based on these 2D crystals.

  13. Nanocomposites Based on Luminescent Colloidal Nanocrystals and Polymeric Ionic Liquids towards Optoelectronic Applications

    Directory of Open Access Journals (Sweden)

    Annamaria Panniello

    2014-01-01

    Full Text Available Polymeric ionic liquids (PILs are an interesting class of polyelectrolytes, merging peculiar physical-chemical features of ionic liquids with the flexibility, mechanical stability and processability typical of polymers. The combination of PILs with colloidal semiconducting nanocrystals leads to novel nanocomposite materials with high potential for batteries and solar cells. We report the synthesis and properties of a hybrid nanocomposite made of colloidal luminescent CdSe nanocrystals incorporated in a novel ex situ synthesized imidazolium-based PIL, namely, either a poly(N-vinyl-3-butylimidazolium hexafluorophosphate or a homologous PIL functionalized with a thiol end-group exhibiting a chemical affinity with the nanocrystal surface. A capping exchange procedure has been implemented for replacing the pristine organic capping molecules of the colloidal CdSe nanocrystals with inorganic chalcogenide ions, aiming to disperse the nano-objects in the PILs, by using a common polar solvent. The as-prepared nanocomposites have been studied by TEM investigation, UV-Vis, steady-state and time resolved photoluminescence spectroscopy for elucidating the effects of the PIL functionalization on the morphological and optical properties of the nanocomposites.

  14. Study of silicone-based materials for the packaging of optoelectronic devices

    Science.gov (United States)

    Lin, Yeong-Her

    degradations, and thus cause reliability issues and shorten the lifetime. A new high performance silicone has been developed and its performance has been compared with other commercial silicone products in the packaging of high power white LEDs. The high performance silicone also has better results than commercial high refractive index silicone and optical grade epoxy under JEDEC reliability standard for moisture sensitivity test. In synthesis of red dye-doped particles by sol-gel method, it is a novel method to get high color rendering index (CRI) LEDs. These red dye-doped particles, with average diameter of 5 mum, can be mixed with liquid encapsulants to form a uniform distribution in polymer matrix. The red dye-doped particles can be excited by phosphor-emitted yellow light instead of blue light from LED chip. Therefore, warm white LEDs with high CRI can be gotten at high lumen efficiency. The second part of this work is silicone elastomer for biomedical applications, especially in making urological implantable devices. A cross-linked, heat curable, addition-reaction silicone material is prepared. The material may be molded or formed into one or more medical devices. One such medical device could be a catheter used in urological applications. The material is a long term indwelling material that resists encrustation like a metal stent, but is more comfortable because it is silicone-based. The material can be made relatively cheaply compared to metal stents. Furthermore, the material is biocompatible with bladder epithelial cells.

  15. 拉曼镊子分析红酵母合成类胡萝卜素%Raman Tweezers-Based Analysis of Carotenoid Synthesis in Rhodotorula Glutinis

    Institute of Scientific and Technical Information of China (English)

    袁玉峰; 陶站华; 刘军贤; 王桂文; 黎永青

    2011-01-01

    Carotenoid synthesis in Rhodotorula glutinis was investigated with Raman tweezers in order to find the effect of nitrogen and carbon resource on carotenoid yield. The cells in fermentation terminus were harvested, and then divided into two parts, one for UV analysis, the other for Raman tweezers detection. Original spectra were preprocessed by carrying out background elimination and baseline correction, and the averaged spectra of cells cultivated in different fermentation medium were analyzed qualitatively. The results showed that the Raman intensity of carotenoid were obviously different. There was a high correlation between UV results and Raman peak height data, the correlation coefficients of fitted parameters were 0.907 8 and 0.912 1, respectively. Quantitative analysis of 1 508 cm-1 peak height indicated that the appropriate nitrogen and carbon resources for the growth of Rhodotorula glutinis cells and synthesis of carotenoid were yeast extract+tryptone, and glucose,respectively. The above results suggest that Raman tweezers can provide information about carotenoids in Rhodotorula glutinis cells and serve as an effective tool for real time measurement of carotenoid synthesis and optimization of fermentation medium.%利用拉曼镊子对红酵母合成类胡萝卜素进行分析,考查氮源和碳源对类胡萝卜素产量的影响.取发酵终点细胞,一部分用于紫外光谱法测定,另一部分用拉曼镊子检测.原始光谱经过背景扣除、基线校正等方法预处理,定性分析不同培养基培养细胞的平均光谱,类胡萝卜素的拉曼信号强度有明显不同;紫外检测结果和拉曼峰高数据有良好的相关性,拟合参数的相关系数分别达到0.907 8和0.9121;定量分析1508cm1峰高表明适宜红酵母细胞生长和类胡萝卜素合成的氮源和碳源分别是酵母粉+胰蛋百胨、葡萄糖.以上结果说明,拉曼镊子能提供红酵母胞内类胡萝卜索的含量信息,是实时检测红酵母细

  16. Fiber optical tweezers for microscale and nanoscale particle manipulation and force sensing

    Science.gov (United States)

    Liu, Yuxiang

    2011-12-01

    Optical tweezers have been an important tool in biology and physics for studying single molecules and colloidal systems. Most of current optical tweezers are built with microscope objectives, which are: i) expensive, ii) bulky and hard to integrate, iii) sensitive to environmental fluctuations, iv) limited in terms of working distances from the substrate, and v) rigid with the requirements on the substrate (transparent substrate made with glass and with a fixed thickness). These limitations of objective-based optical tweezers prevent them from being miniaturized. Fiber optical tweezers can provide a solution for cost reduction and miniaturization, and these optical tweezers can be potentially used in microfluidic systems. However, the existing fiber optical tweezers have the following limitations: i) low trapping efficiency due to weakly focused beams, ii) lack of the ability to control the positions of multiple particles simultaneously, and iii) limited functionalities. The overall objective of this dissertation work is to further the fundamental understanding of fiber optical tweezers through experimental study and modeling, and to develop novel fiber optical tweezers systems to enhance the capability and functionalities of fiber optical tweezers as microscale and nanoscale manipulators/sensors. The contributions of this dissertation work are summarized as follows. i) An enhanced understanding of the inclined dual-fiber optical tweezers (DFOTs) system has been achieved. Stable three dimensional (3D) optical trapping of a single micron-sized particle has been experimentally demonstrated. This is the first time that the trapping efficiency has been calibrated and the stiffness of the trap has been obtained in the experiments, which has been carried out by using two methods: the drag force method and power spectrum analysis. Such calibration enables the system to be used as a picoNewton-level force sensor in addition to a particle manipulator. The influence of

  17. Optoelectronics circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Optoelectronics Circuits Manual covers the basic principles and characteristics of the best known types of optoelectronic devices, as well as the practical applications of many of these optoelectronic devices. The book describes LED display circuits and LED dot- and bar-graph circuits and discusses the applications of seven-segment displays, light-sensitive devices, optocouplers, and a variety of brightness control techniques. The text also tackles infrared light-beam alarms and multichannel remote control systems. The book provides practical user information and circuitry and illustrations.

  18. Laser tweezers Raman spectroscopy of single cells

    Science.gov (United States)

    Chen, De

    platelet products for long term preservation; (6) LTRS based depolarized Raman spectroscopy was developed and used to do bacterial cell identification of similar species. From these experiments, several new findings and conclusions have been obtained. (1) single spore dynamic germination was measured for the first time. The result showed the time-to-germinate of a single spore was stochastic and could be discrete. (2) the thermal nature of spore killing in solution by microwaves was identified, Spores killed directly by microwaves showed death marker in Raman spectrum; (3) The Ca-DPA inside the spore core of a spore would undergo a structure modification during heat shock, which was related to the spores' state transition from a glass-like to a rubbery-like state, this structure modification during heat shock was reversible; (4) the kinetic molecular processes of E. coli cell lysis by lysozyme and by temperature induction of bacterial phage were recorded for the first time. The different cellular processes of the lysis were revealed based on the two different mechanisms; (5) LTRS technique was successfully applied to characterize human platelet fixation; a major procedure for long term preservation of therapeutic human platelet products; (6) A depolarization laser tweezers Raman spectroscopy (DLTRS) technique was developed to enhance the ability to discriminate similar bacterial species.

  19. A Self-Synchronized Optoelectronic Oscillator based on an RTD Photo-Detector and a Laser Diode.

    Science.gov (United States)

    Romeira, Bruno; Seunarine, Kris; Ironside, Charles N; Kelly, Anthony E; Figueiredo, José M L

    2011-08-15

    We propose and demonstrate a simple and stable low-phase noise optoelectronic oscillator (OEO) that uses a laser diode, an optical fiber delay line and a resonant tunneling diode (RTD) free-running oscillator that is monolithic integrated with a waveguide photo-detector. The RTD-OEO exhibits single-side band phase noise power below -100 dBc/Hz with more than 30 dB noise suppression at 10 kHz from the center free-running frequency for fiber loop lengths around 1.2 km. The oscillator power consumption is below 0.55 W, and can be controlled either by the injected optical power or the fiber delay line. The RTD-OEO stability is achieved without using other high-speed optical/optoelectronic components and amplification. PMID:23814452

  20. Holographic Raman Tweezers Controlled by Hand Gestures and Voice Commands

    Czech Academy of Sciences Publication Activity Database

    Tomori, Z.; Antalík, M.; Kesa, P.; Kaňka, Jan; Jákl, Petr; Šerý, Mojmír; Bernatová, Silvie; Zemánek, Pavel

    2013-01-01

    Roč. 3, 2B (2013), s. 331-336. ISSN 2160-8881 Institutional support: RVO:68081731 Keywords : Holographic Optical Tweezers * Raman Tweezers * Natural User Interface * Leap Motion * Gesture Camera Subject RIV: BH - Optics, Masers, Lasers

  1. Optical tweezers: light for manipulating microscopic world

    International Nuclear Information System (INIS)

    Optical tweezers make use of a tightly focused laser beam to trap, move, guide, rotate and even sort microscopic objects solely with light. Although the basic laser tweezers, making use of a TEM00 laser beam to create a single trap point, have proved to be useful for any applications in areas ranging from physics to biology, a major breakthrough in this field came as the use of computer generated holograms enabled researchers to create multiple trap sites from single laser source (holographic optical tweezers). Coupled with microfluidic techniques, holographic optical tweezers have promised development of optical techniques for high throughput sorting of different cell types under a single micro-chip platform. The holographic methods have also helped the use of specialized laser beams like Laguerre-Gaussian beams instead of the conventional laser beam for interesting applications like orienting/rotating the trapped objects or trapping cells with minimum photodamage. Further, combining optical tweezers with Raman spectroscopy is becoming increasingly popular for studying single cell biochemistry as use of optical forces to immobilize the cells under investigations not only avoids the negative effects of fixing the cells onto substrate but also improve the quality of the recorded spectra. These advanced optical trapping techniques as outlined above along with some illustrative biophotonics applications have been explored.

  2. Optoelectronic device for hematocrit measurements

    Science.gov (United States)

    Pluta, M.; Milewska, D.; Mazikowski, A.

    2015-09-01

    An optoelectronic system for measurements of hematocrit level (HCT) in the whole human blood is presented. Proposed system integrates a dedicated optoelectronic sensor, a microcontroller and a small LCD display in a low cost, battery-powered, handheld device. Chosen method for determining blood hematocrit level is based on optical properties of whole blood in visible and NIR wavelength range. Measurements with the use of proposed system require blood samples (small drop in the range of microliters) which is placed in the micro cuvette. Then, absorption of the sample is measured at wavelengths of 570 nm and 880 nm. Prototype of the device was build and tested. Test results confirmed proper operation of the device with correct metrological parameters in application to HCT level measurements. Such a portable device can be used as a tool of bedside diagnosis, which becomes interesting alternative to full laboratory tests.

  3. Simulation of superresolution holography for optical tweezers

    International Nuclear Information System (INIS)

    Optical tweezers manipulate microscopic particles using foci of light beams. Their performance is therefore limited by diffraction. Using computer simulations of a model system, we investigate the application of superresolution holography for two-dimensional (2D) light shaping in optical tweezers, which can beat the diffraction limit. We use the direct-search and Gerchberg algorithms to shape the center of a light beam into one or two bright spots; we do not constrain the remainder of the beam. We demonstrate that superresolution algorithms can significantly improve the normalized stiffness of an optical trap and the minimum separation at which neighboring traps can be resolved. We also test if such algorithms can be used interactively, as is desirable in optical tweezers

  4. Tomographic phase microscopy using optical tweezers

    Science.gov (United States)

    Habaza, Mor; Gilboa, Barak; Roichman, Yael; Shaked, Natan T.

    2015-07-01

    We review our technique for tomographic phase microscopy with optical tweezers [1]. This tomographic phase microscopy approach enables full 3-D refractive-index reconstruction. Tomographic phase microscopy measures quantitatively the 3- D distribution of refractive-index in biological cells. We integrated our external interferometric module with holographic optical tweezers for obtaining quantitative phase maps of biological samples from a wide range of angles. The close-tocommon- path, off-axis interferometric system enables a full-rotation tomographic acquisition of a single cell using holographic optical tweezers for trapping and manipulating with a desired array of traps, while acquiring phase information of a single cell from all different angles and maintaining the native surrounding medium. We experimentally demonstrated two reconstruction algorithms: the filtered back-projection method and the Fourier diffraction method for 3-D refractive index imaging of yeast cells.

  5. Temporally and spectrally resolved studies of mid-infrared to terahertz transitions in silicon-based optoelectronic devices

    International Nuclear Information System (INIS)

    The mid-infrared and terahertz region of the electromagnetic spectrum carry a wide variety of information, leading to a diverse field of applications for these spectral regimes. As further monolithic integrable silicon optoelectronics are one of the possible means of overcoming the challenge faced by integrated circuit scaling associated with the limited bandwidth of electric chip interconnects, there is a strong need for silicon-based detectors as well as laser sources. One of the concepts for implementing a lasing device in the silicon system is that of quantum cascade lasers, which has been successfully realized in III-V materials. Despite the successful demonstration of electroluminescence at various wavelengths in p-type SiGe quantum cascade devices, electrically pumped group-IV lasing has yet to be achieved. With an extensive research interest in the realization of a SiGe quantum cascade laser and due to the inability to achieve population inversion in such a device so far, the thorough study of intersubband transitions in SiGe heterostructures and in particular of intersubband relaxation times has become a crucial issue on the road to an electrically pumped group-IV laser. The main part of this work presents time-resolved photocurrent experiments on p-type SiGe quantum well structures, aiming at the determination of intersubband relaxation times of relevance for pursuing the quantum cascade concept in this material system. The hole lifetimes were measured by photocurrent pump-pump experiments using a free-electron-laser for providing ultrashort pulses in the picosecond to sub-picosecond regime at wavelengths in the mid- to far-infrared. By establishing a non-equilibrium occupation of an excited hole state by one laser pulse and probing this occupation into the valence band continuum by a second pulse delayed from the first, the photocurrent through the individual samples originating from a two-photon process was measured as a function of the delay between

  6. UV-Vis optoelectronic properties of α-SnWO4: A comparative experimental and density functional theory based study

    KAUST Repository

    Ziani, Ahmed

    2015-09-03

    We report a combined experimental and theoretical study on the optoelectronic properties of α-SnWO4 for UV-Vis excitation. The experimentally measured values for thin films were systematically compared with high-accuracy density functional theory and density functional perturbation theory using the HSE06 functional. The α-SnWO4 material shows an indirect bandgap of 1.52 eV with high absorption coefficient in the visible-light range (>2 × 105 cm−1). The results show relatively high dielectric constant (>30) and weak diffusion properties (large effective masses) of excited carriers.

  7. A Self-Synchronized Optoelectronic Oscillator based on an RTD Photo-Detector and a Laser Diode

    OpenAIRE

    Romeira, Bruno; Seunarine, Kris; Charles N. Ironside; Kelly, Anthony E.; Figueiredo, José M. L.

    2011-01-01

    We propose and demonstrate a simple and stable low-phase noise optoelectronic oscillator (OEO) that uses a laser diode, an optical fiber delay line and a resonant tunneling diode (RTD) free-running oscillator that is monolithic integrated with a waveguide photo-detector. The RTD-OEO exhibits single-side band phase noise power below −100 dBc/Hz with more than 30 dB noise suppression at 10 kHz from the center free-running frequency for fiber loop lengths around 1.2 km. The oscillator power cons...

  8. Electric tweezers: negative dielectrophoretic multiple particle positioning

    International Nuclear Information System (INIS)

    Electric tweezers are a touchless positioning apparatus that employs dielectrophoresis and electroorientation to arbitrarily position cell-sized particles. In this paper, we develop an algorithm which enables electric tweezers to operate on multiple particles. Furthermore, we probe the limits of this technique in simulation, examining the range of electric field magnitudes and forces that can be applied. We then demonstrate this new functionality on two particles. The device can apply forces on any particle of non-zero polarizability and here this is highlighted by manipulating negatively polarized glass beads. Additionally, we demonstrate that negligibly polarized particles can also be manipulated through mechanical forces applied by other particles. (paper)

  9. Origin and Future of Plasmonic Optical Tweezers

    Directory of Open Access Journals (Sweden)

    Jer-Shing Huang

    2015-06-01

    Full Text Available Plasmonic optical tweezers can overcome the diffraction limits of conventional optical tweezers and enable the trapping of nanoscale objects. Extension of the trapping and manipulation of nanoscale objects with nanometer position precision opens up unprecedented opportunities for applications in the fields of biology, chemistry and statistical and atomic physics. Potential applications include direct molecular manipulation, lab-on-a-chip applications for viruses and vesicles and the study of nanoscale transport. This paper reviews the recent research progress and development bottlenecks and provides an overview of possible future directions in this field.

  10. Manipulation of Nanoparticles Using Dark-Field-Illumination Optical Tweezers with Compensating Spherical Aberration

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jin-Hua; TAO Run-Zhe; HU Zhi-Bin; ZHONG Min-Cheng; WANG Zi-Qiang; CAI Jun; LI Yin-Mei

    2009-01-01

    Based on our previous investigation of optical tweezers with dark field illumination[Chin.Phys.Lett.25(2008)329],nanoparticles at large trap depth axe better viewed in wide field and real time for a long time,but with poor forces.Here we present the mismatched tube length to compensate for spherical aberration of an oil-immersion objective in a glass-water interface in an optical tweezers system for manipulating nanoparticles.In this way,the critical power of stable trapping particles is measured at different trap depths.It is found that trap depth is enlarged for trapping nanoparticles and trapping forces are enhanced at large trap depth.According to the measurement,70-nm particles are manipulated in three dimensions and observed clearly at large appropriate depth.This will expand applications of optical tweezers in a nanometre-scale colloidal system.

  11. Semiconductor opto-electronics

    CERN Document Server

    Moss, TS; Ellis, B

    1972-01-01

    Semiconductor Opto-Electronics focuses on opto-electronics, covering the basic physical phenomena and device behavior that arise from the interaction between electromagnetic radiation and electrons in a solid. The first nine chapters of this book are devoted to theoretical topics, discussing the interaction of electromagnetic waves with solids, dispersion theory and absorption processes, magneto-optical effects, and non-linear phenomena. Theories of photo-effects and photo-detectors are treated in detail, including the theories of radiation generation and the behavior of semiconductor lasers a

  12. Nanotube electronics and optoelectronics

    Directory of Open Access Journals (Sweden)

    Phaedon Avouris

    2006-10-01

    Full Text Available Among the many materials that have been proposed to supplement and, in the long run, possibly succeed Si as a basis for nanoelectronics, carbon nanotubes (CNTs have attracted the most attention. CNTs are quasi-one-dimensional materials with unique properties ideally suited for electronics. We briefly discuss the electrical and optical properties of CNTs and how they can be employed in electronics and optoelectronics. We focus on single CNT transistors, their fabrication, assembly, doping, electrical characteristics, and integration. We also address the possible use of CNTs in optoelectronic devices such as electroluminescent light emitters and photodetectors.

  13. Single Chromatin Fibre Assembly Using Optical Tweezers

    NARCIS (Netherlands)

    Bennink, M.L.; Pope, L.H.; Leuba, S.H.; Grooth, de B.G.; Greve, J.

    2001-01-01

    Here we observe the formation of a single chromatin fibre using optical tweezers. A single -DNA molecule was suspended between two micron-sized beads, one held by a micropipette and the other in an optical trap. The constrained DNA molecule was incubated with Xenopus laevis egg extract in order to r

  14. Top-down prepared silicon nanocrystals and a conjugated polymer-based bulk heterojunction: Optoelectronic and photovoltaic applications

    International Nuclear Information System (INIS)

    Blends consisting of doped silicon nanocrystals (Si-ncs) and two conjugated polymers (poly(3-hexylthiophene) (P3HT) and poly(methoxy ethylexyloxy phenylenevinilene) (MEH PPV)) with improved photostability were fabricated. We show that a top-down approach by electrochemical etching is suitable for preparing doped (boron and phosphorus) freestanding and surfactant-free Si-ncs. The doping of Si-ncs was confirmed by low temperature photoluminescence and electron spin resonance analysis. It is demonstrated that such Si-ncs can be successfully used for the fabrication of room temperature photoluminescent and photosensitive blends. We argue that the luminescence and transport properties of the blends are controlled by the Si-ncs properties and could be assigned to quantum confinement of excitons in nanocrystalites with an energy band gap of ∼2 eV. Furthermore, the blending of doped Si-ncs in both conjugated polymers led to the establishment of a bulk heterojunction between the Si-ncs and polymer. The difference in electron affinity and ionization potential between nanocrystals and polymer dissociated the excitons. Those blends showed increased carrier transport and photoconductivity under ambient conditions. It was found that introduction of less defective p-type doped Si-ncs significantly improved overall photostability of the blend. The Si-ncs non-toxicity and easy integration into well-established silicon technologies might bring considerable benefit for hybrid optoelectronic and photovoltaic device development.

  15. Graphene Photonics and Optoelectronics

    OpenAIRE

    Bonaccorso, F.; Sun, Z.; Hasan, T.; Ferrari, A. C.

    2010-01-01

    The richness of optical and electronic properties of graphene attracts enormous interest. Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability. So far, the main focus has been on fundamental physics and electronic devices. However, we believe its true potential to be in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, ...

  16. Photonic generation of arbitrary waveform microwave pulse based on tunable optoelectronic oscillator and a dual-drive Mach-Zehnder modulator

    Science.gov (United States)

    Li, Jiao; Yu, Lan

    2016-03-01

    Photonic generation of arbitrary waveform microwave pulse with tunable carrier frequency and phase based on tunable optoelectronic oscillator (TOEO) and a dual-drive Mach-Zehnder modulator (DDMZM) is proposed. Utilizing the frequency tunability of TOEO, the carrier frequency of the microwave signal can be tuned by adjusting the wavelength of the tunable laser source (TLS) and the tunable range can be as large as tens of GHz. By controlling the signals applied to DDMZM, the generation of arbitrary waveform microwave pulse with tunable phase in the range of -180° to 180° is achieved. The proposed scheme can realize the integration of frequency tuning, phase tuning, pulse modulation and radar transmitted waveform generation in the optical domain, which provides a guarantee of transmitting high-quality microwave signal in radar systems.

  17. Probing the Casimir force with optical tweezers

    CERN Document Server

    Ether, D S; Umrath, S; Martinez, D; Ayala, Y; Pontes, B; Araújo, G R de S; Frases, S; Ingold, G -L; Rosa, F S S; Viana, N B; Nussenzveig, H M; Neto, P A Maia

    2015-01-01

    We propose to use optical tweezers to probe the Casimir interaction between microspheres inside a liquid medium for geometric aspect ratios far beyond the validity of the widely employed proximity force approximation. This setup has the potential for revealing unprecedented features associated to the non-trivial role of the spherical curvatures. For a proof of concept, we measure femtonewton double layer forces between polystyrene microspheres at distances above $400$ nm by employing very soft optical tweezers, with stiffness of the order of fractions of a fN/nm. As a future application, we propose to tune the Casimir interaction between a metallic and a polystyrene microsphere in saline solution from attraction to repulsion by varying the salt concentration. With those materials, the screened Casimir interaction may have a larger magnitude than the unscreened one. This line of investigation has the potential for bringing together different fields including classical and quantum optics, statistical physics an...

  18. Soft magnetic tweezers: A proof of principle

    Science.gov (United States)

    Mosconi, Francesco; Allemand, Jean François; Croquette, Vincent

    2011-03-01

    We present here the principle of soft magnetic tweezers which improve the traditional magnetic tweezers allowing the simultaneous application and measurement of an arbitrary torque to a deoxyribonucleic acid (DNA) molecule. They take advantage of a nonlinear coupling regime that appears when a fast rotating magnetic field is applied to a superparamagnetic bead immersed in a viscous fluid. In this work, we present the development of the technique and we compare it with other techniques capable of measuring the torque applied to the DNA molecule. In this proof of principle, we use standard electromagnets to achieve our experiments. Despite technical difficulties related to the present implementation of these electromagnets, the agreement of measurements with previous experiments is remarkable. Finally, we propose a simple way to modify the experimental design of electromagnets that should bring the performances of the device to a competitive level.

  19. A Tweezer for Chimeras in Small Networks

    OpenAIRE

    Omelchenko, Iryna; Omel'chenko, Oleh E.; Zakharova, Anna; Wolfrum, Matthias; Schoell, Eckehard

    2015-01-01

    We propose a control scheme which can stabilize and fix the position of chimera states in small networks. Chimeras consist of coexisting domains of spatially coherent and incoherent dynamics in systems of nonlocally coupled identical oscillators. Chimera states are generally difficult to observe in small networks due to their short lifetime and erratic drifting of the spatial position of the incoherent domain. The control scheme, like a tweezer, might be useful in experiments, where usually o...

  20. Probing the Casimir force with optical tweezers

    OpenAIRE

    Ether Jr, D. S.; Pires, L. B.; Umrath, S.; Martinez, D; Ayala, Y.; Pontes, B.; Araújo, G. R. de S.; Frases, S.; Ingold, G. -L.; Rosa, F. S. S.; Viana, N. B.; Nussenzveig, H. M.; Neto, P A Maia

    2015-01-01

    We propose to use optical tweezers to probe the Casimir interaction between microspheres inside a liquid medium for geometric aspect ratios far beyond the validity of the widely employed proximity force approximation. This setup has the potential for revealing unprecedented features associated to the non-trivial role of the spherical curvatures. For a proof of concept, we measure femtonewton double layer forces between polystyrene microspheres at distances above $400$ nm by employing very sof...

  1. Tweezers for Chimeras in Small Networks

    Science.gov (United States)

    Omelchenko, Iryna; Omel'chenko, Oleh E.; Zakharova, Anna; Wolfrum, Matthias; Schöll, Eckehard

    2016-03-01

    We propose a control scheme which can stabilize and fix the position of chimera states in small networks. Chimeras consist of coexisting domains of spatially coherent and incoherent dynamics in systems of nonlocally coupled identical oscillators. Chimera states are generally difficult to observe in small networks due to their short lifetime and erratic drifting of the spatial position of the incoherent domain. The control scheme, like a tweezer, might be useful in experiments, where usually only small networks can be realized.

  2. Probing the Casimir force with optical tweezers

    Science.gov (United States)

    Ether, D. S., Jr.; Pires, L. B.; Umrath, S.; Martinez, D.; Ayala, Y.; Pontes, B.; Araújo, G. R. de S.; Frases, S.; Ingold, G.-L.; Rosa, F. S. S.; Viana, N. B.; Nussenzveig, H. M.; Neto, P. A. Maia

    2015-11-01

    We propose to use optical tweezers to probe the Casimir interaction between microspheres inside a liquid medium for geometric aspect ratios far beyond the validity of the widely employed proximity force approximation. This setup has the potential for revealing unprecedented features associated to the non-trivial role of the spherical curvatures. For a proof of concept, we measure femtonewton double-layer forces between polystyrene microspheres at distances above 400 nm by employing very soft optical tweezers, with stiffness of the order of fractions of a fN/nm. As a future application, we propose to tune the Casimir interaction between a metallic and a polystyrene microsphere in saline solution from attraction to repulsion by varying the salt concentration. With those materials, the screened Casimir interaction may have a larger magnitude than the unscreened one. This line of investigation has the potential for bringing together different fields including classical and quantum optics, statistical physics and colloid science, while paving the way for novel quantitative applications of optical tweezers in cell and molecular biology.

  3. High Spatiotemporal-Resolution Magnetic Tweezers: Calibration and Applications for DNA Dynamics.

    Science.gov (United States)

    Dulin, David; Cui, Tao Ju; Cnossen, Jelmer; Docter, Margreet W; Lipfert, Jan; Dekker, Nynke H

    2015-11-17

    The observation of biological processes at the molecular scale in real time requires high spatial and temporal resolution. Magnetic tweezers are straightforward to implement, free of radiation or photodamage, and provide ample multiplexing capability, but their spatiotemporal resolution has lagged behind that of other single-molecule manipulation techniques, notably optical tweezers and AFM. Here, we present, to our knowledge, a new high-resolution magnetic tweezers apparatus. We systematically characterize the achievable spatiotemporal resolution for both incoherent and coherent light sources, different types and sizes of beads, and different types and lengths of tethered molecules. Using a bright coherent laser source for illumination and tracking at 6 kHz, we resolve 3 Å steps with a 1 s period for surface-melted beads and 5 Å steps with a 0.5 s period for double-stranded-dsDNA-tethered beads, in good agreement with a model of stochastic bead motion in the magnetic tweezers. We demonstrate how this instrument can be used to monitor the opening and closing of a DNA hairpin on millisecond timescales in real time, together with attendant changes in the hairpin dynamics upon the addition of deoxythymidine triphosphate. Our approach opens up the possibility of observing biological events at submillisecond timescales with subnanometer resolution using camera-based detection. PMID:26588570

  4. Noncontact microsurgery and micromanipulation of living cells with combined system femtosecond laser scalpel-optical tweezers

    Science.gov (United States)

    Il'ina, Inna V.; Sitnikov, Dmitry S.; Ovchinnikov, Andrey V.; Agranat, Mikhail B.; Khramova, Yulia V.; Semenova, Maria L.

    2012-06-01

    We report on the results of using self-developed combined laser system consisting of a femtosecond laser scalpel (Cr:Forsterite seed oscillator and a regenerative amplifier, 620 nm, 100 fs, 10 Hz) and optical tweezers (cw laser, 1064 nm) for performing noncontact laser-mediated polar body (PB) and trophectoderm (TE) biopsy of early mammalian embryos. To perform PB biopsy the femtosecond laser scalpel was initially used to drill an opening in the zona pellucida, and then the PB was extracted out of the zygote with the optical tweezers. Unlike PB biopsy, TE biopsy allows diagnosing maternally-derived as well as paternally-derived defects. Moreover, as multiple TE cells can be taken from the embryo, more reliable diagnosis can be done. TE biopsy was performed by applying laser pulses to dissect the desired amount of TE cells that had just left the zona pellucida during the hatching. Optical tweezers were then used to trap and move the dissected TE cells in a prescribed way. Laser power in optical tweezers and energy of femtosecond laser pulses were thoroughly optimized to prevent cell damage and obtain high viability rates. In conclusion, the proposed techniques of laser-based embryo biopsy enable accurate, contamination-free, simple and quick microprocessing of living cells.

  5. Organics in optoelectronics: advances and roadmap

    Science.gov (United States)

    Eldada, Louay

    2006-02-01

    Over a four-year period from 2001 to 2005, the Microphotonics Center Industry Consortium at MIT evaluated the vast array of new technologies that have disrupted the telecommunications industry. As part of its mission, the consortium researched a variety of communications-related technical and business topics, presented recommendations for the rational restructuring of the industry, and developed a 30-year communications technology roadmap (CTR). The CTR program was guided by industry-led Technology Working Groups (TWGs), with the support of MIT faculty and students. We present the findings of the Organics in Optoelectronics TWG in terms of advances in organic-material based optoelectronic integrated circuits (OEICs), and we propose a roadmap for optoelectronic integration enabled by hybrid organic-inorganic OEICs.

  6. Optoelectronics with 2D semiconductors

    Science.gov (United States)

    Mueller, Thomas

    2015-03-01

    Two-dimensional (2D) atomic crystals, such as graphene and layered transition-metal dichalcogenides, are currently receiving a lot of attention for applications in electronics and optoelectronics. In this talk, I will review our research activities on electrically driven light emission, photovoltaic energy conversion and photodetection in 2D semiconductors. In particular, WSe2 monolayer p-n junctions formed by electrostatic doping using a pair of split gate electrodes, type-II heterojunctions based on MoS2/WSe2 and MoS2/phosphorene van der Waals stacks, 2D multi-junction solar cells, and 3D/2D semiconductor interfaces will be presented. Upon optical illumination, conversion of light into electrical energy occurs in these devices. If an electrical current is driven, efficient electroluminescence is obtained. I will present measurements of the electrical characteristics, the optical properties, and the gate voltage dependence of the device response. In the second part of my talk, I will discuss photoconductivity studies of MoS2 field-effect transistors. We identify photovoltaic and photoconductive effects, which both show strong photoconductive gain. A model will be presented that reproduces our experimental findings, such as the dependence on optical power and gate voltage. We envision that the efficient photon conversion and light emission, combined with the advantages of 2D semiconductors, such as flexibility, high mechanical stability and low costs of production, could lead to new optoelectronic technologies.

  7. Displacement and Force Measurements with Quadrant Photodetector in Optical Tweezers

    Institute of Scientific and Technical Information of China (English)

    郭红莲; 刘春香; 李兆霖; 段建发; 韩学海; 程丙英; 张道中

    2003-01-01

    A technique of displacement and force measurements with a photodiode quadrant detector in an optical tweezers system is presented. The stiffness of optical trap is calibrated and the leukemia cell membrane tension is measured.The results show that the optical tweezers combined with the quadrant detector is a very useful tool for detecting the displacement and force with a millisecond-order response.

  8. Enhancing surface plasmon propagation and leakage in planar thin film and tubular metallic nanostructures for visible-light-based organic optoelectronics

    Science.gov (United States)

    Kohl, Jesse

    Optical fields can be confined and propagated on subwavelength volumes by coupling to surface plasmon polariton (SPP) modes supported by metallic nanostructures. However, SPPs are inherently lossy modes, specifically in the visible regime with losses upwards of 1000 cm-1, resulting in short mode propagation lengths. SPPs are also a significant loss channel (up to 46.8% loss) in visible-light-based optoelectronics such as organic light-emitting diodes, significantly reducing light outcoupling efficiency. Theoretical calculations in the literature have demonstrated that light-emitting organic semiconducting conjugated polymers can compensate for the intrinsic losses of SPPs. Engineering plasmon-polymer interactions may also aid in reducing loss at metal electrodes and increase light outcoupling efficiency in OLEDs. In this study, a fundamental understanding of efficient SPP/polymer emitter coupling, towards the development of low-loss electrodes for visible-light-based organic optoelectronics through the investigation of two distinct structures: (1) semiconductor-metal-insulator (SMI) waveguides and (2) tubular metallic nanostructures. Dispersion relations were solved for the SMI waveguides over a range of metal film thickness and emitter dielectric constants. Solutions demonstrate that at visible wavelengths, SPP mode propagation lengths and magnetic field leakage are enhanced to lengths >1300 mum and >74 mum, respectively, through the optimization of the metal film thickness and by the addition of an organic polymer gain medium. These findings were experimentally validated by collecting pump power dependent emission spectra of SMI waveguides fabricated over a range of metal film thicknesses with controlled emitter dipole orientation. Large area arrays of gold nanotubes were synthesized with wall thickness (WT) tuned from 30 nm to > 140 nm. Their optical response was characterized as a function of wall thickness and excitation condition via polarized bright

  9. Dedicated Optoelectronic Stochastic Parallel Processor for Real-Time Image Processing: Motion-Detection Demonstration and Design of a Hybrid Complementary-Metal-Oxide Semiconductor- Self-Electro-Optic-Device-Based Prototype

    OpenAIRE

    Cassinelli, Alvaro; Chavel, Pierre; Desmulliez, Marc P. Y.

    2001-01-01

    We report experimental results and performance analysis of a dedicated optoelectronic processor that implements stochastic optimization-based image-processing tasks in real time. We first show experimental results using a proof-of-principle-prototype demonstrator based on standard silicon-complementary-metal-oxide-semiconductor (CMOS) technology and liquid-crystal spatial light modulators. We then elaborate on the advantages of using a hybrid CMOS-self-electro-optic-device-based smart-pixel a...

  10. Power spectrum analysis for optical tweezers

    DEFF Research Database (Denmark)

    Berg-Sørensen, K.; Flyvbjerg, H.

    2004-01-01

    Lorentzian provides. This is achieved using old and new theory for Brownian motion in an incompressible fluid, and new results for a popular photodetection system. The trap and photodetection system are then calibrated simultaneously in a manner that makes optical tweezers a tool of precision for force......The force exerted by an optical trap on a dielectric bead in a fluid is often found by fitting a Lorentzian to the power spectrum of Brownian motion of the bead in the trap. We present explicit functions of the experimental power spectrum that give the values of the parameters fitted, including...

  11. Magnetic nanowire-enhanced optomagnetic tweezers

    Science.gov (United States)

    Mehta, Karan K.; Wu, Ting-Hsiang; Chiou, Eric P. Y.

    2008-12-01

    We report an optomagnetic tweezers technique that utilizes the highly localized magnetic field gradients induced near the tip of a magnetic nanowire to provide strong trapping forces on magnetic nanoparticles with high spatial resolution. Integral to our approach is a method to trap, translate, and rotate a single magnetic nanowire in three dimensions. Our simulation predicts that forces in the range of 100 pN can be generated on 200 nm magnetic particles within 0.2 μm from a 200 nm diameter nickel nanowire. Such forces are relevant in many biological processes, suggesting that this approach will be of value in biophysical studies.

  12. Optoelectronics of Molecules and Polymers

    CERN Document Server

    Moliton, André

    2006-01-01

    Optoelectronic devices are being developed at an extraordinary rate. Organic light emitting diodes, photovoltaic devices and electro-optical modulators are pivotal to the future of displays, photosensors and solar cells, and communication technologies. This book details the theories underlying the relevant mechanisms in organic materials and covers, at a basic level, how the organic components are made. The first part of this book introduces the fundamental theories used to detail ordered solids and localised energy levels. The methods used to determine energy levels in perfectly ordered molecular and macromolecular systems are discussed, making sure that the effects of quasi-particles are not missed. The function of excitons and their transfer between two molecules are studied, and the problems associated with interfaces and charge injection into resistive media are presented. The second part details technological aspects such as the fabrication of devices based on organic materials by dry etching. The princ...

  13. TweezPal - Optical tweezers analysis and calibration software

    Science.gov (United States)

    Osterman, Natan

    2010-11-01

    Optical tweezers, a powerful tool for optical trapping, micromanipulation and force transduction, have in recent years become a standard technique commonly used in many research laboratories and university courses. Knowledge about the optical force acting on a trapped object can be gained only after a calibration procedure which has to be performed (by an expert) for each type of trapped objects. In this paper we present TweezPal, a user-friendly, standalone Windows software tool for optical tweezers analysis and calibration. Using TweezPal, the procedure can be performed in a matter of minutes even by non-expert users. The calibration is based on the Brownian motion of a particle trapped in a stationary optical trap, which is being monitored using video or photodiode detection. The particle trajectory is imported into the software which instantly calculates position histogram, trapping potential, stiffness and anisotropy. Program summaryProgram title: TweezPal Catalogue identifier: AEGR_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEGR_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 44 891 No. of bytes in distributed program, including test data, etc.: 792 653 Distribution format: tar.gz Programming language: Borland Delphi Computer: Any PC running Microsoft Windows Operating system: Windows 95, 98, 2000, XP, Vista, 7 RAM: 12 Mbytes Classification: 3, 4.14, 18, 23 Nature of problem: Quick, robust and user-friendly calibration and analysis of optical tweezers. The optical trap is calibrated from the trajectory of a trapped particle undergoing Brownian motion in a stationary optical trap (input data) using two methods. Solution method: Elimination of the experimental drift in position data. Direct calculation of the trap stiffness from the positional

  14. Enhanced Optoelectronic Performance of a Passivated Nanowire-Based Device: Key Information from Real-Space Imaging Using 4D Electron Microscopy.

    Science.gov (United States)

    Khan, Jafar I; Adhikari, Aniruddha; Sun, Jingya; Priante, Davide; Bose, Riya; Shaheen, Basamat S; Ng, Tien Khee; Zhao, Chao; Bakr, Osman M; Ooi, Boon S; Mohammed, Omar F

    2016-05-01

    Managing trap states and understanding their role in ultrafast charge-carrier dynamics, particularly at surface and interfaces, remains a major bottleneck preventing further advancements and commercial exploitation of nanowire (NW)-based devices. A key challenge is to selectively map such ultrafast dynamical processes on the surfaces of NWs, a capability so far out of reach of time-resolved laser techniques. Selective mapping of surface dynamics in real space and time can only be achieved by applying four-dimensional scanning ultrafast electron microscopy (4D S-UEM). Charge carrier dynamics are spatially and temporally visualized on the surface of InGaN NW arrays before and after surface passivation with octadecylthiol (ODT). The time-resolved secondary electron images clearly demonstrate that carrier recombination on the NW surface is significantly slowed down after ODT treatment. This observation is fully supported by enhancement of the performance of the light emitting device. Direct observation of surface dynamics provides a profound understanding of the photophysical mechanisms on materials' surfaces and enables the formulation of effective surface trap state management strategies for the next generation of high-performance NW-based optoelectronic devices. PMID:26938476

  15. Microrheology of concentrated DNA solutions using optical tweezers

    Indian Academy of Sciences (India)

    Arun S Rajkumar; B M Jaffar Ali

    2008-06-01

    Semiflexible biopolymers play a vital role in shaping cellular structure and rigidity. In this work, we report the determination of microrheological properties of concentrated, double-stranded calf thymus DNA (CT-DNA) solutions using passive, laser-scattering based particle-tracking methodology. From power spectral analysis, we obtain dynamic shear moduli of the polymer solutions stretching over three decades of frequency (100–103 Hz) and over concentration ranges spanning from very dilute to concentrated regime. We also study the effects of altered ionic strength and denaturation on the shear modulus. Our results indicate that (CT-DNA) exhibits predominantly elastic behaviour in the concentration range we probed. From the measurements of the plateau shear modulus, p, we conclude that DNA generally behaves like a semiflexible polymer in a good solvent even at low ionic strength. We have thus demonstrated application of passive microrheological method using optical tweezers to DNA solutions. Further extensions of the technique and its applications are discussed.

  16. Nano crystals for Electronic and Optoelectronic Applications

    International Nuclear Information System (INIS)

    Electronic and optoelectronic devices, from computers and smart cell phones to solar cells, have become a part of our life. Currently, devices with featured circuits of 45 nm in size can be fabricated for commercial use. However, further development based on traditional semiconductor is hindered by the increasing thermal issues and the manufacturing cost. During the last decade, nano crystals have been widely adopted in various electronic and optoelectronic applications. They provide alternative options in terms of ease of processing, low cost, better flexibility, and superior electronic/optoelectronic properties. By taking advantage of solution-processing, self-assembly, and surface engineering, nano crystals could serve as new building blocks for low-cost manufacturing of flexible and large area devices. Tunable electronic structures combined with small exciton binding energy, high luminescence efficiency, and low thermal conductivity make nano crystals extremely attractive for FET, memory device, solar cell, solid-state lighting/display, photodetector, and lasing applications. Efforts to harness the nano crystal quantum tunability have led to the successful demonstration of many prototype devices, raising the public awareness to the wide range of solutions that nano technology can provide for an efficient energy economy. This special issue aims to provide the readers with the latest achievements of nano crystals in electronic and optoelectronic applications, including the synthesis and engineering of nano crystals towards the applications and the corresponding device fabrication, characterization and computer modeling.

  17. tweezercalib 2.0: Faster version of MatLab package for precise calibration of optical tweezers

    DEFF Research Database (Denmark)

    Hansen, Poul Martin; Tolic-Nørrelykke, Iva Marija; Flyvbjerg, Henrik;

    2006-01-01

    of factors that affect this power spectrum, as described in vs. 1 of the package. The graphical user interface allows the user to include of leave out each of these factors. Several "health tests" are applied to the experimental data during calibration and test results are displayed graphically. Thus......We present a vectorized version of the MatLab (MathWorks Inc) package tweezercalib for calibration of optical tweezers with precision. The calibration is based on the power spectrum of the Brownian motion of a dielectric bead trapped in the tweezers. Precision is achieved by accounting for a number...

  18. GaAsSb/GaAsN short-period superlattices as a capping layer for improved InAs quantum dot-based optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Utrilla, A. D.; Ulloa, J. M., E-mail: jmulloa@isom.upm.es; Guzman, A.; Hierro, A. [Institute for Systems based on Optoelectronics and Microtechnology (ISOM) and Departamento de Ingeniería Electrónica, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Reyes, D. F.; González, D.; Ben, T. [Departamento de Ciencia de los Materiales e IM y QI, Universidad de Cádiz, 11510 Puerto Real (Cádiz) (Spain)

    2014-07-28

    The application of a GaAsSb/GaAsN short-period superlattice capping layer (CL) on InAs/GaAs quantum dots (QDs) is shown to be an option for providing improved luminescence properties to this system. Separating both GaAsSb and GaAsN ternaries during the growth in 2 monolayer-thick phases solves the GaAsSbN immiscibility-related problems. Strong fluctuations in the CL composition and strain field as well as in the QD size distribution are significantly reduced, and a more regular CL interface is also obtained. Room-temperature (RT) photoluminescence (PL) is obtained for overall N contents as high as 3%, yielding PL peak wavelengths beyond 1.4 μm in samples with a type-II band alignment. High external quantum efficiency electroluminescence and photocurrent from the QD ground state are also demonstrated at RT in a single QD-layer p-i-n device. Thus, it becomes possible to combine and transfer the complementary benefits of Sb- and N-containing GaAs alloys to InAs QD-based optoelectronics.

  19. Shape-dependent optoelectronic cell lysis

    OpenAIRE

    Kremer, Clemens; Witte, Christian; Neale, Steven L.; Reboud, Julien; Barrett, Michael P.; Cooper, Jonathan M.

    2014-01-01

    We show an electrical method to break open living cells amongst a population of different cell types, where cell selection is based upon their shape. We implement the technique on an optoelectronic platform, where light, focused onto a semiconductor surface from a video projector creates a reconfigurable pattern of electrodes. One can choose the area of cells to be lysed in real-time, from single cells to large areas, simply by redrawing the projected pattern. We show that the method, based o...

  20. Emerging optoelectronic technologies and applications

    CERN Document Server

    Lo, Y-H

    1997-01-01

    This book discusses some of the most important emerging optoelectronic technologies foreseen to have major technical and business impact in the future. In this spirit, four general technological areas have been selected: optoelectronic display, optical micro-electro-mechanical systems (MEMS), semiconductor lasers for wireless and loop applications, and optoelectronic integration technologies. In each of the four areas, two review articles that provide the technical background and sample some of the most significant recent breakthroughs were authored by the well regarded experts in the field. T

  1. Dielectrophoretic tweezers for examining particle-surface interactions within microfluidic devices

    OpenAIRE

    Lee, S. W.; LI, HAIBO; Bashir, Rashid

    2007-01-01

    The authors present dielectrophoresis (DEP)-based tweezers that can be used to characterize the interactions between a particle and the surface it is attached to, within a microfluidic device. As a proof of concept, 5.4 mu m polystyrene beads functionalized by carboxyl group were attached on a bare and poly-L-lysine functionalized oxide surface. Negative dielectrophoresis force was generated using interdigitated electrodes and the peak dielectrophoresis voltage where the beads were repelled a...

  2. Optoelectronic and Photovoltaic Performances of Pyridine Based Monomer and Polymer Capped ZnO Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Singh, Satbir; Raj, Tilak; Singh, Amarpal; Kaur, Navneet

    2016-06-01

    The present research work describes the comparative analysis and performance characteristics of 4-pyridine based monomer and polymer capped ZnO dye-sensitized solar cells. The N, N-dimethyl-N4-((pyridine-4yl)methylene) propaneamine (4,monomer) and polyamine-4-pyridyl Schiff base (5, polymer) dyes were synthesized through one step condensation reaction between 4-pyridinecarboxaldehyde 1 and N, N-dimethylpropylamine 2/polyamine 3. Products obtained N, N-dimethyl-N4-((pyridine-4yl)methylene)propaneamine (4) and polyamine-4-pyridyl Schiff base (5) were purified and characterized using 1H, 13C NMR, mass, IR and CHN spectroscopy. Both the dyes 4 and 5 were further coated over ZnO nanoparticles and characterized using SEM, DLS and XRD analysis. Absorption profile and emission profile was monitored using fluorescence and UV-Vis absorption spectroscopy. A thick layer of these inbuilt dye linked ZnO nanoparticles of dyes (4) and (5) was pasted on one of the conductive side of ITO glass followed with a liquid electrolyte and counter electrode of the same conductive glass. Polyamine-4-pyridyl Schiff base polymer (5) decorated dye sensitized solar cell has shown better exciting photovoltaic properties in the form of short circuit current density (J(sc) = 6.3 mA/cm2), open circuit photo voltage (V(oc) = 0.7 V), fill factor (FF = 0.736) than monomer decorated dye sensitized solar cell. Polymer dye (5) based ZnO solar cell has shown a maximum solar power to electrical conversion efficiency of 3.25%, which is enhanced by 2.16% in case of monomer dye based ZnO solar cell under AM 1.5 sun illuminations. PMID:27427659

  3. Rapid formation of size-controllable multicellular spheroids via 3D acoustic tweezers.

    Science.gov (United States)

    Chen, Kejie; Wu, Mengxi; Guo, Feng; Li, Peng; Chan, Chung Yu; Mao, Zhangming; Li, Sixing; Ren, Liqiang; Zhang, Rui; Huang, Tony Jun

    2016-07-01

    The multicellular spheroid is an important 3D cell culture model for drug screening, tissue engineering, and fundamental biological research. Although several spheroid formation methods have been reported, the field still lacks high-throughput and simple fabrication methods to accelerate its adoption in drug development industry. Surface acoustic wave (SAW) based cell manipulation methods, which are known to be non-invasive, flexible, and high-throughput, have not been successfully developed for fabricating 3D cell assemblies or spheroids, due to the limited understanding on SAW-based vertical levitation. In this work, we demonstrated the capability of fabricating multicellular spheroids in the 3D acoustic tweezers platform. Our method used drag force from microstreaming to levitate cells in the vertical direction, and used radiation force from Gor'kov potential to aggregate cells in the horizontal plane. After optimizing the device geometry and input power, we demonstrated the rapid and high-throughput nature of our method by continuously fabricating more than 150 size-controllable spheroids and transferring them to Petri dishes every 30 minutes. The spheroids fabricated by our 3D acoustic tweezers can be cultured for a week with good cell viability. We further demonstrated that spheroids fabricated by this method could be used for drug testing. Unlike the 2D monolayer model, HepG2 spheroids fabricated by the 3D acoustic tweezers manifested distinct drug resistance, which matched existing reports. The 3D acoustic tweezers based method can serve as a novel bio-manufacturing tool to fabricate complex 3D cell assembles for biological research, tissue engineering, and drug development. PMID:27327102

  4. Low cost optical tweezers systems using double coil driving stepping motor to controlling sample stage

    Science.gov (United States)

    Laowattanatham, N.; Cheamanunkul, N.; Plaipichit, S.; Buranasiri, P.; Nuansri, R.

    2013-06-01

    In this research, the low cost optical tweezers systems using X-Y stage has been developed by using 5-phase stepping motor. By using sequential double coil driving, we can obtain the driving torque larger than using the single coil driving. The moving scale is fine resolution at 0.2 micrometer. The overall systems based on microcontroller PIC18F458 and joystick controller with LabView® graphical user interface (GUI). The mechanical damping has been included in the system for decreasing the vibrational noise. By using this method, our optical tweezers system is cheaper than the other commercial system that has been used the piezoelectric driving, and still has the same efficiency.

  5. Optical Nanofiber Integrated into Optical Tweezers for In Situ Fiber Probing and Optical Binding Studies

    Directory of Open Access Journals (Sweden)

    Ivan Gusachenko

    2015-07-01

    Full Text Available Precise control of particle positioning is desirable in many optical propulsion and sorting applications. Here, we develop an integrated platform for particle manipulation consisting of a combined optical nanofiber and optical tweezers system. We show that consistent and reversible transmission modulations arise when individual silica microspheres are introduced to the nanofiber surface using the optical tweezers. The observed transmission changes depend on both particle and fiber diameter and can be used as a reference point for in situ nanofiber or particle size measurement. Thence, we combine scanning electron microscope (SEM size measurements with nanofiber transmission data to provide calibration for particle-based fiber assessment. This integrated optical platform provides a method for selective evanescent field manipulation of micron-sized particles and facilitates studies of optical binding and light-particle interaction dynamics.

  6. Identification of individual biofilm-forming bacterial cells using Raman tweezers

    Science.gov (United States)

    Samek, Ota; Bernatová, Silvie; Ježek, Jan; Šiler, Martin; Šerý, Mojmir; Krzyžánek, Vladislav; Hrubanová, Kamila; Zemánek, Pavel; Holá, Veronika; Růžička, Filip

    2015-05-01

    A method for in vitro identification of individual bacterial cells is presented. The method is based on a combination of optical tweezers for spatial trapping of individual bacterial cells and Raman microspectroscopy for acquisition of spectral "Raman fingerprints" obtained from the trapped cell. Here, Raman spectra were taken from the biofilm-forming cells without the influence of an extracellular matrix and were compared with biofilm-negative cells. Results of principal component analyses of Raman spectra enabled us to distinguish between the two strains of Staphylococcus epidermidis. Thus, we propose that Raman tweezers can become the technique of choice for a clearer understanding of the processes involved in bacterial biofilms which constitute a highly privileged way of life for bacteria, protected from the external environment.

  7. Computational toolbox for optical tweezers in geometrical optics

    CERN Document Server

    Callegari, Agnese; Gököz, A Burak; Volpe, Giovanni

    2014-01-01

    Optical tweezers have found widespread application in many fields, from physics to biology. Here, we explain in detail how optical forces and torques can be described within the geometrical optics approximation and we show that this approximation provides reliable results in agreement with experiments for particles whose characteristic dimensions are larger than the wavelength of the trapping light. Furthermore, we provide an object-oriented software package implemented in MatLab for the calculation of optical forces and torques in the geometrical optics regime: \\texttt{OTGO - Optical Tweezers in Geometrical Optics}. We provide all source codes for \\texttt{OTGO} as well as the documentation and code examples -- e.g., standard optical tweezers, optical tweezers with elongated particle, windmill effect, Kramers transitions between two optical traps -- necessary to enable users to effectively employ it in their research and teaching.

  8. Nanofabrication of Hybrid Optoelectronic Devices

    OpenAIRE

    Dibos, Alan

    2015-01-01

    The material requirements for optoelectronic devices can vary dramatically depending on the application. Often disparate material systems need to be combined to allow for full device functionality. At the nanometer scale, this can often be challenging because of the inherent chemical and structural incompatibilities of nanofabrication. This dissertation concerns the integration of seemingly dissimilar materials into hybrid optoelectronic devices for photovoltaic, plasmonic, and photonic appli...

  9. Radiation effects in optoelectronic devices

    International Nuclear Information System (INIS)

    Purpose of this report is to provide not only a summary of radiation damage studies at Sandia National Laboratories, but also of those in the literature on the components of optoelectronic systems: light emitting diodes (LEDs), laser diodes, photodetectors, optical fibers, and optical isolators. This review of radiation damage in optoelectronic components is structured according to device type. In each section, a brief discussion of those device properties relevant to radiation effects is given

  10. Single Bessel tractor-beam tweezers

    CERN Document Server

    Mitri, F G

    2014-01-01

    The tractor behavior of a zero-order Bessel acoustic beam acting on a fluid sphere, and emanating from a finite circular aperture (as opposed to waves of infinite extent) is demonstrated theoretically. Conditions for an attractive force acting in opposite direction of the radiating waves, determined by the choice of the beam's half-cone angle, the size of the radiator, and its distance from a fluid sphere, are established and discussed. Numerical predictions for the radiation force function, which is the radiation force per unit energy density and cross-sectional surface, are provided using a partial-wave expansion method stemming from the acoustic scattering. The results suggest a simple and reliable analysis for the design of Bessel beam acoustical tweezers and tractor beam devices.

  11. Optical tweezers for studying taxis in parasites

    International Nuclear Information System (INIS)

    In this work we present a methodology to measure force strengths and directions of living parasites with an optical tweezers setup. These measurements were used to study the parasites chemotaxis in real time. We observed behavior and measured the force of: (i) Leishmania amazonensis in the presence of two glucose gradients; (ii) Trypanosoma cruzi in the vicinity of the digestive system walls, and (iii) Trypanosoma rangeli in the vicinity of salivary glands as a function of distance. Our results clearly show a chemotactic behavior in every case. This methodology can be used to study any type of taxis, such as chemotaxis, osmotaxis, thermotaxis, phototaxis, of any kind of living microorganisms. These studies can help us to understand the microorganism sensory systems and their response function to these gradients

  12. Tunable optical tweezers for wavelength-dependent measurements

    OpenAIRE

    Hester, Brooke; Campbell, Gretchen K.; López-Mariscal, Carlos; Filgueira, Carly Levin; Huschka, Ryan; Halas, Naomi J.; Helmerson, Kristian

    2012-01-01

    Optical trapping forces depend on the difference between the trap wavelength and the extinction resonances of trapped particles. This leads to a wavelength-dependent trapping force, which should allow for the optimization of optical tweezers systems, simply by choosing the best trapping wavelength for a given application. Here we present an optical tweezer system with wavelength tunability, for the study of resonance effects. With this system, the optical trap stiffness is measured for single...

  13. Miniaturized Optical Tweezers Through Fiber-End Microfabrication

    KAUST Repository

    Liberale, Carlo

    2014-07-30

    Optical tweezers represent a powerful tool for a variety of applications both in biology and in physics, and their miniaturization and full integration is of great interest so as to reduce size (towards portable systems), and to minimize the required intervention from the operator. Optical fibers represent a natural solution to achieve this goal, and here we review the realization of single-fiber optical tweezers able to create a purely optical three-dimensional trap. © Springer International Publishing Switzerland 2015.

  14. Control and Manipulation of Cold Atoms in Optical Tweezers

    OpenAIRE

    Muldoon, Cecilia; Brandt, Lukas; Dong, Jian; Stuart, Dustin; Brainis, Edouard; Himsworth, Matthew; Kuhn, Axel

    2011-01-01

    Neutral atoms trapped by laser light are amongst the most promising candidates for storing and processing information in a quantum computer or simulator. The application certainly calls for a scalable and flexible scheme for addressing and manipulating the atoms. We have now made this a reality by implementing a fast and versatile method to dynamically control the position of neutral atoms trapped in optical tweezers. The tweezers result from a spatial light modulator (SLM) controlling and sh...

  15. Plasmonic layers based on Au-nanoparticle-doped TiO2 for optoelectronics: structural and optical properties

    International Nuclear Information System (INIS)

    The anti-reflective effect of dielectric coatings used in silicon solar cells has traditionally been the subject of intensive studies and practical applications. In recent years the interest has permanently grown in plasmonic layers based on metal nanoparticles, which are shown to increase light trapping in the underlying silicon. In the present work we have combined these two concepts by means of in situ synthesis of Au nanoparticles in a dielectric matrix (TiO2), which is commonly used as an anti-reflective coating in silicon solar cells, and added the third element: a 10–20% porosity in the matrix. The porosity is formed by means of a controllable wet etching by low concentration HF. As a consequence, the experimentally measured reflectance of silicon coated by such a plasmonic layer decreases to practically zero in a broad wavelength region around the localized surface plasmon resonance. Furthermore, we demonstrate that extinction and reflectance spectra of silicon coated by the plasmonic films can be successfully accounted for by means of Fresnel formulae, in which a double refractive index of the metal–dielectric material is used. This double refractive index cannot be explained by effective medium theory (Maxwell–Garnett, for example) and appears when the contribution of Au nanoparticles located at the TiO2/Si interface is high enough to result in formation of interface surface plasmon modes. (paper)

  16. Opto-electronic properties of a TiO2/PS/mc-Si heterojunction based solar cell

    Science.gov (United States)

    Janene, N.; Ghrairi, N.; Allagui, A.; Alawadhi, H.; Khakani, M. A. El; Bessais, B.; Gaidi, M.

    2016-04-01

    In this work, we show the results of our investigation on the photoelectric properties of heterojunction solar cells based on Au/PS/mc-Si/Al and Au/TiO2/PS/mc-Si/Al structures. Porous silicon (PS) were prepared by an electrochemical etching process with different values of current density. The surface porosity was found to increase with the increase of current density. Pulsed laser deposition was used to deposit 80 nm TiO2 thin films. Surface morphology and structural properties of TiO2/PS were characterized by using scanning electron microscopy (SEM) and atomic force microscopy (AFM). An enhancement of the electrical properties of the TiO2/PS/mc-Si heterojunction was observed after coating with TiO2. As a consequence, the solar cell efficiencies increased from 1.4% for the uncoated PS/mc-Si structure to 5% for the TiO2 coated one. Impedance spectroscopy confirmed the passivation effect of TiO2 through the improvement of the elaborated cells' electron lifetime and the formation of a TiO2/PS/Au heterojunction with the appearance of a second semi-circle in the Nyquist plot.

  17. A theoretical study of the feasibility of acoustical tweezers: Ray acoustics approach

    Science.gov (United States)

    Lee, Jungwoo; Ha, Kanglyeol; Shung, K. Kirk

    2005-05-01

    The optical tweezer has been found to have many biomedical applications in trapping macromolecules and cells. For the trapping mechanism, there has to be a sharp spatial change in axial optical intensity and the particle size must be much greater than the wavelength. Similar phenomenon may exist in acoustics. This work was undertaken to demonstrate theoretically that it is possible to acoustically trap particles near the focal point where most of the acoustic energy is concentrated if certain conditions are met. Acoustic force exerted on a fluid particle in ultrasonic fields is analyzed in a ray acoustics regime where the wavelength of acoustic beam is much smaller than the size of the particle. In order to apply the acoustical tweezer to manipulating macromolecules and cells whose size is in the order of a few microns or less, a prerequisite is that the ultrasound wavelength has to be much smaller than a few microns. In this paper, the analysis is therefore based on the field pattern produced by a strongly focused 100 MHz ultrasonic transducer with Gaussian intensity distribution. For the realization of acoustic trapping, negative axial radiation force has to be generated to pull a particle towards a focus. The fat particle considered for acoustic trapping in this paper has an acoustic impedance of 1.4 MRayls. The magnitude of the acoustic axial radiation force that has been calculated as the size of the fat particle is varied from 8λ to 14λ. In addition, both Fresnel coefficients at various positions are also calculated to assess the interaction of reflection and refraction and their relative contribution to the effect of the acoustical tweezer. The simulation results show that the feasibility of the acoustical tweezer depends on both the degree of acoustic impedance mismatch and the degree of focusing relative to the particle size. .

  18. Optoelectronic memory using two-dimensional materials.

    Science.gov (United States)

    Lei, Sidong; Wen, Fangfang; Li, Bo; Wang, Qizhong; Huang, Yihan; Gong, Yongji; He, Yongmin; Dong, Pei; Bellah, James; George, Antony; Ge, Liehui; Lou, Jun; Halas, Naomi J; Vajtai, Robert; Ajayan, Pulickel M

    2015-01-14

    An atomically thin optoelectronic memory array for image sensing is demonstrated with layered CuIn7Se11 and extended to InSe and MoS2 atomic layers. Photogenerated charge carriers are trapped and subsequently retrieved from the potential well formed by gating a 2D material with Schottky barriers. The atomically thin layered optoelectronic memory can accumulate photon-generated charges during light exposure, and the charges can be read out later for data processing and permanent storage. An array of atomically thin image memory pixels was built to illustrate the potential of fabricating large-scale 2D material-based image sensors for image capture and storage. PMID:25517502

  19. Quantum dot optoelectronic devices: lasers, photodetectors and solar cells

    International Nuclear Information System (INIS)

    Nanometre-scale semiconductor devices have been envisioned as next-generation technologies with high integration and functionality. Quantum dots, or the so-called ‘artificial atoms’, exhibit unique properties due to their quantum confinement in all 3D. These unique properties have brought to light the great potential of quantum dots in optoelectronic applications. Numerous efforts worldwide have been devoted to these promising nanomaterials for next-generation optoelectronic devices, such as lasers, photodetectors, amplifiers, and solar cells, with the emphasis on improving performance and functionality. Through the development in optoelectronic devices based on quantum dots over the last two decades, quantum dot devices with exceptional performance surpassing previous devices are evidenced. This review describes recent developments in quantum dot optoelectronic devices over the last few years. The paper will highlight the major progress made in 1.3 μm quantum dot lasers, quantum dot infrared photodetectors, and quantum dot solar cells. (topical review)

  20. 基于可调谐真相移的可调谐光电振荡器%A tunable optoelectronic oscillator based on tunable true phase shift

    Institute of Scientific and Technical Information of China (English)

    魏志虎; 王荣; 方涛; 蒲涛; 甄飞; 孙帼丹; 陈寅芳

    2013-01-01

    A novel wideband tunable optoelectronic oscillator (OEO) based on the tunable true phae shift is proposed in this paper. A two-tap photonic microwave filter with a tunable complex coefficient and a real coefficient is constructed using double lasers, double Mach-Zehnder modulators (MZMs) and two cascaded fiber Bragg gratings (FBGs). The complex coefficient is realized by the true phae shifter,and the real coefficient can be controlled by the optical power. The reconfiguration of the photonic microwave filter is realized by adjusting the bias voltage applied on the MZM. When the system is closed,a microwave frquency will oscillate around the peak frequency of the bandpass filter,the long fiber will decrease the phae noise of the microwave signal,and the short fiber will increase the mode spacing to keep a single mode oscillating in the loop. The peak frequency of the filter can be tuned by changing the bias voltage according to the need of OEO. As a result,the output frequency of OEO can be tuned from 5 GHz to 10 GHz,the tunability range is large but the method is simple.%提出一种基于真相移(TPS)实现可调谐光电振荡器(OEO)的方案.只需通过调谐Mach-Zehnder调制器(MZM)的偏置电压,就可以实现可谐滤波器的频谱响应的改变,即可实现TPS滤波器.其中,两个抽头的可调谐滤波器是由双光源、双调制器以及叠印光栅来实现.OEO的输出频率由二抽头可调谐滤波器的峰值频率决定,而滤波器可调谐,这样就可以实现输出OEO的输出频率可调.仿真结果表明,输出频率可以实现5~10 GHz宽带宽可调谐.

  1. Constructing Dual Beam Optical Tweezers for Undergraduate Biophysics Research

    Science.gov (United States)

    Daudelin, Brian; West-Coates, Devon; Del'Etoile, Jon; Grotzke, Eric; Paramanathan, Thayaparan

    Optical tweezing, or trapping, is a modern physics technique which allows us to use the radiation pressure from laser beams to trap micron sized particles. Optical tweezers are commonly used in graduate level biophysics research but seldom used at the undergraduate level. Our goal is to construct a dual beam optical tweezers for future undergraduate biophysical research. Dual beam optical tweezers use two counter propagating laser beams to provide a stronger trap. In this study we discuss how the assembly of the dual beam optical tweezers is done through three main phases. The first phase was to construct a custom compressed air system to isolate the optical table from the vibrations from its surroundings so that we can measure pico-newton scale forces that are observed in biological systems. In addition, the biomaterial flow system was designed with a flow cell to trap biomolecules by combining several undergraduate semester projects. During the second phase we set up the optics to image and display the inside of the flow cell. Currently we are in the process of aligning the laser to create an effective trap and developing the software to control the data collection. This optical tweezers set up will enable us to study potential cancer drug interactions with DNA at the single molecule level and will be a powerful tool in promoting interdisciplinary research at the undergraduate level.

  2. How safe is gamete micromanipulation by laser tweezers?

    Science.gov (United States)

    Koenig, Karsten; Tromberg, Bruce J.; Tadir, Yona; Berns, Michael W.

    1998-04-01

    Laser tweezers, used as novel sterile micromanipulation tools of living cells, are employed in laser-assisted in vitro fertilization (IVF). For example, controlled spermatozoa transport with 1064 nm tweezers to human egg cells has been performed in European clinics in cases of male infertility. The interaction of approximately 100 mW near infrared (NIR) trapping beams at MW/cm2 intensity with human gametes results in low mean less than 2 K temperature increases and less than 100 pN trapping forces. Therefore, photothermal or photomechanical induced destructive effects appear unlikely. However, the high photon flux densities may induce simultaneous absorption of two NIR photons resulting in nonlinear interactions. These nonlinear interactions imply non-resonant two-photon excitation of endogenous cellular chromophores. In the case of less than 800 nm tweezers, UV- like damage effects may occur. The destructive effect is amplified when multimode cw lasers are used as tweezer sources due to longitudinal mode-beating effects and partial mode- locking. Spermatozoa damage within seconds using 760 nm traps due to formation of unstable ps pulses in a cw Ti:Sa ring laser is demonstrated. We recommend the use of greater than or equal to 800 nm traps for optical gamete micromanipulation. To our opinion, further basic studies on the influence of nonlinear effects of laser tweezers on human gamete are necessary.

  3. Traceable assembly of microparts using optical tweezers

    International Nuclear Information System (INIS)

    Assembly of components with a size in the order of tens of micrometers or less is difficult because the gravitational forces become smaller than weak forces such as capillary, electrostatic and van der Waals forces. As such, the picked-up components commonly adhere to the manipulator, making the release operation troublesome, and the repeatable supply of components cannot be guaranteed because the magazining and bunkering scheme available in conventional scale assembly cannot be extended to these small objects. Moreover, there are also no effective ways known to deliver the finalized assembly externally. In this paper, we present the manipulation and assembly of microparts using optical tweezers, which by nature do not have stiction problems. Techniques allowing bunkering and finalizing the assembly for exporting are also presented. Finally, we demonstrate an exemplary microassembly formed by assembling two microparts: a movable microring and a microrod fixed on a glass substrate. We believe this traceable microassembly to be an important step forward for micro- and nano-manufacturing. (paper)

  4. Low frequency dynamical stabilisation in optical tweezers

    Science.gov (United States)

    Richards, Christopher J.; Smart, Thomas J.; Jones, Philip H.; Cubero, David

    2015-08-01

    It is well known that a rigid pendulum with minimal friction will occupy a stable equilibrium position vertically upwards when its suspension point is oscillated at high frequency. The phenomenon of the inverted pendulum was explained by Kapitza by invoking a separation of timescales between the high frequency modulation and the much lower frequency pendulum motion, resulting in an effective potential with a minimum in the inverted position. We present here a study of a microscopic optical analogue of Kapitza's pendulum that operates in different regimes of both friction and driving frequency. The pendulum is realized using a microscopic particle held in a scanning optical tweezers and subject to a viscous drag force. The motion of the optical pendulum is recorded and analyzed by digital video microscopy and particle tracking to extract the trajectory and stable orientation of the particle. In these experiments we enter the regime of low driving frequency, where the period of driving is comparable to the characteristic relaxation time of the radial motion of the pendulum with finite stiffness. In this regime we find stabilization of the pendulum at angles other than the vertical (downwards) is possible for modulation amplitudes exceeding a threshold value where, unlike the truly high frequency case studied previously, both the threshold amplitude and equilibrium position are found to be functions of friction. Experimental results are complemented by an analytical theory for induced stability in the low frequency driving regime with friction.

  5. Organic ferroelectric opto-electronic memories

    Directory of Open Access Journals (Sweden)

    Kamal Asadi

    2011-12-01

    Full Text Available Memory is a prerequisite for many electronic devices. Organic non-volatile memory devices based on ferroelectricity are a promising approach towards the development of a low-cost memory technology based on a simple cross-bar array. In this review article we discuss the latest developments in this area with a focus on the most promising opto-electronic device concept, i.e., bistable rectifying diodes. The integration of these diodes into larger memory arrays is discussed. Through a clever design of the electrodes we demonstrate light emitting diodes with integrated built-in switches that can be applied in signage applications.

  6. Multiplexed single-molecule measurements with magnetic tweezers

    International Nuclear Information System (INIS)

    We present a method for performing multiple single-molecule manipulation experiments in parallel with magnetic tweezers. We use a microscope with a low magnification, and thus a wide field of view, to visualize multiple DNA-tethered paramagnetic beads and apply an optimized image analysis routine to track the three-dimensional position of each bead simultaneously in real time. Force is applied to each bead using an externally applied magnetic field. Since variations in the field parameters are negligible across the field of view, nearly identical manipulation of all visible beads is possible. However, we find that the error in the position measurement is inversely proportional to the microscope's magnification. To mitigate the increased error caused by demagnification, we have developed a strategy based on tracking multiple fixed beads. Our system is capable of simultaneously manipulating and tracking up to 34 DNA-tethered beads at 60 Hz with ∼1.5 nm resolution and with ∼10% variation in applied force.

  7. A new real non-invasive single fiber tweezers

    Science.gov (United States)

    Zhang, Yu; Liu, Zhihai; Yang, Jun; Yuan, Libo

    2012-02-01

    A new real non-invasive two-core single fiber optical tweezers is proposed and fabricated by fiber grinding and polishing technology. The yeast cells trapping performance of this special designed truncated cone tip fiber probe is demonstrated and investigated. The distributions of the optical field emerging from the truncated cone fiber tip are simulated by Beam Prop Method. Both axial and transverse trapping forces are calculated by FDTD method. This new optical tweezers can realize truly non-invasive remote trapping and manipulating bio-cells.

  8. Optical tweezers reveal how proteins alter replication

    Science.gov (United States)

    Chaurasiya, Kathy

    Single molecule force spectroscopy is a powerful method that explores the DNA interaction properties of proteins involved in a wide range of fundamental biological processes such as DNA replication, transcription, and repair. We use optical tweezers to capture and stretch a single DNA molecule in the presence of proteins that bind DNA and alter its mechanical properties. We quantitatively characterize the DNA binding mechanisms of proteins in order to provide a detailed understanding of their function. In this work, we focus on proteins involved in replication of Escherichia coli (E. coli ), endogenous eukaryotic retrotransposons Ty3 and LINE-1, and human immunodeficiency virus (HIV). DNA polymerases replicate the entire genome of the cell, and bind both double-stranded DNA (dsDNA) and single-stranded DNA (ssDNA) during DNA replication. The replicative DNA polymerase in the widely-studied model system E. coli is the DNA polymerase III subunit alpha (DNA pol III alpha). We use optical tweezers to determine that UmuD, a protein that regulates bacterial mutagenesis through its interactions with DNA polymerases, specifically disrupts alpha binding to ssDNA. This suggests that UmuD removes alpha from its ssDNA template to allow DNA repair proteins access to the damaged DNA, and to facilitate exchange of the replicative polymerase for an error-prone translesion synthesis (TLS) polymerase that inserts nucleotides opposite the lesions, so that bacterial DNA replication may proceed. This work demonstrates a biophysical mechanism by which E. coli cells tolerate DNA damage. Retroviruses and retrotransposons reproduce by copying their RNA genome into the nuclear DNA of their eukaryotic hosts. Retroelements encode proteins called nucleic acid chaperones, which rearrange nucleic acid secondary structure and are therefore required for successful replication. The chaperone activity of these proteins requires strong binding affinity for both single- and double-stranded nucleic

  9. Optoelectronic Receiver For Communication And Control

    Science.gov (United States)

    Kunath, Richard; Bendett, Mark; Mactaggart, I. Ross

    1994-01-01

    Many operational and diagnostic features integrated into circuit chip. GaAs-based integrated circuit designed to serve as optoelectronic interface in phased-array antenna. Intended function to receive digital control signals transmitted on optical fiber and to convert signals to electronic control signals, which then applied to monolithic microwave integrated circuit (MMIC). Also used in reception of high-rate optical digital communications within computers, between computers, and in signal-distribution systems in aircraft, automobiles, and ships. Interface circuit represents significant improvement over preexisting interface circuits in that its clock-signal-recovery subcircuit requires little or no preamble for immediate synchronization.

  10. Focused Ion Beam Technology for Optoelectronic Devices

    Science.gov (United States)

    Reithmaier, J. P.; Bach, L.; Forchel, A.

    2003-08-01

    High-resolution proximity free lithography was developed using InP as anorganic resist for ion beam exposure. InP is very sensitive on ion beam irradiation and show a highly nonlinear dose dependence with a contrast function comparable to organic electron beam resists. In combination with implantation induced quantum well intermixing this new lithographic technique based on focused ion beams is used to realize high performance nano patterned optoelectronic devices like complex coupled distributed feedback (DFB) and distributed Bragg reflector (DBR) lasers.

  11. Organic 'Plastic' Optoelectronic Devices

    International Nuclear Information System (INIS)

    Recent developments on conjugated polymer based photovoltaic diodes and photoactive organic field effect transistors (photOFETs) are discussed. The photophysics of such devices is based on the photoinduced charge transfer from donor type semiconducting conjugated polymers onto acceptor type conjugated polymers or acceptor molecules such as Buckminsterfullerene, C60. Potentially interesting applications include sensitization of the photoconductivity and photovoltaic phenomena as well as photoresponsive organic field effect transistors (photOFETs). Furthermore, organic polymeric/inorganic nanoparticle based 'hybrid' solar cells will be discussed. This talk gives an overview of materials' aspect, charge-transport, and device physics of organic diodes and field-effect transistors. Furthermore, due to the compatibility of carbon/hydrogen based organic semiconductors with organic biomolecules and living cells there can be a great opportunity to integrate such organic semiconductor devices (biOFETs) with the living organisms. In general the largely independent bio/lifesciences and information technology of today, can be thus bridged in an advanced cybernetic approach using organic semiconductor devices embedded in bio-lifesciences. This field of bio-organic electronic devices is proposed to be an important mission of organic semiconductor devices

  12. Mid-infrared Semiconductor Optoelectronics

    CERN Document Server

    Krier, Anthony

    2006-01-01

    The practical realisation of optoelectronic devices operating in the 2–10 µm (mid-infrared) wavelength range offers potential applications in a variety of areas from environmental gas monitoring around oil rigs and landfill sites to the detection of pharmaceuticals, particularly narcotics. In addition, an atmospheric transmission window exists between 3 µm and 5 µm that enables free-space optical communications, thermal imaging applications and the development of infrared measures for "homeland security". Consequently, the mid-infrared is very attractive for the development of sensitive optical sensor instrumentation. Unfortunately, the nature of the likely applications dictates stringent requirements in terms of laser operation, miniaturisation and cost that are difficult to meet. Many of the necessary improvements are linked to a better ability to fabricate and to understand the optoelectronic properties of suitable high-quality epitaxial materials and device structures. Substantial progress in these m...

  13. III-Nitride nanowire optoelectronics

    Science.gov (United States)

    Zhao, Songrui; Nguyen, Hieu P. T.; Kibria, Md. G.; Mi, Zetian

    2015-11-01

    Group-III nitride nanowire structures, including GaN, InN, AlN and their alloys, have been intensively studied in the past decade. Unique to this material system is that its energy bandgap can be tuned from the deep ultraviolet (~6.2 eV for AlN) to the near infrared (~0.65 eV for InN). In this article, we provide an overview on the recent progress made in III-nitride nanowire optoelectronic devices, including light emitting diodes, lasers, photodetectors, single photon sources, intraband devices, solar cells, and artificial photosynthesis. The present challenges and future prospects of III-nitride nanowire optoelectronic devices are also discussed.

  14. Quantitative characterization for dielectrophoretic behavior of biological cells using optical tweezers

    Science.gov (United States)

    Park, In Soo; Hee Park, Se; Woo Lee, Sang; Sung Yoon, Dae; Kim, Beop-Min

    2014-02-01

    We report a method to precisely quantify dielectrophoretic (DEP) forces and cutoff frequencies (fc) of viable and nonviable yeast cells. The method consists of a two-step process in which generated DEP forces act upon a cell through a micro-electrode device, followed by direct measurement of DEP forces using optical tweezers. DEP behaviors of viable and nonviable yeast cells are monitored as a function of AC frequency. We believe that the proposed method can be used as a powerful platform for cell-based assays to characterize the DEP behavior of various cell types including cancer and normal cells.

  15. Interfacial structure in organic optoelectronics

    OpenAIRE

    Turak, Ayse; Grozea, Dan; Huang, Chanjun; Lu, Zheng-Hong

    2012-01-01

    The interfacial structure plays a critical role in modern optoelectronics. Currently multilayer electrodes are used to optimize the injection and lifetime properties. The choice of interlayer is not universal, with different effects for the same material with different capping metals. Using a novel in-situ characterization method with X-ray photoelectron spectroscopy, the organic/inorganic interface in OLEDs was examined for two common cathode metals with a LiF interlayer. The impact of the i...

  16. Packaging investigation of optoelectronic devices

    Science.gov (United States)

    Zhike, Zhang; Yu, Liu; Jianguo, Liu; Ninghua, Zhu

    2015-10-01

    Compared with microelectronic packaging, optoelectronic packaging as a new packaging type has been developed rapidly and it will play an essential role in optical communication. In this paper, we try to summarize the development history, research status, technology issues and future prospects, and hope to provide a meaningful reference. Project supported by the National High Technology Research and Development Program of China (Nos. 2013AA014201, 2013AA014203) and the National Natural Science Foundation of China (Nos. 61177080, 61335004, 61275031).

  17. Two- and three-beam interferometric optical tweezers

    Czech Academy of Sciences Publication Activity Database

    Casaburi, A.; Pesce, G.; Zemánek, Pavel; Sasso, A.

    2005-01-01

    Roč. 251, 4-6 (2005), s. 393-404. ISSN 0030-4018 R&D Projects: GA AV ČR(CZ) IAA1065203 Keywords : Optical force * Mie particle * Interferometric optical tweezers * Optical trapping Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.456, year: 2005

  18. Fiber remote and real time optoelectronic dosimetry based on the optically stimulated luminescence phenomenon: Development of sensors based on aluminium oxide doped with carbon for applications in personal dosimetry

    International Nuclear Information System (INIS)

    An optical fiber sensor based on the use of classical technologies (optoelectronic, laser, optical fibers,...) can be connected to the Optically Stimulated Luminescence properties (or OSL) of the aluminium oxide doped with carbon in order to provide several new capabilities compared to usual dosimeters: remote dose measurements, quasi 'real time' dose measurements, applied to personal dosimetry thanks to a low fading level at room temperature. This thesis work shows the studies about: 1)the state of the art about dosimetry based on the aluminium oxide doped with carbon and its OSL properties (emission and stimulation spectra, glow curves, trap and recombination energy levels,...), 2)the state of the art about international standardization, not only, with regard to personal dosimetry (IEC 61066 Standard) but also to the description of operational quantities called personal dose equivalent Hp(10) and Hp(0,07), 3)the experimental development of a new sensor device based on aluminium oxide crystals (design, realization, tests,...), 4)the application of statistical Monte Carlo calculation methods (code MCNP4B) to the simulation of the sensor head in accordance with the IEC Standard 61066 with regard to the energy and angular response Hp(10). (author)

  19. Fabrication and optoelectronic properties of novel films based on functionalized multiwalled carbon nanotubes and (phthalocyaninato)ruthenium(II) via coordination bonded layer-by-layer self-assembly.

    Science.gov (United States)

    Zhao, Wei; Tong, Bin; Shi, Jianbing; Pan, Yuexiu; Shen, Jinbo; Zhi, Junge; Chan, Wai Kin; Dong, Yuping

    2010-10-19

    4-(2-(4-pyridinyl)Ethynyl)benzenic diazonium salt (PBD) was used to modify multiwalled carbon nanotubes (MWCNTs) by the self-assembly technique. After the decomposition of the diazonium group in PBD under UV irradiation, the PBD monolayer film covalently anchored on multiwalled carbon nanotubes is very stable. The obtained pyridine-modified MWCNTs (Py(Ar)-MWCNTs) have good solubility in common organic solvents. Furthermore, the layer-by-layer (LBL) self-assembled fully conjugated films of Py(Ar)-MWCNTs and (phthalocyaninato)ruthenium(II) (RuPc) were fabricated on the PBD-modified substrates, and characterized using UV-vis absorption spectroscopy, scanning electron microscopy (SEM), and electrochemistry. The UV-vis analysis results indicate that the LBL RuPc/Py(Ar)-MWCNTs self-assembled multilayer films with axial ligands between the ruthenium atom and pyridine group were successfully fabricated, and the progressive assembly runs regularly with almost equal amounts of deposition in each cycle. A top view SEM image shows a random and homogeneous distribution of Py(Ar)-MWCNTs over the PBD-modified silicon substrate, which indicates well independence between all Py(Ar)-MWCNTs. Moreover, the opto-electronic conversion was also studied by assembling RuPc/Py(Ar)-MWCNTs multilayer films on PBD-modified ITO substrate. Under illumination, the LBL self-assembled films on ITO showed an effective photoinduced charge transfer because of their conjugated structure and the ITO current density changed with the number of bilayer. As the number of bilayers was increased, the photocurrent increases and reaches its maximum value (∼300 nA/cm(2)) at nine bilayers. These results allow us to design novel materials for applications in optoelectronic devices by using LBL self-assembly techniques. PMID:20853832

  20. Polymeric optoelectronic interconnects

    Science.gov (United States)

    Eldada, Louay A.

    2000-04-01

    Electrical interconnects are reaching their fundamental limits and are becoming the speed bottleneck as processor speeds are increasing. A polymer-based interconnect technology was developed for affordable integrated optical circuits that address the optical signal processing needs in the telecom, datacom, and performance computing industries. We engineered organic polymers that can be readily made into single-mode, multimode, and micro-optical waveguide structures of controlled numerical apertures and geometries. These materials are formed from highly-crosslinked acrylate monomers with specific linkages that determine properties such as flexibility, robustness, optical loss, thermal stability, and humidity resistance. These monomers are intermiscible, providing for precise continuous adjustment of the refractive index over a wide range. In polymer form, they exhibit state-of-the-art loss values and exceptional environmental stability, enabling use in a variety of demanding applications. A wide range of rigid and flexible substrates can be used, including glass, quartz, silicon, glass-filled epoxy printed circuit board substrates, and flexible plastic films. The devices we describe include a variety of routing elements that can be sued as part of a massively parallel photonic integrated circuit on the MCM, board, or backplane level.

  1. Scanning probe and optical tweezer investigations of biomolecular interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rigby-Singleton, Shellie

    2002-07-01

    A complex array of intermolecular forces controls the interactions between and within biological molecules. The desire to empirically explore the fundamental forces has led to the development of several biophysical techniques. Of these, the atomic force microscope (AFM) and the optical tweezers have been employed throughout this thesis to monitor the intermolecular forces involved in biomolecular interactions. The AFM is a well-established force sensing technique capable of measuring biomolecular interactions at a single molecule level. However, its versatility has not been extrapolated to the investigation of a drug-enzyme complex. The energy landscape for the force induced dissociation of the DHFR-methotrexate complex was studied. Revealing an energy barrier to dissociation located {approx}0.3 nm from the bound state. Unfortunately, the AFM has a limited range of accessible loading rates and in order to profile the complete energy landscape alternative force sensing instrumentation should be considered, for example the BFP and optical tweezers. Thus, this thesis outlines the development and construction an optical trap capable of measuring intermolecular forces between biomolecules at the single molecule level. To demonstrate the force sensing abilities of the optical set up, proof of principle measurements were performed which investigate the interactions between proteins and polymer surfaces subjected to varying degrees of argon plasma treatment. Complementary data was gained from measurements performed independently by the AFM. Changes in polymer resistance to proteins as a response to changes in polymer surface chemistry were detected utilising both AFM and optical tweezers measurements. Finally, the AFM and optical tweezers were employed as ultrasensitive biosensors. Single molecule investigations of the antibody-antigen interaction between the cardiac troponin I marker and its complementary antibody, reveals the impact therapeutic concentrations of heparin

  2. Practical opto-electronics an illustrated guide for the laboratory

    CERN Document Server

    Protopopov, Vladimir

    2014-01-01

    This book explains how to create opto-electronic systems in a most efficient way, avoiding typical mistakes. It covers light detection techniques, imaging, interferometry, spectroscopy, modulation-demodulation, heterodyning, beam steering, and many other topics common to laboratory applications. The focus is made on self-explanatory figures rather than on words. The book guides the reader through the entire process of creating problem-specific opto-electronic systems, starting from optical source, through beam transportation optical arrangement, to photodetector and data acquisition system. The relevant basics of beam propagation and computer-based raytracing routines are also explained, and sample codes are listed. the book teaches important know-how and practical tricks that are never disclosed in scientific publications.  The book can become the reader's personal adviser in the world of opto-electronics and navigator in the ocean of the market of optical components and systems. Succinct, well-illustrate...

  3. Engineering heterojunctions with carbon nanostructures: towards high-performance optoelectronics

    Science.gov (United States)

    Wu, Judy Z.

    2015-08-01

    Low-dimensional carbon nanostructures such as nanotubes (CNTs) and graphene have excellent electronic, optoelectronic and mechanical properties, which provide fresh opportunities for designs of optoelectronic devices of extraordinary performance in addition to the benefits of low cost, large abundance, and light weight. This work investigates photodetectors made with CNTs and graphene with a particular focus on carbon-based nanohybrids aiming at a nanoscale control of photon absorption, exciton dissociation and charge transfer. Through several examples including graphene/GaSe-nanosheets, graphene/aligned ZnO nanorods, SWCNT/P3HT, and SWCNT/biomolecule, we show an atomic-scale control on the interfacial heterojunctions is the key to high responsivity and fast photoresponse in these nanohybrids optoelectronic devices.

  4. Integrated optoelectronic materials and circuits for optical interconnects

    International Nuclear Information System (INIS)

    Conventional interconnect and switching technology is rapidly becoming a critical issue in the realization of systems using high speed silicon and GaAs based technologies. In recent years clock speeds and on-chip density for VLSI/VHSIC technology has made packaging these high speed chips extremely difficult. A strong case can be made for using optical interconnects for on-chip/on-wafer, chip-to-chip and board-to-board high speed communications. GaAs integrated optoelectronic circuits (IOC's) are being developed in a number of laboratories for performing Input/Output functions at all levels. In this paper integrated optoelectronic materials, electronics and optoelectronic devices are presented. IOC's are examined from the standpoint of what it takes to fabricate the devices and what performance can be expected

  5. Optical nanofibre integrated into an optical tweezers for particle manipulation, in situ fibre probing, and optical binding studies

    CERN Document Server

    Gusachenko, Ivan; Frawley, Mary C; Chormaic, Síle Nic

    2015-01-01

    Precise control of particle positioning is desirable in many optical propulsion and sorting applications. Here, we develop an integrated platform for particle manipulation consisting of a combined optical nanofibre and optical tweezers system. Individual silica microspheres were introduced to the nanofibre at arbitrary points using the optical tweezers, thereby producing pronounced dips in the fibre transmission. We show that such consistent and reversible transmission modulations depend on both particle and fibre diameter, and can be used as a reference point for in situ nanofibre or particle size measurement. Thence, we combine scanning electron microscope (SEM) size measurements with nanofibre transmission data to provide calibration for particle-based fibre assessment. This integrated optical platform provides a method for selective evanescent field manipulation of micron-sized particles and facilitates studies of optical binding and light-particle interaction dynamics.

  6. Terahertz optoelectronics with surface plasmon polariton diode.

    Science.gov (United States)

    Vinnakota, Raj K; Genov, Dentcho A

    2014-01-01

    The field of plasmonics has experience a renaissance in recent years by providing a large variety of new physical effects and applications. Surface plasmon polaritons, i.e. the collective electron oscillations at the interface of a metal/semiconductor and a dielectric, may bridge the gap between electronic and photonic devices, provided a fast switching mechanism is identified. Here, we demonstrate a surface plasmon-polariton diode (SPPD) an optoelectronic switch that can operate at exceedingly large signal modulation rates. The SPPD uses heavily doped p-n junction where surface plasmon polaritons propagate at the interface between n and p-type GaAs and can be switched by an external voltage. The devices can operate at transmission modulation higher than 98% and depending on the doping and applied voltage can achieve switching rates of up to 1 THz. The proposed switch is compatible with the current semiconductor fabrication techniques and could lead to nanoscale semiconductor-based optoelectronics. PMID:24811083

  7. Lasers and optoelectronics fundamentals, devices and applications

    CERN Document Server

    Maini, Anil K

    2013-01-01

    With emphasis on the physical and engineering principles, this book provides a comprehensive and highly accessible treatment of modern lasers and optoelectronics. Divided into four parts, it explains laser fundamentals, types of lasers, laser electronics & optoelectronics, and laser applications, covering each of the topics in their entirety, from basic fundamentals to advanced concepts. Key features include: exploration of technological and application-related aspects of lasers and optoelectronics, detailing both existing and emerging applications in industry, medical diag

  8. Crosstalk elimination in the detection of dual-beam optical tweezers by spatial filtering

    Energy Technology Data Exchange (ETDEWEB)

    Ott, Dino; Oddershede, Lene B., E-mail: oddershede@nbi.dk [Niels Bohr Institute (NBI), University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen (Denmark); Reihani, S. Nader S. [Department of Physics, Sharif University of Technology, 11369-9161 Tehran (Iran, Islamic Republic of)

    2014-05-15

    In dual-beam optical tweezers, the accuracy of position and force measurements is often compromised by crosstalk between the two detected signals, this crosstalk leading to systematic and significant errors on the measured forces and distances. This is true both for dual-beam optical traps where the splitting of the two traps is done by polarization optics and for dual optical traps constructed by other methods, e.g., holographic tweezers. If the two traps are orthogonally polarized, most often crosstalk is minimized by inserting polarization optics in front of the detector; however, this method is not perfect because of the de-polarization of the trapping beam introduced by the required high numerical aperture optics. Here we present a simple and easy-to-implement method to efficiently eliminate crosstalk. The method is based on spatial filtering by simply inserting a pinhole at the correct position and is highly compatible with standard back focal plane photodiode based detection of position and force. Our spatial filtering method reduces crosstalk up to five times better than polarization filtering alone. The effectiveness is dependent on pinhole size and distance between the traps and is here quantified experimentally and reproduced by theoretical modeling. The method here proposed will improve the accuracy of force-distance measurements, e.g., of single molecules, performed by dual-beam optical traps and hence give much more scientific value for the experimental efforts.

  9. Crosstalk elimination in the detection of dual-beam optical tweezers by spatial filtering

    Science.gov (United States)

    Ott, Dino; Reihani, S. Nader S.; Oddershede, Lene B.

    2014-05-01

    In dual-beam optical tweezers, the accuracy of position and force measurements is often compromised by crosstalk between the two detected signals, this crosstalk leading to systematic and significant errors on the measured forces and distances. This is true both for dual-beam optical traps where the splitting of the two traps is done by polarization optics and for dual optical traps constructed by other methods, e.g., holographic tweezers. If the two traps are orthogonally polarized, most often crosstalk is minimized by inserting polarization optics in front of the detector; however, this method is not perfect because of the de-polarization of the trapping beam introduced by the required high numerical aperture optics. Here we present a simple and easy-to-implement method to efficiently eliminate crosstalk. The method is based on spatial filtering by simply inserting a pinhole at the correct position and is highly compatible with standard back focal plane photodiode based detection of position and force. Our spatial filtering method reduces crosstalk up to five times better than polarization filtering alone. The effectiveness is dependent on pinhole size and distance between the traps and is here quantified experimentally and reproduced by theoretical modeling. The method here proposed will improve the accuracy of force-distance measurements, e.g., of single molecules, performed by dual-beam optical traps and hence give much more scientific value for the experimental efforts.

  10. Stabilizing an optoelectronic microwave oscillator with photonic filters

    Science.gov (United States)

    Strekalov, D.; Aveline, D.; Yu, N.; Thompson, R.; Matsko, A. B.; Maleki, L.

    2003-01-01

    This paper compares methods of active stabilization of an optoelectronic microwave oscillator (OEO) based on insertion of a source of optical group delay into an OEO loop. The performance of an OEO stabilized with either a high- optical cavity or an atomic cell is analyzed. We show that the elements play a role of narrow-band microwave filters improving an OEO stability.

  11. Implementation of a 10.24 GS/s 12-bit Optoelectronics Analog-to- Digital Converter Based on a Polyphase Demultiplexing Architecture

    Directory of Open Access Journals (Sweden)

    C. Villa-Angulo

    2013-01-01

    Full Text Available In this paper we present the practical implementation of a high-speed polyphase sampling and demultiplexingarchitecture for optoelectronics analog-to-digital converters (OADCs. The architecture consists of a one-stage divideby-eight decimator circuit where optically-triggered samplers are cascaded to sample an analog input signal, anddemultiplex different phases of the sampled signal to yield low data rate for electronic quantization. Electrical-in toelectrical-out data format is maintained through the sampling, demultiplexing and quantization processes of thearchitecture thereby avoiding the need for electrical-to-optical and optical-to-electrical signal conversions. Weexperimentally demonstrate a 10.24 giga samples per second (GS/s, 12-bit resolution OADC system comprising theoptically-triggered sampling circuits integrated with commercial electronic quantizers. Measurements performed on theOADC yielded an effective bit resolution (ENOB of 10.3 bits, spurious free dynamic range (SFDR of -32 dB andsignal-to-noise and distortion ratio (SNDR of 63.7 dB.

  12. A theoretical study of the feasibility of acoustical tweezer: Ray acoustics approach

    Science.gov (United States)

    Lee, Jungwoo; Shung, Kirk

    2005-04-01

    Optical tweezer has been found to have many biomedical applications in trapping macromolecules and cells. For the trapping mechanism, there has to be a sharp spatial change in axial optical intensity and the particle size must be much greater than the wavelength. Similar phenomenon may exist in acoustics. This work was undertaken to demonstrate theoretically that it is possible to acoustically trap particles near the focal point if certain conditions are met. Acoustic force exerted on fat tissue in ultrasonic fields is analyzed in ray acoustics regime where the wavelength of acoustic beam is much smaller than the size of the particle. In this paper, the analysis is therefore based on the field pattern produced by a strongly focused 100 MHz ultrasonic transducer with Gaussian intensity distribution. The magnitude of force and Fresnel coefficients at various positions are calculated. According to the simulation results, acoustical tweezer works particularly when the beam width at focus is one wavelength and the tolerance of acoustic impedance mismatch between two media lies within 6.7%. [Work supported by NIH Grant P41-EB2182.

  13. Single-fiber tweezers applied for dye lasing in a fluid droplet.

    Science.gov (United States)

    Liu, Zhihai; Chen, Yunhao; Zhao, Li; Zhang, Yu; Wei, Yong; Li, Hanyang; Liu, Yongjun; Zhang, Yaxun; Zhao, Enming; Yang, Xinghua; Zhang, Jianzhong; Yuan, Libo

    2016-07-01

    We report on the first demonstration of a single-fiber optical tweezer that is utilized to stabilize and control the liquid droplet for dye lasing. In order to trap a liquid droplet with a diameter of 15-30 μm, an annular core micro-structured optical fiber is adopted. By using wavelength division multiplexing technology, we couple a trapping light source (980 nm) and a pumping light source (532 nm) into the annular core of the fiber to realize the trapping, controlling, and pumping of the oil droplet. We show that the laser emission spectrum tunes along the same size as the oil droplet. The lasing threshold of the oil droplet with the diameter of 24 μm is 0.7 μJ. The presented fiber-based optical manipulation of liquid droplet micro-lasers can be easily combined with the micro-fluidic chip technology and also may extend the application of optical fiber tweezers for micro-droplet lasing technology in the biological field. PMID:27367077

  14. Measurement of particle motion in optical tweezers embedded in a Sagnac interferometer.

    Science.gov (United States)

    Galinskiy, Ivan; Isaksson, Oscar; Salgado, Israel Rebolledo; Hautefeuille, Mathieu; Mehlig, Bernhard; Hanstorp, Dag

    2015-10-19

    We have constructed a counterpropagating optical tweezers setup embedded in a Sagnac interferometer in order to increase the sensitivity of position tracking for particles in the geometrical optics regime. Enhanced position determination using a Sagnac interferometer has previously been described theoretically by Taylor et al. [Journal of Optics 13, 044014 (2011)] for Rayleigh-regime particles trapped in an antinode of a standing wave. We have extended their theory to a case of arbitrarily-sized particles trapped with orthogonally-polarized counter-propagating beams. The working distance of the setup was sufficiently long to optically induce particle oscillations orthogonally to the axis of the tweezers with an auxiliary laser beam. Using these oscillations as a reference, we have experimentally shown that Sagnac-enhanced back focal plane interferometry is capable of providing an improvement of more than 5 times in the signal-to-background ratio, corresponding to a more than 30-fold improvement of the signal-to-noise ratio. The experimental results obtained are consistent with our theoretical predictions. In the experimental setup, we used a method of optical levitator-assisted liquid droplet delivery in air based on commercial inkjet technology, with a novel method to precisely control the size of droplets. PMID:26480368

  15. Enhanced cell sorting and manipulation with combined optical tweezer and microfluidic chip technologies.

    Science.gov (United States)

    Wang, Xiaolin; Chen, Shuxun; Kong, Marco; Wang, Zuankai; Costa, Kevin D; Li, Ronald A; Sun, Dong

    2011-11-01

    Sorting (or isolation) and manipulation of rare cells with high recovery rate and purity are of critical importance to a wide range of physiological applications. In the current paper, we report on a generic single cell manipulation tool that integrates optical tweezers and microfluidic chip technologies for handling small cell population sorting with high accuracy. The laminar flow nature of microfluidics enables the targeted cells to be focused on a desired area for cell isolation. To recognize the target cells, we develop an image processing methodology with a recognition capability of multiple features, e.g., cell size and fluorescence label. The target cells can be moved precisely by optical tweezers to the desired destination in a noninvasive manner. The unique advantages of this sorter are its high recovery rate and purity in small cell population sorting. The design is based on dynamic fluid and dynamic light pattern, in which single as well as multiple laser traps are employed for cell transportation, and a recognition capability of multiple cell features. Experiments of sorting yeast cells and human embryonic stem cells are performed to demonstrate the effectiveness of the proposed cell sorting approach. PMID:21918752

  16. Holographic optical tweezers: microassembling of shape-complementary 2PP building blocks

    Science.gov (United States)

    Ksouri, Sarah Isabelle; Mattern, Manuel; Köhler, Jannis; Aumann, Andreas; Zyla, Gordon; Ostendorf, Andreas

    2014-09-01

    Based on an ongoing trend in miniaturization and due to the increased complexity in MEMS-technology new methods of assembly need to be developed. Recent developments show that particularly optical forces are suitable to meet the requirements. The unique advantages of optical tweezers (OT) are attractive due to their contactless and precise manipulation forces. Spherical as well as non-spherical shaped pre-forms can already be assembled arbitrarily by using appropriate beam profiles generated by a spatial light modulator (SLM), resulting in a so called holographic optical tweezer (HOT) setup. For the fabrication of shape-complementary pre-forms, a two-photon-polymerization (2PP) process is implemented. The purpose of the process combination of 2PP and HOT is the development of an optical microprocessing platform for assembling arbitrary building blocks. Here, the optimization of the 2PP and HOT processes is described in order to allow the fabrication and 3D assembling of interlocking components. Results include the analysis of the dependence of low and high qualities of 2PP microstructures and their manufacturing accuracy for further HOT assembling processes. Besides, the applied detachable interlocking connections of the 2PP building blocks are visualized by an application example. In the long-term a full optical assembly method without applying any mechanical forces can thus be realized.

  17. Construction of an optical tweezer for nanometer scale rheology

    Indian Academy of Sciences (India)

    A Raghu; Sharath Ananthamurthy

    2005-10-01

    The optical tweezer is a versatile set-up that can be employed in a wide variety of studies investigating the microscopic properties of materials. In particular, this set-up has in recent times been gainfully employed in probing rheological properties of materials that exhibit viscoelasticity. These measurements can provide data at the micro and nanometer scales, not normally accessible by rheometers that are used for measurements on bulk samples. In this work we describe a single laser beam optical tweezer set-up, which is built around an inverted open microscope. The trapped polystyrene particle bead's deviation from the trap potential minimum is monitored by laser back-scattering technique and the bead position measured by a quadrant photodiode detector. Additionally, a provision is made for video microscopic studies on dispersed beads using a CCD camera. A single particle microrheological experiment that can be performed using the set-up is described with relevant calculations.

  18. Synthesis and Characterization of Carbazole-Linked Porphyrin Tweezers.

    Science.gov (United States)

    Chang, Yi; Michelin, Clément; Bucher, Léo; Desbois, Nicolas; Gros, Claude P; Piant, Sébastien; Bolze, Frédéric; Fang, Yuanyuan; Jiang, Xiaoqin; Kadish, Karl M

    2015-08-17

    Herein the synthesis, spectroscopic characterization, two-photon absorption and electrochemical properties of 3,6-disubstituted carbazole tweezers is reported. A dimer resulting from a Glaser homocoupling was isolated during a Sonogashira coupling reaction between a diethynyl-carbazole spacer and a 5-bromo-triarylporphyrin and the properties of this original compound were compared with the 3,6-disubstituted carbazole bisporphyrin tweezers. The dyads reported herein present a two-photon absorption maximum at 920 nm with two-photon absorption cross-section in the 1200 GM range. Despite a strong linear absorption in the Soret region and moderate fluorescence quantum yield, they both lead to a high brightness reaching 30 000 M(-1)  cm(-1) . PMID:26177731

  19. Optical tweezers for the study of microbubble dynamics in ultrasound

    OpenAIRE

    Garbin, Valeria

    2007-01-01

    Optical tweezers enable for non-destructive, contact-free manipulation of ultrasound contrast agent (UCA) microbubbles, which are used in medical imaging for enhancing the echogenicity of the blood pool and to quantify organ perfusion. Understanding the dynamics of ultrasound-driven contrast agent microbubbles from a fundamental physical standpoint is a first step for exploiting their acoustical properties and to develop new diagnostic and therapeutic applications. However, ...

  20. Mechanical Forces Impeding Exocytotic Surfactant Release Revealed by Optical Tweezers

    OpenAIRE

    Singer, Wolfgang; Frick, Manfred; Haller, Thomas; Bernet, Stefan; Ritsch-Marte, Monika; Dietl, Paul

    2003-01-01

    The release of surfactant from alveolar type II cells is essential to lower the surface tension in the lung and to facilitate inspiration. However, the factors controlling dispersal and diffusion of this hydrophobic material are still poorly understood. Here we report that release of surfactant from the fused vesicle, termed lamellar body (LB), resisted mechanical forces applied by optical tweezers: At constant trapping force, the probability to expand LB contents, i.e., to “pull” surfactant ...

  1. Optical Fiber Tweezers Fabricated by Guided Wave Photo-Polymerization

    OpenAIRE

    Rita S. Rodrigues Ribeiro; Raquel Queirós; Olivier Soppera; Ariel Guerreiro; Jorge, Pedro A. S.

    2015-01-01

    In this work the use of guided wave photo-polymerization for the fabrication of novel polymeric micro tips for optical trapping is demonstrated. It is shown that the selective excitation of linear polarized modes, during the fabrication process, has a direct impact on the shape of the resulting micro structures. Tips are fabricated with modes LP02 and LP21 and their shapes and output intensity distribution are compared. The application of the micro structures as optical tweezers is demonstrat...

  2. Cluster formation in ferrofluids induced by holographic optical tweezers.

    Science.gov (United States)

    Masajada, Jan; Bacia, Marcin; Drobczyński, Sławomir

    2013-10-01

    Holographic optical tweezers were used to show the interaction between a strongly focused laser beam and magnetic nanoparticles in ferrofluid. When the light intensity was high enough, magnetic nanoparticles were removed from the beam center and formed a dark ring. The same behavior was observed when focusing vortex or Bessel beams. The interactions between two or more separated rings of magnetic nanoparticles created by independent optical traps were also observed. PMID:24081086

  3. Dynamic array generation and pattern formation for optical tweezers

    DEFF Research Database (Denmark)

    Mogensen, P.C.; Glückstad, J.

    2000-01-01

    The generalised phase contrast approach is used for the generation of optical arrays of arbitrary beam shape, suitable for applications in optical tweezers for the manipulation of biological specimens. This approach offers numerous advantages over current techniques involving the use of computer-......-generated holograms or diffractive optical elements. We demonstrate a low-loss system for generating intensity patterns suitable for the trapping and manipulation of small particles or specimens....

  4. Seeing smells: development of an optoelectronic nose

    Directory of Open Access Journals (Sweden)

    Kenneth S. Suslick

    2007-06-01

    Full Text Available The development of an array of chemically-responsive dyes on a porous membrane and in its use as a general sensor for odors and volatile organic compounds (VOCs is reviewed. These colorimetric sensor arrays (CSA act as an "optoelectronic nose" by using an array of multiple dyes whose color changes are based on the full range of intermolecular interactions. The CSA is digitally imaged before and after exposure and the resulting difference map provides a digital fingerprint for any VOC or mixture of odorants. The result is an enormous increase in discriminatory power among odorants compared to prior electronic nose technologies. For the detection of biologically important analytes, including amines, carboxylic acids, and thiols, high sensitivities (ppbv have been demonstrated. The array is essentially non-responsive to changes in humidity due to the hydrophobicity of the dyes and membrane.

  5. Organic optoelectronics:materials,devices and applications

    Institute of Scientific and Technical Information of China (English)

    LIU Yi; CUI Tian-hong

    2005-01-01

    The interest in organic materials for optoelectronic devices has been growing rapidly in the last two decades. This growth has been propelled by the exciting advances in organic thin films for displays, low-cost electronic circuits, etc. An increasing number of products employing organic electronic devices have become commercialized, which has stimulated the age of organic optoelectronics. This paper reviews the recent progress in organic optoelectronic technology. First, organic light emitting electroluminescent materials are introduced. Next, the three kinds of most important organic optoelectronic devices are summarized, including light emitting diode, organic photovoltaic cell, and photodetectors. The various applications of these devices are also reviewed and discussed in detail. Finally, the market and future development of optoelectronic devices are also demonstrated.

  6. Thirty Gigahertz Optoelectronic Mixing in Chemical Vapor Deposited Graphene.

    Science.gov (United States)

    Montanaro, Alberto; Mzali, Sana; Mazellier, Jean-Paul; Bezencenet, Odile; Larat, Christian; Molin, Stephanie; Morvan, Loïc; Legagneux, Pierre; Dolfi, Daniel; Dlubak, Bruno; Seneor, Pierre; Martin, Marie-Blandine; Hofmann, Stephan; Robertson, John; Centeno, Alba; Zurutuza, Amaia

    2016-05-11

    The remarkable properties of graphene, such as broadband optical absorption, high carrier mobility, and short photogenerated carrier lifetime, are particularly attractive for high-frequency optoelectronic devices operating at 1.55 μm telecom wavelength. Moreover, the possibility to transfer graphene on a silicon substrate using a complementary metal-oxide-semiconductor-compatible process opens the ability to integrate electronics and optics on a single cost-effective chip. Here, we report an optoelectronic mixer based on chemical vapor-deposited graphene transferred on an oxidized silicon substrate. Our device consists in a coplanar waveguide that integrates a graphene channel, passivated with an atomic layer-deposited Al2O3 film. With this new structure, 30 GHz optoelectronic mixing in commercially available graphene is demonstrated for the first time. In particular, using a 30 GHz intensity-modulated optical signal and a 29.9 GHz electrical signal, we show frequency downconversion to 100 MHz. These results open promising perspectives in the domain of optoelectronics for radar and radio-communication systems. PMID:27043922

  7. Integrated NEMS and optoelectronics for sensor applications.

    Energy Technology Data Exchange (ETDEWEB)

    Czaplewski, David A.; Serkland, Darwin Keith; Olsson, Roy H., III; Bogart, Gregory R. (Symphony Acoustics, Rio Rancho, NM); Krishnamoorthy, Uma; Warren, Mial E.; Carr, Dustin Wade (Symphony Acoustics, Rio Rancho, NM); Okandan, Murat; Peterson, Kenneth Allen

    2008-01-01

    This work utilized advanced engineering in several fields to find solutions to the challenges presented by the integration of MEMS/NEMS with optoelectronics to realize a compact sensor system, comprised of a microfabricated sensor, VCSEL, and photodiode. By utilizing microfabrication techniques in the realization of the MEMS/NEMS component, the VCSEL and the photodiode, the system would be small in size and require less power than a macro-sized component. The work focused on two technologies, accelerometers and microphones, leveraged from other LDRD programs. The first technology was the nano-g accelerometer using a nanophotonic motion detection system (67023). This accelerometer had measured sensitivity of approximately 10 nano-g. The Integrated NEMS and optoelectronics LDRD supported the nano-g accelerometer LDRD by providing advanced designs for the accelerometers, packaging, and a detection scheme to encapsulate the accelerometer, furthering the testing capabilities beyond bench-top tests. A fully packaged and tested die was never realized, but significant packaging issues were addressed and many resolved. The second technology supported by this work was the ultrasensitive directional microphone arrays for military operations in urban terrain and future combat systems (93518). This application utilized a diffraction-based sensing technique with different optical component placement and a different detection scheme from the nano-g accelerometer. The Integrated NEMS LDRD supported the microphone array LDRD by providing custom designs, VCSELs, and measurement techniques to accelerometers that were fabricated from the same operational principles as the microphones, but contain proof masses for acceleration transduction. These devices were packaged at the end of the work.

  8. Linear microrheology with optical tweezers of living cells 'is not an option'!

    Science.gov (United States)

    Tassieri, Manlio

    2015-08-01

    Optical tweezers have been successfully adopted as exceptionally sensitive transducers for microrheology studies of complex fluids. Despite the general trend, in this article I explain why a similar approach should not be adopted for microrheology studies of living cells. This conclusion is acheived on the basis of statistical mechanics principles that indicate the unsuitability of optical tweezers for such purpose. PMID:26100967

  9. Linear microrheology with optical tweezers of living cells 'is not an option'!

    OpenAIRE

    Tassieri, Manlio

    2015-01-01

    Optical tweezers have been successfully adopted as exceptionally sensitive transducers for microrheology studies of complex fluids. Despite the general trend, in this article I explain why a similar approach should not be adopted for microrheology studies of living cells. This conclusion is reached on the basis of statistical mechanics principles that indicate the unsuitability of optical tweezers for such purpose.

  10. Rapid feedback control and stabilization of an optical tweezers with a budget microcontroller

    Science.gov (United States)

    Nino, Daniel; Wang, Haowei; Milstein, Joshua N.

    2014-09-01

    Laboratories ranging the scientific disciplines employ feedback control to regulate variables within their experiments, from the flow of liquids within a microfluidic device to the temperature within a cell incubator. We have built an inexpensive, yet fast and rapidly deployed, feedback control system that is straightforward and flexible to implement from a commercially available Arduino Due microcontroller. This is in comparison with the complex, time-consuming and often expensive electronics that are commonly implemented. As an example of its utility, we apply our feedback controller to the task of stabilizing the main trapping laser of an optical tweezers. The feedback controller, which is inexpensive yet fast and rapidly deployed, was implemented from hacking an open source Arduino Due microcontroller. Our microcontroller based feedback system can stabilize the laser intensity to a few tenths of a per cent at 200 kHz, which is an order of magnitude better than the laser's base specifications, illustrating the utility of these devices.

  11. Rapid feedback control and stabilization of an optical tweezers with a budget microcontroller

    International Nuclear Information System (INIS)

    Laboratories ranging the scientific disciplines employ feedback control to regulate variables within their experiments, from the flow of liquids within a microfluidic device to the temperature within a cell incubator. We have built an inexpensive, yet fast and rapidly deployed, feedback control system that is straightforward and flexible to implement from a commercially available Arduino Due microcontroller. This is in comparison with the complex, time-consuming and often expensive electronics that are commonly implemented. As an example of its utility, we apply our feedback controller to the task of stabilizing the main trapping laser of an optical tweezers. The feedback controller, which is inexpensive yet fast and rapidly deployed, was implemented from hacking an open source Arduino Due microcontroller. Our microcontroller based feedback system can stabilize the laser intensity to a few tenths of a per cent at 200 kHz, which is an order of magnitude better than the laser's base specifications, illustrating the utility of these devices. (paper)

  12. Optoelectronic Study of Interface and Its Related Effects in Organic Electronic Devices

    OpenAIRE

    Singh, Vipul

    2009-01-01

    1 Introduction|2 Experimental Methods|3 Study of LiF/P3HT interface and its application in P3HT based OFETs|4 Optoelectronic modeling of Al/P3HT interface and its application|5 Application of optoelectronic model to study the role of morphology in exciton quenching|6 Optoelectronic evidence of exciton quenching due to injected charge carriers|7 Conclusion|A Built in Field as a function of applied bias|B Different values of X|C Publication list|D List of conference attended

  13. Metal oxides for optoelectronic applications

    Science.gov (United States)

    Yu, Xinge; Marks, Tobin J.; Facchetti, Antonio

    2016-04-01

    Metal oxides (MOs) are the most abundant materials in the Earth's crust and are ingredients in traditional ceramics. MO semiconductors are strikingly different from conventional inorganic semiconductors such as silicon and III-V compounds with respect to materials design concepts, electronic structure, charge transport mechanisms, defect states, thin-film processing and optoelectronic properties, thereby enabling both conventional and completely new functions. Recently, remarkable advances in MO semiconductors for electronics have been achieved, including the discovery and characterization of new transparent conducting oxides, realization of p-type along with traditional n-type MO semiconductors for transistors, p-n junctions and complementary circuits, formulations for printing MO electronics and, most importantly, commercialization of amorphous oxide semiconductors for flat panel displays. This Review surveys the uniqueness and universality of MOs versus other unconventional electronic materials in terms of materials chemistry and physics, electronic characteristics, thin-film fabrication strategies and selected applications in thin-film transistors, solar cells, diodes and memories.

  14. Metamaterial mirrors in optoelectronic devices

    KAUST Repository

    Esfandyarpour, Majid

    2014-06-22

    The phase reversal that occurs when light is reflected from a metallic mirror produces a standing wave with reduced intensity near the reflective surface. This effect is highly undesirable in optoelectronic devices that use metal films as both electrical contacts and optical mirrors, because it dictates a minimum spacing between the metal and the underlying active semiconductor layers, therefore posing a fundamental limit to the overall thickness of the device. Here, we show that this challenge can be circumvented by using a metamaterial mirror whose reflection phase is tunable from that of a perfect electric mirror († = €) to that of a perfect magnetic mirror († = 0). This tunability in reflection phase can also be exploited to optimize the standing wave profile in planar devices to maximize light-matter interaction. Specifically, we show that light absorption and photocurrent generation in a sub-100 nm active semiconductor layer of a model solar cell can be enhanced by ∼20% over a broad spectral band. © 2014 Macmillan Publishers Limited.

  15. Progress on the optoelectronic functional organic crystals

    Institute of Scientific and Technical Information of China (English)

    WANG Huan; XIE ZengQi; Ma YuGuang; Shen JiaCong

    2007-01-01

    Organic crystals constructed by pi-conjugated molecules have been paid great attention to in the field of organic optoelectronic materials. The superiorities of these organic crystal materials, such as high thermal stability, highly ordered structure, and high carrier mobility over the amorphous thin film materials, make them attractive candidates for optoelectronic devices. Single crystal with definite structure provides a model to investigate the basic interactions between the molecules (supramolecular interaction), and the relationship between molecular stacking modes and optoelectronic performance (luminescence and carrier mobility). Through modulating molecular arrangement in organic crystal, the luminescence efficiency of organic crystal has exceeded 80% and carrier mobility has been up to the level of 10 cm2·V-1·s-1. Amplified stimulated emission phenomena have been observed in many crystals. In this paper, we will emphatically introduce the progress in optoelectronic functional organic crystals and some correlative principle.

  16. Dynamics of resonant tunneling diode optoelectronic oscillators

    OpenAIRE

    Romeira, Bruno

    2012-01-01

    The nonlinear dynamics of optoelectronic integrated circuit (OEIC) oscillators comprising semiconductor resonant tunneling diode (RTD) nanoelectronic quantum devices has been investigated. The RTD devices used in this study oscillate in the microwave band frequency due to the negative di erential conductance (NDC) of their nonlinear current voltage characteristics, which is preserved in the optoelectronic circuit. The aim was to study RTD circuits incorporating laser diodes and...

  17. Robert Feulgen Prize Lecture. Laser tweezers and multiphoton microscopes in life sciences.

    Science.gov (United States)

    König, K

    2000-08-01

    Near infrared (NIR) laser microscopy enables optical micromanipulation, piconewton force determination, and sensitive fluorescence studies by laser tweezers. Otherwise, fluorescence images with high spatial and temporal resolution of living cells and tissues can be obtained via non-resonant fluorophore excitation with multiphoton NIR laser scanning microscopes. Furthermore, NIR femtosecond laser pulses at TW/cm2 intensities can be used to realize non-invasive contact-free surgery of nanometer-sized structures within living cells and tissues. Applications of these novel versatile NIR laser-based tools for the determination of motility forces, coenzyme and chlorophyll imaging, three-dimensional multigene detection, non-invasive optical sectioning of tissues ("optical biopsy"), functional protein imaging, and nanosurgery of chromosomes are described. PMID:11052257

  18. Nanoplasmonic Tweezers Visualize Protein p53 Suppressing Unzipping of Single DNA-Hairpins

    CERN Document Server

    Kotnala, Abhay

    2014-01-01

    Here we report on the use of double-nanohole (DNH) optical tweezers as a label-free and free-solution single-molecule probe for protein-DNA interactions. Using this approach, we demonstrate the unzipping of individual 10 base pair DNA-hairpins, and quantify how tumor suppressor p53 protein delays the unzipping. From the Arrhenius behavior, we find the energy barrier to unzipping introduced by p53 to be $2\\times 10^{-20}$ J, whereas cys135ser mutant p53 does not show suppression of unzipping, which gives clues to its functional inability to suppress tumor growth. This transformative approach to single molecule analysis allows for ultra-sensitive detection and quantification of protein-DNA interactions to revolutionize the fight against genetic diseases.

  19. Parallel analysis of individual biological cells using multifocal laser tweezers Raman spectroscopy.

    Science.gov (United States)

    Liu, Rui; Taylor, Douglas S; Matthews, Dennis L; Chan, James W

    2010-11-01

    We report on the development and characterization of a multifocal laser tweezers Raman spectroscopy (M-LTRS) technique for parallel Raman spectral acquisition of individual biological cells. Using a 785-nm diode laser and a time-sharing laser trapping scheme, multiple laser foci are generated to optically trap single polystyrene beads and suspension cells in a linear pattern. Raman signals from the trapped objects are simultaneously projected through the slit of a spectrometer and spatially resolved on a charge-coupled device (CCD) detector with minimal signal crosstalk between neighboring cells. By improving the rate of single-cell analysis, M-LTRS is expected to be a valuable method for studying single-cell dynamics of cell populations and for the development of high-throughput Raman based cytometers. PMID:21073802

  20. Trapping and rotating nanoparticles using a plasmonic nano-tweezer with an integrated heat sink.

    Science.gov (United States)

    Wang, Kai; Schonbrun, Ethan; Steinvurzel, Paul; Crozier, Kenneth B

    2011-01-01

    Although optical tweezers based on far-fields have proven highly successful for manipulating objects larger than the wavelength of light, they face difficulties at the nanoscale because of the diffraction-limited focused spot size. This has motivated interest in trapping particles with plasmonic nanostructures, as they enable intense fields confined to sub-wavelength dimensions. A fundamental issue with plasmonics, however, is Ohmic loss, which results in the water, in which the trapping is performed, being heated and to thermal convection. Here we demonstrate the trapping and rotation of nanoparticles using a template-stripped plasmonic nanopillar incorporating a heat sink. Our simulations predict an ~100-fold reduction in heating compared with previous designs. We further demonstrate the stable trapping of polystyrene particles, as small as 110 nm in diameter, which can be rotated around the nanopillar actively, by manual rotation of the incident linear polarization, or passively, using circularly polarized illumination. PMID:21915111

  1. Light-Induced Agglomeration and Diffusion of Different Particles with Optical Tweezers

    Institute of Scientific and Technical Information of China (English)

    LI Xue-Cong; SUN Xiu-Dong; LIU Hong-Peng; ZHANG Jian-Long

    2010-01-01

    @@ The dynamic process of light-induced agglomeration of carbon nanotubes(CNTs),C60 and Escherichia coli(E.coli)in aqueous solutions is demonstrated using an optical tweezers system.Based on the results,the diameter of the agglomerated region and the agglomeration rate increase with the increasing laser power.After the saturation-stable period,CNTs diffuse completely,C60 dusters only diffuse partially,and E.coli never diffuses in the agglomeration region.Theoretical analyses show that the molecular polarization and thermal diffusion of particles play crucial roles in the diffusion process.The results indicate the possibility of using light to aggregate and sort nanoparticles.

  2. Towards optoelectronic architectures for integrated neuromorphic computers

    Science.gov (United States)

    Martinenghi, Romain; Baylon Fuentes, Antonio; Jacquot, Maxime; Chembo, Yanne K.; Larger, Laurent

    2014-03-01

    We investigate theoretically and experimentally the computational properties of an optoelectronic neuromorphic processor based on a complex nonlinear dynamics. This neuromorphic approach is based on a new paradigm of or reservoir computing, which is intrinsically different from the concept of Turing machines. It essentially consists in expanding the input information to be processed into a higher dimensional phase space, through the nonlinear transient response of a complex dynamics excited by the input information. The computed output is then extracted via a linear separation of the transient trajectory in the complex phase space, performed through a learning phase consisting of the resolution of a regression problem. We here investigate an architecture for photonic neuromorphic computing via these complex nonlinear dynamical transients. A versatile photonic nonlinear transient computer based on a multiple-delay is reported. Its hybrid analogue and digital architecture allows for an easy reconfiguration, and for direct implementation of in-line processing. Its computational efficiency in parameter space is also analyzed, and the computational performance of this system is successfully evaluated on a standard spoken digit recognition task. We then discuss the pathways that can lead to its effective integration.

  3. Optoelectronic microdevices for combined phototherapy

    Science.gov (United States)

    Zharov, Vladimir P.; Menyaev, Yulian A.; Hamaev, V. A.; Antropov, G. M.; Waner, Milton

    2000-03-01

    In photomedicine in some of cases radiation delivery to local zones through optical fibers can be changed for the direct placing of tiny optical sources like semiconductor microlasers or light diodes in required zones of ears, nostrils, larynx, nasopharynx cochlea or alimentary tract. Our study accentuates the creation of optoelectronic microdevices for local phototherapy and functional imaging by using reflected light. Phototherapeutic micromodule consist of the light source, microprocessor and miniature optics with different kind of power supply: from autonomous with built-in batteries to remote supply by using pulsed magnetic field and supersmall coils. The developed prototype photomodule has size (phi) 8X16 mm and work duration with built-in battery and light diode up several hours at the average power from several tenths of mW to few mW. Preliminary clinical tests developed physiotherapeutic micrimodules in stomatology for treating the inflammation and in otolaryngology for treating tonsillitis and otitis are presented. The developed implanted electro- optical sources with typical size (phi) 4X0,8 mm and with remote supply were used for optical stimulation of photosensitive retina structure and electrostimulation of visual nerve. In this scheme the superminiature coil with 30 electrical integrated levels was used. Such devices were implanted in eyes of 175 patients with different vision problems during clinical trials in Institute of Eye's Surgery in Moscow. For functional imaging of skin layered structure LED arrays coupled photodiodes arrays were developed. The possibilities of this device for study drug diffusion and visualization small veins are discussed.

  4. Functional Carbon Nanocomposite, Optoelectronic, and Catalytic Coatings

    Science.gov (United States)

    Liang, Yu Teng

    coatings have been demonstrated. In particular, co-deposited platinum, silicon, and carbon nanomaterial films were fashioned into electronic hydrogen gas sensors, cost efficient dye sensitized solar cell electrodes, and high capacity lithium ion battery anodes. Furthermore, concentrated graphene inks were coated to form aligned graphene-polymer nanocomposites and outstanding carbon nanotube-graphene hybrid semitransparent electrical conductors. Nanocomposite graphene-titanium dioxide catalysts produced from these cellulosic inks have low covalent defect densities and were shown to be approximately two and seven times more active than those based on reduced graphene oxide in photo-oxidation and photo-reduction reactions, respectively. Using a broad range of material characterization techniques, mechanistic insight was obtained using composite photocatalysts fabricated from well defined nanomaterials. For instance, optical spectroscopy and electronic measurements revealed a direct correlation between graphene charge transport performance and composite photochemical activity. Moreover, investigations into multidimensional composites based on 1D carbon nanotubes, 2D graphene, and 2D titanium dioxide nanosheets generated additional mechanistic insight for extending photocatalytic spectral response and increasing reaction specificity. Together, these results demonstrate the versatility of vacuum co-deposition and cellulosic nanomaterial inks for fabricating carbon nanocomposite optoelectronic and energy conversion coatings.

  5. Organic Optoelectronic Devices Employing Small Molecules

    Science.gov (United States)

    Fleetham, Tyler Blain

    Organic optoelectronic devices have remained a research topic of great interest over the past two decades, particularly in the development of efficient organic photovoltaics (OPV) and organic light emitting diodes (OLED). In order to improve the efficiency, stability, and materials variety for organic optoelectronic devices a number of emitting materials, absorbing materials, and charge transport materials were developed and employed in a device setting. Optical, electrical, and photophysical studies of the organic materials and their corresponding devices were thoroughly carried out. Two major approaches were taken to enhance the efficiency of small molecule based OPVs: developing material with higher open circuit voltages or improved device structures which increased short circuit current. To explore the factors affecting the open circuit voltage (VOC) in OPVs, molecular structures were modified to bring VOC closer to the effective bandgap, DeltaE DA, which allowed the achievement of 1V VOC for a heterojunction of a select Ir complex with estimated exciton energy of only 1.55eV. Furthermore, the development of anode interfacial layer for exciton blocking and molecular templating provide a general approach for enhancing the short circuit current. Ultimately, a 5.8% PCE was achieved in a single heterojunction of C60 and a ZnPc material prepared in a simple, one step, solvent free, synthesis. OLEDs employing newly developed deep blue emitters based on cyclometalated complexes were demonstrated. Ultimately, a peak EQE of 24.8% and nearly perfect blue emission of (0.148,0.079) was achieved from PtON7dtb, which approaches the maximum attainable performance from a blue OLED. Furthermore, utilizing the excimer formation properties of square-planar Pt complexes, highly efficient and stable white devices employing a single emissive material were demonstrated. A peak EQE of over 20% for pure white color (0.33,0.33) and 80 CRI was achieved with the tridentate Pt complex, Pt

  6. Colloidal quantum dot materials for infrared optoelectronics

    Science.gov (United States)

    Arinze, Ebuka S.; Nyirjesy, Gabrielle; Cheng, Yan; Palmquist, Nathan; Thon, Susanna M.

    2015-09-01

    Colloidal quantum dots (CQDs) are an attractive material for optoelectronic applications because they combine flexible, low-cost solution-phase synthesis and processing with the potential for novel functionality arising from their nanostructure. Specifically, the bandgap of films composed of arrays of CQDs can be tuned via the quantum confinement effect for tailored spectral utilization. PbS-based CQDs can be tuned throughout the near and mid-infrared wavelengths and are a promising materials system for photovoltaic devices that harvest non-visible solar radiation. The performance of CQD solar cells is currently limited by an absorption-extraction compromise, whereby photon absorption lengths in the near infrared spectral regime exceed minority carrier diffusion lengths in the bulk films. Several light trapping strategies for overcoming this compromise and increasing the efficiency of infrared energy harvesting will be reviewed. A thin-film interference technique for creating multi-colored and transparent solar cells will be presented, and a discussion of designing plasmonic nanomaterials based on earth-abundant materials for integration into CQD solar cells is developed. The results indicate that it should be possible to achieve high absorption and color-tunability in a scalable nanomaterials system.

  7. Hybrid optoelectronic device with multiple bistable outputs

    International Nuclear Information System (INIS)

    Optoelectronic circuits which exhibit optical and electrical bistability with hysteresis behavior are proposed and experimentally demonstrated. The systems are based on semiconductor optical amplifiers (SOA), bipolar junction transistors (BJT), PIN photodiodes (PD) and laser diodes externally modulated with integrated electro-absorption modulators (LD-EAM). The device operates based on two independent phenomena leading to both electrical bistability and optical bistability. The electrical bistability is due to the series connection of two p-i-n structures (SOA, BJT, PD or LD) in reverse bias. The optical bistability is consequence of the quantum confined Stark effect (QCSE) in the multi-quantum well (MQW) structure in the intrinsic region of the device. This effect produces the optical modulation of the transmitted light through the SOA (or reflected from the PD). Finally, because the optical transmission of the SOA (in reverse bias) and the reflected light from the PD are so small, a LD-EAM modulated by the voltage across these devices are employed to obtain a higher output optical power. Experiments show that the maximum switching frequency is in MHz range and the rise/fall times lower than 1 us. The temporal response is mainly limited by the electrical capacitance of the devices and the parasitic inductances of the connecting wires. The effects of these components can be reduced in current integration technologies.

  8. Direct measurement of the dielectrophoresis forces acting on micro-objects using optical tweezers and a simple microfluidic chip

    Science.gov (United States)

    Park, In Soo; Park, Se Hee; Yoon, Dae Sung; Lee, Sang Woo; Kim, Beop-Min

    2014-09-01

    We constructed a reliable frequency-dependent dielectrophoretic (DEP) force measurement system based on optical tweezers and a microfluidic chip. Using this system, we directly measured the frequency-dependent DEP forces acting on polystyrene beads while varying various parameters, which were all verified by theoretical simulations. We also investigated the DEP characteristics of non-functionalized and carboxyl-functionalized polystyrene beads in solutions with different conductivities by associating the measured crossover frequencies with a theoretical DEP model. This system can be used as a quantifying tool for surface conductance assays by characterizing the DEP forces acting on micro-objects in various experimental conditions.

  9. Fiber-pigtailed optical tweezer for single-atom trapping and single-photon generation

    CERN Document Server

    Garcia, Sébastien; Hohmann, Leander; Reichel, Jakob; Long, Romain

    2013-01-01

    We demonstrate a miniature, fiber-coupled optical tweezer to trap a single atom. The same fiber is used to trap a single atom and to read out its fluorescence. To obtain a low background level, the tweezer light is chopped, and we measure the influence of the chopping frequency on the atom's lifetime. We use the single atom as a single-photon source at 780 nm and measure the second-order correlation function of the emitted photons. Because of its miniature, robust, fiber-pigtailed design, this tweezer can be implemented in a broad range of experiments where single atoms are used as a resource.

  10. Optical sorting of particles by dual-channel line optical tweezers

    International Nuclear Information System (INIS)

    A novel configuration of dual-channel line optical tweezers with a ‘Y’ shape is constructed for sorting of particles within a microfluidic chip. When yeast cells with different size pass the intersection of the specially designed line optical tweezers, they are separated and transported to different channels due to a difference in the forces exerted by the line tweezers that depends on the size of the cells. The influences of some experimental conditions, such as laser power and flow velocity, on the sorting efficiency are discussed. (paper)

  11. Recent trend in graphene for optoelectronics

    International Nuclear Information System (INIS)

    This study analyzes the scientific knowledge diffusion paths of graphene for optoelectronics (GFO), where graphene offers wide applications due to its thinness, high conductivity, excellent transparency, chemical stability, robustness, and flexibility. Our investigation is based on the main path analysis which establishes the citation links among the literature data in order to trace the significant sequence of knowledge development in this emerging field. We identify the main development paths of GFO up to the year 2012, along which a series of influential papers in this field are identified. The main path graph shows that knowledge diffusion occurs in key subareas, including reduced graphene oxide, chemical vapor deposition, and exfoliation techniques, which are developed for the preparation and applications of GFO. The applications cover solar cells, laser devices, sensing devices, and LCD. In addition, the main theme of GFO research evolves in sequence from small-graphene-sample preparation, to large-scale film growth, and onto prototype device fabrication. This evolution reflects a strong industrial demand for a new transparent–conductive film technology.

  12. Recent trend in graphene for optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu-Bin, E-mail: benechen.bvo@gmail.com [National Taiwan University of Science and Technology, Graduate Institute of Management, Taiwan (China); Liu, John S., E-mail: johnliu@mail.ntust.edu.tw [National Taiwan University of Science and Technology, Graduate Institute of Technology Management, Taiwan (China); Lin Pang, E-mail: panglin@mail.nctu.edu.tw [National Chiao Tung University, Department of Materials Science and Engineering, Taiwan (China)

    2013-02-15

    This study analyzes the scientific knowledge diffusion paths of graphene for optoelectronics (GFO), where graphene offers wide applications due to its thinness, high conductivity, excellent transparency, chemical stability, robustness, and flexibility. Our investigation is based on the main path analysis which establishes the citation links among the literature data in order to trace the significant sequence of knowledge development in this emerging field. We identify the main development paths of GFO up to the year 2012, along which a series of influential papers in this field are identified. The main path graph shows that knowledge diffusion occurs in key subareas, including reduced graphene oxide, chemical vapor deposition, and exfoliation techniques, which are developed for the preparation and applications of GFO. The applications cover solar cells, laser devices, sensing devices, and LCD. In addition, the main theme of GFO research evolves in sequence from small-graphene-sample preparation, to large-scale film growth, and onto prototype device fabrication. This evolution reflects a strong industrial demand for a new transparent-conductive film technology.

  13. Construction of high-quality CdS:Ga nanoribbon/silicon heterojunctions and their nano-optoelectronic applications

    International Nuclear Information System (INIS)

    Silicon based optoelectronic integration is restricted by its poor optoelectronic properties arising from the indirect band structure. Here, by combining silicon with another promising optoelectronic material, the CdS nanoribbon (NR), devices with heterojunction structure were constructed. The CdS NRs were also doped with gallium to improve their n-type conductivity. A host of nano-optoelectronic devices, including light emitting diodes, photovoltaic devices, and photodetectors, were successfully constructed on the basis of the CdS:Ga NR/Si heterojunctions. They all exhibited excellent device performances as regards high stability, high efficiency, and fast response speed. It is expected that the CdS NR/Si heterojunctions will have great potential for future applications of Si based optoelectronic integration.

  14. Strain engineered optoelectronic properties of transition metal dichalcogenides lateral heterostructures

    Science.gov (United States)

    Lee, Jaekwang; Yoon, Mina

    2015-03-01

    Most three-dimensional bulk-scale materials rarely survive beyond 1% strain, while recently spotlighted two-dimensional (2-D) materials can sustain a high elastic strain (up to 10%) to optimize optical quantities such as band gaps and absorption spectra governing optoelectronic device performance. Despite the enormous interest in strained 2-D materials, most researches are focused on single materials or vertical heterostructures where precise control of stacking orientation is challenging. Here, using first-principles density-functional calculations, we explore how uniaxial tensile strains modify overall electronic and optical properties of transition metal dichalcogenides lateral heterostructures, such as MoX2/WX2 (X =S, Se). Based on the detailed optoelectronic information, we predict the optimal strain condition for maximal power efficiency. Furthermore, we find that uniaxial tensile strain readily develops a continuously varying direct-bandgap across the lateral heterojunctions, which results in the broad range absorption of solar spectrum useful for future optoelectronic devices. This research was conducted at the CNMS, which is sponsored at Oak Ridge National Laboratory (ORNL) by the Office of Basic Energy Sciences, U.S. Department of Energy; a portion of theory work was supported by the LDRD Program of ORNL.

  15. Web-Enabled Optoelectronic Particle-Fallout Monitor

    Science.gov (United States)

    Lineberger, Lewis P.

    2008-01-01

    A Web-enabled optoelectronic particle- fallout monitor has been developed as a prototype of future such instruments that (l) would be installed in multiple locations for which assurance of cleanliness is required and (2) could be interrogated and controlled in nearly real time by multiple remote users. Like prior particle-fallout monitors, this instrument provides a measure of particles that accumulate on a surface as an indication of the quantity of airborne particulate contaminants. The design of this instrument reflects requirements to: Reduce the cost and complexity of its optoelectronic sensory subsystem relative to those of prior optoelectronic particle fallout monitors while maintaining or improving capabilities; Use existing network and office computers for distributed display and control; Derive electric power for the instrument from a computer network, a wall outlet, or a battery; Provide for Web-based retrieval and analysis of measurement data and of a file containing such ancillary data as a log of command attempts at remote units; and Use the User Datagram Protocol (UDP) for maximum performance and minimal network overhead.

  16. Bio-inspired networks for optoelectronic applications

    Science.gov (United States)

    Han, Bing; Huang, Yuanlin; Li, Ruopeng; Peng, Qiang; Luo, Junyi; Pei, Ke; Herczynski, Andrzej; Kempa, Krzysztof; Ren, Zhifeng; Gao, Jinwei

    2014-11-01

    Modern optoelectronics needs development of new materials characterized not only by high optical transparency and electrical conductivity, but also by mechanical strength, and flexibility. Recent advances employ grids of metallic micro- and nanowires, but the overall performance of the resulting material composites remains unsatisfactory. In this work, we propose a new strategy: application of natural scaffoldings perfected by evolution. In this context, we study two bio-inspired networks for two specific optoelectronic applications. The first network, intended for solar cells, light sources and similar devices, has a quasi-fractal structure and is derived directly from a chemically extracted leaf venation system. The second network is intended for touch screens and flexible displays, and is obtained by metalizing a spider’s silk web. We demonstrate that each of these networks attain an exceptional optoelectonic and mechanical performance for its intended purpose, providing a promising direction in the development of more efficient optoelectronic devices.

  17. Contemporary optoelectronics materials, metamaterials and device applications

    CERN Document Server

    Sukhoivanov, Igor

    2016-01-01

    This book presents a collection of extended contributions on the physics and application of optoelectronic materials and metamaterials.   The book is divided into three parts, respectively covering materials, metamaterials and optoelectronic devices.  Individual chapters cover topics including phonon-polariton interaction, semiconductor and nonlinear organic materials, metallic, dielectric and gyrotropic metamaterials, singular optics, parity-time symmetry, nonlinear plasmonics, microstructured optical fibers, passive nonlinear shaping of ultrashort pulses, and pulse-preserving supercontinuum generation. The book contains both experimental and theoretical studies, and each contribution is a self-contained exposition of a particular topic, featuring an extensive reference list.  The book will be a useful resource for graduate and postgraduate students, researchers and engineers involved in optoelectronics/photonics, quantum electronics, optics, and adjacent areas of science and technology.

  18. Graphene and Two-Dimensional Materials for Optoelectronic Applications

    Directory of Open Access Journals (Sweden)

    Andreas Bablich

    2016-03-01

    Full Text Available This article reviews optoelectronic devices based on graphene and related two-dimensional (2D materials. The review includes basic considerations of process technology, including demonstrations of 2D heterostructure growth, and comments on the scalability and manufacturability of the growth methods. We then assess the potential of graphene-based transparent conducting electrodes. A major part of the review describes photodetectors based on lateral graphene p-n junctions and Schottky diodes. Finally, the progress in vertical devices made from 2D/3D heterojunctions, as well as all-2D heterostructures is discussed.

  19. Dual optoelectronic visual detection and quantification of spectroscopically silent heavy metal toxins: A multi-measurand sensing strategy based on Rhodamine 6G as chromo or fluoro ionophore

    Energy Technology Data Exchange (ETDEWEB)

    Prathish, K.P.; James, D.; Jaisy, J. [Inorganic and Polymeric Materials Group, National Institute for Interdisciplinary Science and Technology (CSIR), Industrial Estate (P.O), Pappanamcode, Trivandrum 695019 (India); Prasada Rao, T., E-mail: rao@csrrltrd.ren.nic.in [Inorganic and Polymeric Materials Group, National Institute for Interdisciplinary Science and Technology (CSIR), Industrial Estate (P.O), Pappanamcode, Trivandrum 695019 (India)

    2009-08-04

    A novel colorimetric chemo-sensor for the simultaneous visual detection and quantification of spectroscopically silent heavy metal toxins viz. cadmium, lead and mercury has been developed. This is based on the proposed sequential ligand exchange (SLE) mechanism of iodide from Pb-I{sup -}-Rhodamine 6G ion associate with citrate (without affecting ion associates of Cd and Hg) and subsequently from Cd-I{sup -}-Rhodamine 6G ion associate with EDTA (without affecting Hg-I{sup -}-Rhodamine 6G). Multi-measurand detection and quantification by colorimetry is possible as the individual toxins gives identical bathochromic shifts in aqueous solution, i.e. from 530 to 575 nm on formation of ternary ion associates in singular, binary and ternary mixtures. The visual detection provides a simple, quick and sensitive detection method in addition to quantification via spectrophotometry with Sandell sensitivities of 1.1, 15 and 2.5 {mu}g dm{sup -2} for cadmium, lead and mercury, respectively. The developed procedure has been successfully tested for the analysis of environmental (cast alkali, lead acid battery and zinc manufacturing industry effluents) samples. Furthermore, the multi-measurand quantification of the above-mentioned heavy metal toxins based on fluorescence quenching and use of Pyronine G as chromo-ionophore instead of Rhodamine 6G is also described.

  20. Efficient loading of a single neutral atom into an optical microscopic tweezer

    Institute of Scientific and Technical Information of China (English)

    何军; 刘贝; 刁文婷; 王杰英; 靳刚; 王军民

    2015-01-01

    A single atom in a magneto–optical trap (MOT) with trap size (hundreds of micrometers) can be transferred into an optical microscopic tweezer with a probability of∼100%. The ability to transfer a single atom into two traps back and forth allows us to study the loading process. The loading probability is found to be insensitive to the geometric overlap of the MOT and the tweezer. It is therefore possible to perform simultaneously loading of a single atom into all sites of the tweezer array for many qubits. In particular, we present a simulation of the one-dimensional and two-dimensional arrays of an optical microscopic tweezer. We find the same qualitative behavior for all of the trap parameters.

  1. Construction of force measuring optical tweezers instrumentation and investigations of biophysical properties of bacterial adhesion organelles

    CERN Document Server

    Andersson, Magnus

    2015-01-01

    Optical tweezers are a technique in which microscopic-sized particles, including living cells and bacteria, can be non-intrusively trapped with high accuracy solely using focused light. The technique has therefore become a powerful tool in the field of biophysics. Optical tweezers thereby provide outstanding manipulation possibilities of cells as well as semi-transparent materials, both non-invasively and non-destructively, in biological systems. In addition, optical tweezers can measure minute forces (< 10-12 N), probe molecular interactions and their energy landscapes, and apply both static and dynamic forces in biological systems in a controlled manner. The assessment of intermolecular forces with force measuring optical tweezers, and thereby the biomechanical structure of biological objects, has therefore considerably facilitated our understanding of interactions and structures of biological systems. Adhesive bacterial organelles, so called pili, mediate adhesion to host cells and are therefore crucial...

  2. A study of multi-trapping of tapered-tip single fiber optical tweezers

    International Nuclear Information System (INIS)

    We develop a pair of tapered-tip single fiber optical tweezers, and study its multi-trapping characteristic. The finite difference time domain method is employed to simulate the trapping force characteristic of this pair of single fiber optical tweezers, and the results show that the number of trapped particles depends on the refractive index and the size of the particles. The trapping force of this pair of tapered-tip single fiber optical tweezers is calibrated by the experimental method, and the experimental results are consistent with the theoretical calculation results. The multi-trapping capability realized by the tapered-tip single fiber optical tweezers will be practical and useful for applications in biomedical research fields. (interdisciplinary physics and related areas of science and technology)

  3. Application of BP neural networks in non-linearity correction of optical tweezers

    Institute of Scientific and Technical Information of China (English)

    Ziqiang WANG; Yinmei LI; Liren LOU; Henghua WEI; Zhong WANG

    2008-01-01

    The back-propagation (BP) neural network is proposed to correct nonlinearity and optimize the force measurement and calibration of an optical tweezer sys-tem. Considering the low convergence rate of the BP algo-rithm, the Levenberg-Marquardt (LM) algorithm is used to improve the BP network. The proposed method is experimentally studied for force calibration in a typical optical tweezer system using hydromechanics. The result shows that with the nonlinear correction using BP net-works, the range of force measurement of an optical tweezer system is enlarged by 30% and the precision is also improved compared with the polynomial fitting method. It is demonstrated that nonlinear correction by the neural network method effectively improves the per-formance of optical tweezers without adding or changing the measuring system.

  4. Optical nanofiber integrated into an optical tweezers for particle probing and manipulation

    CERN Document Server

    Frawley, Mary C; Truong, Viet Giang; Chormaic, Sile Nic

    2014-01-01

    We present an integrated platform for particle manipulation consisting of a combined optical nanofiber and optical tweezers system. Individual silica microspheres were introduced to the nanofiber at arbitrary points using the optical tweezers, thereby producing pronounced dips in the fiber transmission. We show that such consistent and reversible transmission modulations depend on both particle and fiber diameter, and may be used as a reference point for in-situ nanofiber or particle size calibration. Particle arrays can be released from the optical tweezers onto the nanofiber and are propelled along the fiber length via guided light. We also demonstrate how the optical tweezers can be used to create a "particle jet" to feed a supply of microspheres to the nanofiber surface, forming a particle conveyor belt. This integrated optical platform provides a method for selective evanescent field manipulation of micron-sized particles and may facilitate studies of optical binding and light-particle interaction dynami...

  5. Extending a release-and-recapture scheme to single atom optical tweezer for effective temperature evaluation

    International Nuclear Information System (INIS)

    By recording the fluorescence fraction of the cold atoms remaining in the magneto-optical trap (MOT) as a function of the release time, the release-and-recapture (R and R) method is utilized to evaluate the effective temperature of the cold atomic ensemble. We prepare a single atom in a large-magnetic-gradient MOT and then transfer the trapped single atom into a 1064-nm microscopic optical tweezer. The energy of the single atom trapped in the tweezer is further reduced by polarization gradient cooling (PGC) and the effective temperature is evaluated by extending the R and R technique to a single atom tweezer. The typical effective temperature of a single atom in the tweezer is improved from about 105 μK to about 17 μK by applying the optimum PGC phase. (atomic and molecular physics)

  6. Opto-electronic oscillators having optical resonators

    Science.gov (United States)

    Yao, Xiaotian Steve (Inventor); Maleki, Lutfollah (Inventor); Ilchenko, Vladimir (Inventor)

    2003-01-01

    Systems and techniques of incorporating an optical resonator in an optical part of a feedback loop in opto-electronic oscillators. This optical resonator provides a sufficiently long energy storage time and hence to produce an oscillation of a narrow linewidth and low phase noise. Certain mode matching conditions are required. For example, the mode spacing of the optical resonator is equal to one mode spacing, or a multiplicity of the mode spacing, of an opto-electronic feedback loop that receives a modulated optical signal and to produce an electrical oscillating signal.

  7. Design and construction of an optical compact and affordable tweezers

    International Nuclear Information System (INIS)

    The following paper presents a new design allowing a reduction on the amount of required optical elements for the construction of the optical tweezers, which results in a compact and affordable system. The latter is composed by a 40 mW Nd: YAG (532 nm) laser and commercially available optics and mounts. A virtual instrument, developed using Lab View 8.0, controls both a XYZ table and a web camera for visualizing. The quality of the laser beam at the end of optical system was characterized using the knife-edge method, resulting in a Gaussian shaped (TEM00) intensity profile. It is presented as well the necessary information to align and calibrate each optical element. (Author)

  8. Dynamic properties of bacterial pili measured by optical tweezers

    CERN Document Server

    Fallman, Erik; Schedin, Staffan; Jass, Jana; Uhlin, Bernt Eric; Axner, Ove

    2014-01-01

    The ability of uropathogenic Escherichia coli (UPEC) to cause urinary tract infections is dependent on their ability to colonize the uroepithelium. Infecting bacteria ascend the urethra to the bladder and then kidneys by attaching to the uroepithelial cells via the differential expression of adhesins. P pili are associated with pyelonephritis, the more severe infection of the kidneys. In order to find means to treat pyelonephritis, it is therefore of interest to investigate the properties P pili. The mechanical behavior of individual P pili of uropathogenic Escherichia coli has recently been investigated using optical tweezers. P pili, whose main part constitutes the PapA rod, composed of ~1000 PapA subunits in a helical arrangement, are distributed over the bacterial surface and mediate adhesion to host cells. We have earlier studied P pili regarding its stretching/elongation properties where we have found and characterized three different elongation regions, of which one constitute an unfolding of the quate...

  9. Selectively Transparent and Conducting Photonic Crystals and their Potential to Enhance the Performance of Thin-Film Silicon-Based Photovoltaics and Other Optoelectronic Devices

    Science.gov (United States)

    O'Brien, Paul G.

    2011-12-01

    The byproducts of human engineered energy production are increasing atmospheric CO2 concentrations well above their natural levels and accompanied continual decline in the natural reserves of fossil fuels necessitates the development of green energy alternatives. Solar energy is attractive because it is abundant, can be produced in remote locations and consumed on site. Specifically, thin-film silicon-based photovoltaic (PV) solar cells have numerous inherent advantages including their availability, non-toxicity, and they are relatively inexpensive. However, their low-cost and electrical performance depends on reducing their thickness to as great an extent as possible. This is problematic because their thickness is much less than their absorption length. Consequently, enhanced light trapping schemes must be incorporated into these devices. Herein, a transparent and conducting photonic crystal (PC) intermediate reflector (IR), integrated into the rear side of the cell and serving the dual function as a back-reflector and a spectral splitter, is identified as a promising method of boosting the performance of thin-film silicon-based PV. To this end a novel class of PCs, namely selectively transparent and conducting photonic crystals (STCPC), is invented. These STCPCs are a significant advance over existing 1D PCs because they combine intense wavelength selective broadband reflectance with the transmissive and conductive properties of sputtered ITO. For example, STCPCs are made to exhibit Bragg-reflectance peaks in the visible spectrum of 95% reflectivity and have a full width at half maximum that is greater than 200nm. At the same time, the average transmittance of these STCPCs is greater than 80% over the visible spectrum that is outside their stop-gap. Using wave-optics analysis, it is shown that STCPC intermediate reflectors increase the current generated in micromorph cells by 18%. In comparison, the more conventional IR comprised of a single homogeneous

  10. Interrogating Biology with Force: Single Molecule High-Resolution Measurements with Optical Tweezers

    OpenAIRE

    Capitanio, Marco; Pavone, Francesco S.

    2013-01-01

    Single molecule force spectroscopy methods, such as optical and magnetic tweezers and atomic force microscopy, have opened up the possibility to study biological processes regulated by force, dynamics of structural conformations of proteins and nucleic acids, and load-dependent kinetics of molecular interactions. Among the various tools available today, optical tweezers have recently seen great progress in terms of spatial resolution, which now allows the measurement of atomic-scale conformat...

  11. Measurement of interaction forces between red blood cells in aggregates by optical tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Maklygin, A Yu; Priezzhev, A V; Karmenian, A; Nikitin, Sergei Yu; Obolenskii, I S; Lugovtsov, Andrei E; Kisun Li

    2012-06-30

    We have fabricated double-beam optical tweezers and demonstrated the possibility of their use for measuring the interaction forces between red blood cells (erythrocytes). It has been established experimentally that prolonged trapping of red blood cells in a tightly focused laser beam does not cause any visible changes in their shape or size. We have measured the interaction between red blood cells in the aggregate, deformed by optical tweezers.

  12. Synthesis and electrochemical characterization of new optoelectronic materials based on conjugated donor-acceptor system containing oligo-tri(heteroaryl)-1,3,5-triazines

    Energy Technology Data Exchange (ETDEWEB)

    Idzik, Krzysztof R., E-mail: krzysztof.idzik@pwr.wroc.p [Institute of Organic and Macromolecular Chemistry, Friedrich Schiller Universitaet Jena, Humboldstrasse 10, D-07743 Jena (Germany)] [Department of Chemistry, Faculty of Medicinal Chemistry and Microbiology, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Rapta, Peter [Leibniz-Institute for Solid State and Materials Research, Group of Electrochemistry and Conducting Polymers, D-01171 Dresden (Germany)] [Department of Physical Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinskeho 9, SK-81237 Bratislava (Slovakia); Cywinski, Piotr J. [Department of Physical Chemistry, Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam-Golm (Germany); Beckert, Rainer, E-mail: rainer.beckert@uni-jena.d [Institute of Organic and Macromolecular Chemistry, Friedrich Schiller Universitaet Jena, Humboldstrasse 10, D-07743 Jena (Germany); Dunsch, Lothar, E-mail: l.dunsch@ifw-dresden.d [Leibniz-Institute for Solid State and Materials Research, Group of Electrochemistry and Conducting Polymers, D-01171 Dresden (Germany)

    2010-07-01

    A series of novel oligoarylenes based on donor-acceptor system, containing triazine moiety as an electron-transporting central core, have been prepared by electrochemical polymerization. The redox behaviour of poly(2,4,6-tri[p-(2-(3,4-ethylenedioxythienyl))-phenyl]-1,3,5-triazine) was studied by cyclic voltammetry and triple in situ ESR/UV-vis-NIR spectroelectrochemistry to get more details on the type of charge carriers within the film. To obtain desired oligoarylenes, triazine-core monomers possessing various electrochromic side groups have been synthesized by the Stille cross-coupling methodology. The structures have been confirmed by {sup 1}H NMR, {sup 13}C NMR, and elemental analysis. Monomers show good chemical stability in common organic solvents such as chloroform, dichloromethane or toluene and also exhibit excellent thermal stability over wide range of temperatures. Furthermore, their photophysical properties have been established with the use of fluorescence spectroscopy. Electrochemical results accompanied with fluorescence spectroscopy suggest that these derivatives of triazine can be successfully used in the fabrication of organic light-emitting diodes (OLEDs).

  13. Synthesis and electrochemical characterization of new optoelectronic materials based on conjugated donor-acceptor system containing oligo-tri(heteroaryl)-1,3,5-triazines

    International Nuclear Information System (INIS)

    A series of novel oligoarylenes based on donor-acceptor system, containing triazine moiety as an electron-transporting central core, have been prepared by electrochemical polymerization. The redox behaviour of poly(2,4,6-tri[p-(2-(3,4-ethylenedioxythienyl))-phenyl]-1,3,5-triazine) was studied by cyclic voltammetry and triple in situ ESR/UV-vis-NIR spectroelectrochemistry to get more details on the type of charge carriers within the film. To obtain desired oligoarylenes, triazine-core monomers possessing various electrochromic side groups have been synthesized by the Stille cross-coupling methodology. The structures have been confirmed by 1H NMR, 13C NMR, and elemental analysis. Monomers show good chemical stability in common organic solvents such as chloroform, dichloromethane or toluene and also exhibit excellent thermal stability over wide range of temperatures. Furthermore, their photophysical properties have been established with the use of fluorescence spectroscopy. Electrochemical results accompanied with fluorescence spectroscopy suggest that these derivatives of triazine can be successfully used in the fabrication of organic light-emitting diodes (OLEDs).

  14. GaAs optoelectronic neuron arrays

    Science.gov (United States)

    Lin, Steven; Grot, Annette; Luo, Jiafu; Psaltis, Demetri

    1993-01-01

    A simple optoelectronic circuit integrated monolithically in GaAs to implement sigmoidal neuron responses is presented. The circuit integrates a light-emitting diode with one or two transistors and one or two photodetectors. The design considerations for building arrays with densities of up to 10,000/sq cm are discussed.

  15. Photoemission from optoelectronic materials and their nanostructures

    CERN Document Server

    Ghatak, Kamakhya Prasad; Bhattacharya, Sitangshu

    2009-01-01

    This monograph investigates photoemission from optoelectronic materials and their nanostructures. It contains open-ended research problems which form an integral part of the text and are useful for graduate courses as well as aspiring Ph.D.'s and researchers..

  16. Using optoelectronic sensors in the system PROTEUS

    Science.gov (United States)

    Zyczkowski, M.; Szustakowski, M.; Ciurapinski, W.; Piszczek, M.

    2010-10-01

    The paper presents the concept of optoelectronic devices for human protection in rescue activity. The system consists of an ground robots with predicted sensor. The multisensor construction of the system ensures significant improvement of security of using on-situ like chemical or explosive sensors. The article show a various scenario of use for individual sensor in system PROTEUS.

  17. Manipulation of Self-Assembled Microparticle Chains by Electroosmotic Flow Assisted Electrorotation in an Optoelectronic Device

    Directory of Open Access Journals (Sweden)

    Xiaolu Zhu

    2015-09-01

    Full Text Available A method incorporating the optically induced electrorotation (OER and alternating current electroosmotic (ACEO effects, for the formation and motion control of microparticle chains, is numerically and experimentally demonstrated. In this method, both the rotating electric field and ACEO fluid roll are generated around the border between light and dark area of the fluidic chamber in an optoelectronic tweezers (OET device. The experimental results show that the particle chains can self-rotate in their pitch axes under the rotating electric field produced due to the different impedances of the photoconductive layer in light and dark areas, and have a peak self-rotating rate at around 1 MHz. The orbital movement of entire particle chain around the center of ACEO fluid roll can be achieved from 0.5 to 600 kHz. The strength of OER motion and ACEO-caused orbital movement of particle chains can be adjusted by changing the frequency of alternating current (AC voltage. This non-contact method has the potential for spatially regulating the posture, orientation and position of microparticle chains.

  18. Optoelectronic line transmission an introduction to fibre optics

    CERN Document Server

    Tricker, Raymond L

    2013-01-01

    Optoelectronic Line Transmission: An Introduction to Fibre Optics presents a basic introduction as well as a background reference manual on fiber optic transmission. The book discusses the basic principles of optical line transmission; the advantages and disadvantages of optical fibers and optoelectronic signalling; the practical applications of optoelectronics; and the future of optoelectronics. The text also describes the theories of optical line transmission; fibers and cables for optical transmission; transmitters including light-emitting diodes and lasers; and receivers including photodi

  19. All-optoelectronic continuous wave THz imaging for biomedical applications

    International Nuclear Information System (INIS)

    We present an all-optoelectronic THz imaging system for ex vivo biomedical applications based on photomixing of two continuous-wave laser beams using photoconductive antennas. The application of hyperboloidal lenses is discussed. They allow for f-numbers less than 1/2 permitting better focusing and higher spatial resolution compared to off-axis paraboloidal mirrors whose f-numbers for practical reasons must be larger than 1/2. For a specific histological sample, an analysis of image noise is discussed

  20. Synchrotron x-ray microdiffraction diagnostics of multilayer optoelectronic devices

    International Nuclear Information System (INIS)

    Synchrotron-based x-ray microbeam techniques have been used to map crystallographic strain and multilayer thickness in micro-optoelectronic devices produced with the selective area growth technique. Our main results show that growth enhancements in InGaAsP multilayer device material are different for well and barrier material. Comparison with a vapor-phase model for selective area growth suggests that this difference is due to different vapor-phase incorporation rates for the group III metals. copyright 1999 American Institute of Physics

  1. Advances in wide bandgap SiC for optoelectronics

    DEFF Research Database (Denmark)

    Ou, Haiyan; Ou, Yiyu; Argyraki, Aikaterini;

    2014-01-01

    Silicon carbide (SiC) has played a key role in power electronics thanks to its unique physical properties like wide bandgap, high breakdown field, etc. During the past decade, SiC is also becoming more and more active in optoelectronics thanks to the progress in materials growth and nanofabrication....... This paper will review the advances in fluorescent SiC for white light-emitting diodes, covering the poly-crystalline doped SiC source material growth, single crystalline epitaxy growth of fluorescent SiC, and nanofabrication of SiC to enhance the extraction efficiency for fluorescent SiC based white...

  2. Photodiode Based Detection for Multiple Trap Optical Tweezers

    DEFF Research Database (Denmark)

    Ott, Dino

    This thesis is concerned with the position tracking of microscopic, optically trapped particles and the quantification of the forces acting on them. A new detection method for simultaneous, three-dimensional tracking of multiple particles is presented, its performance is evaluated, and its...... one of the workhorses of biophysical research. There exists a variety of implementations of optical traps, from simple single traps to complex multiple traps with engineered three-dimensional light fields. In comparison to single beam optical traps, multiple beam optical traps offer more freedom in...... respective optical traps that contain information about the movement of the trapped particles....

  3. Blind predictions of DNA and RNA tweezers experiments with force and torque.

    Directory of Open Access Journals (Sweden)

    Fang-Chieh Chou

    2014-08-01

    Full Text Available Single-molecule tweezers measurements of double-stranded nucleic acids (dsDNA and dsRNA provide unprecedented opportunities to dissect how these fundamental molecules respond to forces and torques analogous to those applied by topoisomerases, viral capsids, and other biological partners. However, tweezers data are still most commonly interpreted post facto in the framework of simple analytical models. Testing falsifiable predictions of state-of-the-art nucleic acid models would be more illuminating but has not been performed. Here we describe a blind challenge in which numerical predictions of nucleic acid mechanical properties were compared to experimental data obtained recently for dsRNA under applied force and torque. The predictions were enabled by the HelixMC package, first presented in this paper. HelixMC advances crystallography-derived base-pair level models (BPLMs to simulate kilobase-length dsDNAs and dsRNAs under external forces and torques, including their global linking numbers. These calculations recovered the experimental bending persistence length of dsRNA within the error of the simulations and accurately predicted that dsRNA's "spring-like" conformation would give a two-fold decrease of stretch modulus relative to dsDNA. Further blind predictions of helix torsional properties, however, exposed inaccuracies in current BPLM theory, including three-fold discrepancies in torsional persistence length at the high force limit and the incorrect sign of dsRNA link-extension (twist-stretch coupling. Beyond these experiments, HelixMC predicted that 'nucleosome-excluding' poly(A/poly(T is at least two-fold stiffer than random-sequence dsDNA in bending, stretching, and torsional behaviors; Z-DNA to be at least three-fold stiffer than random-sequence dsDNA, with a near-zero link-extension coupling; and non-negligible effects from base pair step correlations. We propose that experimentally testing these predictions should be powerful next

  4. Blind predictions of DNA and RNA tweezers experiments with force and torque.

    Science.gov (United States)

    Chou, Fang-Chieh; Lipfert, Jan; Das, Rhiju

    2014-08-01

    Single-molecule tweezers measurements of double-stranded nucleic acids (dsDNA and dsRNA) provide unprecedented opportunities to dissect how these fundamental molecules respond to forces and torques analogous to those applied by topoisomerases, viral capsids, and other biological partners. However, tweezers data are still most commonly interpreted post facto in the framework of simple analytical models. Testing falsifiable predictions of state-of-the-art nucleic acid models would be more illuminating but has not been performed. Here we describe a blind challenge in which numerical predictions of nucleic acid mechanical properties were compared to experimental data obtained recently for dsRNA under applied force and torque. The predictions were enabled by the HelixMC package, first presented in this paper. HelixMC advances crystallography-derived base-pair level models (BPLMs) to simulate kilobase-length dsDNAs and dsRNAs under external forces and torques, including their global linking numbers. These calculations recovered the experimental bending persistence length of dsRNA within the error of the simulations and accurately predicted that dsRNA's "spring-like" conformation would give a two-fold decrease of stretch modulus relative to dsDNA. Further blind predictions of helix torsional properties, however, exposed inaccuracies in current BPLM theory, including three-fold discrepancies in torsional persistence length at the high force limit and the incorrect sign of dsRNA link-extension (twist-stretch) coupling. Beyond these experiments, HelixMC predicted that 'nucleosome-excluding' poly(A)/poly(T) is at least two-fold stiffer than random-sequence dsDNA in bending, stretching, and torsional behaviors; Z-DNA to be at least three-fold stiffer than random-sequence dsDNA, with a near-zero link-extension coupling; and non-negligible effects from base pair step correlations. We propose that experimentally testing these predictions should be powerful next steps for

  5. Optoelectronic Systems Trained With Backpropagation Through Time.

    Science.gov (United States)

    Hermans, Michiel; Dambre, Joni; Bienstman, Peter

    2015-07-01

    Delay-coupled optoelectronic systems form promising candidates to act as powerful information processing devices. In this brief, we consider such a system that has been studied before in the context of reservoir computing (RC). Instead of viewing the system as a random dynamical system, we see it as a true machine-learning model, which can be fully optimized. We use a recently introduced extension of backpropagation through time, an optimization algorithm originally designed for recurrent neural networks, and use it to let the network perform a difficult phoneme recognition task. We show that full optimization of all system parameters of delay-coupled optoelectronics systems yields a significant improvement over the previously applied RC approach. PMID:25137733

  6. Terahertz Optoelectronics with Surface Plasmon Polariton Diode

    OpenAIRE

    Vinnakota, Raj K.; Genov, Dentcho A

    2014-01-01

    The field of plasmonics has experience a renaissance in recent years by providing a large variety of new physical effects and applications. Surface plasmon polaritons, i.e. the collective electron oscillations at the interface of a metal/semiconductor and a dielectric, may bridge the gap between electronic and photonic devices, provided a fast switching mechanism is identified. Here, we demonstrate a surface plasmon-polariton diode (SPPD) an optoelectronic switch that can operate at exceeding...

  7. Optoelectronic properties and characteristics of doping superlattices

    OpenAIRE

    Kononenko, V.K.; I. S. Manak; Ushakov, D. V.

    1998-01-01

    Optical and electric properties of doping superlattices, or n-i-p-i crystals, can be varied in a wide range under excitation and through the choice of the thicknesses and doping of the crystal layers. Some basic results concerned the transformation of the electron energy spectrum of doping superlattices are summarized. Parameters and characteristics of doping superlattices related to optoelectronics devices, such as photodetectors, laser diodes, and optical modulators, are presented.

  8. Amphiphilic Fullerenes for Biomedical and Optoelectronical Applications

    OpenAIRE

    Witte, Patrick

    2009-01-01

    Fullerenes have an enormous potential in applications to physics and biology. Specifically [60]fullerene with its unique electronic, optical and structural properties has attracted considerable attention for its application in biomedical materials and optoelectronic devices. In this context the selective functionalization of C60, which allows to combine the parent properties with new attributes like water-solubility or amphiphilicity is still a challenging topic for the synthetic chemist. In ...

  9. Drug-DNA interactions at single molecule level: A view with optical tweezers

    Science.gov (United States)

    Paramanathan, Thayaparan

    Studies of small molecule--DNA interactions are essential for developing new drugs for challenging diseases like cancer and HIV. The main idea behind developing these molecules is to target and inhibit the reproduction of the tumor cells and infected cells. We mechanically manipulate single DNA molecule using optical tweezers to investigate two molecules that have complex and multiple binding modes. Mononuclear ruthenium complexes have been extensively studied as a test for rational drug design. Potential drug candidates should have high affinity to DNA and slow dissociation kinetics. To achieve this, motifs of the ruthenium complexes are altered. Our collaborators designed a dumb-bell shaped binuclear ruthenium complex that can only intercalate DNA by threading through its bases. Studying the binding properties of this complex in bulk studies took hours. By mechanically manipulating a single DNA molecule held with optical tweezers, we lower the barrier to thread and make it fast compared to the bulk experiments. Stretching single DNA molecules with different concentration of drug molecules and holding it at a constant force allows the binding to reach equilibrium. By this we can obtain the equilibrium fractional ligand binding and length of DNA at saturated binding. Fitting these results yields quantitative measurements of the binding thermodynamics and kinetics of this complex process. The second complex discussed in this study is Actinomycin D (ActD), a well studied anti-cancer agent that is used as a prototype for developing new generations of drugs. However, the biophysical basis of its activity is still unclear. Because ActD is known to intercalate double stranded DNA (dsDNA), it was assumed to block replication by stabilizing dsDNA in front of the replication fork. However, recent studies have shown that ActD binds with even higher affinity to imperfect duplexes and some sequences of single stranded DNA (ssDNA). We directly measure the on and off rates by

  10. Progress in complementary metal–oxide–semiconductor silicon photonics and optoelectronic integrated circuits

    International Nuclear Information System (INIS)

    Silicon photonics is an emerging competitive solution for next-generation scalable data communications in different application areas as high-speed data communication is constrained by electrical interconnects. Optical interconnects based on silicon photonics can be used in intra/inter-chip interconnects, board-to-board interconnects, short-reach communications in datacenters, supercomputers and long-haul optical transmissions. In this paper, we present an overview of recent progress in silicon optoelectronic devices and optoelectronic integrated circuits (OEICs) based on a complementary metal–oxide–semiconductor-compatible process, and focus on our research contributions. The silicon optoelectronic devices and OEICs show good characteristics, which are expected to benefit several application domains, including communication, sensing, computing and nonlinear systems. (review)

  11. Mechanics of protein-DNA interaction studied with ultra-fast optical tweezers

    Science.gov (United States)

    Monico, Carina; Tempestini, Alessia; Vanzi, Francesco; Pavone, Francesco S.; Capitanio, Marco

    2014-05-01

    The lac operon is a well known example of gene expression regulation, based on the specific interaction of Lac repressor protein (LacI) with its target DNA sequence (operator). LacI and other DNA-binding proteins bind their specific target sequences with rates higher than allowed by 3D diffusion alone. Generally accepted models predict a combination of free 3D diffusion and 1D sliding along non-specific DNA. We recently developed an ultrafast force-clamp laser trap technique capable of probing molecular interactions with sub-ms temporal resolution, under controlled pN-range forces. With this technique, we tested the interaction of LacI with two different DNA constructs: a construct with two copies of the O1 operator separated by 300 bp and a construct containing the native E.coli operator sequences. Our measurements show at least two classes of LacI-DNA interactions: long (in the tens of s range) and short (tens of ms). Based on position along the DNA sequence, the observed interactions can be interpreted as specific binding to operator sequences (long events) and transient interactions with nonspecific sequences (short events). Moreover, we observe continuous sliding of the protein along DNA, passively driven by the force applied with the optical tweezers.

  12. Optoelectronic sensor device for monitoring ethanol concentration in winemaking applications

    Science.gov (United States)

    Jiménez-Márquez, F.; Vázquez, J.; Úbeda, J.; Rodríguez-Rey, J.; Sánchez-Rojas, J. L.

    2015-05-01

    The supervision of key variables such as sugar, alcohol, released CO2 and microbiological evolution in fermenting grape must is of great importance in the winemaking industry. However, the fermentation kinetics is assessed by monitoring the evolution of the density as it varies during a fermentation, since density is an indicator of the total amount of sugars, ethanol and glycerol. Even so, supervising the fermentation process is an awkward and non-comprehensive task, especially in wine cellars where production rates are massive, and enologists usually measure the density of the extracted samples from each fermentation tank manually twice a day. This work aims at the design of a fast, low-cost, portable and reliable optoelectronic sensor for measuring ethanol concentration in fermenting grape must samples. Different sets of model solutions, which contain ethanol, fructose, glucose, glycerol dissolved in water and emulate the grape must composition at different stages of the fermentation, were prepared both for calibration and validation. The absorption characteristics of these model solutions were analyzed by a commercial spectrophotometer in the NIR region, in order to identify key wavelengths from which valuable information regarding the sample composition can be extracted. Finally, a customized optoelectronic prototype based on absorbance measurements at two wavelengths belonging to the NIR region was designed, fabricated and successfully tested. The system, whose optoelectronics is reduced after a thorough analysis to only two LED lamps and their corresponding paired photodiodes operating at 1.2 and 1.3 μm respectively, calculates the ethanol content by a multiple linear regression.

  13. Accurate measurement of microscopic forces and torques using optical tweezers

    Directory of Open Access Journals (Sweden)

    Andrew Forbes

    2011-09-01

    Full Text Available It is now well known that matter may be trapped by optical fields with high intensity gradients. Once trapped, it is then possible to manipulate microscopic particles using such optical fields, in so-called optical tweezers. Such optical trapping and tweezing systems have found widespread application across diverse fields in science, from applied biology to fundamental physics. In this article we outline the design and construction of an optical trapping and tweezing system, and show how the resulting interaction of the laser light with microscopic particles may be understood in terms of the transfer of linear and angular momentum of light. We demonstrate experimentally the use of our optical tweezing configuration for the measurement of microscopic forces and torques. In particular, we make use of digital holography to create so-called vortex laser beams, capable of transferring orbital angular momentum to particles. The use of such novel laser beams in an optical trapping and tweezing set-up allows for the control of biological species at the single-cell level.

  14. Dispersive light-matter interaction in programmable optical tweezers

    Science.gov (United States)

    Sawyer, Bianca J.; Horvath, Milena S. J.; Deb, Amita B.; Kjørgaard, Niels

    2015-08-01

    We have developed a robust interrogation system using frequency modulation spectroscopy to measure the quantum state-dependent phase shift incurred on an off-resonant optical probe when transmitted by an atomic medium. Recently, our focus has been on extending this technique for the detection of Feshbach resonances in 87Rb atoms. Feshbach resonance is a mechanism which allows the atomic interaction strength to be precisely tuned via an external magnetic field. To access a Feshbach resonance atoms must be independently prepared in certain internal states, during which we utilize programmable optical tweezers to perform precise spatial micro-manipulation of the ensemble in laser "test-tubes." We use our dispersive probing system to identify the resonant magnetic field value in a sample with a dense "ball" geometry. An important design consideration for such a probing scheme is the three-dimensional mode-matching at the interface between light and the atomic sample when coupled by the dispersive interaction. We discuss challenges which dealing with this new geometry compared to the previously used prolate geometry, and consider the possibility of dipole-dipole interactions in our sample leading to cooperative light scattering processes.

  15. Calibration of femtosecond optical tweezers as a sensitive thermometer

    Science.gov (United States)

    Mondal, Dipankar; Goswami, Debabrata

    2015-08-01

    We present cumulative perturbation effects of femtosecond laser pulses on an optical tweezer. Our experiments involve a dual wavelength high repetition rate femtosecond laser, one at the non-heating wavelength of 780 nm while the other at 1560 nm to cause heating in the trapped volume under low power (100-800 μW) conditions. The 1560 nm high repetition rate laser acts as a resonant excitation source for the vibrational combination band of the hydroxyl group (OH) of water, which helps create the local heating effortlessly within the trapping volume. With such an experimental system, we are the first to observe direct effect of temperature on the corner frequency deduced from power spectrum. We can, thus, control and measure temperature precisely at the optical trap. This observation has lead us to calculate viscosity as well as temperature in the vicinity of the trapping zone. These experimental results also support the well-known fact that the nature of Brownian motion is the response of the optically trapped bead from the temperature change of surroundings. Temperature rise near the trapping zone can significantly change the viscosity of the medium. However, we notice that though the temperature and viscosity are changing as per our corner frequency calculations, the trap stiffness remains the same throughout our experiments within the temperature range of about 20 K.

  16. Nanomaterials for Electronics and Optoelectronics

    Science.gov (United States)

    Koehne, Jessica E.; Meyyappan, M.

    2011-01-01

    Nanomaterials such as carbon nanotubes(CNTs), graphene, and inorganic nanowires(INWs) have shown interesting electronic, mechanical, optical, thermal, and other properties and therefore have been pursued for a variety of applications by the nanotechnology community ranging from electronics to nanocomposites. While the first two are carbon-based materials, the INWs in the literature include silicon, germanium, III-V, II-VI, a variety of oxides, nitrides, antimonides and others. In this talk, first an overview of growth of these three classes of materials by CVD and PECVD will be presented along with results from characterization. Then applications in development of chemical sensors, biosensors, energy storage devices and novel memory architectures will be discussed.

  17. A novel dual-axis optoelectronic level with refraction principle

    International Nuclear Information System (INIS)

    Levels are fundamental metrological tools for machine leveling and angle measurements. Current levels are all based on the pendulum principle and bubble vial principle. The former is precise but complicated, while the latter is not precise enough. This paper presents a novel, simple and precise optoelectronic level. It is based on the principle of light refraction in the transparent and viscous fluid. The fluid surface is always in leveling condition regardless whether the ground is level or not. Measuring the refraction angle with precise dual-axis autocollimator can directly reflect the inclined angle of the level. A leakage prevention design is also proposed to allow the level to be placed in any pose. Calibrated by an angular interferometer, the error of the dual-axis optoelectronic level is better than ±0.7 arcsec in the measuring range of ±100 arcsec, and better than ±0.4 arcsec for the range of ±30 arcsec, for both axes. Without the need of a pendulum mechanism, this is a simpler design for precision level. (paper)

  18. Titania Nanostructures for Optoelectronics Applications

    Science.gov (United States)

    Wang, Lili

    Titanium dioxide (titania) nanotubular structure discovered in 2001 have been attracting extensive interest due to their widely applications in photocatalysis, catalysis and solar cells. The final products of titania nanotube (TiNT) arrays can be synthesized in three forms. One is in form of ordered arrays attached to original Ti substrate, another one is in form of free-standing arrays and the last form is white powders. In this dissertation, we review the development history of these three types of TiNT arrays and introduce the fabrication process of TiNTs products in detail including morphology characterization, fabrication parameter study and optimization of synthesis condition. Since titania is a semiconductor with large band gap (3.2 eV), the large bandgap leads to only UV light absorption, which constitutes less than 5% of the whole solar spectrum. In order to efficiently harvest solar energy for the solar cells made of titania, several methods depositing TiNT arrays with metal oxides to improve the light harvesting are presented in this dissertation. A comprehensive study of forced hydrolysis method is carried out and investigated. Preliminary devices are built up in DSSCs concept based on the hybrid structure of TiO2/Fe2O3. Some important parameters, such as open circuit voltage (VOC), short circuit current (ISC), and fill factor (FF) are evaluated. Optical properties of the samples with the hybrid architecture are studied to achieve an optimal performance in DSSCs-type solar cells.

  19. Cell manipulation tool with combined microwell array and optical tweezers for cell isolation and deposition

    International Nuclear Information System (INIS)

    Isolation from rare cells and deposition of sorted cells with high accuracy for further study are critical to a wide range of biomedical applications. In the current paper, we report an automated cell manipulation tool with combined optical tweezers and a uniquely designed microwell array, which functions for recognition, isolation, assembly, transportation and deposition of the interesting cells. The microwell array allows the passive hydrodynamic docking of cells, while offering the opportunity to inspect the interesting cell phenotypes with high spatio-temporal resolution based on the flexible image processing technique. In addition, dynamic and parallel cell manipulation in three dimensions can realize the target cell levitation from microwell and pattern assembly with multiple optical traps. Integrated with the programmed motorized stage, the optically levitated and assembled cells can be transported and deposited to the predefined microenvironment, so the tool can facilitate the integration of other on-chip functionalities for further study without removing these isolated cells from the chip. Experiments on human embryonic stem cells and yeast cells are performed to demonstrate the effectiveness of the proposed cell manipulation tool. Besides the application to cell isolation and deposition, three other biological applications with this tool are also presented. (paper)

  20. Trapping, manipulation and rapid rotation of NBD-C8 fluorescent single microcrystals in optical tweezers

    International Nuclear Information System (INIS)

    We have built an optical tweezers experiment based on an inverted microscope to trap and manipulate single crystals of micro or sub-micrometer size made from fluorescent molecules of 4-octylamino-7-nitrobenzoxadiazole (NBD-C8). These single crystals have parallelepiped shapes and exhibit birefringence properties evidenced through optical experiments between crossed polarizers in a polarizing microscope. The crystals are uniaxial with their optical axis oriented along their largest dimension. Trapped in the optical trap, the organic micro-crystals are oriented in such a way that their long axis is along the direction of the beam propagation, and their short axis follows the direction of the linear polarization. Therefore, with linearly polarized light, simply rotating the light polarization can orient the crystal. When using circularly or only elliptically polarized light, the crystal can spontaneously rotate and reach rotation speed of several hundreds of turns per second. A surprising result has been observed: when the incident power is growing up, the rotation speed increases to reach a maximum value and then decreases even when the power is still growing up. Moreover, this evolution is irreversible. Different possible explanations can be considered. The development of a 3D control of the crystals by dynamical holography using liquid crystal spatial modulators will be presented and discussed on the basis of the most recent results obtained. (Author)

  1. Single-molecule kinetics under force: probing protein folding and enzymatic activity with optical tweezers

    Science.gov (United States)

    Wong, Wesley

    2010-03-01

    Weak non-covalent bonds between and within single molecules govern many aspects of biological structure and function (e.g. DNA base-paring, receptor-ligand binding, protein folding, etc.) In living systems, these interactions are often subject to mechanical forces, which can greatly alter their kinetics and activity. My group develops and applies novel single-molecule manipulation techniques to explore and quantify these force-dependent kinetics. Using optical tweezers, we have quantified the force-dependent unfolding and refolding kinetics of different proteins, including the cytoskeletal protein spectrin in collaboration with E. Evans's group [1], and the A2 domain of the von Willebrand factor blood clotting protein in collaboration with T. Springer's group [2]. Furthermore, we have studied the kinetics of the ADAMTS13 enzyme acting on a single A2 domain, and have shown that physiolgical forces in the circulation can act as a cofactor for enzymatic cleavage, regulating hemostatic activity [2]. References: 1. E. Evans, K. Halvorsen, K. Kinoshita, and W.P. Wong, Handbook of Single Molecule Biophysics, P. Hinterdorfer, ed., Springer (2009). 2. X. Zhang, K. Halvorsen, C.-Z. Zhang, W.P. Wong, and T.A. Springer, Science 324 (5932), 1330-1334 (2009).

  2. Probing Protein Folding Kinetics with High-resolution, Stabilized Optical Tweezers

    Science.gov (United States)

    Wong, Wesley; Halvorsen, Ken

    2009-03-01

    Single-molecule techniques provide a powerful means of exploring molecular transitions such as the unfolding and refolding of a protein. However, the quantification of bi-directional transitions and near-equilibrium phenomena poses unique challenges, and is often limited by the detection resolution and long-term stability of the instrument. We have developed unique optical tweezers methods that address these problems, including an interference-based method for high-resolution 3D bead tracking (˜1 nm laterally, ˜0.3 nm vertically, at > 100 Hz), and a continuous autofocus system that stabilizes the trap height to within 1-2 nm longterm [1,2]. We have used our instruments to quantify the force-dependent unfolding and refolding kinetics of single protein domains (e.g. spectrin in collaboration with E. Evans). These single-molecule studies are presented, together with the accompanying probabilistic analysis that we have developed. References: 1. W.P. Wong, V. Heinrich, E. Evans, Mat. Res. Soc. Symp. Proc., 790, P5.1-P5.10 (2004). 2. V. Heinrich, W.P. Wong, K. Halvorsen, E. Evans, Langmuir, 24, 1194-1203 (2008).

  3. Hong-Ou-Mandel atom interferometry in tunnel-coupled optical tweezers

    Science.gov (United States)

    Lester, Brian; Kaufman, Adam; Reynolds, Collin; Wall, Michael; Foss-Feig, Michael; Hazzard, Kaden; Rey, Ana Maria; Regal, Cindy

    2014-05-01

    We present recent work in which we demonstrate near-complete control over all the internal and external degrees of freedom of laser-cooled 87Rb atoms trapped in sub-micron optical tweezers. Utilizing this control for two atoms in two optical tweezers, we implement a massive-particle analog of the Hong-Ou-Mandel interferometer where atom tunneling plays the role of the photon beamsplitter. The interferometer is used to probe the effect of atomic indistinguishability on the two-atom dynamics for a variety of initial conditions. These experiments demonstrate the viability of the optical tweezer platform for bottom-up generation of low-entropy quantum systems and pave the way toward the direct observation of quantum dynamics in more complex finite-sized systems.

  4. Optical disassembly of cellular clusters by tunable tug-of-war tweezers

    CERN Document Server

    Bezryadina, Anna; Chen, Joseph C; Chen, Zhigang

    2016-01-01

    Bacterial biofilms underlie many persistent infections, posing major hurdles in antibiotic treatment. Here, we design and demonstrate tug-of-war optical tweezers that can facilitate assessment of cell-cell adhesion - a key contributing factor to biofilm development, thanks to the combined actions of optical scattering and gradient forces. With a customized optical landscape distinct from that of conventional tweezers, not only can such tug-of-war tweezers stably trap and stretch a rod-shaped bacterium in the observing plane, but, more importantly, they can also impose a tunable lateral force that pulls apart cellular clusters without any tethering or mechanical movement. As a proof of principle, we examined a Sinorhizobium meliloti strain that forms robust biofilms and found that the strength of intercellular adhesion depends on the growth medium. This technique may herald new photonic tools for optical manipulation and biofilm study, as well as other biological applications.

  5. Rare-earth implanted MOS devices for silicon photonics. Microstructural, electrical and optoelectronic properties

    Energy Technology Data Exchange (ETDEWEB)

    Rebohle, Lars; Skorupa, Wolfgang [Forschungszentrum Rossendorf e.V. (FZR), Dresden (Germany). Inst. fuer Ionenstrahlphysik und Materialforschung

    2010-07-01

    The book concentrates on the microstructural, electric and optoelectronic properties of rare-earth implanted MOS structures and their use as light emitters in potential applications. It describes the structural formation processes in the gate oxide during fabrication and under operation, how this microstructure development will affect the electrical device performance and how both microstructure and electrical characteristics determine the optoelectronic features of the light emitters. However, most of the discussed physical processes as well as the described fabrication methods and device characterization techniques are of general interest and are beyond the scope of this type of light emitter. The book will be of value to engineers, physicists, and scientists dealing either with Si based photonics in particular or optoelectronic device fabrication and characterization in general. (orig.)

  6. A new switching parameter varying optoelectronic delayed feedback model with computer simulation

    Science.gov (United States)

    Liu, Lingfeng; Miao, Suoxia; Cheng, Mengfan; Gao, Xiaojing

    2016-02-01

    In this paper, a new switching parameter varying optoelectronic delayed feedback model is proposed and analyzed by computer simulation. This model is switching between two parameter varying optoelectronic delayed feedback models based on chaotic pseudorandom sequences. Complexity performance results show that this model has a high complexity compared to the original model. Furthermore, this model can conceal the time delay effectively against the auto-correlation function, delayed mutual information and permutation information analysis methods, and can extent the key space, which greatly improve its security.

  7. Near-field enhanced optical tweezers utilizing femtosecond-laser nanostructured substrates

    International Nuclear Information System (INIS)

    We present experimental evidence of plasmonic-enhanced optical tweezers, of polystyrene beads in deionized water in the vicinity of metal-coated nanostructures. The optical tweezers operate with a continuous wave near-infrared laser. We employ a Cu/Au bilayer that significantly improves dissipation of heat generated by the trapping laser beam and avoid de-trapping from heat convection currents. We investigate the improvement of the optical trapping force and the effective trapping quality factor, and observe an exponential distance dependence of the trapping force from the nanostructures, indicative of evanescent plasmonic enhancement

  8. Single DNA molecule grafting and manipulation using a combined atomic force microscope and an optical tweezer

    Science.gov (United States)

    Shivashankar, G. V.; Libchaber, A.

    1997-12-01

    In this letter, we report on spatially selecting and grafting a DNA-tethered bead to an atomic force microscope (AFM) cantilever, using an optical tweezer. To quantify this technique, we measure force versus extension of a single DNA molecule using AFM. For such studies, we have developed a micromanipulation approach by combining an AFM, an optical tweezer, and visualization setup. The ability to select a single DNA polymer and specifically graft it to a localized position on a substrate opens up new possibilities in biosensors and bioelectronic devices.

  9. tweezercalib 2.0: Faster version of MatLab package for precise calibration of optical tweezers

    Science.gov (United States)

    Hansen, Poul Martin; Tolić-Nørrelykke, Iva Marija; Flyvbjerg, Henrik; Berg-Sørensen, Kirstine

    2006-03-01

    We present a vectorized version of the MatLab (MathWorks Inc.) package tweezercalib for calibration of optical tweezers with precision. The calibration is based on the power spectrum of the Brownian motion of a dielectric bead trapped in the tweezers. Precision is achieved by accounting for a number of factors that affect this power spectrum, as described in vs. 1 of the package [I.M. Tolić-Nørrelykke, K. Berg-Sørensen, H. Flyvbjerg, Matlab program for precision calibration of optical tweezers, Comput. Phys. Comm. 159 (2004) 225-240]. The graphical user interface allows the user to include or leave out each of these factors. Several "health tests" are applied to the experimental data during calibration, and test results are displayed graphically. Thus, the user can easily see whether the data comply with the theory used for their interpretation. Final calibration results are given with statistical errors and covariance matrix. New version program summaryTitle of program: tweezercalib Catalogue identifier: ADTV_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTV_v2_0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Reference in CPC to previous version: I.M. Tolić-Nørrelykke, K. Berg-Sørensen, H. Flyvbjerg, Comput. Phys. Comm. 159 (2004) 225 Catalogue identifier of previous version: ADTV Does the new version supersede the original program: Yes Computer for which the program is designed and others on which it has been tested: General computer running MatLab (Mathworks Inc.) Operating systems under with the program has been tested: Windows2000, Windows-XP, Linux Programming language used: MatLab (Mathworks Inc.), standard license Memory required to execute with typical data: Of order four times the size of the data file High speed storage required: none No. of lines in distributed program, including test data, etc.: 135 989 No. of bytes in distributed program, including test data, etc.: 1 527 611 Distribution

  10. Substrate-dependent cell elasticity measured by optical tweezers indentation

    Science.gov (United States)

    Yousafzai, Muhammad S.; Ndoye, Fatou; Coceano, Giovanna; Niemela, Joseph; Bonin, Serena; Scoles, Giacinto; Cojoc, Dan

    2016-01-01

    In the last decade, cell elasticity has been widely investigated as a potential label free indicator for cellular alteration in different diseases, cancer included. Cell elasticity can be locally measured by pulling membrane tethers, stretching or indenting the cell using optical tweezers. In this paper, we propose a simple approach to perform cell indentation at pN forces by axially moving the cell against a trapped microbead. The elastic modulus is calculated using the Hertz-model. Besides the axial component, the setup also allows us to examine the lateral cell-bead interaction. This technique has been applied to measure the local elasticity of HBL-100 cells, an immortalized human cell line, originally derived from the milk of a woman with no evidence of breast cancer lesions. In addition, we have studied the influence of substrate stiffness on cell elasticity by performing experiments on cells cultured on two substrates, bare and collagen-coated, having different stiffness. The mean value of the cell elastic modulus measured during indentation was 26±9 Pa for the bare substrate, while for the collagen-coated substrate it diminished to 19±7 Pa. The same trend was obtained for the elastic modulus measured during the retraction of the cell: 23±10 Pa and 13±7 Pa, respectively. These results show the cells adapt their stiffness to that of the substrate and demonstrate the potential of this setup for low-force probing of modifications to cell mechanics induced by the surrounding environment (e.g. extracellular matrix or other cells).

  11. Dynamic properties of bacterial pili measured by optical tweezers

    Science.gov (United States)

    Fallman, Erik G.; Andersson, Magnus J.; Schedin, Staffan S.; Jass, Jana; Uhlin, Bernt Eric; Axner, Ove

    2004-10-01

    The ability of uropathogenic Escherichia coli (UPEC) to cause urinary tract infections is dependent on their ability to colonize the uroepithelium. Infecting bacteria ascend the urethra to the bladder and then kidneys by attaching to the uroepithelial cells via the differential expression of adhesins. P pili are associated with pyelonephritis, the more severe infection of the kidneys. In order to find means to treat pyelonephritis, it is therefore of interest to investigate the properties P pili. The mechanical behavior of individual P pili of uropathogenic Escherichia coli has recently been investigated using optical tweezers. P pili, whose main part constitutes the PapA rod, composed of ~1000 PapA subunits in a helical arrangement, are distributed over the bacterial surface and mediate adhesion to host cells. We have earlier studied P pili regarding its stretching/elongation properties where we have found and characterized three different elongation regions, of which one constitute an unfolding of the quaternary (helical) structure of the PapA rod. It was shown that this unfolding takes place at an elongation independent force of 27 +/- 2 pN. We have also recently performed studies on its folding properties and shown that the unfolding/folding of the PapA rod is completely reversible. Here we present a study of the dynamical properties of the PapA rod. We show, among other things, that the unfolding force increases and that the folding force decreases with the speed of unfolding and folding respectively. Moreover, the PapA rod can be folded-unfolded a significant number of times without loosing its characteristics, a phenomenon that is believed to be important for the bacterium to keep close contact to the host tissue and consequently helps the bacterium to colonize the host tissue.

  12. GaAs Optoelectronic Integrated-Circuit Neurons

    Science.gov (United States)

    Lin, Steven H.; Kim, Jae H.; Psaltis, Demetri

    1992-01-01

    Monolithic GaAs optoelectronic integrated circuits developed for use as artificial neurons. Neural-network computer contains planar arrays of optoelectronic neurons, and variable synaptic connections between neurons effected by diffraction of light from volume hologram in photorefractive material. Basic principles of neural-network computers explained more fully in "Optoelectronic Integrated Circuits For Neural Networks" (NPO-17652). In present circuits, devices replaced by metal/semiconductor field effect transistors (MESFET's), which consume less power.

  13. Graphene optoelectronics synthesis, characterization, properties, and applications

    CERN Document Server

    bin M Yusoff, Abdul Rashid

    2014-01-01

    This first book on emerging applications for this innovative material gives an up-to-date account of the many opportunities graphene offers high-end optoelectronics.The text focuses on potential as well as already realized applications, discussing metallic and passive components, such as transparent conductors and smart windows, as well as high-frequency devices, spintronics, photonics, and terahertz devices. Also included are sections on the fundamental properties, synthesis, and characterization of graphene. With its unique coverage, this book will be welcomed by materials scientists, solid-

  14. Optoelectronic image processing for cervical cancer screening

    Science.gov (United States)

    Narayanswamy, Ramkumar; Sharpe, John P.; Johnson, Kristina M.

    1994-05-01

    Automation of the Pap-smear cervical screening method is highly desirable as it relieves tedium for the human operators, reduces cost and should increase accuracy and provide repeatability. We present here the design for a high-throughput optoelectronic system which forms the first stage of a two stage system to automate pap-smear screening. We use a mathematical morphological technique called the hit-or-miss transform to identify the suspicious areas on a pap-smear slide. This algorithm is implemented using a VanderLugt architecture and a time-sequential ANDing smart pixel array.

  15. Visualizing Optoelectronic Processes at the Nanoscale.

    Science.gov (United States)

    Mishra, Puneet; Komeda, Tadahiro

    2015-11-24

    In this issue of ACS Nano, Nienhaus et al. report the optoelectronic properties of carbon nanotube chiral junctions with nanometer resolution in the presence of strong electric fields (∼1 V/nm). Here, we provide an overview of recent studies that combine scanning tunneling microscope (STM) and laser or microwave illumination. These techniques reveal nanoscale laser- or microwave-induced phenomena utilizing the intrinsic atomic resolution of the tunneling current, and do not require substantial modification of the STM itself. The merits of atomic-scale spatial resolution and chemical sensitivity of the laser or microwave spectroscopes make these techniques useful for nanoscale characterization. PMID:26524228

  16. Broadband Chaos Generated by an Optoelectronic Oscillator

    Science.gov (United States)

    Callan, Kristine E.; Illing, Lucas; Gao, Zheng; Gauthier, Daniel J.; Schöll, Eckehard

    2010-03-01

    We study an optoelectronic time-delay oscillator that displays high-speed chaotic behavior with a flat, broad power spectrum. The chaotic state coexists with a linearly stable fixed point, which, when subjected to a finite-amplitude perturbation, loses stability initially via a periodic train of ultrafast pulses. We derive approximate mappings that do an excellent job of capturing the observed instability. The oscillator provides a simple device for fundamental studies of time-delay dynamical systems and can be used as a building block for ultrawide-band sensor networks.

  17. Optoelectronic Infrastructure for RF/Optical Phased Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Optoelectronic integrated circuits offer radiation-hard solutions for satellite systems with much improved SWPB (size, weight, power and bandwidth). The phased...

  18. Elimination or minimisation of optoelectronic crosstalk between photodiodes and electronic devices in OEIC on Si

    NARCIS (Netherlands)

    Zhou, M.-J.; Holleman, J.; Wallinga, H.

    1994-01-01

    The optoelectronic crosstalk between photodiodes and electronic devices is observed and investigated in OEICs based on silicon. Results show that the phenomenon is closely related to the diffusion of minority carriers, generated by photon absorption. The crosstalk can be eliminated or minimised by e

  19. Functional inks of graphene, metal dichalcogenides and black phosphorus for photonics and (opto)electronics

    Science.gov (United States)

    Howe, Richard C. T.; Hu, Guohua; Yang, Zongyin; Hasan, Tawfique

    2015-08-01

    We discuss the emerging role of solution processing and functional ink formulation in the fabrication of devices based on two dimensional (2d) materials. By drawing on examples from our research, we show that these inks allow 2d materials to be exploited in a wide variety of applications, including in photonics and (opto)electronics.

  20. Millimeter-wave and optoelectronic applications of heterostructure integrated circuits

    Science.gov (United States)

    Pavlidis, Dimitris

    1991-01-01

    The properties are reviewed of heterostructure devices for microwave-monolithic-integrated circuits (MMICs) and optoelectronic integrated circuits (OICs). Specific devices examined include lattice-matched and pseudomorphic InAlAs/InGaAs high-electron mobility transistors (HEMTs), mixer/multiplier diodes, and heterojunction bipolar transistors (HBTs) developed with a number of materials. MMICs are reviewed that can be employed for amplification, mixing, and signal generation, and receiver/transmitter applications are set forth for OICs based on GaAs and InP heterostructure designs. HEMTs, HBTs, and junction-FETs can be utilized in combination with PIN, MSM, and laser diodes to develop novel communication systems based on technologies that combine microwave and photonic capabilities.

  1. Optical thin film metrology for optoelectronics

    International Nuclear Information System (INIS)

    The manufacturing of optoelectronic thin films is of key importance, because it underpins a significant number of industries. The aim of the European joint research project for optoelectronic thin film characterization (IND07) in the European Metrology Research Programme of EURAMET is to develop optical and X-ray metrologies for the assessment of quality as well as key parameters of relevant materials and layer systems. This work is intended to be a step towards the establishment of validated reference metrologies for the reliable characterization, and the development of calibrated reference samples with well-defined and controlled parameters. In a recent comprehensive study (including XPS, AES, GD-OES, GD-MS, SNMS, SIMS, Raman, SE, RBS, ERDA, GIXRD), Abou-Ras et al. (Microscopy and Microanalysis 17 [2011] 728) demonstrated that most characterization techniques have limitations and bottle-necks, and the agreement of the measurement results in terms of accurate, absolute values is not as perfect as one would expect. This paper focuses on optical characterization techniques, laying emphasis on hardware and model development, which determine the kind and number of parameters that can be measured, as well as their accuracy. Some examples will be discussed including optical techniques and materials for photovoltaics, biosensors and waveguides.

  2. Optoelectronic inventory system for special nuclear material

    Energy Technology Data Exchange (ETDEWEB)

    Sieradzki, F.H.

    1994-01-01

    In support of the Department of Energy`s Dismantlement Program, the Optoelectronics Characterization and Sensor Development Department 2231 at Sandia National Laboratories/New Mexico has developed an in situ nonintrusive Optoelectronic Inventory System (OIS) that has the potential for application wherever periodic inventory of selected material is desired. Using a network of fiber-optic links, the OIS retrieves and stores inventory signatures from data storage devices (which are permanently attached to material storage containers) while inherently providing electromagnetic pulse immunity and electrical noise isolation. Photovoltaic cells (located within the storage facility) convert laser diode optic power from a laser driver to electrical energy. When powered and triggered, the data storage devices sequentially output their digital inventory signatures through light-emitting diode/photo diode data links for retrieval and storage in a mobile data acquisition system. An item`s exact location is determined through fiber-optic network and software design. The OIS provides an on-demand method for obtaining acceptable inventory reports while eliminating the need for human presence inside the material storage facility. By using modularization and prefabricated construction with mature technologies and components, an OIS installation with virtually unlimited capacity can be tailored to the customer`s requirements.

  3. Optoelectronic pH Meter: Further Details

    Science.gov (United States)

    Jeevarajan, Antony S.; Anderson, Mejody M.; Macatangay, Ariel V.

    2009-01-01

    A collection of documents provides further detailed information about an optoelectronic instrument that measures the pH of an aqueous cell-culture medium to within 0.1 unit in the range from 6.5 to 7.5. The instrument at an earlier stage of development was reported in Optoelectronic Instrument Monitors pH in a Culture Medium (MSC-23107), NASA Tech Briefs, Vol. 28, No. 9 (September 2004), page 4a. To recapitulate: The instrument includes a quartz cuvette through which the medium flows as it is circulated through a bioreactor. The medium contains some phenol red, which is an organic pH-indicator dye. The cuvette sits between a light source and a photodetector. [The light source in the earlier version comprised red (625 nm) and green (558 nm) light-emitting diodes (LEDs); the light source in the present version comprises a single green- (560 nm)-or-red (623 nm) LED.] The red and green are repeatedly flashed in alternation. The responses of the photodiode to the green and red are processed electronically to obtain the ratio between the amounts of green and red light transmitted through the medium. The optical absorbance of the phenol red in the green light varies as a known function of pH. Hence, the pH of the medium can be calculated from the aforesaid ratio.

  4. Optoelectronic inventory system for special nuclear material

    International Nuclear Information System (INIS)

    In support of the Department of Energy's Dismantlement Program, the Optoelectronics Characterization and Sensor Development Department 2231 at Sandia National Laboratories/New Mexico has developed an in situ nonintrusive Optoelectronic Inventory System (OIS) that has the potential for application wherever periodic inventory of selected material is desired. Using a network of fiber-optic links, the OIS retrieves and stores inventory signatures from data storage devices (which are permanently attached to material storage containers) while inherently providing electromagnetic pulse immunity and electrical noise isolation. Photovoltaic cells (located within the storage facility) convert laser diode optic power from a laser driver to electrical energy. When powered and triggered, the data storage devices sequentially output their digital inventory signatures through light-emitting diode/photo diode data links for retrieval and storage in a mobile data acquisition system. An item's exact location is determined through fiber-optic network and software design. The OIS provides an on-demand method for obtaining acceptable inventory reports while eliminating the need for human presence inside the material storage facility. By using modularization and prefabricated construction with mature technologies and components, an OIS installation with virtually unlimited capacity can be tailored to the customer's requirements

  5. Optical thin film metrology for optoelectronics

    Science.gov (United States)

    Petrik, Peter

    2012-12-01

    The manufacturing of optoelectronic thin films is of key importance, because it underpins a significant number of industries. The aim of the European joint research project for optoelectronic thin film characterization (IND07) in the European Metrology Research Programme of EURAMET is to develop optical and X-ray metrologies for the assessment of quality as well as key parameters of relevant materials and layer systems. This work is intended to be a step towards the establishment of validated reference metrologies for the reliable characterization, and the development of calibrated reference samples with well-defined and controlled parameters. In a recent comprehensive study (including XPS, AES, GD-OES, GD-MS, SNMS, SIMS, Raman, SE, RBS, ERDA, GIXRD), Abou-Ras et al. (Microscopy and Microanalysis 17 [2011] 728) demonstrated that most characterization techniques have limitations and bottle-necks, and the agreement of the measurement results in terms of accurate, absolute values is not as perfect as one would expect. This paper focuses on optical characterization techniques, laying emphasis on hardware and model development, which determine the kind and number of parameters that can be measured, as well as their accuracy. Some examples will be discussed including optical techniques and materials for photovoltaics, biosensors and waveguides.

  6. Combining optical tweezers and scanning probe microscopy to study DNA-protein interactions

    NARCIS (Netherlands)

    Huisstede, Jurgen H.G.; Subramaniam, Vinod; Bennink, Martin L.

    2007-01-01

    We present the first results obtained with a new instrument designed and built to study DNA-protein interactions at the single molecule level. This microscope combines optical tweezers with scanning probe microscopy and allows us to locate DNA-binding proteins on a single suspended DNA molecule. A s

  7. Research Advances: Nanoscale Molecular Tweezers; Cinnamon as Pesticide?; Recently Identified Dietary Sources of Antioxidants

    Science.gov (United States)

    King, Angela G.

    2004-12-01

    This Report from Other Journals surveys articles of interest to chemists that have been recently published in other science journals. Topics surveyed include reports that receptors have been designed to act as molecular tweezers; cinnamon has potential in the fight against mosquitoes; and high levels of antioxidants are found in some surprising foods. See Featured Molecules .

  8. Holographic Raman tweezers controlled by multi-modal natural user interface

    Czech Academy of Sciences Publication Activity Database

    Tomori, Z.; Keša, P.; Nikorovič, M.; Kaňka, Jan; Jákl, Petr; Šerý, Mojmír; Bernatová, Silvie; Valušová, E.; Antalík, M.; Zemánek, Pavel

    2016-01-01

    Roč. 18, č. 1 (2016), 015602:1-9. ISSN 2040-8978 R&D Projects: GA MŠk(CZ) LO1212; GA MŠk(CZ) LD14069 Institutional support: RVO:68081731 Keywords : holographic optical tweezers * Raman microspectroscopy * human-computer interface Subject RIV: BH - Optics, Masers, Laser s Impact factor: 2.059, year: 2014

  9. High-refractive index particles in counter-propagating optical tweezers - manipulation and forces

    NARCIS (Netherlands)

    Horst, Astrid van der

    2006-01-01

    With a tightly focused single laser beam, also called optical tweezers, particles of a few nanometers up to several micrometers in size can be trapped and manipulated in 3D. The size, shape and refractive index of such colloidal particles are of influence on the optical forces exerted on them in the

  10. Construction and actuation of a microscopic gear assembly formed using optical tweezers

    International Nuclear Information System (INIS)

    The assembly of micrometer-sized parts is an important manufacturing process; any development in it could potentially change the current manufacturing practices for micrometer-scale devices. Due to the lack of reliable microassembly techniques, these devices are often manufactured using silicon, which includes etching and depositions with little use of assembly processes. The result is the requirement of specialized manufacturing conditions with hazardous byproducts and limited applications where only simple mechanisms are allowed. Optical tweezers are non-contact type manipulators that are very suitable for assembling microparts and solve one of the most difficult problems for microassembly, which is the sticking of the physical manipulator to the micropart. Although contact type manipulators can be surface modified to be non-sticky, this involves extra preprocessing—optical tweezers do not require such additional efforts. The weakness of using optical tweezers is that the permanent assembly of parts is not possible as only very small forces can be applied. We introduce an advanced microassembly environment with the combined use of optical tweezers and a motorized microtip, where the former is used to position two parts and the latter is used to introduce deformation in the parts so that they form a strongly fitted assembly. (paper)

  11. Listening to proteins and viruses with nanoaperture optical tweezers (Presentation Recording)

    Science.gov (United States)

    Gordon, Reuven

    2015-08-01

    This talk will present a nanoaperture tweezer approach to measure the acoustic spectra of viruses and single proteins. The approach, termed extraordinary optical Raman (EAR), shows promise for uncovering the structure and mechanical properties of nanoparticles as well as the effects of their interactions.

  12. Optical alignment and confinement of an ellipsoidal nanorod in optical tweezers: a theoretical study

    Czech Academy of Sciences Publication Activity Database

    Trojek, Jan; Chvátal, Lukáš; Zemánek, Pavel

    2012-01-01

    Roč. 29, č. 7 (2012), s. 1224-1236. ISSN 1084-7529 R&D Projects: GA ČR GA202/09/0348; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : ellipsoidal nanorod * optical tweezers * Rayleigh approximation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.665, year: 2012

  13. RBC aggregation dynamics in autologous plasma and serum studied with double-channel optical tweezers

    Science.gov (United States)

    Lee, Kisung; Danilina, Anna; Potkin, Anton; Kinnunen, Matti; Priezzhev, Alexander; Meglinski, Igor

    2016-04-01

    Red blood cells aggregating and disaggregating forces were measured in the autologous plasma and serum using the double-channeled optical tweezers. A significant, three-fold decrease of the both forces was observed in the serum compared to the plasma. The results of this study help to better assess the RBC aggregation mechanism.

  14. Optimizing Optoelectronic Properties of Pyrimidine-Based TADF Emitters by Changing the Substituent for Organic Light-Emitting Diodes with External Quantum Efficiency Close to 25 % and Slow Efficiency Roll-Off.

    Science.gov (United States)

    Wu, Kailong; Zhang, Tao; Zhan, Lisi; Zhong, Cheng; Gong, Shaolong; Jiang, Nan; Lu, Zheng-Hong; Yang, Chuluo

    2016-07-25

    A series of green butterfly-shaped thermally activated delayed fluorescence (TADF) emitters, namely PXZPM, PXZMePM, and PXZPhPM, are developed by integrating an electron-donor (D) phenoxazine unit and electron-acceptor (A) 2-substituted pyrimidine moiety into one molecule via a phenyl-bridge π linkage to form a D-π-A-π-D configuration. Changing the substituent at pyrimidine unit in these emitters can finely tune their emissive characteristics, thermal properties, and energy gaps between the singlet and triplet states while maintaining frontier molecular orbital levels, and thereby optimizing their optoelectronic properties. Employing these TADF emitters results in a green fluorescent organic light-emitting diode (OLED) that exhibits a peak forward-viewing external quantum efficiency (EQE) close to 25 % and a slow efficiency roll-off characteristic at high luminance. PMID:27331374

  15. Synthesis and Properties of Bis-Porphyrin Molecular Tweezers: Effects of Spacer Flexibility on Binding and Supramolecular Chirogenesis

    Directory of Open Access Journals (Sweden)

    Magnus Blom

    2015-12-01

    Full Text Available Ditopic binding of various dinitrogen compounds to three bisporphyrin molecular tweezers with spacers of varying conformational rigidity, incorporating the planar enediyne (1, the helical stiff stilbene (2, or the semi-rigid glycoluril motif fused to the porphyrins (3, are compared. Binding constants Ka = 104–106 M−1 reveal subtle differences between these tweezers, that are discussed in terms of porphyrin dislocation modes. Exciton coupled circular dichroism (ECCD of complexes with chiral dinitrogen guests provides experimental evidence for the conformational properties of the tweezers. The results are further supported and rationalized by conformational analysis.

  16. Preparation and Photo-thermal Isomerization of Azo [2.2.1]-and Azo[2.2.3]metacyclophane Tweezers

    OpenAIRE

    Sawada, Tsuyoshi; Thiemann, Thies; Mataka, Shuntaro

    1999-01-01

    Azo[2.2.1]metacyclophane (MCP) tweezer 11 and azo[2.2.3]MCP tweezer 12 were prepared from [2.2.1]MCP 1a and [2.2.3]MCP 8, respectively, by ipso-nitration followed by reductive coupling using LiAlH_4. The photochemical and thermal isomerization of azo[2.2.n]MCP tweezers were studied by UV spectroscopy. The activation parameter (E_a) of the thermal cis-trans isomerization of 11 and 12 was determined as 81.7 kJmol^ and 90.9 kJmol^, respectively.

  17. Design of Optoelectronic Method for Diabetic Nefropathy Diagnose

    Czech Academy of Sciences Publication Activity Database

    Dordová, L.; Wilfert, O.; Bartušek, Karel

    Bilbao : Publicaciones - Escuela Técnica Superior de Ingenieria , 2007, s. 173-179. ISBN 978-84-95809-29-2. [International Conference on Engineering and Mathematics 2007. Bilbao (ES), 09.07.2007-11.07.2007] Institutional research plan: CEZ:AV0Z20650511 Keywords : optoelectronic method * diabetic nefropathy Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  18. Optoelectronic hit/miss transform for screening cervical smear slides

    Science.gov (United States)

    Narayanswamy, R.; Turner, R. M.; McKnight, D. J.; Johnson, K. M.; Sharpe, J. P.

    1995-06-01

    An optoelectronic morphological processor for detecting regions of interest (abnormal cells) on a cervical smear slide using the hit/miss transform is presented. Computer simulation of the algorithm tested on 184 Pap-smear images provided 95% detection and 5% false alarm. An optoelectronic implementation of the hit/miss transform is presented, along with preliminary experimental results.

  19. Spatially resolved optoelectronic characterization of perovskite lead iodide nanostructures

    Science.gov (United States)

    Xiao, Rui; Peng, Xingyu; Hou, Yasen; Yu, Dong

    The high power conversion efficiency of organo-lead halide perovskite-based solar cells has attracted world-wide attention over the past few years. The high efficiency was believed to originate from the unusual properties including long carrier lifetimes and consequent long carrier diffusion lengths in these materials. Ion drift, ferroelectricity, and charge traps have been proposed to account for the efficient charge separation and photocurrent hysteresis. However, it remains unclear which mechanism is dominating. We fabricate field effect transistors (FETs) incorporating single nanoplates/nanowires of organic perovskite and perform scanning photocurrent microscopic (SPCM) measurements to extract carrier diffusion lengths as a function of gate voltage, source-drain bias. Spatially resolved optoelectronic investigations of single crystalline perovskite nanostructures provide valuable information and key evidence on distinguishing the dominating charge transport/separation mechanism.

  20. 77 FR 65713 - Certain Optoelectronic Devices for Fiber Optic Communications, Components Thereof, and Products...

    Science.gov (United States)

    2012-10-30

    ... COMMISSION Certain Optoelectronic Devices for Fiber Optic Communications, Components Thereof, and Products... the United States after importation of certain optoelectronic devices for fiber optic communications... importation of certain optoelectronic devices for fiber optic communications, components thereof, and...

  1. Introduction to the new journal: Frontiers of Optoelectronics in China

    Institute of Scientific and Technical Information of China (English)

    Bingkun ZHOU

    2008-01-01

    @@ China, together with the world, has made enormous achievements in the field of optoelectronics in recent years and is still now undergoing the processes of rapid advancement.Chinese Researchers have devoted themselves to finding out ways to solve the problems in optoelectronics, and have made substantial progress theoretically and experimentally.Thus, a platform is needed on which researchers could share their new findings and technological advances in the field of optoelectronics and related disciplines with colleagues around the world.The new launched journal, Frontiers of Optoelectronics in China, aims to serve such a platform that provides a way for scientists all over the world to share the ideas and technologies in the field of optoelectronics.

  2. Optoelectronic circuits in nanometer CMOS technology

    CERN Document Server

    Atef, Mohamed

    2016-01-01

    This book describes the newest implementations of integrated photodiodes fabricated in nanometer standard CMOS technologies. It also includes the required fundamentals, the state-of-the-art, and the design of high-performance laser drivers, transimpedance amplifiers, equalizers, and limiting amplifiers fabricated in nanometer CMOS technologies. This book shows the newest results for the performance of integrated optical receivers, laser drivers, modulator drivers and optical sensors in nanometer standard CMOS technologies. Nanometer CMOS technologies rapidly advanced, enabling the implementation of integrated optical receivers for high data rates of several Giga-bits per second and of high-pixel count optical imagers and sensors. In particular, low cost silicon CMOS optoelectronic integrated circuits became very attractive because they can be extensively applied to short-distance optical communications, such as local area network, chip-to-chip and board-to-board interconnects as well as to imaging and medical...

  3. Electroactive and Optoelectronically Active Graphene Nanofilms

    DEFF Research Database (Denmark)

    Chi, Qijin

    As an atomic-scale-thick two-dimensional material, graphene has emerged as one of the most miracle materials and has generated intensive interest in physics, chemistry and even biology in the last decade [1, 2]. Nanoscale engineering and functionalization of graphene is a crucial step for many...... applications ranging from catalysis, electronic devices, sensors to advanced energy conversion and storage [3]. This talk highlights our recent studies on electroactive and optoelectronically active graphene ultrathin films for chemical sensors and energy technology. The presentation includes a general theme...... for functionalization of graphene nanosheets, followed by showing several case studies. Our systems cover redox-active nanoparticles, electroactive supramolecular ensembles and redox enzymes which are integrated with graphene nanosheets as building blocks for the construction of functional thin films or graphene papers....

  4. Compound Semiconductor Nano structures for Optoelectronic Applications

    International Nuclear Information System (INIS)

    Compound semiconductors belong to an important class of semiconductors which have direct band gaps and are exploited in optoelectronic applications for efficient emission of optical radiation ranging in wavelengths from the infrared to the ultraviolet. They are principally classified into Gp II-Vs such as GaN, GaAs and InP and Gp II-VIs such as ZnO, CdS and CdTe. Besides being used as light emitters, some compound semiconductors have large carrier mobility and high breakdown voltage compared to Si, the mainstay of the integrated circuit industry. They are now being considered for high power and very high speed electronic devices. Device performance for optoelectronic applications are measured in terms of internal and external quantum efficiency. These are related to materials quality and light extraction efficiency. Defects are generally generated because of lattice mismatch between the device epitaxial layers and the substrate. Ways have to be found to reduce the stress or through compensation by introducing intermediate layers. The wide range of band gaps available is utilized in heterojunctions to create potential barriers for confining charge carriers such as in quantum wells and quantum dots that result in more efficient radiative recombination. For solid-state lighting application, the quality of lighting is measured by an additional parameter known the color rendering index. In all the above-mentioned considerations, nano structures have been used to provide solutions to enhance the performance parameters of the optical devices. In this presentation, some examples of applications of nano structures are described together with their motivations, fabrication techniques and the results. Two compound semiconductors, GaN for Gp III-V and ZnO for Gp II-VI, are used for the fabrication of the nano structures. (author)

  5. Hydrogel-colloid interfacial interactions: a study of tailored adhesion using optical tweezers.

    Science.gov (United States)

    Sheikhi, Amir; Hill, Reghan J

    2016-08-21

    Dynamics of colloidal particles adhering to soft, deformable substrates, such as tissues, biofilms, and hydrogels play a key role in many biological and biomimetic processes. These processes, including, but not limited to colloid-based delivery, stitching, and sorting, involve microspheres exploring the vicinity of soft, sticky materials in which the colloidal dynamics are affected by the fluid environment (e.g., viscous coupling), inter-molecular interactions between the colloids and substrates (e.g., Derjaguin-Landau-Verwey-Overbeek (DLVO) theory), and the viscoelastic properties of contact region. To better understand colloidal dynamics at soft interfaces, an optical tweezers back-focal-plane interferometry apparatus was developed to register the transverse Brownian motion of a silica microsphere in the vicinity of polyacrylamide (PA) hydrogel films. The time-dependent mean-squared displacements are well described by a single exponential relaxation, furnishing measures of the transverse interfacial diffusion coefficient and binding stiffness. Substrates with different elasticities were prepared by changing the PA crosslinking density, and the inter-molecular interactions were adjusted by coating the microspheres with fluid membranes. Stiffer PA hydrogels (with bulk Young's moduli ≈1-10 kPa) immobilize the microspheres more firmly (lower diffusion coefficient and position variance), and coating the particles with zwitterionic lipid bilayers (DOPC) completely eliminates adhesion, possibly by repulsive dispersion forces. Remarkably, embedding polyethylene glycol-grafted lipid bilayers (DSPE-PEG2k-Amine) in the zwitterionic fluid membranes produces stronger adhesion, possibly because of polymer-hydrogel attraction and entanglement. This study provides new insights to guide the design of nanoparticles and substrates with tunable adhesion, leading to smarter delivery, sorting, and screening of micro- and nano-systems. PMID:27425660

  6. Investigation into local cell mechanics by atomic force microscopy mapping and optical tweezer vertical indentation.

    Science.gov (United States)

    Coceano, G; Yousafzai, M S; Ma, W; Ndoye, F; Venturelli, L; Hussain, I; Bonin, S; Niemela, J; Scoles, G; Cojoc, D; Ferrari, E

    2016-02-12

    Investigating the mechanical properties of cells could reveal a potential source of label-free markers of cancer progression, based on measurable viscoelastic parameters. The Young's modulus has proved to be the most thoroughly studied so far, however, even for the same cell type, the elastic modulus reported in different studies spans a wide range of values, mainly due to the application of different experimental conditions. This complicates the reliable use of elasticity for the mechanical phenotyping of cells. Here we combine two complementary techniques, atomic force microscopy (AFM) and optical tweezer microscopy (OTM), providing a comprehensive mechanical comparison of three human breast cell lines: normal myoepithelial (HBL-100), luminal breast cancer (MCF-7) and basal breast cancer (MDA-MB-231) cells. The elastic modulus was measured locally by AFM and OTM on single cells, using similar indentation approaches but different measurement parameters. Peak force tapping AFM was employed at nanonewton forces and high loading rates to draw a viscoelastic map of each cell and the results indicated that the region on top of the nucleus provided the most meaningful results. OTM was employed at those locations at piconewton forces and low loading rates, to measure the elastic modulus in a real elastic regime and rule out the contribution of viscous forces typical of AFM. When measured by either AFM or OTM, the cell lines' elasticity trend was similar for the aggressive MDA-MB-231 cells, which were found to be significantly softer than the other two cell types in both measurements. However, when comparing HBL-100 and MCF-7 cells, we found significant differences only when using OTM. PMID:26683826

  7. Investigation into local cell mechanics by atomic force microscopy mapping and optical tweezer vertical indentation

    Science.gov (United States)

    Coceano, G.; Yousafzai, M. S.; Ma, W.; Ndoye, F.; Venturelli, L.; Hussain, I.; Bonin, S.; Niemela, J.; Scoles, G.; Cojoc, D.; Ferrari, E.

    2016-02-01

    Investigating the mechanical properties of cells could reveal a potential source of label-free markers of cancer progression, based on measurable viscoelastic parameters. The Young’s modulus has proved to be the most thoroughly studied so far, however, even for the same cell type, the elastic modulus reported in different studies spans a wide range of values, mainly due to the application of different experimental conditions. This complicates the reliable use of elasticity for the mechanical phenotyping of cells. Here we combine two complementary techniques, atomic force microscopy (AFM) and optical tweezer microscopy (OTM), providing a comprehensive mechanical comparison of three human breast cell lines: normal myoepithelial (HBL-100), luminal breast cancer (MCF-7) and basal breast cancer (MDA-MB-231) cells. The elastic modulus was measured locally by AFM and OTM on single cells, using similar indentation approaches but different measurement parameters. Peak force tapping AFM was employed at nanonewton forces and high loading rates to draw a viscoelastic map of each cell and the results indicated that the region on top of the nucleus provided the most meaningful results. OTM was employed at those locations at piconewton forces and low loading rates, to measure the elastic modulus in a real elastic regime and rule out the contribution of viscous forces typical of AFM. When measured by either AFM or OTM, the cell lines’ elasticity trend was similar for the aggressive MDA-MB-231 cells, which were found to be significantly softer than the other two cell types in both measurements. However, when comparing HBL-100 and MCF-7 cells, we found significant differences only when using OTM.

  8. Optical tweezers for single molecule force spectroscopy on bacterial adhesion organelles

    Science.gov (United States)

    Andersson, Magnus; Axner, Ove; Uhlin, Bernt Eric; Fällman, Erik

    2006-08-01

    Instrumentation and methodologies for single molecule force spectroscopy on bacterial adhesion organelles by the use of force measuring optical tweezers have been developed. A thorough study of the biomechanical properties of fimbrial adhesion organelles expressed by uropathogenic E. coli, so-called pili, is presented. Steady-state as well as dynamic force measurements on P pili, expressed by E. coli causing pyelonephritis, have revealed, among other things, various unfolding and refolding properties of the helical structure of P pili, the PapA rod. Based on these properties an energy landscape model has been constructed by which specific biophysical properties of the PapA rod have been extracted, e.g. the number of subunits, the length of a single pilus, bond lengths and activation energies for bond opening and closure. Moreover, long time repetitive measurements have shown that the rod can be unfolded and refolded repetitive times without losing its intrinsic properties. These properties are believed to be of importance for the bacteria's ability to maintain close contact with host cells during initial infections. The results presented are considered to be of importance for the field of biopolymers in general and the development of new pharmaceuticals towards urinary tract infections in particular. The results show furthermore that the methodology can be used to gain knowledge of the intrinsic biomechanical function of adhesion organelles. The instrumentation is currently used for characterization of type 1 pili, expressed by E. coli causing cystitis, i.e. infections in the bladder. The first force spectrometry investigations of these pili will be presented.

  9. Computational Design of Optoelectronic and Spintronic Devices in Graphene Nanoribbon Heterojunctions

    Science.gov (United States)

    Prakash, Avinash; Ertekin, Elif

    2014-03-01

    Graphene is well known to possess outstanding electronic and structural properties. The potential of two-dimensional materials in creating next-generation optoelectronic computing systems has been exhibited both computationally and experimentally. In this contribution, we use first-principles total energy electronic structure methods to develop design principles for optoelectronic devices, such as resonant tunneling diodes and double heterostructure lasers, in nanostructured graphene. A density functional theory approach utilizing non-equilibrium Green's functions and the Landauer-Büttiker formalism for ballistic transport provides the spin-polarized transmission spectrum and I-V characteristics of the devices. These calculations can quantify the effects of nanoribbon topology on the device characteristics. We report negative differential resistance and spin filtering effects that can be engineered in novel logic circuits based on resonant tunneling. Our results provide the impetus to fabricate optoelectronic and spintronic devices from monomer organic molecules via bottom-up chemical synthesis methods. We elucidate the applicability of graphene nanoribbons in optoelectronic molecular computing.

  10. Communications with chaotic optoelectronic systems cryptography and multiplexing

    Science.gov (United States)

    Rontani, Damien

    With the rapid development of optical communications and the increasing amount of data exchanged, it has become utterly important to provide effective architectures to protect sensitive data. The use of chaotic optoelectronic devices has already demonstrated great potential in terms of additional computational security at the physical layer of the optical network. However, the determination of the security level and the lack of a multi-user framework are two hurdles which have prevented their deployment on a large scale. In this thesis, we propose to address these two issues. First, we investigate the security of a widely used chaotic generator, the external cavity semiconductor laser (ECSL). This is a time-delay system known for providing complex and high-dimensional chaos, but with a low level of security regarding the identification of its most critical parameter, the time delay. We perform a detailed analysis of the in uence of the ECSL parameters to devise how higher levels of security can be achieved and provide a physical interpretation of their origin. Second, we devise new architectures to multiplex optical chaotic signals and realize multi-user communications at high bit rates. We propose two different approaches exploiting known chaotic optoelectronic devices. The first one uses mutually coupled ECSL and extends typical chaos-based encryption strategies, such as chaos-shift keying (CSK) and chaos modulation (CMo). The second one uses an electro-optical oscillator (EOO) with multiple delayed feedback loops and aims first at transposing coded-division multiple access (CDMA) and then at developing novel strategies of encryption and decryption, when the time-delays of each feedback loop are time-dependent.

  11. OLED-on-CMOS integration for optoelectronic sensor applications

    Science.gov (United States)

    Vogel, Uwe; Kreye, Daniel; Reckziegel, Sven; Törker, Michael; Grillberger, Christiane; Amelung, Jörg

    2007-02-01

    Highly-efficient, low-voltage organic light emitting diodes (OLEDs) are well suitable for post-processing integration onto the top metal layer of CMOS devices. This has been proven for OLED microdisplays so far. Moreover, OLEDon- CMOS technology may also be excellently suitable for various optoelectronic sensor applications by combining highly efficient emitters, use of low-cost materials and cost-effective manufacturing together with silicon-inherent photodetectors and CMOS circuitry. The use of OLEDs on CMOS substrates requires a top-emitting, low-voltage and highly efficient OLED structure. By reducing the operating voltage for the OLED below 5V, the costs for the CMOS process can be reduced, because a process without high-voltage option can be used. Red, orange, white, green and blue OLED-stacks with doped charge transport layers were prepared on different dualmetal layer CMOS test substrates without active transistor area. Afterwards, the different devices were measured and compared with respect to their performance (current, luminance, voltage, luminance dependence on viewing angle, optical outcoupling etc.). Low operating voltages of 2.4V at 100cd/m2 for the red p-i-n type phosphorescent emitting OLED stack, 2.5V at 100cd/m2 for the orange phosphorescent emitting OLED stack and 3.2V at 100cd/m2 for the white fluorescent emitting OLED have been achieved here. Therefore, those OLED stacks are suitable for use in a CMOS process even within a regular 5V process option. Moreover, the operating voltage achieved so far is expected to be reduced further when using different top electrode materials. Integrating such OLEDs on a CMOS-substrate provide a preferable choice for silicon-based optical microsystems targeted towards optoelectronic sensor applications, as there are integrated light barriers, optocouplers, or lab-onchip devices.

  12. Membrane tether formation from voltage-clamped outer hair cells using optical tweezers

    Science.gov (United States)

    Qian, Feng; Ermilov, Sergey A.; Murdock, David R.; Brownell, William E.; Anvari, Bahman

    2004-06-01

    Outer hair cells contribute an active mechanical feedback to the vibrations of the cochlear structures resulting in the high sensitivity and frequency selectivity of normal hearing. We have designed and implemented a novel experimental setup that combines optical tweezers with patch-clamp apparatus to investigate the electromechanical properties of cellular plasma membranes. A micron-size bead trapped by the optical tweezers is brought in contact with the membrane of a voltage-clamped cell, and subsequently moved away to form a plasma membrane tether. Bead displacement during tether elongation is monitored by a quadrant photodetector to obtain time-resolved measurements of the tethering force. Salient information associated with the mechanical properties of the membrane tether can thus be obtained. Tethers can be pulled from the cell membrane at different holding potentials, and the tether force response can be measured while changing transmembrane potential. Experimental results from outer hair cells and human embryonic kidney cells are presented.

  13. Observation of a single-beam gradient force acoustical trap for elastic particles: acoustical tweezers

    CERN Document Server

    Baresch, Diego; Marchiano, Régis

    2016-01-01

    The ability to manipulate matter precisely is critical for the study and development of a large variety of systems. Optical tweezers are excellent tools to handle particles ranging in size from a few micrometers to hundreds of nanometers but become inefficient and damaging on larger objects. We demonstrate for the first reported time the trapping of elastic particles by the large gradient force of a single acoustical beam in three dimensions. We show that at equal power, acoustical forces overtake by 8 orders of magnitude that of optical ones on macroscopic objects. Acoustical tweezers can push, pull and accurately control both the position of the particle and the forces exerted under damage-free conditions. The large spectrum of frequencies covered by coherent ultrasonic sources will provide a wide variety of manipulation possibilities from macro- to microscopic length scales. We believe our observations improve the prospects for wider use of non-contact manipulation in biology, biophysics, microfluidics and...

  14. In Vivo Quantification of Peroxisome Tethering to Chloroplasts in Tobacco Epidermal Cells Using Optical Tweezers.

    Science.gov (United States)

    Gao, Hongbo; Metz, Jeremy; Teanby, Nick A; Ward, Andy D; Botchway, Stanley W; Coles, Benjamin; Pollard, Mark R; Sparkes, Imogen

    2016-01-01

    Peroxisomes are highly motile organelles that display a range of motions within a short time frame. In static snapshots, they can be juxtaposed to chloroplasts, which has led to the hypothesis that they are physically interacting. Here, using optical tweezers, we tested the dynamic physical interaction in vivo. Using near-infrared optical tweezers combined with TIRF microscopy, we were able to trap peroxisomes and approximate the forces involved in chloroplast association in vivo in tobacco (Nicotiana tabacum) and observed weaker tethering to additional unknown structures within the cell. We show that chloroplasts and peroxisomes are physically tethered through peroxules, a poorly described structure in plant cells. We suggest that peroxules have a novel role in maintaining peroxisome-organelle interactions in the dynamic environment. This could be important for fatty acid mobilization and photorespiration through the interaction with oil bodies and chloroplasts, highlighting a fundamentally important role for organelle interactions for essential biochemistry and physiological processes. PMID:26518344

  15. Measurement of particle motion in optical tweezers embedded in a Sagnac interferometer

    CERN Document Server

    Galinskiy, Ivan; Salgado, Israel Rebolledo; Hautefeuille, Mathieu; Mehlig, Bernhard; Hanstorp, Dag

    2015-01-01

    We have constructed a counterpropagating optical tweezers setup embedded in a Sagnac interferometer in order to increase the sensitivity of position tracking for particles in the geometrical optics regime. The enhancement of the position determination using a Sagnac interferometer has previously been described theoretically by Taylor et al. [Journal of Optics 13, 044014 (2011)] for Rayleigh-regime particles trapped in an antinode of a standing wave. We have extended their theory to a case of arbitrarily-sized particles trapped with orthogonally-polarized counterpropagating beams. The working distance of the setup was sufficiently long to optically induce particle oscillations orthogonally to the axis of the tweezers with an auxiliary laser beam. Using these oscillations as a reference, we have experimentally shown that Sagnac-enhanced back focal plane interferometry is capable of providing an improvement of more than 5 times in the signal-to-background ratio, corresponding to a more than 30-fold improvement o...

  16. Image stabilization for SWIR advanced optoelectronic device

    Science.gov (United States)

    Schiopu, Paul; Manea, Adrian; Cristea, Ionica; Grosu, Neculai; Craciun, Anca-Ileana; Craciun, Alexandru; Granciu, Dana

    2015-02-01

    At long ranges and under low visibility conditions, Advanced Optoelectronic Device provides the signal-to-noise ratio and image quality in the Short-wave Infra-red - SWIR (wavelengths between 1,1 ÷2,5 μm), significantly better than in the near wave infrared - NWIR and visible spectral bands [1,2]. The quality of image is nearly independent of the polarization in the incoming light, but it is influenced by the relative movement between the optical system and the observer (the operators' handshake), and the movement towards the support system (land and air vehicles). All these make it difficult to detect objectives observation in real time. This paper presents some systems enhance which the ability of observation and sighting through the optical systems without the use of the stands, tripods or other means. We have to eliminate the effect of "tremors of the hands" and the vibration in order to allow the use of optical devices by operators on the moving vehicles on land, on aircraft, or on boats, and to provide additional comfort for the user to track the moving object through the optical system, without losing the control in the process of detection and tracking. The practical applications of stabilization image process, in SWIR, are the most advanced part of the optical observation systems available worldwide [3,4,5]. This application has a didactic nature, because it ensures understanding by the students about image stabilization and their participation in research.

  17. Colloidal Quantum dot photovoltaics: Tuning optoelectronic properties

    International Nuclear Information System (INIS)

    Full text: Colloidal quantum dots combine processing from the solution phase with tunability of the bandgap. Via the size-effect the optical properties can be matched to the solar spectrum for a wide-range photon harvesting. To engineer photovoltaic devices, quantum dots are compressed from their colloidal form into a close-packed nanocrystal matrix, while undergoing a systematic layer-by-layer process. The resulting quantum dot solid is treated as semiconductor medium - one having electron-hole mobilites, free carrier densities and a dielectric constant. While the size-effect determined the band-gap before, it is now the nature of ligand and the treatment route, that influences mentioned electronic parameters. We took the view on the processing steps and found a concept for analysing trap states, moblility and device performance in real quantum dot solids. Our findings emphasize the interplay of mobility and trap-distribution with routes that take special care on the nanocrystal surface and hence conserve optoelectronic qualities of quantum dots for efficient photovoltaic cells. (author)

  18. Assessment of dental plaque by optoelectronic methods

    Science.gov (United States)

    Negrutiu, Meda-Lavinia; Sinescu, Cosmin; Bortun, Cristina Maria; Levai, Mihaela-Codrina; Topala, Florin Ionel; Crǎciunescu, Emanuela Lidia; Cojocariu, Andreea Codruta; Duma, Virgil Florin; Podoleanu, Adrian Gh.

    2016-03-01

    The formation of dental biofilm follows specific mechanisms of initial colonization on the surface, microcolony formation, development of organized three dimensional community structures, and detachment from the surface. The structure of the plaque biofilm might restrict the penetration of antimicrobial agents, while bacteria on a surface grow slowly and display a novel phenotype; the consequence of the latter is a reduced sensitivity to inhibitors. The aim of this study was to evaluate with different optoelectronic methods the morphological characteristics of the dental biofilm. The study was performed on samples from 25 patients aged between 18 and 35 years. The methods used in this study were Spectral Domain Optical Coherence Tomography (SD-OCT) working at 870 nm for in vivo evaluations and Scanning Electron Microscopy (SEM) for validations. For each patient a sample of dental biofilm was obtained directly from the vestibular surface of the teeth's. SD-OCT produced C- and B-scans that were used to generate three dimensional (3D) reconstructions of the sample. The results were compared with SEM evaluations. The biofilm network was dramatically destroyed after the professional dental cleaning. OCT noninvasive methods can act as a valuable tool for the 3D characterization of dental biofilms.

  19. Optoelectronic devices incorporating fluoropolymer compositions for protection

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xuming; Chum, Pak-Wing S.; Howard, Kevin E.; Lopez, Leonardo C.; Sumner, William C.; Wu, Shaofu

    2015-12-22

    The fluoropolymer compositions of the present invention generally incorporate ingredients comprising one or more fluoropolymers, an ultraviolet light protection component (hereinafter UV protection component), and optionally one or more additional ingredients if desired. The UV protection component includes a combination of at least one hindered tertiary amine (HTA) compound having a certain structure and a weight average molecular weight of at least 1000. This tertiary amine is used in combination with at least one organic, UV light absorbing compound (UVLA compound) having a weight average molecular weight greater than 500. When the HTA compound and the UVLA compound are selected according to principles of the present invention, the UV protection component provides fluoropolymer compositions with significantly improved weatherability characteristics for protecting underlying materials, features, structures, components, and/or the like. In particular, fluoropolymer compositions incorporating the UV protection component of the present invention have unexpectedly improved ability to resist blackening, coloration, or other de gradation that may be caused by UV exposure. As a consequence, devices protected by these compositions would be expected to have dramatically improved service life. The compositions have a wide range of uses but are particularly useful for forming protective layers in optoelectronic devices.

  20. Measurement of particle motion in optical tweezers embedded in a Sagnac interferometer

    OpenAIRE

    Galinskiy, Ivan; Isaksson, Oscar; Salgado, Israel Rebolledo; Hautefeuille, Mathieu; Mehlig, Bernhard; Hanstorp, Dag

    2015-01-01

    We have constructed a counterpropagating optical tweezers setup embedded in a Sagnac interferometer in order to increase the sensitivity of position tracking for particles in the geometrical optics regime. Enhanced position determination using a Sagnac interferometer has previously been described theoretically by Taylor et al. [Journal of Optics 13, 044014 (2011)] for Rayleigh-regime particles trapped in an antinode of a standing wave. We have extended their theory to a case of arbitrarily-si...

  1. A journey in bioinspired supramolecular chemistry: from molecular tweezers to small molecules that target myotonic dystrophy

    OpenAIRE

    Zimmerman, Steven C

    2016-01-01

    This review summarizes part of the author’s research in the area of supramolecular chemistry, beginning with his early life influences and early career efforts in molecular recognition, especially molecular tweezers. Although designed to complex DNA, these hosts proved more applicable to the field of host–guest chemistry. This early experience and interest in intercalation ultimately led to the current efforts to develop small molecule therapeutic agents for myotonic dystrophy using a rationa...

  2. Force mapping during the formation and maturation of cell adhesion sites with multiple optical tweezers

    OpenAIRE

    Schwingel, Melanie; Bastmeyer, Martin

    2014-01-01

    Focal contacts act as mechanosensors allowing cells to respond to their biomechanical environment. Force transmission through newly formed contact sites is a highly dynamic process requiring a stable link between the intracellular cytoskeleton and the extracellular environment. To simultaneously investigate cellular traction forces in several individual maturing adhesion sites within the same cell, we established a custom-built multiple trap optical tweezers setup. Beads functionalized with f...

  3. Identification of individual biofilm-forming bacterial cells using Raman tweezers

    Czech Academy of Sciences Publication Activity Database

    Samek, Ota; Bernatová, Silvie; Ježek, Jan; Šiler, Martin; Šerý, Mojmír; Krzyžánek, Vladislav; Hrubanová, Kamila; Zemánek, Pavel; Holá, V.; Růžička, F.

    2015-01-01

    Roč. 20, č. 5 (2015), 051038:1-6. ISSN 1083-3668 R&D Projects: GA ČR GAP205/11/1687; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : Raman tweezers * Staphylococcus epidermidis * biofilm Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.859, year: 2014

  4. Red blood cell membrane viscoelasticity, agglutination and zeta potential measurements with double optical tweezers

    Science.gov (United States)

    Fontes, Adriana; Fernandes, Heloise P.; Barjas-Castro, Maria L.; de Thomaz, André A.; de Ysasa Pozzo, Liliana; Barbosa, Luiz C.; Cesar, Carlos L.

    2006-02-01

    The red blood cell (RBC) viscoelastic membrane contains proteins and glycolproteins embedded in, or attached, to a fluid lipid bilayer and are negatively charged, which creates a repulsive electric (zeta) potential between the cells and prevents their aggregation in the blood stream. There are techniques, however, to decrease the zeta potential to allow cell agglutination which are the basis of most of the tests of antigen-antibody interactions in blood banks. This report shows the use of a double optical tweezers to measure RBC membrane viscosity, agglutination and zeta potential. In our technique one of the optical tweezers trap a silica bead that binds strongly to a RBC at the end of a RBCs rouleaux and, at the same time, acts as a pico-Newton force transducer, after calibration through its displacement from the equilibrium position. The other optical tweezers trap the RBC at the other end. To measure the membrane viscosity the optical force is measured as a function of the velocity between the RBCs. To measure the adhesion the tweezers are slowly displaced apart until the RBCs disagglutination happens. The RBC zeta potential is measured in two complimentary ways, by the force on the silica bead attached to a single RBC in response to an applied electric field, and the conventional way, by the measurement of terminal velocity of the RBC after released from the optical trap. These two measurements provide information about the RBC charges and, also, electrolytic solution properties. We believe this can improve the methods of diagnosis in blood banks.

  5. Optoelectronic properties of individually positioned InAs nanowires

    International Nuclear Information System (INIS)

    Small bandgap semiconducting nanowires offer a promising approach to fabricating nanoscale light-sensitive devices like broadband solar cells or mid-infrared photodetectors. We discuss the optoelectronic properties of individually positioned InAs nanowires on p-Si(111) substrates. The substrates exhibit a top layer of SiO2 which is structured via e-beam lithography creating holes in the oxide with a diameter of ∝80 nm. The nanowires are then grown vertically on the patterned substrates by solid-source molecular beam epitaxy. To fabricate optoelectronic devices, the nanowires are subsequently contacted via a thin, semitransparent metal film evaporated on top of an insulating layer (BCB). The p-Si substrate forms the second contact of the optoelectronic two-terminal devices. We discuss spatially resolved photocurrent measurements which give insights into the interplay of optoelectronic dynamics in single nanowires and in the Si-substrates.

  6. Optoelectronic Infrastructure for RF/Optical Phased Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Optoelectronic integrated holds the key to higher performance, reduced mass and radiation-hard space systems. A special need is increased flexibility of phased...

  7. Scanning a DNA molecule for bound proteins using hybrid magnetic and optical tweezers.

    Directory of Open Access Journals (Sweden)

    Marijn T J van Loenhout

    Full Text Available The functional state of the genome is determined by its interactions with proteins that bind, modify, and move along the DNA. To determine the positions and binding strength of proteins localized on DNA we have developed a combined magnetic and optical tweezers apparatus that allows for both sensitive and label-free detection. A DNA loop, that acts as a scanning probe, is created by looping an optically trapped DNA tether around a DNA molecule that is held with magnetic tweezers. Upon scanning the loop along the λ-DNA molecule, EcoRI proteins were detected with ~17 nm spatial resolution. An offset of 33 ± 5 nm for the detected protein positions was found between back and forwards scans, corresponding to the size of the DNA loop and in agreement with theoretical estimates. At higher applied stretching forces, the scanning loop was able to remove bound proteins from the DNA, showing that the method is in principle also capable of measuring the binding strength of proteins to DNA with a force resolution of 0.1 pN/[Formula: see text]. The use of magnetic tweezers in this assay allows the facile preparation of many single-molecule tethers, which can be scanned one after the other, while it also allows for direct control of the supercoiling state of the DNA molecule, making it uniquely suitable to address the effects of torque on protein-DNA interactions.

  8. Acoustic tweezers via sub–time-of-flight regime surface acoustic waves

    Science.gov (United States)

    Collins, David J.; Devendran, Citsabehsan; Ma, Zhichao; Ng, Jia Wei; Neild, Adrian; Ai, Ye

    2016-01-01

    Micrometer-scale acoustic waves are highly useful for refined optomechanical and acoustofluidic manipulation, where these fields are spatially localized along the transducer aperture but not along the acoustic propagation direction. In the case of acoustic tweezers, such a conventional acoustic standing wave results in particle and cell patterning across the entire width of a microfluidic channel, preventing selective trapping. We demonstrate the use of nanosecond-scale pulsed surface acoustic waves (SAWs) with a pulse period that is less than the time of flight between opposing transducers to generate localized time-averaged patterning regions while using conventional electrode structures. These nodal positions can be readily and arbitrarily positioned in two dimensions and within the patterning region itself through the imposition of pulse delays, frequency modulation, and phase shifts. This straightforward concept adds new spatial dimensions to which acoustic fields can be localized in SAW applications in a manner analogous to optical tweezers, including spatially selective acoustic tweezers and optical waveguides. PMID:27453940

  9. Optoelectronic device with nanoparticle embedded hole injection/transport layer

    Science.gov (United States)

    Wang, Qingwu; Li, Wenguang; Jiang, Hua

    2012-01-03

    An optoelectronic device is disclosed that can function as an emitter of optical radiation, such as a light-emitting diode (LED), or as a photovoltaic (PV) device that can be used to convert optical radiation into electrical current, such as a photovoltaic solar cell. The optoelectronic device comprises an anode, a hole injection/transport layer, an active layer, and a cathode, where the hole injection/transport layer includes transparent conductive nanoparticles in a hole transport material.

  10. An advanced diffusion model to identify emergent research issues: the case of optoelectronic devices

    OpenAIRE

    Schiebel, Edgar L; Hörlesberger, Marianne; Roche, Ivana; François, Claire; Besagni, Dominique

    2010-01-01

    Scientific progress in technology oriented research fields is made by incremental or fundamental inventions concerning natural science effects, materials, methods, tools and applications. Therefore our approach focuses on research activities of such technological elements on the basis of keywords in published articles. In this paper we show how emerging topics in the field of optoelectronic devices based on scientific literature data from the PASCAL-database can be identified. We use Results ...

  11. Dual-wavelength method and optoelectronic sensor for online monitoring of the efficiency of dialysis treatment

    Science.gov (United States)

    Vasilevsky, A. M.; Konoplev, G. A.; Stepanova, O. S.; Zemchenkov, A. Yu; Gerasimchuk, R. P.; Frorip, A.

    2015-11-01

    The absorption spectra of effluent dialysate in the ultraviolet region were investigated. A novel dual-wavelength spectrophotometric method for uric acid determination in effluent dialysate and an optoelectronic sensor based on UV LED were developed. Clinical trials of the proposed sensor were carried out in the dialysis unit of St. Petersburg Mariinsky Hospital. The relative error of measurement for the concentration of uric acid does not exceed 10%.

  12. Optoelectronic System Measures Distances to Multiple Targets

    Science.gov (United States)

    Liebe, Carl Christian; Abramovici, Alexander; Bartman, Randall; Chapsky, Jacob; Schmalz, John; Coste, Keith; Litty, Edward; Lam, Raymond; Jerebets, Sergei

    2007-01-01

    An optoelectronic metrology apparatus now at the laboratory-prototype stage of development is intended to repeatedly determine distances of as much as several hundred meters, at submillimeter accuracy, to multiple targets in rapid succession. The underlying concept of optoelectronic apparatuses that can measure distances to targets is not new; such apparatuses are commonly used in general surveying and machining. However, until now such apparatuses have been, variously, constrained to (1) a single target or (2) multiple targets with a low update rate and a requirement for some a priori knowledge of target geometry. When fully developed, the present apparatus would enable measurement of distances to more than 50 targets at an update rate greater than 10 Hz, without a requirement for a priori knowledge of target geometry. The apparatus (see figure) includes a laser ranging unit (LRU) that includes an electronic camera (photo receiver), the field of view of which contains all relevant targets. Each target, mounted at a fiducial position on an object of interest, consists of a small lens at the output end of an optical fiber that extends from the object of interest back to the LRU. For each target and its optical fiber, there is a dedicated laser that is used to illuminate the target via the optical fiber. The targets are illuminated, one at a time, with laser light that is modulated at a frequency of 10.01 MHz. The modulated laser light is emitted by the target, from where it returns to the camera (photodetector), where it is detected. Both the outgoing and incoming 10.01-MHz laser signals are mixed with a 10-MHz local-oscillator to obtain beat notes at 10 kHz, and the difference between the phases of the beat notes is measured by a phase meter. This phase difference serves as a measure of the total length of the path traveled by light going out through the optical fiber and returning to the camera (photodetector) through free space. Because the portion of the path

  13. Toward high-resolution optoelectronic retinal prosthesis

    Science.gov (United States)

    Palanker, Daniel; Huie, Philip; Vankov, Alexander; Asher, Alon; Baccus, Steven

    2005-04-01

    It has been already demonstrated that electrical stimulation of retina can produce visual percepts in blind patients suffering from macular degeneration and retinitis pigmentosa. Current retinal implants provide very low resolution (just a few electrodes), while several thousand pixels are required for functional restoration of sight. We present a design of the optoelectronic retinal prosthetic system that can activate a retinal stimulating array with pixel density up to 2,500 pix/mm2 (geometrically corresponding to a visual acuity of 20/80), and allows for natural eye scanning rather than scanning with a head-mounted camera. The system operates similarly to "virtual reality" imaging devices used in military and medical applications. An image from a video camera is projected by a goggle-mounted infrared LED-LCD display onto the retina, activating an array of powered photodiodes in the retinal implant. Such a system provides a broad field of vision by allowing for natural eye scanning. The goggles are transparent to visible light, thus allowing for simultaneous utilization of remaining natural vision along with prosthetic stimulation. Optical control of the implant allows for simple adjustment of image processing algorithms and for learning. A major prerequisite for high resolution stimulation is the proximity of neural cells to the stimulation sites. This can be achieved with sub-retinal implants constructed in a manner that directs migration of retinal cells to target areas. Two basic implant geometries are described: perforated membranes and protruding electrode arrays. Possibility of the tactile neural stimulation is also examined.

  14. Highly conductive transparent organic electrodes with multilayer structures for rigid and flexible optoelectronics.

    Science.gov (United States)

    Guo, Xiaoyang; Liu, Xingyuan; Lin, Fengyuan; Li, Hailing; Fan, Yi; Zhang, Nan

    2015-01-01

    Transparent electrodes are essential components for optoelectronic devices, such as touch panels, organic light-emitting diodes, and solar cells. Indium tin oxide (ITO) is widely used as transparent electrode in optoelectronic devices. ITO has high transparency and low resistance but contains expensive rare elements, and ITO-based devices have poor mechanical flexibility. Therefore, alternative transparent electrodes with excellent opto-electrical performance and mechanical flexibility will be greatly demanded. Here, organics are introduced into dielectric-metal-dielectric structures to construct the transparent electrodes on rigid and flexible substrates. We show that organic-metal-organic (OMO) electrodes have excellent opto-electrical properties (sheet resistance of below 10 Ω sq(-1) at 85% transmission), mechanical flexibility, thermal and environmental stabilities. The OMO-based polymer photovoltaic cells show performance comparable to that of devices based on ITO electrodes. This OMO multilayer structure can therefore be used to produce transparent electrodes suitable for use in a wide range of optoelectronic devices. PMID:26014889

  15. Prospects of III-nitride optoelectronics grown on Si.

    Science.gov (United States)

    Zhu, D; Wallis, D J; Humphreys, C J

    2013-10-01

    The use of III-nitride-based light-emitting diodes (LEDs) is now widespread in applications such as indicator lamps, display panels, backlighting for liquid-crystal display TVs and computer screens, traffic lights, etc. To meet the huge market demand and lower the manufacturing cost, the LED industry is moving fast from 2 inch to 4 inch and recently to 6 inch wafer sizes. Although Al2O3 (sapphire) and SiC remain the dominant substrate materials for the epitaxy of nitride LEDs, the use of large Si substrates attracts great interest because Si wafers are readily available in large diameters at low cost. In addition, such wafers are compatible with existing processing lines for 6 inch and larger wafers commonly used in the electronics industry. During the last decade, much exciting progress has been achieved in improving the performance of GaN-on-Si devices. In this contribution, the status and prospects of III-nitride optoelectronics grown on Si substrates are reviewed. The issues involved in the growth of GaN-based LED structures on Si and possible solutions are outlined, together with a brief introduction to some novel in situ and ex situ monitoring/characterization tools, which are especially useful for the growth of GaN-on-Si structures. PMID:24088511

  16. State-of-the-art photodetectors for optoelectronic integration at telecommunication wavelength

    Directory of Open Access Journals (Sweden)

    Eng Png Ching

    2015-01-01

    Full Text Available Photodetectors hold a critical position in optoelectronic integrated circuits, and they convert light into electricity. Over the past decades, high-performance photodetectors (PDs have been aggressively pursued to enable high-speed, large-bandwidth, and low-noise communication applications. Various material systems have been explored and different structures designed to improve photodetection capability as well as compatibility with CMOS circuits. In this paper, we review state-of-theart photodetection technologies in the telecommunications spectrum based on different material systems, including traditional semiconductors such as InGaAs, Si, Ge and HgCdTe, as well as recently developed systems such as low-dimensional materials (e.g. graphene, carbon nanotube, etc. and noble metal plasmons. The corresponding material properties, fundamental mechanisms, fabrication, theoretical modelling and performance of the typical PDs are presented, including the emerging directions and perspectives of the PDs for optoelectronic integration applications are discussed.

  17. High throughput optoelectronic smart pixel systems using diffractive optics

    Science.gov (United States)

    Chen, Chih-Hao

    1999-12-01

    Recent developments in digital video, multimedia technology and data networks have greatly increased the demand for high bandwidth communication channels and high throughput data processing. Electronics is particularly suited for switching, amplification and logic functions, while optics is more suitable for interconnections and communications with lower energy and crosstalk. In this research, we present the design, testing, integration and demonstration of several optoelectronic smart pixel devices and system architectures. These systems integrate electronic switching/processing capability with parallel optical interconnections to provide high throughput network communication and pipeline data processing. The Smart Pixel Array Cellular Logic processor (SPARCL) is designed in 0.8 m m CMOS and hybrid integrated with Multiple-Quantum-Well (MQW) devices for pipeline image processing. The Smart Pixel Network Interface (SAPIENT) is designed in 0.6 m m GaAs and monolithically integrated with LEDs to implement a highly parallel optical interconnection network. The Translucent Smart Pixel Array (TRANSPAR) design is implemented in two different versions. The first version, TRANSPAR-MQW, is designed in 0.5 m m CMOS and flip-chip integrated with MQW devices to provide 2-D pipeline processing and translucent networking using the Carrier- Sense-MultipleAccess/Collision-Detection (CSMA/CD) protocol. The other version, TRANSPAR-VM, is designed in 1.2 m m CMOS and discretely integrated with VCSEL-MSM (Vertical-Cavity-Surface- Emitting-Laser and Metal-Semiconductor-Metal detectors) chips and driver/receiver chips on a printed circuit board. The TRANSPAR-VM provides an option of using the token ring network protocol in addition to the embedded functions of TRANSPAR-MQW. These optoelectronic smart pixel systems also require micro-optics devices to provide high resolution, high quality optical interconnections and external source arrays. In this research, we describe an innovative

  18. Electronic and optoelectronic materials and devices inspired by nature

    Science.gov (United States)

    Meredith, P.; Bettinger, C. J.; Irimia-Vladu, M.; Mostert, A. B.; Schwenn, P. E.

    2013-03-01

    Inorganic semiconductors permeate virtually every sphere of modern human existence. Micro-fabricated memory elements, processors, sensors, circuit elements, lasers, displays, detectors, etc are ubiquitous. However, the dawn of the 21st century has brought with it immense new challenges, and indeed opportunities—some of which require a paradigm shift in the way we think about resource use and disposal, which in turn directly impacts our ongoing relationship with inorganic semiconductors such as silicon and gallium arsenide. Furthermore, advances in fields such as nano-medicine and bioelectronics, and the impending revolution of the ‘ubiquitous sensor network’, all require new functional materials which are bio-compatible, cheap, have minimal embedded manufacturing energy plus extremely low power consumption, and are mechanically robust and flexible for integration with tissues, building structures, fabrics and all manner of hosts. In this short review article we summarize current progress in creating materials with such properties. We focus primarily on organic and bio-organic electronic and optoelectronic systems derived from or inspired by nature, and outline the complex charge transport and photo-physics which control their behaviour. We also introduce the concept of electrical devices based upon ion or proton flow (‘ionics and protonics’) and focus particularly on their role as a signal interface with biological systems. Finally, we highlight recent advances in creating working devices, some of which have bio-inspired architectures, and summarize the current issues, challenges and potential solutions. This is a rich new playground for the modern materials physicist.

  19. Optoelectronic pantography diagnostics of temporomandibular disorders in patients with bruxism.

    Science.gov (United States)

    Mehulić, Ketij; Gospić, Renata Kevilj; Dundjer, Alenko; Skrinjarić, Tomislav; Stefancić, Sanja; Vojvodić, Denis; Perinić, Margareta

    2009-09-01

    Temporomandibular disorders (TMD) is a joint term that encompasses a number of clinical symptoms that involve the teeth, masticatory musculature and temporomandibular joints (TMJ). They are a frequent cause of orofacial medical conditions. The aetiology of disorders is complex and individual etiologic factors are not sufficiently defined. Bruxism, in its centric or eccentric form, is becoming a frequent problem for dentists. The purpose of this study is to show factors of the condyle leading in patients with bruxism by optoelectronic pantography, and to establish the possibility of using optoelectronic pantography in the diagnostic procedure of TMD. Patients were selected (N = 42), with incomplete sets of teeth, without prosthodontic appliances and with traces and symptoms of TMD. After completing the history questionnaire a clinical check up and plaster cast analysis patients with bruxism were selected (N = 22) and without bruxism (N = 20). During the study optoelectronic String-condylocomp LR3, Dentron, D-Höchberg (software JAWS 30) was used. This study showed the possibility of applying optoelectronic pantography in TMD diagnostics and compares history, clinical and condylographic parameters in TMD patients with and without bruxism. Optoelectronic pantography enables us, by using relatively easy methods, to determine a more accurate diagnosis, highly important when choosing therapeutic methods and control of the aforementioned disorders. PMID:19860114

  20. Disrupting self-assembly and toxicity of amyloidogenic protein oligomers by "molecular tweezers" - from the test tube to animal models.

    Science.gov (United States)

    Attar, Aida; Bitan, Gal

    2014-01-01

    Despite decades of research, therapy for diseases caused by abnormal protein folding and aggregation (amyloidoses) is limited to treatment of symptoms and provides only temporary and moderate relief to sufferers. The failure in developing successful disease-modifying drugs for amyloidoses stems from the nature of the targets for such drugs - primarily oligomers of amyloidogenic proteins, which are distinct from traditional targets, such as enzymes or receptors. The oligomers are metastable, do not have well-defined structures, and exist in dynamically changing mixtures. Therefore, inhibiting the formation and toxicity of these oligomers likely will require out-of-the-box thinking and novel strategies. We review here the development of a strategy based on targeting the combination of hydrophobic and electrostatic interactions that are key to the assembly and toxicity of amyloidogenic proteins using lysine (K)-specific "molecular tweezers" (MTs). Our discussion includes a survey of the literature demonstrating the important role of K residues in the assembly and toxicity of amyloidogenic proteins and the development of a lead MT derivative called CLR01, from an inhibitor of protein aggregation in vitro to a drug candidate showing effective amelioration of disease symptoms in animal models of Alzheimer's and Parkinson's diseases. PMID:23859557

  1. Alkyl-π engineering in state control toward versatile optoelectronic soft materials

    Science.gov (United States)

    Lu, Fengniu; Nakanishi, Takashi

    2015-02-01

    Organic π-conjugated molecules with extremely rich and tailorable electronic and optical properties are frequently utilized for the fabrication of optoelectronic devices. To achieve high solubility for facile solution processing and desirable softness for flexible device fabrication, the rigid π units were in most cases attached by alkyl chains through chemical modification. Considerable numbers of alkylated-π molecular systems with versatile applications have been reported. However, a profound understanding of the molecular state control through proper alkyl chain substitution is still highly demanded because effective applications of these molecules are closely related to their physical states. To explore the underlying rule, we review a large number of alkylated-π molecules with emphasis on the interplay of van der Waals interactions (vdW) of the alkyl chains and π-π interactions of the π moieties. Based on our comprehensive investigations of the two interactions’ impacts on the physical states of the molecules, a clear guidance for state control by alkyl-π engineering is proposed. Specifically, either with proper alkyl chain substitution or favorable additives, the vdW and π-π interactions can be adjusted, resulting in modulation of the physical states and optoelectronic properties of the molecules. We believe the strategy summarized here will significantly benefit the alkyl-π chemistry toward wide-spread applications in optoelectronic devices.

  2. History of modern optics ad optoelectronics development in China

    CERN Document Server

    Tian, Shouyun

    2014-01-01

    This book presents a collection of memoir papers on the development of modern and contemporary optics and optoelectronics in China from the 18th to 20th centuries. The papers were written by famous scientists in China, including members of the Chinese Academy of Sciences and the Chinese Academy of Engineering, sharing their experience in different fields of optics and optoelectronics development. This is a unique book in understanding the natural science history of optics and optoelectronics. It gives you the general idea about how the western optical science spread to China in the 17th to 18th century; the cradle of the contemporary optics in China; Birth, development and application of lasers in China; high energy and high power lasers for laser antiballistic missile and laser nuclear fusion; development of Chinese optical communication and optical information storage; laser and infrared optics research for space science; development of Chinese optical instruments, etc.

  3. Vertical Organic Field-Effect Transistors for Integrated Optoelectronic Applications.

    Science.gov (United States)

    Yu, Hyeonggeun; Dong, Zhipeng; Guo, Jing; Kim, Doyoung; So, Franky

    2016-04-27

    Direct integration of a vertical organic field-effect transistor (VOFET) and an optoelectronic device offers a single stacked, low power optoelectronic VOFET with high aperture ratios. However, a functional optoelectronic VOFET could not be realized because of the difficulty in fabricating transparent source and gate electrodes. Here, we report a VOFET with an on/off ratio up to 10(5) as well as output current saturation by fabricating a transparent gate capacitor consisting of a perforated indium tin oxide (ITO) source electrode, HfO2 gate dielectric, and ITO gate electrode. Effects of the pore size and the pore depth within the porous ITO electrodes on the on/off characteristic of a VOFET are systematically explained in this work. By combining a phosphorescent organic light-emitting diode with an optimized VOFET structure, a vertical organic light-emitting transistor with a luminance on/off ratio of 10(4) can be fabricated. PMID:27082815

  4. Optical macro-tweezers: trapping of highly motile micro-organisms

    International Nuclear Information System (INIS)

    Optical micromanipulation stands for contact-free handling of microscopic particles by light. Optical forces can manipulate non-absorbing objects in a large range of sizes, e.g., from biological cells down to cold atoms. Recently much progress has been made going from the micro- down to the nanoscale. Less attention has been paid to going the other way, trapping increasingly large particles. Optical tweezers typically employ a single laser beam tightly focused by a microscope objective of high numerical aperture to stably trap a particle in three dimensions (3D). As the particle size increases, stable 3D trapping in a single-beam trap requires scaling up the optical power, which eventually induces adverse biological effects. Moreover, the restricted field of view of standard optical tweezers, dictated by the use of high NA objectives, is particularly unfavorable for catching actively moving specimens. Both problems can be overcome by traps with counter-propagating beams. Our 'macro-tweezers' are especially designed to trap highly motile organisms, as they enable three-dimensional all-optical trapping and guiding in a volume of 2 × 1 × 2 mm3. Here we report for the first time the optical trapping of large actively swimming organisms, such as for instance Euglena protists and dinoflagellates of up to 70 µm length. Adverse bio-effects are kept low since trapping occurs outside high intensity regions, e.g., focal spots. We expect our approach to open various possibilities in the contact-free handling of 50–100 µm sized objects that could hitherto not be envisaged, for instance all-optical holding of individual micro-organisms for taxonomic identification, selective collecting or tagging

  5. Measurement of Breaking Force of Fluorescence Labelled Microtubules with Optical Tweezers

    Institute of Scientific and Technical Information of China (English)

    LIU Chun-Xiang; GUO Hong-Lian; XU Chun-Hua; YUAN Ming; LI Znao-Lin; CHENG Bing-Ying; ZHANG Dao-Zhong

    2005-01-01

    @@ Under illumination of excitation light, the force that can make fluorescent dye-labelled microtubules break up is measured by using dual-beam optical tweezers. It is found that this force is about several piconewtons, which is two orders of magnitude smaller than that without fluorescence label. Microtubules can be elongated about 20% and the increase of the tensile force is nonlinear with the microtubule elongation. Some qualitative explanations are given for the mechanisms about the breakup and elongation of microtubules exposed to excitation light.

  6. A journey in bioinspired supramolecular chemistry: from molecular tweezers to small molecules that target myotonic dystrophy

    Science.gov (United States)

    2016-01-01

    Summary This review summarizes part of the author’s research in the area of supramolecular chemistry, beginning with his early life influences and early career efforts in molecular recognition, especially molecular tweezers. Although designed to complex DNA, these hosts proved more applicable to the field of host–guest chemistry. This early experience and interest in intercalation ultimately led to the current efforts to develop small molecule therapeutic agents for myotonic dystrophy using a rational design approach that heavily relies on principles of supramolecular chemistry. How this work was influenced by that of others in the field and the evolution of each area of research is highlighted with selected examples. PMID:26877815

  7. Template stripped double nanohole in a gold film for nano-optical tweezers

    International Nuclear Information System (INIS)

    Double nanohole (DNH) laser tweezers can optically trap and manipulate objects such as proteins, nanospheres, and other nanoparticles; however, precise fabrication of those DNHs has been expensive with low throughput. In this work, template stripping was used to pattern DNHs with gaps as small as 7 nm, in optically thick Au films. These DNHs were used to trap streptavidin as proof of operation. The structures were processed multiple times from the same template to demonstrate reusability. Template stripping is a promising method for high-throughput, reproducible, and cost efficient fabrication of DNH apertures for optical trapping. (paper)

  8. Fast acoustic tweezers for the two-dimensional manipulation of individual particles in microfluidic channels

    CERN Document Server

    Tran, S B Q; Thibault, Pierre; 10.1063/1.4751348

    2012-01-01

    This paper presents a microfluidic device that implements standing surface acoustic waves in order to handle single cells, droplets, and generally particles. The particles are moved in a very controlled manner by the two-dimensional drifting of a standing wave array, using a slight frequency modulation of two ultrasound emitters around their resonance. These acoustic tweezers allow any type of motion at velocities up to few 10mm/s, while the device transparency is adapted for optical studies. The possibility of automation provides a critical step in the development of lab-on-a-chip cell sorters and it should find applications in biology, chemistry, and engineering domains.

  9. Laser-induced fusion of human embryonic stem cells with optical tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Chen Shuxun; Wang Xiaolin; Sun Dong [Department of Mechanical and Biomedical Engineering, City University of Hong Kong (Hong Kong); Cheng Jinping; Han Cheng, Shuk [Department of Biology and Chemistry, City University of Hong Kong (Hong Kong); Kong, Chi-Wing [Stem Cell and Regenerative Medicine Consortium, and Departments of Medicine and Physiology, LKS Faculty of Medicine, University of Hong Kong (Hong Kong); Li, Ronald A. [Stem Cell and Regenerative Medicine Consortium, and Departments of Medicine and Physiology, LKS Faculty of Medicine, University of Hong Kong (Hong Kong); Center of Cardiovascular Research, Mount Sinai School of Medicine, New York, New York 10029 (United States)

    2013-07-15

    We report a study on the laser-induced fusion of human embryonic stem cells (hESCs) at the single-cell level. Cells were manipulated by optical tweezers and fused under irradiation with pulsed UV laser at 355 nm. Successful fusion was indicated by green fluorescence protein transfer. The influence of laser pulse energy on the fusion efficiency was investigated. The fused products were viable as gauged by live cell staining. Successful fusion of hESCs with somatic cells was also demonstrated. The reported fusion outcome may facilitate studies of cell differentiation, maturation, and reprogramming.

  10. Data on force-dependent structural changes of chromatin fibers measured with magnetic tweezers

    Directory of Open Access Journals (Sweden)

    Fan-Tso Chien

    2014-12-01

    Full Text Available The compaction of chromatin fibers regulates the accessibility of embedded DNA, highly associated with transcriptional activities [1]. Single molecule force spectroscopy has revealed the great details of the structural changes of chromatin fibers in the presence of external exerted force [2–7]. However, most of the studies focus on a specific force regime [2,3,8,9]. The data here show force-extension (FE traces of chromatin fibers as measured with magnetic tweezers, covering the force regime from 0 pN to 27 pN. Those traces provide information for further studies at varied force regimes.

  11. Optical tweezers study of red blood cell aggregation and disaggregation in plasma and protein solutions

    Science.gov (United States)

    Lee, Kisung; Kinnunen, Matti; Khokhlova, Maria D.; Lyubin, Evgeny V.; Priezzhev, Alexander V.; Meglinski, Igor; Fedyanin, Andrey A.

    2016-03-01

    Kinetics of optical tweezers (OT)-induced spontaneous aggregation and disaggregation of red blood cells (RBCs) were studied at the level of cell doublets to assess RBC interaction mechanics. Measurements were performed under in vitro conditions in plasma and fibrinogen and fibrinogen + albumin solutions. The RBC spontaneous aggregation kinetics was found to exhibit different behavior depending on the cell environment. In contrast, the RBC disaggregation kinetics was similar in all solutions qualitatively and quantitatively, demonstrating a significant contribution of the studied proteins to the process. The impact of the study on assessing RBC interaction mechanics and the protein contribution to the reversible RBC aggregation process is discussed.

  12. Applications of HTSC films in hybrid optoelectronic devices

    Science.gov (United States)

    Pavuna, Davor

    1992-03-01

    An overview is given of potential applications of high-Tc superconductors (HTSC) in the context of hybrid optoelectronic technology. The main requirements are described for the in situ growth of epitaxial YBa2Cu3O(7-delta) (YBCO) films on SrTiO3 and discuss the properties of YBCO layers grown on Si and GaAs substrates with intermediate, conducting indium-tin-oxide buffer layers. The performances of the microbridge and the meander type of HTSC bolometer are compared, and several concepts are discussed that may become relevant for future hybrid optoelectronic technology.

  13. Strain-tuned optoelectronic properties of hollow gallium sulphide microspheres

    Science.gov (United States)

    Zhang, Yin; Chen, Chen; Liang, C. Y.; Liu, Z. W.; Li, Y. S.; Che, Renchao

    2015-10-01

    Sulfide semiconductors have attracted considerable attention. The main challenge is to prepare materials with a designable morphology, a controllable band structure and optoelectronic properties. Herein, we report a facile chemical transportation reaction for the synthesis of Ga2S3 microspheres with novel hollow morphologies and partially filled volumes. Even without any extrinsic dopant, photoluminescence (PL) emission wavelength could be facilely tuned from 635 to 665 nm, depending on its intrinsic inhomogeneous strain distribution. Geometric phase analysis (GPA) based on high-resolution transmission electron microscopy (HRTEM) imaging reveals that the strain distribution and the associated PL properties can be accurately controlled by changing the growth temperature gradient, which depends on the distance between the boats used for raw material evaporation and microsphere deposition. The stacking-fault density, lattice distortion degree and strain distribution at the shell interfacial region of the Ga2S3 microspheres could be readily adjusted. Ab initio first-principles calculations confirm that the lowest conductive band (LCB) is dominated by S-3s and Ga-4p states, which shift to the low-energy band as a result of the introduction of tensile strain, well in accordance with the observed PL evolution. Therefore, based on our strain driving strategy, novel guidelines toward the reasonable design of sulfide semiconductors with tunable photoluminescence properties are proposed.Sulfide semiconductors have attracted considerable attention. The main challenge is to prepare materials with a designable morphology, a controllable band structure and optoelectronic properties. Herein, we report a facile chemical transportation reaction for the synthesis of Ga2S3 microspheres with novel hollow morphologies and partially filled volumes. Even without any extrinsic dopant, photoluminescence (PL) emission wavelength could be facilely tuned from 635 to 665 nm, depending on its

  14. Optoelectronic blood oximetry as a tool of health safety monitoring

    Science.gov (United States)

    Cysewska-Sobusiak, Anna

    2001-08-01

    A metrological approach of some selected problems connected with the significant field of biomedical optics i.e., monitoring of arterial blood oxygenation by use of the tissues as optical media exposed to the controlled light action, has been presented. The subject of the measurements based on utilization of the selection absorption properties of blood is the hemoglobin oxygen saturation. Using optoelectronic sensing allows to convert sophisticated effects of noninvasive light-living tissue interaction to electrical signals which may be convenient to measure. Pulse oximetry which is based upon such a way of sensing and processing, is the recent advance in noninvasive oximetry. The unique advantages of that marvelous diagnostic technique have caused to recommend pulse oximeters as standard equipment in intensive care and other critical situations impending hypoxemia appearance. However, end-users of the pulse oximeters not always are aware of that these devices fall under specific limitations, of both physiological and technical nature. The author of this paper is a metrologist and deals mainly with various interdisciplinary problems of a measurement reliability including the aspects such as uncertainty of an outcome accessible to the user, causes affecting sensitivity, resolution and repeatability of processing function, and response time and stability of results. Referring to the subject discussed herein, and taking into account some open questions, the author's contribution is her own experience in modeling as well as in in vivo measuring of transilluminated living objects. A proposed novel use of the known pulse oximetry concept may be considered as complementary results against a general review background of the achievements obtained in oximetry as the state-of-the-art, and furthermore, the developing studies which are still in progress.

  15. Optoelectronic Reader for Accidental Chemical Radiation Dosimetric System

    International Nuclear Information System (INIS)

    Full text: The use of chlorobenzene solutions (10% by vol.) in ethanol-trimethylpentane mixture (1:8 by vol.) in radiation dosimetry is based on radiolytic dechlorination of chlorobenzene and subsequent reaction of hydrochloric acid formed with a dissolved pH indicator, thymolsulphonphthalein. The amount of the acid (red) form of the indicator is proportional to dose. High molar absorbtivity of the red form of the indicator at 550 nm is responsible for a high sensitivity of the system, enabling its application in radiation therapy and/or radiation accident dosimetry: doses in the range 0.2-12 Gy can be determined. Additional favourable dosimetric properties of the system are its linear response with dose, independence of the dose rate and quality of the incident radiation, and, most interestingly, the approximately equal response to gamma rays and neutrons for the same dose in tissue. Together with a visual colour comparator it has formed a personal dosimetry system, which had been adopted for the military and civil defence use. The precision of the readout by means of a colour comparator depended on the width of an interval between any two neighbouring colour standards and the ability of a person taking the reading to estimate the nuances and make interpolations. The newly constructed optoelectronic reader takes the subjectivity out of the readout process and enables full automatisation and computerisation. In addition, it offers a continuous dose estimation, as compared to discrete values only, as given by the colour comparator. The reader is based on shining the output of a two-colour light emitting diode (550 and 690 nm) through a dosimeter solution in an ampoule, and calculating the differential absorbance, which is directly related to dose. Further development towards self-contained, hand-held instrument is in progress. (author)

  16. Chip scale low dimensional materials: optoelectronics & nonlinear optics

    Science.gov (United States)

    Gu, Tingyi

    The CMOS foundry infrastructure enables integration of high density, high performance optical transceivers. We developed integrated devices that assemble resonators, waveguide, tapered couplers, pn junction and electrodes. Not only the volume standard manufacture in silicon foundry is promising to low-lost optical components operating at IR and mid-IR range, it also provides a robust platform for revealing new physical phenomenon. The thesis starts from comparison between photonic crystal and micro-ring resonators based on chip routers, showing photonic crystal switches have small footprint, consume low operation power, but its higher linear loss may require extra energy for signal amplification. Different designs are employed in their implementation in optical signal routing on chip. The second part of chapter 2 reviews the graphene based optoelectronic devices, such as modulators, lasers, switches and detectors, potential for group IV optoelectronic integrated circuits (OEIC). In chapter 3, the highly efficient thermal optic control could act as on-chip switches and (transmittance) tunable filters. Local temperature tuning compensates the wavelength differences between two resonances, and separate electrode is used for fine tuning of optical pathways between two resonators. In frequency domain, the two cavity system also serves as an optical analogue of Autler-Towns splitting, where the cavity-cavity resonance detuning is controlled by the length of pathway (phase) between them. The high thermal sensitivity of cavity resonance also effectively reflects the heat distribution around the nanoheaters, and thus derives the thermal conductivity in the planar porous suspended silicon membrane. Chapter 4 & 5 analyze graphene-silicon photonic crystal cavities with high Q and small mode volume. With negligible nonlinear response to the milliwatt laser excitation, the monolithic silicon PhC turns into highly nonlinear after transferring the single layer graphene with

  17. Formation of an artificial blood vessel: adhesion force measurements with optical tweezers

    Science.gov (United States)

    Knoener, Gregor; Campbell, Julie H.; Heckenberg, Norman R.; Rubinsztein-Dunlop, Halina

    2004-10-01

    We are investigating the formation of a tissue capsule around a foreign body. This tissue capsule can be used as an autologous graft for the replacement of diseased blood vessels or for bypass surgery. The graft is grown in the peritoneal cavity of the recipient and the formation starts with the adhesion of cells to the foreign body. We identify the cell type and measure the adhesion of these cells to foreign materials using optical tweezers. Cell adhesion to macroscopic samples and microspheres is investigated. No difference in the adhesion force was measurable for polyethylene, silicon and Tygon on a scale accessible to optical tweezers. The density of adherent cells was found to vary strongly, being highest on polyethylene. The mean rupture forces for cell-microsphere adhesion ranged from 24 to 39 pN and changed upon preadsorption of bovine serum albumin. For plain microspheres, the highest mean rupture force was found for PMMA, which also showed the highest adhesion probability for the cell-microsphere interaction.

  18. High-resolution dual-trap optical tweezers with differential detection: alignment of instrument components.

    Science.gov (United States)

    Bustamante, Carlos; Chemla, Yann R; Moffitt, Jeffrey R

    2009-10-01

    Optical traps or "optical tweezers" have become an indispensable tool in understanding fundamental biological processes. Using our design, a dual-trap optical tweezers with differential detection, we can detect length changes to a DNA molecule tethering the trapped beads of 1 bp. By forming two traps from the same laser and maximizing the common optical paths of the two trapping beams, we decouple the instrument from many sources of environmental and instrumental noise that typically limit spatial resolution. The performance of a high-resolution instrument--the formation of strong traps, the minimization of background signals from trap movements, or the mitigation of the axial coupling, for example--can be greatly improved through careful alignment. This procedure, which is described in this article, starts from the laser and advances through the instrument, component by component. Alignment is complicated by the fact that the trapping light is in the near infrared (NIR) spectrum. Standard infrared viewing cards are commonly used to locate the beam, but unfortunately, bleach quickly. As an alternative, we use an IR-viewing charge-coupled device (CCD) camera equipped with a C-mount telephoto lens and display its image on a monitor. By visualizing the scattered light on a pair of irises of identical height separated by >12 in., the beam direction can be set very accurately along a fixed axis. PMID:20147041

  19. A study of red blood cell deformability in diabetic retinopathy using optical tweezers

    Science.gov (United States)

    Smart, Thomas J.; Richards, Christopher J.; Bhatnagar, Rhythm; Pavesio, Carlos; Agrawal, Rupesh; Jones, Philip H.

    2015-08-01

    Diabetic retinopathy (DR) is a microvascular complication of diabetes mellitus (DM) in which high blood sugar levels cause swelling, leaking and occlusions in the blood vessels of the retina, often resulting in a loss of sight. The microvascular system requires red blood cells (RBCs) to undergo significant cellular deformation in order to pass through vessels whose diameters are significantly smaller than their own. There is evidence to suggest that DM impairs the deformability of RBCs, and this loss of deformability has been associated with diabetic kidney disease (or nephropathy) - another microvascular complication of DM. However, it remains unclear whether reduced deformability of RBCs correlates with the presence of DR. Here we present an investigation into the deformability of RBCs in patients with diabetic retinopathy using optical tweezers. To extract a value for the deformability of RBCs we use a dual-trap optical tweezers set-up to stretch individual RBCs. RBCs are trapped directly (i.e. without micro-bead handles), so rotate to assume a `side-on' orientation. Video microscopy is used to record the deformation events, and shape analysis software is used to determine parameters such as initial and maximum RBC length, allowing us to calculate the deformability for each RBC. A small decrease in deformability of diabetes cells subject to this stretching protocol is observed when compared to control cells. We also report on initial results on three dimensional imaging of individual RBCs using defocussing microscopy.

  20. Probing Mechanical Properties of Jurkat Cells under the Effect of ART Using Oscillating Optical Tweezers

    Science.gov (United States)

    2015-01-01

    Acute lymphoid leukemia is a common type of blood cancer and chemotherapy is the initial treatment of choice. Quantifying the effect of a chemotherapeutic drug at the cellular level plays an important role in the process of the treatment. In this study, an oscillating optical tweezer was employed to characterize the frequency-dependent mechanical properties of Jurkat cells exposed to the chemotherapeutic agent, artesunate (ART). A motion equation for a bead bound to a cell was applied to describe the mechanical characteristics of the cell cytoskeleton. By comparing between the modeling results and experimental results from the optical tweezer, the stiffness and viscosity of the Jurkat cells before and after the ART treatment were obtained. The results demonstrate a weak power-law dependency of cell stiffness with frequency. Furthermore, the stiffness and viscosity were increased after the treatment. Therefore, the cytoskeleton cell stiffness as the well as power-law coefficient can provide a useful insight into the chemo-mechanical relationship of drug treated cancer cells and may serve as another tool for evaluating therapeutic performance quantitatively. PMID:25928073

  1. Probing mechanical properties of Jurkat cells under the effect of ART using oscillating optical tweezers.

    Directory of Open Access Journals (Sweden)

    Samaneh Khakshour

    Full Text Available Acute lymphoid leukemia is a common type of blood cancer and chemotherapy is the initial treatment of choice. Quantifying the effect of a chemotherapeutic drug at the cellular level plays an important role in the process of the treatment. In this study, an oscillating optical tweezer was employed to characterize the frequency-dependent mechanical properties of Jurkat cells exposed to the chemotherapeutic agent, artesunate (ART. A motion equation for a bead bound to a cell was applied to describe the mechanical characteristics of the cell cytoskeleton. By comparing between the modeling results and experimental results from the optical tweezer, the stiffness and viscosity of the Jurkat cells before and after the ART treatment were obtained. The results demonstrate a weak power-law dependency of cell stiffness with frequency. Furthermore, the stiffness and viscosity were increased after the treatment. Therefore, the cytoskeleton cell stiffness as the well as power-law coefficient can provide a useful insight into the chemo-mechanical relationship of drug treated cancer cells and may serve as another tool for evaluating therapeutic performance quantitatively.

  2. Chemotaxis study using optical tweezers to observe the strength and directionality of forces of Leishmania amazonensis

    Science.gov (United States)

    Pozzo, Liliana d. Y.; Fontes, Adriana; de Thomaz, André A.; Barbosa, Luiz C.; Ayres, Diana C.; Giorgio, Selma; Cesar, Carlos L.

    2006-08-01

    The displacements of a dielectric microspheres trapped by an optical tweezers (OT) can be used as a force transducer for mechanical measurements in life sciences. This system can measure forces on the 50 femto Newtons to 200 pico Newtons range, of the same order of magnitude of a typical forces induced by flagellar motion. The process in which living microorganisms search for food and run away from poison chemicals is known is chemotaxy. Optical tweezers can be used to obtain a better understanding of chemotaxy by observing the force response of the microorganism when placed in a gradient of attractors and or repelling chemicals. This report shows such observations for the protozoa Leishmania amazomenzis, responsible for the leishmaniasis, a serious tropical disease. We used a quadrant detector to monitor the movement of the protozoa for different chemicals gradient. This way we have been able to observe both the force strength and its directionality. The characterization of the chemotaxis of these parasites can help to understand the infection mechanics and improve the diagnosis and the treatments employed for this disease.

  3. Application of optical tweezers and excimer laser to study protoplast fusion

    Science.gov (United States)

    Kantawang, Titirat; Samipak, Sompid; Limtrakul, Jumras; Chattham, Nattaporn

    2015-07-01

    Protoplast fusion is a physical phenomenon that two protoplasts come in contact and fuse together. Doing so, it is possible to combine specific genes from one protoplast to another during fusion such as drought resistance and disease resistance. There are a few possible methods to induce protoplast fusion, for example, electrofusion and chemical fusion. In this study, chemical fusion was performed with laser applied as an external force to enhance rate of fusion and observed under a microscope. Optical tweezers (1064 nm with 100X objective N.A. 1.3) and excimer laser (308 nm LMU-40X-UVB objective) were set with a Nikon Ti-U inverted microscope. Samples were prepared by soaking in hypertonic solution in order to induce cell plasmolysis. Elodea Canadensis and Allium cepa plasmolysed leaves were cut and observed under microscope. Concentration of solution was varied to induce difference turgor pressures on protoplasts pushing at cell wall. Free protoplasts in solution were trapped by optical tweezers to study the effect of Polyethylene glycol (PEG) solution. PEG was diluted by Ca+ solution during the process to induced protoplast cell contact and fusion. Possibility of protoplast fusion by excimer laser was investigated and found possible. Here we report a novel tool for plant cell fusion using excimer laser. Plant growth after cell fusion is currently conducted.

  4. Luminescent nanoparticle trapping with far-field optical fiber-tip tweezers.

    Science.gov (United States)

    Decombe, Jean-Baptiste; Valdivia-Valero, Francisco J; Dantelle, Géraldine; Leménager, Godefroy; Gacoin, Thierry; Colas des Francs, Gérard; Huant, Serge; Fick, Jochen

    2016-03-01

    We report stable and reproducible trapping of luminescent dielectric YAG:Ce(3+) nanoparticles with sizes down to 60 nm using far-field dual fiber tip optical tweezers. The particles are synthesized by a specific glycothermal route followed by an original protected annealing step, resulting in significantly enhanced photostability. The tweezers properties are analyzed by studying the trapped particles residual Brownian motion using video or reflected signal records. The trapping potential is harmonic in the transverse direction to the fiber axis, but reveals interference fringes in the axial direction. Large trapping stiffness of 35 and 2 pN μm(-1) W(-1) is measured for a fiber tip-to-tip distance of 3 μm and 300 nm and 60 nm particles, respectively. The forces acting on the nanoparticles are discussed within the dipolar approximation (gradient and scattering force contributions) or exact calculations using the Maxwell Stress Tensor formalism. Prospects for trapping even smaller particles are discussed. PMID:26883602

  5. Simultaneous Thermoelectric and Optoelectronic Characterization of Individual Nanowires.

    Science.gov (United States)

    Léonard, François; Song, Erdong; Li, Qiming; Swartzentruber, Brian; Martinez, Julio A; Wang, George T

    2015-12-01

    Semiconducting nanowires have been explored for a number of applications in optoelectronics such as photodetectors and solar cells. Currently, there is ample interest in identifying the mechanisms that lead to photoresponse in nanowires in order to improve and optimize performance. However, distinguishing among the different mechanisms, including photovoltaic, photothermoelectric, photoemission, bolometric, and photoconductive, is often difficult using purely optoelectronic measurements. In this work, we present an approach for performing combined and simultaneous thermoelectric and optoelectronic measurements on the same individual nanowire. We apply the approach to GaN/AlGaN core/shell and GaN/AlGaN/GaN core/shell/shell nanowires and demonstrate the photothermoelectric nature of the photocurrent observed at the electrical contacts at zero bias, for above- and below-bandgap illumination. Furthermore, the approach allows for the experimental determination of the temperature rise due to laser illumination, which is often obtained indirectly through modeling. We also show that under bias, both above- and below-bandgap illumination leads to a photoresponse in the channel with signatures of persistent photoconductivity due to photogating. Finally, we reveal the concomitant presence of photothermoelectric and photogating phenomena at the contacts in scanning photocurrent microscopy under bias by using their different temporal response. Our approach is applicable to a broad range of nanomaterials to elucidate their fundamental optoelectronic and thermoelectric properties. PMID:26529491

  6. Optoelectronic reservoir computing: tackling noise-induced performance degradation.

    Science.gov (United States)

    Soriano, M C; Ortín, S; Brunner, D; Larger, L; Mirasso, C R; Fischer, I; Pesquera, L

    2013-01-14

    We present improved strategies to perform photonic information processing using an optoelectronic oscillator with delayed feedback. In particular, we study, via numerical simulations and experiments, the influence of a finite signal-to-noise ratio on the computing performance. We illustrate that the performance degradation induced by noise can be compensated for via multi-level pre-processing masks. PMID:23388891

  7. Optoelectronic reservoir computing: tackling noise-induced performance degradation

    OpenAIRE

    Soriano, Miguel C.; Ortín, S.; Brunner, Daniel; Larger, Laurent; Mirasso, Claudio R; Fischer, Ingo; Pesquera, Luis

    2013-01-01

    We present improved strategies to perform photonic information processing using an optoelectronic oscillator with delayed feedback. In particular, we study, via numerical simulations and experiments, the influence of a finite signal-to-noise ratio on the computing performance. We illustrate that the performance degradation induced by noise can be compensated for via multi-level pre-processing masks.

  8. Optoelectronic devices utilizing materials having enhanced electronic transitions

    Science.gov (United States)

    Black, Marcie R.

    2011-02-22

    An optoelectronic device that includes a material having enhanced electronic transitions. The electronic transitions are enhanced by mixing electronic states at an interface. The interface may be formed by a nano-well, a nano-dot, or a nano-wire.

  9. Electronic and optoelectronic materials and devices inspired by nature

    International Nuclear Information System (INIS)

    Inorganic semiconductors permeate virtually every sphere of modern human existence. Micro-fabricated memory elements, processors, sensors, circuit elements, lasers, displays, detectors, etc are ubiquitous. However, the dawn of the 21st century has brought with it immense new challenges, and indeed opportunities—some of which require a paradigm shift in the way we think about resource use and disposal, which in turn directly impacts our ongoing relationship with inorganic semiconductors such as silicon and gallium arsenide. Furthermore, advances in fields such as nano-medicine and bioelectronics, and the impending revolution of the ‘ubiquitous sensor network’, all require new functional materials which are bio-compatible, cheap, have minimal embedded manufacturing energy plus extremely low power consumption, and are mechanically robust and flexible for integration with tissues, building structures, fabrics and all manner of hosts. In this short review article we summarize current progress in creating materials with such properties. We focus primarily on organic and bio-organic electronic and optoelectronic systems derived from or inspired by nature, and outline the complex charge transport and photo-physics which control their behaviour. We also introduce the concept of electrical devices based upon ion or proton flow (‘ionics and protonics’) and focus particularly on their role as a signal interface with biological systems. Finally, we highlight recent advances in creating working devices, some of which have bio-inspired architectures, and summarize the current issues, challenges and potential solutions. This is a rich new playground for the modern materials physicist. (review article)

  10. The integration of a micropipette in a closed microfluidic chip with optical tweezers for investigations of single cells: erratum

    OpenAIRE

    Alrifaiy, Ahmed; Ramser, Kerstin

    2012-01-01

    In July 2011 a new concept of a closed microfluidic system equipped with a fixed micropipette, optical tweezers and a UV-Vis spectrometer was presented [Biomed. Opt. Express 2, 2299 (2011)]. Figure 1 showed falsely oriented mirrors. To clarify the design of the setup, this erratum presents a correct schematic.

  11. Absolute Position Total Internal Reflection Microscopy with an Optical Tweezer

    CERN Document Server

    Liu, Lulu; Rodriguez, Alejandro W; Capasso, Federico

    2014-01-01

    A non-invasive, in-situ calibration method for Total Internal Reflection Microscopy (TIRM) based on optical tweezing is presented which greatly expands the capabilities of this technique. We show that by making only simple modifications to the basic TIRM sensing setup and procedure, a probe particle's absolute position relative to a dielectric interface may be known with better than 10 nm precision out to a distance greater than 1 $\\mu$m from the surface. This represents an approximate 10x improvement in error and 3x improvement in measurement range over conventional TIRM methods. The technique's advantage is in the direct measurement of the probe particle's scattering intensity vs. height profile in-situ, rather than relying on calculations or inexact system analogs for calibration. To demonstrate the improved versatility of the TIRM method in terms of tunability, precision, and range, we show our results for the hindered near-wall diffusion coefficient for a spherical dielectric particle.

  12. A control unit for a laser module of optoelectronic computing environment with dynamic architecture

    Directory of Open Access Journals (Sweden)

    Lipinskii A. Y.

    2013-06-01

    Full Text Available The paper presents the developed control unit of laser modules of optoelectronic acousto-optic computing environment. The unit is based on ARM micro¬con¬troller of Cortex M3 family, and allows alternating between recording (erase and reading modes in accordance with a predetermined algorithm and settings — exposure time and intensity. The principal electric circuit of the presented device, the block diagram of microcontroller algorithm, and the example application of the developed control unit in the layout of the experimental setup are provided.

  13. High-performance optoelectronic switching network with vertical-cavity surface-emitting laser arrays

    International Nuclear Information System (INIS)

    A schematic solution is proposed for creating a highly efficient switching network with fully connected switching topology for use in supercomputers and telecommunication systems. An important characteristic of this solution is the use of vertical-cavity surface-emitting semiconductor laser arrays and polarising beamsplitters. Estimates show that the commercially available elemental base can be used for a practical realisation of an optoelectronic switching network with basic parameters and functional properties that are superior to those in known electronic analogues. (laser applications and other topics in quantum electronics)

  14. Carbon dots—Emerging light emitters for bioimaging, cancer therapy and optoelectronics

    KAUST Repository

    Hola, Katerina

    2014-10-01

    © 2014 Elsevier Ltd. All rights reserved. Carbon dots represent an emerging class of fluorescent materials and provide a broad application potential in various fields of biomedicine and optoelectronics. In this review, we introduce various synthetic strategies and basic photoluminescence properties of carbon dots, and then address their advanced in vitro and in vivo bioapplications including cell imaging, photoacoustic imaging, photodynamic therapy and targeted drug delivery. We further consider the applicability of carbon dots as components of light emitting diodes, which include carbon dot based electroluminescence, optical down-conversion, and hybrid plasmonic devices. The review concludes with an outlook towards future developments of these emerging light-emitting materials.

  15. Flexible radio-frequency photonics: Optoelectronic frequency combs and integrated pulse shaping

    Science.gov (United States)

    Metcalf, Andrew J.

    Microwave photonics is a discipline which leverages optoelectronics to enhance the generation, transport, and processing of high-frequency electrical signals. At the heart of many emerging techniques is the optical frequency comb. A comb is a lightwave source whose spectrum is made up of discrete equally spaced spectral components that share a fixed phase relationship. These discrete coherent oscillators --known as comb lines-- collectively form a Fourier basis that describe a periodic optical waveform. Within the last two decades frequency-stabilized broadband combs produced from mode-locked lasers have led to revolutionary advancements in precision optical frequency synthesis and metrology. Meanwhile, Fourier-transform optical pulse shaping, which provides a means to control a comb's Fourier basis in both amplitude and phase, has emerged as an integral tool in optical communications, broadband waveform generation, and microwave photonic filtering. However, traditional comb and pulse shaping architectures are often plagued by complex and bulky setups, rendering robust and cost effective implementation outside of the laboratory a challenge. In addition, traditional comb sources based on short-pulse lasers do not possess qualities which are ideally suited for this new application regime. Motivated by the shortcomings in current architectures, and empowered by recent advancements in optoelectronic technology, this dissertation focuses on developing novel and robust schemes in optical frequency comb generation and line-by-line pulse shaping. Our results include: the invention and low-noise characterization of a broadband flat-top comb source; the realization of an optoelectronic-based time cloak; and finally, the development of an integrated pulse shaper, which we use in conjunction with our flat-top comb source to demonstrate a rapidly reconfigurable microwave photonic filter.

  16. Growing perovskite into polymers for easy-processable optoelectronic devices.

    Science.gov (United States)

    Masi, Sofia; Colella, Silvia; Listorti, Andrea; Roiati, Vittoria; Liscio, Andrea; Palermo, Vincenzo; Rizzo, Aurora; Gigli, Giuseppe

    2015-01-01

    Here we conceive an innovative nanocomposite to endow hybrid perovskites with the easy processability of polymers, providing a tool to control film quality and material crystallinity. We verify that the employed semiconducting polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), controls the self-assembly of CH₃NH₃PbI₃ (MAPbI₃) crystalline domains and favors the deposition of a very smooth and homogenous layer in one straightforward step. This idea offers a new paradigm for the implementation of polymer/perovskite nanocomposites towards versatile optoelectronic devices combined with the feasibility of mass production. As a proof-of-concept we propose the application of such nanocomposite in polymer solar cell architecture, demonstrating a power conversion efficiency up to 3%, to date the highest reported for MEH-PPV. On-purpose designed polymers are expected to suit the nanocomposite properties for the integration in diverse optoelectronic devices via facile processing condition. PMID:25579988

  17. Research and Development of Electronic and Optoelectronic Materials in China

    Institute of Scientific and Technical Information of China (English)

    王占国

    2000-01-01

    A review on the research and development of electronic and optoelectronic materials in China, including the main scientific activities in this field, is presented. The state-of-the-arts and prospects of the electronic and optoelectronic materials in China are briefly introduced, such as those of silicon crystals, compound semiconductors, synthetic crystals, especially nonlinear optical crystals and rare-earth permanent magnets materials, etc. , with a greater emphasis on Chinese scientist's contributions to the frontier area of nanomaterials and nanostructures in the past few years. A new concept of the trip chemistry proposed by Dr. Liu Zhongfan from Peking University has also been described. Finally the possible research grants and the national policy to support the scientific research have been discussed.

  18. Van der Waals stacked 2D layered materials for optoelectronics

    Science.gov (United States)

    Zhang, Wenjing; Wang, Qixing; Chen, Yu; Wang, Zhuo; Wee, Andrew T. S.

    2016-06-01

    The band gaps of many atomically thin 2D layered materials such as graphene, black phosphorus, monolayer semiconducting transition metal dichalcogenides and hBN range from 0 to 6 eV. These isolated atomic planes can be reassembled into hybrid heterostructures made layer by layer in a precisely chosen sequence. Thus, the electronic properties of 2D materials can be engineered by van der Waals stacking, and the interlayer coupling can be tuned, which opens up avenues for creating new material systems with rich functionalities and novel physical properties. Early studies suggest that van der Waals stacked 2D materials work exceptionally well, dramatically enriching the optoelectronics applications of 2D materials. Here we review recent progress in van der Waals stacked 2D materials, and discuss their potential applications in optoelectronics.

  19. Optically-driven red blood cell rotor in linearly polarized laser tweezers

    Indian Academy of Sciences (India)

    Manas Khan; Samarendra K Mohanty; A K Sood

    2005-11-01

    We have constructed a dual trap optical tweezers set-up around an inverted microscope where both the traps can be independently controlled and manipulated in all the three dimensions. Here we report our observations on rotation of red blood cells (RBCs) in a linearly polarized optical trap. Red blood cells deform and become twisted in hypertonic phosphate buffer saline and when trapped, experience an unbalanced radiation pressure force. The torque generated from the unbalanced force causes the trapped RBC to rotate. Addition of Ca++ ions in the solution, keeping the osmolarity same, makes the cell membranes stiffer and the cells deform less. Thus the speed of rotation of the red blood cells can be controlled, as less deformation and in turn less asymmetry in shape produces less torque under the radiation pressure resulting in slower rotation at the same laser power.

  20. Microfluidic platform combining droplets and magnetic tweezers: application to HER2 expression in cancer diagnosis.

    Science.gov (United States)

    Ferraro, Davide; Champ, Jérôme; Teste, Bruno; Serra, Marco; Malaquin, Laurent; Viovy, Jean-Louis; de Cremoux, Patricia; Descroix, Stephanie

    2016-01-01

    The development of precision medicine, together with the multiplication of targeted therapies and associated molecular biomarkers, call for major progress in genetic analysis methods, allowing increased multiplexing and the implementation of more complex decision trees, without cost increase or loss of robustness. We present a platform combining droplet microfluidics and magnetic tweezers, performing RNA purification, reverse transcription and amplification in a fully automated and programmable way, in droplets of 250nL directly sampled from a microtiter-plate. This platform decreases sample consumption about 100 fold as compared to current robotized platforms and it reduces human manipulations and contamination risk. The platform's performance was first evaluated on cell lines, showing robust operation on RNA quantities corresponding to less than one cell, and then clinically validated with a cohort of 21 breast cancer samples, for the determination of their HER2 expression status, in a blind comparison with an established routine clinical analysis. PMID:27157697

  1. Dynamic measurements and simulations of airborne picolitre-droplet coalescence in holographic optical tweezers

    Science.gov (United States)

    Bzdek, Bryan R.; Collard, Liam; Sprittles, James E.; Hudson, Andrew J.; Reid, Jonathan P.

    2016-08-01

    We report studies of the coalescence of pairs of picolitre aerosol droplets manipulated with holographic optical tweezers, probing the shape relaxation dynamics following coalescence by simultaneously monitoring the intensity of elastic backscattered light (EBL) from the trapping laser beam (time resolution on the order of 100 ns) while recording high frame rate camera images (time resolution inhibits quantitative determination of the relaxation time scale. Droplet coalescence was simulated using a computational framework to validate both experimental approaches. The results indicate that time-dependent monitoring of droplet shape from the EBL intensity allows for robust determination of properties such as surface tension and viscosity. Finally, the potential of high frame rate imaging to examine the coalescence of dissimilar viscosity droplets is discussed.

  2. Mechanism of termination of bacteriophage DNA packaging investigated with optical tweezers

    Science.gov (United States)

    delToro, Damian J.; Smith, Douglas E.

    2012-10-01

    The genomes of many dsDNA viruses are replicated by a mechanism that produces a long concatemer of multiple genomes. These viruses utilize multifunctional molecular motor complexes referred to as "terminases" that can excise a unit genome length of DNA and package it into preformed viral shells. Remarkably, the terminase motor can initiate packaging at the appropriate start point, translocate DNA, sense when a sufficient length has been packaged, and then switch into a mode where it arrests and cleaves the DNA to release a filled virus particle. We have recently developed an improved method to measure single phage lambda DNA packaging using dual-trap optical tweezers and pre-stalled motor-DNA-procapsid complexes. We are applying this method to test proposed mechanisms for the sensor that triggers termination; specifically a velocity-monitor model vs. energy-monitor model vs. capsid-filling monitor model.

  3. Custom-Built Optical Tweezers for Locally Probing the Viscoelastic Properties of Cancer Cells

    Science.gov (United States)

    Tavano, Federica; Bonin, Serena; Pinato, Giulietta; Stanta, Giorgio; Cojoc, Dan

    2011-07-01

    We report a home built optical tweezers setup to investigate the mechanism of the membrane tether formation from single cells in vitro. Using an optically trapped microbead as probe, we have determined the force-elongation curve during tether formation and extracted several parameters characterizing the viscoelastic behavior of the cell membrane: tether stiffness, force, and viscosity. Breast cancer MDA-MB-231 cells have been studied in two different conditions, at room and physiological temperatures, showing a strong temperature dependence of the visoelastic properties of the cell membrane. To get detailed inside information about the tether formation mechanism we have extended the analysis of the force-elongation curves fitting them with a Kelvin model. These preliminary results are part of a larger project of whose goal is to compare the viscoelastic properties of several types of cancer cell lines, characterized by different aggressiveness and metastatic potential.

  4. Characterization of the mechanical properties of HL-1 cardiomyocytes with high throughput magnetic tweezers

    International Nuclear Information System (INIS)

    We characterized the mechanical properties of cardiomyocyte-like HL-1 cells using our recently developed multi-pole magnetic tweezers. With the optimized design, both high force and high throughput are achieved at the same time. Force up to 100 pN can be applied on a 1 μm diameter superparamagnetic bead in a workspace with 60 μm radius, which is encircled symmetrically by 3 sharp magnetic tips. By adjusting the coil currents, both the strength and direction of force can be controlled. The result shows that both viscosity and shear elastic modulus of HL-1 cells exhibit an approximately log-normal distribution. The cells became stiffer as they matured, consistent with a transition from proliferating cells to contractile muscle tissue. Moreover, the mechanical properties of HL-1 cells show high heterogeneity, which agrees well with their physiological structure

  5. Optical tweezers assisted imaging of the Z-ring in Escherichia coli: measuring its radial width

    Science.gov (United States)

    Carmon, G.; Kumar, P.; Feingold, M.

    2014-01-01

    Using single-beam, oscillating optical tweezers we can trap and rotate rod-shaped bacterial cells with respect to the optical axis. This technique allows imaging fluorescently labeled three-dimensional sub-cellular structures from different, optimized viewpoints. To illustrate our method we measure D, the radial width of the Z-ring in unconstricted Escherichia coli. We use cells that express FtsZ-GFP and have their cytoplasmic membrane stained with FM4-64. In a vertically oriented cell, both the Z-ring and the cytoplasmic membrane images appear as symmetric circular structures that lend themselves to quantitative analysis. We found that D ≅ 100 nm, much larger than expected.

  6. Microfluidic platform combining droplets and magnetic tweezers: application to HER2 expression in cancer diagnosis

    Science.gov (United States)

    Ferraro, Davide; Champ, Jérôme; Teste, Bruno; Serra, Marco; Malaquin, Laurent; Viovy, Jean-Louis; de Cremoux, Patricia; Descroix, Stephanie

    2016-05-01

    The development of precision medicine, together with the multiplication of targeted therapies and associated molecular biomarkers, call for major progress in genetic analysis methods, allowing increased multiplexing and the implementation of more complex decision trees, without cost increase or loss of robustness. We present a platform combining droplet microfluidics and magnetic tweezers, performing RNA purification, reverse transcription and amplification in a fully automated and programmable way, in droplets of 250nL directly sampled from a microtiter-plate. This platform decreases sample consumption about 100 fold as compared to current robotized platforms and it reduces human manipulations and contamination risk. The platform’s performance was first evaluated on cell lines, showing robust operation on RNA quantities corresponding to less than one cell, and then clinically validated with a cohort of 21 breast cancer samples, for the determination of their HER2 expression status, in a blind comparison with an established routine clinical analysis.

  7. Optoelectronic timing system. Period covered: April--June 1976

    Energy Technology Data Exchange (ETDEWEB)

    Hanes, L.D.

    1976-01-01

    An optoelectronic timing system is being developed for the measurement of detonation front arrival times in an initiation sensitivity test currently in use at Pantex. The primary goal this quarter was the design, construction, and testing of a photodiode circuit which would have a two-nanosecond rise time response proportional to light intensity and which would have an adequate voltage output for the level of light intensity encountered in the sensitivity test. The results were satisfactory.

  8. Preparation for Ultra High Pure Indium Metal for Optoelectronic Applications

    OpenAIRE

    Shashwat V. Joshi; Amit Kachhadiya; Prof. Minal S. Dani; Prof.Indravadan B Dave

    2014-01-01

    Ultra high pure Indium metal is extensively used in optoelectronic devices. Indium and its alloys become potential candidates in aerospace, defense and communication sectors. Purification of Indium has been done by Instrolec-200 Refiner followed by Directional Melting/ Freezing and Solidification Systems. Major targeted impurities are Metallic impurities Ag, Al, As, Bi, Ca, Cu, Fe, Ga, Ge, Mg, Pb, Sb, Si, Sn, and Zn. Purified Indium is characterized by analytical tec...

  9. Toward polymeric materials with optoelectronic properties tunable by mechanical and optical stimuli

    Science.gov (United States)

    Harvey, Christopher P.

    Stimuli responsive materials have properties that can be reversibly altered through treatment with a controllable external factor such as heat, light, or mechanical force. The work presented herein was focused on creating materials with optoelectronic properties tunable through mechanical stress or light irradiation. The optical properties of mechanochromic systems change under mechanical stress. There are several ways of achieving this response. Physical deformation may disrupt electronic interactions that have been established within the material or it may change the spatial arrangement of internal components in such a way as to alter their interaction with light. Breaking and reestablishing pi-pi interactions between conjugated units within elastic polymers may also lead to a mechanochromic response. Systems which respond to deformation with reversible, visible color changes may be useful for stress detection within materials. Segmented polyurethanes are elastomers composed of amorphous, saturated chain soft segments and rigid, more crystalline hard domains. Within aggregates of hard domains pi-pi interactions may form and result in alteration of the optoelectronic properties of the system. These electronic interactions may be disrupted by mechanical deformation leading to an observable mechanochromic response. A series of oligothiophene diols and diamines, as well as a naphthalene diimide diol, have been synthesized for incorporation into the hard domains of segmented polyurethanes and polyureas using long poly(tetramethylene oxide) chains as soft segments in order to evaluate such systems for possible mechanochromic response. Photochromic molecules undergo reversible changes in properties in response to irradiation with light. These compounds are found in a variety of natural pigment systems and organic electronic applications. The observed changes in properties are the results of rearrangements within the molecules which alter their optoelectronic

  10. The Cellulose Nanofibers for Optoelectronic Conversion and Energy Storage

    Directory of Open Access Journals (Sweden)

    Yongfeng Luo

    2014-01-01

    Full Text Available Cellulose widely exists in plant tissues. Due to the large pores between the cellulose units, the regular paper is nontransparent that cannot be used in the optoelectronic devices. But some chemical and physical methods such as 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO oxidation can be used to improve the pores scale between the cellulose units to reach nanometer level. The cellulose nanofibers (CNFs have good mechanical strength, flexibility, thermostability, and low thermal expansion. The paper made of these nanofibers represent a kind of novel nanostructured material with ultrahigh transparency, ultrahigh haze, conductivity, biodegradable, reproducible, low pollution, environment friendly and so on. These advantages make the novel nanostructured paper apply in the optoelectronic device possible, such as electronics energy storage devices. This kind of paper is considered most likely to replace traditional materials like plastics and glass, which is attracting widespread attention, and the related research has also been reported. The purpose of this paper is to review CNFs which are applied in optoelectronic conversion and energy storage.

  11. Optoelectronic and nonlinear optical processes in low dimensional semiconductors

    Indian Academy of Sciences (India)

    B P Singh

    2006-11-01

    Spatial confinement of quantum excitations on their characteristic wavelength scale in low dimensional materials offers unique possibilities to engineer the electronic structure and thereby control their physical properties by way of simple manipulation of geometrical parameters. This has led to an overwhelming interest in quasi-zero dimensional semiconductors or quantum dots as tunable materials for multitude of exciting applications in optoelectronic and nonlinear optical devices and quantum information processing. Large nonlinear optical response and high luminescence quantum yield expected in these systems is a consequence of huge enhancement of transition probabilities ensuing from quantum confinement. High quantum efficiency of photoluminescence, however, is not usually realized in the case of bare semiconductor nanoparticles owing to the presence of surface states. In this talk, I will focus on the role of quantum confinement and surface states in ascertaining nonlinear optical and optoelectronic properties of II–VI semiconductor quantum dots and their nanocomposites. I will also discuss the influence of nonlinear optical processes on their optoelectronic characteristics.

  12. Optoelectronic properties of valence-state-controlled amorphous niobium oxide

    Science.gov (United States)

    Onozato, Takaki; Katase, Takayoshi; Yamamoto, Akira; Katayama, Shota; Matsushima, Koichi; Itagaki, Naho; Yoshida, Hisao; Ohta, Hiromichi

    2016-06-01

    In order to understand the optoelectronic properties of amorphous niobium oxide (a-NbO x ), we have investigated the valence states, local structures, electrical resistivity, and optical absorption of a-NbO x thin films with various oxygen contents. It was found that the valence states of Nb ion in a-NbO x films can be controlled from 5+  to 4+  by reducing oxygen pressure during film deposition at room temperature, together with changing the oxide-ion arrangement around Nb ion from Nb2O5-like to NbO2-like local structure. As a result, a four orders of magnitude reduction in the electrical resistivity of a-NbO x films was observed with decreasing oxygen content, due to the carrier generation caused by the appearance and increase of an oxygen-vacancy-related subgap state working as an electron donor. The tunable optoelectronic properties of a-NbO x films by valence-state-control with oxygen-vacancy formation will be useful for potential flexible optoelectronic device applications.

  13. Transparent electrodes for organic optoelectronic devices: a review

    Science.gov (United States)

    Cao, Weiran; Li, Jian; Chen, Hongzheng; Xue, Jiangeng

    2014-01-01

    Transparent conductive electrodes are one of the essential components for organic optoelectronic devices, including photovoltaic cells and light-emitting diodes. Indium-tin oxide (ITO) is the most common transparent electrode in these devices due to its excellent optical and electrical properties. However, the manufacturing of ITO film requires precious raw materials and expensive processes, which limits their compatibility with mass production of large-area, low-cost devices. The optical/electrical properties of ITO are strongly dependent on the deposition processes and treatment conditions, whereas its brittleness and the potential damage to underlying films during deposition also present challenges for its use in flexible devices. Recently, several other transparent conductive materials, which have various degrees of success relative to commercial applications have been developed to address these issues. Starting from the basic properties of ITO and the effect of various ITO surface modification methods, here we review four different groups of materials, doped metal oxides, thin metals, conducting polymers, and nanomaterials (including carbon nanotubes, graphene, and metal nanowires), that have been reported as transparent electrodes in organic optoelectronic materials. Particular emphasis is given to their optical/electrical and other material properties, deposition techniques, and applications in organic optoelectronic devices.

  14. Optoelectronic properties of valence-state-controlled amorphous niobium oxide.

    Science.gov (United States)

    Onozato, Takaki; Katase, Takayoshi; Yamamoto, Akira; Katayama, Shota; Matsushima, Koichi; Itagaki, Naho; Yoshida, Hisao; Ohta, Hiromichi

    2016-06-29

    In order to understand the optoelectronic properties of amorphous niobium oxide (a-NbO x ), we have investigated the valence states, local structures, electrical resistivity, and optical absorption of a-NbO x thin films with various oxygen contents. It was found that the valence states of Nb ion in a-NbO x films can be controlled from 5+  to 4+  by reducing oxygen pressure during film deposition at room temperature, together with changing the oxide-ion arrangement around Nb ion from Nb2O5-like to NbO2-like local structure. As a result, a four orders of magnitude reduction in the electrical resistivity of a-NbO x films was observed with decreasing oxygen content, due to the carrier generation caused by the appearance and increase of an oxygen-vacancy-related subgap state working as an electron donor. The tunable optoelectronic properties of a-NbO x films by valence-state-control with oxygen-vacancy formation will be useful for potential flexible optoelectronic device applications. PMID:27168317

  15. Optoelectronics-related competence building in Japanese and Western firms

    Science.gov (United States)

    Miyazaki, Kumiko

    1992-05-01

    In this paper, an analysis is made of how different firms in Japan and the West have developed competence related to optoelectronics on the basis of their previous experience and corporate strategies. The sample consists of a set of seven Japanese and four Western firms in the industrial, consumer electronics and materials sectors. Optoelectronics is divided into subfields including optical communications systems, optical fibers, optoelectronic key components, liquid crystal displays, optical disks, and others. The relative strengths and weaknesses of companies in the various subfields are determined using the INSPEC database, from 1976 to 1989. Parallel data are analyzed using OTAF U.S. patent statistics and the two sets of data are compared. The statistical analysis from the database is summarized for firms in each subfield in the form of an intra-firm technology index (IFTI), a new technique introduced to assess the revealed technology advantage of firms. The quantitative evaluation is complemented by results from intensive interviews with the management and scientists of the firms involved. The findings show that there is a marked variation in the way firms' technological trajectories have evolved giving rise to strength in some and weakness in other subfields for the different companies, which are related to their accumulated core competencies, previous core business activities, organizational, marketing, and competitive factors.

  16. Erasure of Time Delay Signatures in the Output of an Optoelectronic Feedback Laser with Modulated Delays and Chaos Synchronization

    OpenAIRE

    Shahverdiev, E. M.; Shore, K. A.

    2009-01-01

    By studying the autocorrelation function of the optoelectronic feedback semiconductor laser output we establish that the signatures of time delays can be erased in systems incorporating modulated feedback time delays. This property is of importance for the suitability of such laser systems for secure chaos-based communication systems. We also make the first report on chaos synchronization in both unidirectionally and bidirectionally coupled multiple time delay chaotic semiconductor lasers wit...

  17. Materials for optoelectronic device packaging/manufacturing

    Science.gov (United States)

    Lin, Yuan-Chang

    The first part of this work is to review the materials challenges and solutions for the packaging of high power LEDs, i.e., the light extraction efficiency, thermal and UV stability, and stress/delamination, which are all related to the reliability and lifetime of high power LEDs. The second part of this work is related to the development of transparent epoxy and silicone materials for the packaging of LEDs and the studies of light transmission stability under various treatments, including thermal, UV and combined treatments. It is found out that packaged high power blue LEDs encapsulated by epoxy materials have a very short lifetime due to the severe discoloration of epoxy at die-encapsulant interface caused by high flux radiation and junction temperature from LED chip. However, the reliability of formulated silicone outperforms epoxy materials, which can be explain by highly transparent in the UV-visible wavelength region and better thermal and UV resistance of silicone materials. The third part of this work is related to the study of optical properties of white LEDs, i.e., optical power, luminous efficiency, CCT, chromaticity coordinate and CRI as a function of phosphor wt% in silicone for the flat-top (FT) and flat-top-with lens (FTWL) packages. Due to the total internal reflection (TIR) at the encapsulant-air interface, the FT package shows a 10˜11% power (in mW) reduction compared with the FTWL package at the same phosphor concentration. However, it is demonstrated that the FT package provides a more efficient way of utilizing phosphor than the FTWL package based on the same targeted chromaticity coordinates due to the TIR effect inside, resulting in a reduced phosphor usage with a lumen output only about 3% lower than that of the FTWL package. Furthermore, the effects of fumed silica on optical properties are studied for these packages. In comparison to the package without fumed silica, the package with fumed silica has the advantages in anti-settling of

  18. Nanostructured optoelectronic devices compatible with Si

    International Nuclear Information System (INIS)

    In this work I develop concepts for the realization of integrated light sources and detectors in Si technology. I report on the experimental realization of three kinds of active photonic devices, employing quantum dots as an active medium. The first device consists of silicon waveguides with quantum dots integrated in them. Both planar and rib waveguides are investigated in this work. They incorporate colloidal lead sulphide (PbS), lead selenide (PbSe), mercury telluride (HgTe) quantum dots and epitaxial Ge islands. Whereas the first three types of quantum dots are synthesized chemically in the form of nanocrystals in colloidal solutions, the last type of dots is grown by molecular beam epitaxy (MBE). These active waveguides with a width of 5 μm, 10 μm and 20 μm and a length 10 mm have the complex functionality of emitting infrared light at a wavelength λ=1.55 μm and guiding of this light to the necessary place on the single platform or to the detection unit. Moderate net optical gain of 2% has been observed from HgTe quantum dots in Si waveguide in pump-probe experiments with a tunable cw probe laser and an Ar+ 488 nm pump laser. A distributed Bragg grating (DFB), introduced on the surface of these waveguides, can provide an optical feedback of the propagating 1.55 μm light. Under proper conditions this works as a DFB laser. The second device is a Si - Ge photodetector. The photodetector is based on a vertical p - i - n junction with Ge quantum dots grown in Si matrix on SOI (silicon-on-insulator) substrates. The role of p- and n- layers is fulfilled by Boron (B) doped Si and antimony (Sb) doped Si, respectively. The operation, on the other hand, is based on the principle of electron-hole generation close to the Ge quantum dots and their separation by an externally applied electric field to the Ohmic contacts on the p- and n- layers. This device operates in the spectral range around λ = 1.55 μm. The last device is a nano- imprinted quantum dot laser. Core

  19. Lysine-specific molecular tweezers are broad-spectrum inhibitors of assembly and toxicity of amyloid proteins

    OpenAIRE

    Sinha, Sharmistha; Lopes, Dahabada H. J.; Du, Zhenming; Pang, Eric S.; Shanmugam, Akila; Lomakin, Aleksey; Talbiersky, Peter; Tennstaedt, Annette; McDaniel, Kirsten; Bakshi, Reena; Kuo, Pei-Yi; Ehrmann, Michael; Benedek, George B.; Loo, Joseph A.; Klärner, Frank-Gerrit

    2011-01-01

    Amyloidoses are diseases characterized by abnormal protein folding and self-assembly, for which no cure is available. Inhibition or modulation of abnormal protein self-assembly therefore is an attractive strategy for prevention and treatment of amyloidoses. We examined Lys-specific molecular tweezers and discovered a lead compound termed CLR01, which is capable of inhibiting the aggregation and toxicity of multiple amyloidogenic proteins by binding to Lys residues and disrupting hydrophobic a...

  20. Vehicle tethered aerostat optoelectronic monitoring platform system for Shanghai World EXPO

    Science.gov (United States)

    Zhou, Weihu; Wang, Yawei; Han, Xiaoquan; Yuan, Jiang

    2010-08-01

    To monitor the whole Shanghai Expo Park, a vehicle tethered aerostat optoelectronic monitoring platform with the characteristic of time-sensitive and all-weather monitoring is described in detail in this paper, which is hung beneath the tethered balloon and equipped with a variety of payloads, including visible light monitoring system, infrared monitoring system, hyperspectral monitoring system, GPS/INS system, monitoring and control system and so on. These equipments can be used for real-time monitoring, environmental monitoring, and ground target location of Shanghai Expo Park. The output High Definition (HD) image of Shanghai Expo Park from visible light monitoring system is clear and stable, and the stabilization accuracy of visual axis is 0.07°(3δ). The optoelectronic monitoring platform system uses the target location technology based on Global Position System/Inertial Navigation System (GPS/INS) system to output real-time location data compatible with Geographic Information System (GIS). Test results show that the maximum errors between the location results (latitude and longitude) solved by the target location program and the reference target are 0.2 0/00(latitude) and 2 0/00(longitude). Now the whole system has been used for surveillance the Shanghai Expo Park since April 2010.

  1. Bridging Photonics and Optoelectronics Curriculum for the Solar Photovoltaic and LED Industries

    Directory of Open Access Journals (Sweden)

    Yu-Shan Su

    2014-01-01

    Full Text Available The gap between learning courses and practical demands has existed in Taiwanese solar photovoltaic and LED industries; therefore, this study attempts to analyze the existing curriculum design of universities. This study collected the current 103 course programs from all optoelectronics-related departments in Taiwanese 36 colleges and universities and sorted these curriculums by three domains of education objectives theory. This theoretical framework was verified on the basis of samples from 150 Taiwanese industrial experts and 354 optoelectronics-related undergraduates and postgraduates. We found that the levels of correlation among the independent variables including cognitive, affective, and skill-based domains and the dependent variable employability are all positively related to each other. We also found the currently curriculum design in Taiwanese universities rarely fit into theory of education objectives from the results of multiple regression analysis. Industrial and student’s group also have few consistent ideas on courses within the curriculum. Finally in order to bridge the gap between learning and practical application, the study provides an idea on curriculum design and suggests that curriculum review should be executed by industrial experts to confirm the courses related to the employability.

  2. Tunable optoelectronic properties of CBD-CdS thin films via bath temperature alterations

    Science.gov (United States)

    Kumarage, W. G. C.; Wijesundera, R. P.; Seneviratne, V. A.; Jayalath, C. P.; Dassanayake, B. S.

    2016-03-01

    The tunability of the band-gap value and electron affinity of the n-CdS by adjusting the growth parameters is very important as it paves the way to improve the efficiency of CdS-based solar cells by adjusting the band lineup with other p-type semiconductors. In this respect, polycrystalline n-CdS thin films were grown on FTO glass substrates at different bath temperatures (40-80 °C) by the chemical bath deposition technique. The structural, morphological and optoelectronic properties of CdS thin films were studied using x-ray diffraction, scanning electron microscopy, UV-Vis spectrometry, profilometry, atomic force microscopy, photoelectrochemical and Mott-Schottky measurements. Absorption measurements reveal that an energy-gap value of n-CdS can be adjusted from 2.27 to 2.57 eV and Mott-Schottky measurements indicate that the flat-band potential is increased from  -699 to  -835 V with respect to a Ag/AgCl electrode by decreasing the deposition bath temperature from 60 to 40 °C. This tunability of optoelectronic properties of n-CdS is very useful for applications in thin film solar cells and other devices.

  3. Assessment of Density Functional Methods for Exciton Binding Energies and Related Optoelectronic Properties

    CERN Document Server

    Lee, Jui-Che; Lin, Shiang-Tai

    2015-01-01

    The exciton binding energy, the energy required to dissociate an excited electron-hole pair into free charge carriers, is one of the key factors to the optoelectronic performance of organic materials. However, it remains unclear whether modern quantum-mechanical calculations, mostly based on Kohn-Sham density functional theory (KS-DFT) and time-dependent density functional theory (TDDFT), are reliably accurate for exciton binding energies. In this study, the exciton binding energies and related optoelectronic properties (e.g., the ionization potentials, electron affinities, fundamental gaps, and optical gaps) of 121 small- to medium-sized molecules are calculated using KS-DFT and TDDFT with various density functionals. Our KS-DFT and TDDFT results are compared with those calculated using highly accurate CCSD and EOM-CCSD methods, respectively. The omegaB97, omegaB97X, and omegaB97X-D functionals are shown to generally outperform (with a mean absolute error of 0.36 eV) other functionals for the properties inve...

  4. Design and fabrication of a 3x3 optoelectronic integrated switch

    Science.gov (United States)

    Gouin, Francois L.; Beaulieu, Christian; Noad, Julian P.

    1996-01-01

    With the increasing number of optical networks comes a growing demand for hardware to allow management of interconnections. One of the important elements in a network is the cross-point switch. In this presentation, we describe a GaAs 3 multiplied by 3 optoelectronic switch based on a monolithic optoelectronic integrated circuit which combines a receiver array of MSM photodetectors and three transimpedance amplifiers providing gain for the three output channels. The 3 multiplied by 3 matrix of photodetectors acts at the switching element. The three electrical output channels from this receiver are amplified further by MIC circuits using chip amplifiers. This restores the signal to a level sufficient to drive semiconductor lasers thereby converting the electrical signal back to an optical signal for use as an optical- optical router. A critical step in the switch construction is the delivery of the optical signals to the photodetectors. A special mount was designed and fabricated to support and align the 9 fibers in front of their respective detectors. The switch was evaluated in terms of the responsivity, the isolation and the cross-talk. The overall responsivity exceeds 20 A/W with a bandwidth of 400 MHz, limited by the speed of the detectors. The isolation varies between 33 and 55 dB and depends on the device selected and on the bias condition of the detector in the off-state. The operation of the switch was demonstrated using three television signals.

  5. Graduate studies on optoelectronics in Argentina: an experience

    Science.gov (United States)

    Fernández, Juan C.; Garea, María. T.; Isaurralde, Silvia; Perez, Liliana I.; Raffo, Carlos A.

    2014-07-01

    The number of graduate programs in Optoelectronics in Argentina is scarce. The current Optics and Photonics Education Directory lists only three programs. One of them was launched in 2001 in the Facultad de Ingeniería (College of Engineering), Universidad de Buenos Aires (UBA). This was the first graduate program in the field, leading to a Master Degree in Optoelectronics. This decision arose from the demand of telecommunications industries and several estate- or private-funded research institutions working with us in the fields of lasers, optics, remote sensing, etc. A great bonus was the steady work, during several decades, of research groups in the College on the development of different type of lasers and optical non destructive tests and their engineering applications. As happened in many engineering graduate programs in Argentina at that time, few non full-time students could finish their studies, which called for 800 hours of traditional lecture-recitation classes, and the Master Thesis. In recent years Argentine Education authorities downsized the Master programs to 700 hours of blended learning and we redesigned the Graduate Optoelectronic Engineering Program to meet the challenge, dividing it in two successive one year programs, the first aimed at a professional training for almost immediate insertion in the labor market (called Especialización en Ingeniería Optoelectrónica), and the second (called Maestría en Ingeniería Optoelectrónica y Fotónica) aimed at a more academic and research target to comply with the UBA standards for Master degrees. The present work is a presentation of the new program design, which has begun in the current year.

  6. MEMS oscillating squeeze-film pressure sensor with optoelectronic feedback

    International Nuclear Information System (INIS)

    This work reports on an oscillating pressure sensor that converts pressure into frequency using the squeeze-film effect. A new aspect is the laser Doppler vibrometer (LDV) in the optoelectronic feedback loop that is used to bring the sensor element into sustained mechanical oscillation. A phase shifter and automatic gain control circuit stabilize the oscillation. The frequency stability of the pressure sensor is investigated by measuring its Allan deviation and is compared to the performance of a quartz oscillating pressure sensor. Finally, the pressure resolution of this oscillating sensor is compared to conventional pressure sensors. (paper)

  7. Epsilon-near-zero mode for active optoelectronic devices.

    Science.gov (United States)

    Vassant, S; Archambault, A; Marquier, F; Pardo, F; Gennser, U; Cavanna, A; Pelouard, J L; Greffet, J J

    2012-12-01

    The electromagnetic modes of a GaAs quantum well between two AlGaAs barriers are studied. At the longitudinal optical phonon frequency, the system supports a phonon polariton mode confined in the thickness of the quantum well that we call epsilon-near-zero mode. This epsilon-near-zero mode can be resonantly excited through a grating resulting in a very large absorption localized in the single quantum well. We show that the reflectivity can be modulated by applying a voltage. This paves the way to a new class of active optoelectronic devices working in the midinfrared and far infrared at ambient temperature. PMID:23368264

  8. Gamma spectroscopy and optoelectronic imaging with hybrid photon detector

    CERN Document Server

    D'Ambrosio, C; Piedigrossi, D; Rosso, E; Cenceelli, V; De Notaristefani, F; Masini, Gérald; Puertolas, D; Cindolo, F; Mares, J A; Nikl, M; Abreu, M; Rato-Mendes, P; Sousa, P

    2003-01-01

    Hybrid Photon Detectors (HPD) detect light via photocathodes and accelerate the emitted photoelectrons by an electric field towards silicon PIN-anodes, where they are absorbed and generate electronic signals. We have developed two specific types of HPDs: (1) Hybrid photomultiplier tubes for photon counting and gamma spectroscopy; (2) Imaging silicon pixel array tubes for optoelectronic cameras. This paper will illustrate the main achievements, which we obtained in the last years, and will describe and discuss our present main R&D efforts, in particular, in the biomedical imaging field. (27 refs).

  9. Optoelectronic analysis of multijunction wire array solar cells

    OpenAIRE

    Turner-Evans, Daniel B.; Chen, Christopher T.; Emmer, Hal; McMahon, William E.; Atwater, Harry A.

    2013-01-01

    Wire arrays have demonstrated promising photovoltaic performance as single junction solar cells and are well suited to defect mitigation in heteroepitaxy. These attributes can combine in tandem wire array solar cells, potentially leading to high efficiencies. Here, we demonstrate initial growths of GaAs on Si_(0.9)Ge_(0.1) structures and investigate III-V on Si_(1-x)Ge_x device design with an analytical model and optoelectronic simulations. We consider Si_(0.1)Ge_(0.9) wires coated with a GaA...

  10. Preparation for Ultra High Pure Indium Metal for Optoelectronic Applications

    Directory of Open Access Journals (Sweden)

    Shashwat V. Joshi

    2014-11-01

    Full Text Available Ultra high pure Indium metal is extensively used in optoelectronic devices. Indium and its alloys become potential candidates in aerospace, defense and communication sectors. Purification of Indium has been done by Instrolec-200 Refiner followed by Directional Melting/ Freezing and Solidification Systems. Major targeted impurities are Metallic impurities Ag, Al, As, Bi, Ca, Cu, Fe, Ga, Ge, Mg, Pb, Sb, Si, Sn, and Zn. Purified Indium is characterized by analytical techniques Inductively Coupled Plasma- Optical Emission Spectrophotometry and Inductively Coupled Plasma- Mass Spectrometry.

  11. Measuring processes with opto-electronic semiconductor components

    International Nuclear Information System (INIS)

    This is a report on the state of commercially available semiconductor emitters and detectors for the visible, near, middle and remote infrared range. A survey is given on the distance, speed, flow and length measuring techniques using opto-electronic components. Automatic focussing, the use of light barriers, non-contact temperature measurements, spectroscopic gas, liquid and environmental measurement techniques and gas analysis in medical techniques show further applications of the new components. The modern concept of guided radiation in optical fibres and their use in system technology is briefly explained. (DG)

  12. Neuromorphic opto-electronic integrated circuits for optical signal processing

    Science.gov (United States)

    Romeira, B.; Javaloyes, J.; Balle, S.; Piro, O.; Avó, R.; Figueiredo, J. M. L.

    2014-08-01

    The ability to produce narrow optical pulses has been extensively investigated in laser systems with promising applications in photonics such as clock recovery, pulse reshaping, and recently in photonics artificial neural networks using spiking signal processing. Here, we investigate a neuromorphic opto-electronic integrated circuit (NOEIC) comprising a semiconductor laser driven by a resonant tunneling diode (RTD) photo-detector operating at telecommunication (1550 nm) wavelengths capable of excitable spiking signal generation in response to optical and electrical control signals. The RTD-NOEIC mimics biologically inspired neuronal phenomena and possesses high-speed response and potential for monolithic integration for optical signal processing applications.

  13. Analysis of optoelectronic strategic planning in Taiwan by artificial intelligence portfolio tool

    Science.gov (United States)

    Chang, Rang-Seng

    1992-05-01

    Taiwan ROC has achieved significant advances in the optoelectronic industry with some Taiwan products ranked high in the world market and technology. Six segmentations of optoelectronic were planned. Each one was divided into several strategic items, design artificial intelligent portfolio tool (AIPT) to analyze the optoelectronic strategic planning in Taiwan. The portfolio is designed to provoke strategic thinking intelligently. This computer- generated strategy should be selected and modified by the individual. Some strategies for the development of the Taiwan optoelectronic industry also are discussed in this paper.

  14. A self-starting hybrid optoelectronic oscillator generating ultra low jitter 10-GHz optical pulses and low phase noise electrical signals

    DEFF Research Database (Denmark)

    Lasri, J.; Bilenca, A.; Dahan, D.; Sidorov, V.; Eisenstein, G.; Ritter, D.; Yvind, Kresten

    2002-01-01

    In this letter, we describe a self-starting optical pulse source generating ultra low noise 15-ps-wide pulses at 10 GHz. It is based on a hybrid optoelectronic oscillator comprising a fiber extended cavity mode-locked diode laser which injection locks a self-oscillating heterojunction bipolar...

  15. Mild Conditions for Deuteration of Primary and Secondary Arylamines for the Synthesis of Deuterated Optoelectronic Organic Molecules

    Directory of Open Access Journals (Sweden)

    Anwen M. Krause-Heuer

    2014-11-01

    Full Text Available Deuterated arylamines demonstrate great potential for use in optoelectronic devices, but their widespread utility requires a method for large-scale synthesis. The incorporation of these deuterated materials into optoelectronic devices also provides the opportunity for studies of the functioning device using neutron reflectometry based on the difference in the scattering length density between protonated and deuterated compounds. Here we report mild deuteration conditions utilising standard laboratory glassware for the deuteration of: diphenylamine, N-phenylnaphthylamine, N-phenyl-o-phenylenediamine and 1-naphthylamine (via H/D exchange in D2O at 80 °C, catalysed by Pt/C and Pd/C. These conditions were not successful in the deuteration of triphenylamine or N,N-dimethylaniline, suggesting that these mild conditions are not suitable for the deuteration of tertiary arylamines, but are likely to be applicable for the deuteration of other primary and secondary arylamines. The deuterated arylamines can then be used for synthesis of larger organic molecules or polymers with optoelectronic applications.

  16. Copper(I) thiocyanate (CuSCN) as a hole-transport material for large-area opto/electronics

    International Nuclear Information System (INIS)

    Recent advances in large-area optoelectronics research have demonstrated the tremendous potential of copper(I) thiocyanate (CuSCN) as a universal hole-transport interlayer material for numerous applications, including transparent thin-film transistors, high-efficiency organic and hybrid organic-inorganic photovoltaic cells, and organic light-emitting diodes. CuSCN combines intrinsic hole-transport (p-type) characteristics with a large bandgap (>3.5 eV) which facilitates optical transparency across the visible to near infrared part of the electromagnetic spectrum. Furthermore, CuSCN is readily available from commercial sources while it is inexpensive and can be processed at low-temperatures using solution-based techniques. This unique combination of desirable characteristics makes CuSCN a promising material for application in emerging large-area optoelectronics. In this review article, we outline some important properties of CuSCN and examine its use in the fabrication of potentially low-cost optoelectronic devices. The merits of using CuSCN in numerous emerging applications as an alternative to conventional hole-transport materials are also discussed. (paper)

  17. Cooperation and competition in business on example of Internet research of opto-electronic companies

    Science.gov (United States)

    Kaliczyńska, Małgorzata

    2006-10-01

    Based on findings from earlier studies which showed that links to academic web sites contain important information, the following study examines the practicability of using co-link data to describe cooperation and competition in optoelec-tronic business. The analysis was based on 32 companies and organizations which were found in an issue of a specialist magazine. For the purpose of the research three search engines - Google, Yahoo! and MSN Search were used. Assuming that a number of co-links to a pair of Web sites is a measure of the similarity between the two companies, the study aims at search for the sets of companies that would be similar to one another. The method applied is the MDS - multidimensional scaling that allows to present results of the analysis on a 2D map.

  18. Microfluidic optoelectronic sensor for salivary diagnostics of stomach cancer.

    Science.gov (United States)

    Zilberman, Yael; Sonkusale, Sameer R

    2015-05-15

    We present a microfluidic optoelectronic sensor for saliva diagnostics with a potential application for non-invasive early diagnosis of stomach cancer. Stomach cancer is the second most common cause of cancer-related deaths in the world. The primary identified cause is infection by a gram-negative bacterium Helicobacter pylori. These bacteria secrete the enzyme urease that converts urea into carbon dioxide (CO2) and ammonia (NH3), leading to their elevated levels in breath and body fluids. The proposed optoelectronic sensor will detect clinically relevant levels of CO2 and NH3 in saliva that can potentially be used for early diagnosis of stomach cancer. The sensor is composed of the embedded in a microfluidic device array of microwells filled with ion-exchange polymer microbeads doped with various organic dyes. The optical response of this unique highly diverse sensor is monitored over a broad spectrum, which provides a platform for cross-reactive sensitivity and allows detection of CO2 and NH3 in saliva at ppm levels. PMID:25223554

  19. Nanoengineered quantum dot medium for space optoelectronic devices

    Science.gov (United States)

    Oktyabrsky, S.; Tokranov, V.; Yakimov, M.; Sergeev, A.; Mitin, V.

    2012-10-01

    Resistance to temperature and ionizing radiation of space optoelectronic devices can be improved through control of carrier kinetics in nanoscale systems. Recent results in the science and technology of self-assembled heteroepitaxial InAs quantum dot (QD) medium related to photonic applications are discussed. Focus is placed on management of carrier kinetics via nanoengineering of electronic spectrum and potential profiles in the QD ensemble using modeling and controlled fabrication of QDs with molecular beam epitaxy. Shape-engineered QD sheets embedded into GaAs quantum wells were found to withstand two orders of magnitude higher proton dose than QWs and to account for high luminescence efficiency and thermally stable laser diodes. Built-in charge in QDs is responsible for improvement of both near and mid-IR optical absorption, but also control photoelectron lifetime in the structures. The negatively charged QD medium was the first QD material that has recently shown credible improvement of solar cell efficiency. It has resulted from IR energy harvesting and suppressed fast electron capture processes. It is thus expected that QD InAs/GaAs photovoltaics will overcome the efficiency and lifespan of multi-junction solar cells. Potentials due to QD built-in charge are also responsible for improved photoelectron lifetime in QD infrared photodetectors. QD correlated clusters provide even higher collective potential barriers around clusters and constitute the novel approach to the optoelectronic materials combining manageable photoelectron lifetime, high mobility, and tunable localized and conducting states.

  20. Growing perovskite into polymers for easy-processable optoelectronic devices

    Science.gov (United States)

    Masi, Sofia; Colella, Silvia; Listorti, Andrea; Roiati, Vittoria; Liscio, Andrea; Palermo, Vincenzo; Rizzo, Aurora; Gigli, Giuseppe

    2015-01-01

    Here we conceive an innovative nanocomposite to endow hybrid perovskites with the easy processability of polymers, providing a tool to control film quality and material crystallinity. We verify that the employed semiconducting polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), controls the self-assembly of CH3NH3PbI3 (MAPbI3) crystalline domains and favors the deposition of a very smooth and homogenous layer in one straightforward step. This idea offers a new paradigm for the implementation of polymer/perovskite nanocomposites towards versatile optoelectronic devices combined with the feasibility of mass production. As a proof-of-concept we propose the application of such nanocomposite in polymer solar cell architecture, demonstrating a power conversion efficiency up to 3%, to date the highest reported for MEH-PPV. On-purpose designed polymers are expected to suit the nanocomposite properties for the integration in diverse optoelectronic devices via facile processing condition.

  1. High-resolution detection of Brownian motion for quantitative optical tweezers experiments.

    Science.gov (United States)

    Grimm, Matthias; Franosch, Thomas; Jeney, Sylvia

    2012-08-01

    We have developed an in situ method to calibrate optical tweezers experiments and simultaneously measure the size of the trapped particle or the viscosity of the surrounding fluid. The positional fluctuations of the trapped particle are recorded with a high-bandwidth photodetector. We compute the mean-square displacement, as well as the velocity autocorrelation function of the sphere, and compare it to the theory of Brownian motion including hydrodynamic memory effects. A careful measurement and analysis of the time scales characterizing the dynamics of the harmonically bound sphere fluctuating in a viscous medium directly yields all relevant parameters. Finally, we test the method for different optical trap strengths, with different bead sizes and in different fluids, and we find excellent agreement with the values provided by the manufacturers. The proposed approach overcomes the most commonly encountered limitations in precision when analyzing the power spectrum of position fluctuations in the region around the corner frequency. These low frequencies are usually prone to errors due to drift, limitations in the detection, and trap linearity as well as short acquisition times resulting in poor statistics. Furthermore, the strategy can be generalized to Brownian motion in more complex environments, provided the adequate theories are available. PMID:23005790

  2. Force unfolding kinetics of RNA using optical tweezers. I. Effects of experimental variables on measured results

    CERN Document Server

    Wen, J -D; Li, P T X; Smith, S B; Bustamante, C; Ritort, F; Tinoco, I

    2007-01-01

    Experimental variables of optical tweezers instrumentation that affect RNA folding/unfolding kinetics were investigated. A model RNA hairpin, P5ab, was attached to two micron-sized beads through hybrid RNA/DNA handles; one bead was trapped by dual-beam lasers and the other was held by a micropipette. Several experimental variables were changed while measuring the unfolding/refolding kinetics, including handle lengths, trap stiffness, and modes of force applied to the molecule. In constant-force mode where the tension applied to the RNA was maintained through feedback control, the measured rate coefficients varied within 40% when the handle lengths were changed by 10 fold (1.1 to 10.2 Kbp); they increased by two- to three-fold when the trap stiffness was lowered to one third (from 0.1 to 0.035 pN/nm). In the passive mode, without feedback control and where the force applied to the RNA varied in response to the end-to-end distance change of the tether, the RNA hopped between a high-force folded-state and a low-...

  3. Dynamic translocation of ligand-complexed DNA through solid-state nanopores with optical tweezers

    International Nuclear Information System (INIS)

    We investigated the threading and controlled translocation of individual lambda-DNA (λ-DNA) molecules through solid-state nanopores with piconewton force sensitivity, millisecond time resolution and picoampere ionic current sensitivity with a set-up combining quantitative 3D optical tweezers (OT) with electrophysiology. With our virtually interference-free OT set-up the binding of RecA and single peroxiredoxin protein molecules to λ-DNA was quantitatively investigated during dynamic translocation experiments where effective forces and respective ionic currents of the threaded DNA molecule through the nanopore were measured during inward and outward sliding. Membrane voltage-dependent experiments of reversible single protein/DNA translocation scans yield hysteresis-free, asymmetric single-molecule fingerprints in the measured force and conductance signals that can be attributed to the interplay of optical trap and electrostatic nanopore potentials. These experiments allow an exact localization of the bound protein along the DNA strand and open fascinating applications for label-free detection of DNA-binding ligands, where structural and positional binding phenomena can be investigated at a single-molecule level.

  4. Acoustical tweezers using single spherically focused piston, X-cut, and Gaussian beams.

    Science.gov (United States)

    Mitri, Farid G

    2015-10-01

    Partial-wave series expansions (PWSEs) satisfying the Helmholtz equation in spherical coordinates are derived for circular spherically focused piston (i.e., apodized by a uniform velocity amplitude normal to its surface), X-cut (i.e., apodized by a velocity amplitude parallel to the axis of wave propagation), and Gaussian (i.e., apodized by a Gaussian distribution of the velocity amplitude) beams. The Rayleigh-Sommerfeld diffraction integral and the addition theorems for the Legendre and spherical wave functions are used to obtain the PWSEs assuming weakly focused beams (with focusing angle α ⩽ 20°) in the Fresnel-Kirchhoff (parabolic) approximation. In contrast with previous analytical models, the derived expressions allow computing the scattering and acoustic radiation force from a sphere of radius a without restriction to either the Rayleigh (a ≪ λ, where λ is the wavelength of the incident radiation) or the ray acoustics (a ≫λ) regimes. The analytical formulations are valid for wavelengths largely exceeding the radius of the focused acoustic radiator, when the viscosity of the surrounding fluid can be neglected, and when the sphere is translated along the axis of wave propagation. Computational results illustrate the analysis with particular emphasis on the sphere's elastic properties and the axial distance to the center of the concave surface, with close connection of the emergence of negative trapping forces. Potential applications are in single-beam acoustical tweezers, acoustic levitation, and particle manipulation. PMID:26470046

  5. A new approach to follow a single extracellular vesicle-cell interaction using optical tweezers.

    Science.gov (United States)

    Prada, Ilaria; Amin, Ladan; Furlan, Roberto; Legname, Giuseppe; Verderio, Claudia; Cojoc, Dan

    2016-01-01

    Extracellular vesicles (EVs) are spherical membrane structures released by most cells. These highly conserved mediators of intercellular communication carry proteins, lipids, and nucleic acids, and transfer these cellular components between cells by different mechanisms, such as endocytosis, macropinocytosis, or fusion. However, the temporal and spatial dynamics of vesicle-cell interactions still remain largely unexplored. Here we used optical tweezers to drive single EVs produced by microglial cells onto the surface of astrocytes or microglia in primary culture. By visualizing single EV-cell contacts, we observed that microglial vesicles displayed different motilities on the surface of astrocytes compared with microglia. After contact, EVs positioned on astrocytes displayed some minor oscillatory motion around the point of adhesion, while vesicles dragged to microglia displayed quite regular directional movement on the plasma membrane. Both the adhesion and motion of vesicles on glial cells were strongly reduced by cloaking phosphatidylserine (PS) residues, which are externalized on the vesicle membrane and act as determinants for vesicle recognition by target cells. These data identify optical manipulation as a powerful tool to monitor in vitro vesicle-cell dynamics with high temporal and spatial resolution and to determine in a quantitative manner the contribution of surface receptors/extracellular protein ligands to the contact. PMID:26757810

  6. Proposed triaxial atomic force microscope contact-free tweezers for nanoassembly

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Keith A; Westervelt, Robert M, E-mail: westervelt@seas.harvard.ed [School of Engineering and Applied Science, Harvard University, Cambridge, MA 02138 (United States)

    2009-09-23

    We propose a triaxial atomic force microscope contact-free tweezer (TACT) for the controlled assembly of nanoparticles suspended in a liquid. The TACT overcomes four major challenges faced in nanoassembly, as follows. (1) The TACT can hold and position a single nanoparticle with spatial accuracy smaller than the nanoparticle size ({approx}5 nm). (2) The nanoparticle is held away from the surface of the TACT by negative dielectrophoresis to prevent van der Waals forces from making it stick to the TACT. (3) The TACT holds nanoparticles in a trap that is size-matched to the particle and surrounded by a repulsive region so that it will only trap a single particle at a time. (4) The trap can hold a semiconductor nanoparticle in water with a trapping energy greater than the thermal energy. For example, a 5 nm radius silicon nanoparticle is held with 10 k{sub B}T at room temperature. We propose methods for using the TACT as a nanoscale pick-and-place tool to assemble semiconductor quantum dots, biological molecules, semiconductor nanowires, and carbon nanotubes.

  7. Holographic Raman tweezers controlled by multi-modal natural user interface

    Science.gov (United States)

    Tomori, Zoltán; Keša, Peter; Nikorovič, Matej; Kaňka, Jan; Jákl, Petr; Šerý, Mojmír; Bernatová, Silvie; Valušová, Eva; Antalík, Marián; Zemánek, Pavel

    2016-01-01

    Holographic optical tweezers provide a contactless way to trap and manipulate several microobjects independently in space using focused laser beams. Although the methods of fast and efficient generation of optical traps are well developed, their user friendly control still lags behind. Even though several attempts have appeared recently to exploit touch tablets, 2D cameras, or Kinect game consoles, they have not yet reached the level of natural human interface. Here we demonstrate a multi-modal ‘natural user interface’ approach that combines finger and gaze tracking with gesture and speech recognition. This allows us to select objects with an operator’s gaze and voice, to trap the objects and control their positions via tracking of finger movement in space and to run semi-automatic procedures such as acquisition of Raman spectra from preselected objects. This approach takes advantage of the power of human processing of images together with smooth control of human fingertips and downscales these skills to control remotely the motion of microobjects at microscale in a natural way for the human operator.

  8. Dynamic translocation of ligand-complexed DNA through solid-state nanopores with optical tweezers

    Science.gov (United States)

    Sischka, Andy; Spiering, Andre; Khaksar, Maryam; Laxa, Miriam; König, Janine; Dietz, Karl-Josef; Anselmetti, Dario

    2010-11-01

    We investigated the threading and controlled translocation of individual lambda-DNA (λ-DNA) molecules through solid-state nanopores with piconewton force sensitivity, millisecond time resolution and picoampere ionic current sensitivity with a set-up combining quantitative 3D optical tweezers (OT) with electrophysiology. With our virtually interference-free OT set-up the binding of RecA and single peroxiredoxin protein molecules to λ-DNA was quantitatively investigated during dynamic translocation experiments where effective forces and respective ionic currents of the threaded DNA molecule through the nanopore were measured during inward and outward sliding. Membrane voltage-dependent experiments of reversible single protein/DNA translocation scans yield hysteresis-free, asymmetric single-molecule fingerprints in the measured force and conductance signals that can be attributed to the interplay of optical trap and electrostatic nanopore potentials. These experiments allow an exact localization of the bound protein along the DNA strand and open fascinating applications for label-free detection of DNA-binding ligands, where structural and positional binding phenomena can be investigated at a single-molecule level.

  9. Dynamic translocation of ligand-complexed DNA through solid-state nanopores with optical tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Sischka, Andy; Spiering, Andre; Anselmetti, Dario [Experimental Biophysics and Applied Nanoscience, Faculty of Physics, Bielefeld University, D-33615 Bielefeld (Germany); Khaksar, Maryam [Fachbereich Physik, University of Konstanz, Fach 688, D-78457 Konstanz (Germany); Laxa, Miriam; Koenig, Janine; Dietz, Karl-Josef, E-mail: andy.sischka@physik.uni-bielefeld.d [Biochemistry and Plant Physiology, Faculty of Biology, Bielefeld University, D-33615 Bielefeld (Germany)

    2010-11-17

    We investigated the threading and controlled translocation of individual lambda-DNA ({lambda}-DNA) molecules through solid-state nanopores with piconewton force sensitivity, millisecond time resolution and picoampere ionic current sensitivity with a set-up combining quantitative 3D optical tweezers (OT) with electrophysiology. With our virtually interference-free OT set-up the binding of RecA and single peroxiredoxin protein molecules to {lambda}-DNA was quantitatively investigated during dynamic translocation experiments where effective forces and respective ionic currents of the threaded DNA molecule through the nanopore were measured during inward and outward sliding. Membrane voltage-dependent experiments of reversible single protein/DNA translocation scans yield hysteresis-free, asymmetric single-molecule fingerprints in the measured force and conductance signals that can be attributed to the interplay of optical trap and electrostatic nanopore potentials. These experiments allow an exact localization of the bound protein along the DNA strand and open fascinating applications for label-free detection of DNA-binding ligands, where structural and positional binding phenomena can be investigated at a single-molecule level.

  10. Haptic Manipulation of Microspheres Using Optical Tweezers Under the Guidance of Artificial Force Fields

    CERN Document Server

    Bukusoglu, Ibrahim; Kiraz, Alper; Kurt, Adnan

    2007-01-01

    Using optical tweezers and a haptic device, microspheres having diameters ranging from 3 to 4 um (floating in a fluid solution) are manipulated in order to form patterns of coupled optical microresonators by assembling the spheres via chemical binding. For this purpose, biotin-coated microspheres trapped by a laser beam are steered and chemically attached to an immobilized streptavidin-coated sphere (i.e. anchor sphere) one by one using an XYZ piezo scanner controlled by a haptic device. The positions of all spheres in the scene are detected using a CCD camera and a collision-free path for each manipulated sphere is generated using the potential field approach. The forces acting on the manipulated particle due to the viscosity of the fluid and the artificial potential field are scaled and displayed to the user through the haptic device for better guidance and control during steering. In addition, a virtual fixture is implemented such that the desired angle of approach and strength are achieved during the bind...

  11. Effect of neighboring cells on cell stiffness measured by optical tweezers indentation

    Science.gov (United States)

    Yousafzai, Muhammad S.; Coceano, Giovanna; Mariutti, Alberto; Ndoye, Fatou; Amin, Ladan; Niemela, Joseph; Bonin, Serena; Scoles, Giacinto; Cojoc, Dan

    2016-05-01

    We report on the modification of mechanical properties of breast cancer cells when they get in contact with other neighboring cells of the same type. Optical tweezers vertical indentation was employed to investigate cell mechanics in isolated and contact conditions, by setting up stiffness as a marker. Two human breast cancer cell lines with different aggressiveness [MCF-7 (luminal breast cancer) and MDA-MB-231 (basal-like breast cancer)] and one normal immortalized breast cell line HBL-100 (normal and myoepithelial) were selected. We found that neighboring cells significantly alter cell stiffness: MDA-MB-231 becomes stiffer when in contact, while HBL-100 and MCF-7 exhibit softer character. Cell stiffness was probed at three cellular subregions: central (above nucleus), intermediate (cytoplasm), and near the leading edge. In an isolated condition, all cells showed a significant regional variation in stiffness: higher at the center and fading toward the leading edge. However, the regional variation becomes statistically insignificant when the cells were in contact with other neighboring cells. The proposed approach will contribute to understand the intriguing temporal sequential alterations in cancer cells during interaction with their surrounding microenvironment.

  12. Initiation of bacteriophage Φ29 DNA packaging studied by optical tweezers manipulation of single DNA molecules

    Science.gov (United States)

    Rickgauer, John Peter; Fuller, Derek N.; Hu, Bo; Grimes, Shelley; Jardine, Paul J.; Anderson, Dwight L.; Smith, Douglas E.

    2006-08-01

    A key step in the life cycle of many viruses, including bacteriophages, adenoviruses, and herpesviruses, is the packaging of replicated viral genomes into pre-assembled proheads by the action of ATP-dependent portal motor complexes. Here we present a method that allows the initiation of packaging by single complexes to be studied using optical tweezers. A procedure is developed for assembling phage Φ29 prohead-motor complexes, which are demonstrated to bind and begin translocation of a target DNA molecule within only a few seconds. We show that the Φ29 DNA terminal protein (gene product 3), which functions to prime DNA replication, also has a dramatic effect on packaging. The DNA tether length measured immediately after binding varied from ~30-100% of the full length, yet shortened monotonically, indicating that packaging does not strictly begin at the terminal end of the DNA. Removal of the terminal protein eliminated this variability, causing packaging to initiate at or very near the end of the DNA. These findings, taken together with electron microscopy data, suggest that rather than simply threading into the portal, the motor captures and dynamically tensions a DNA loop, and that the function of the terminal protein is to load DNA segments on both sides of the loop junction onto separate DNA translocating units.

  13. A model for inertial particle trapping locations in hydrodynamic tweezers arrays

    International Nuclear Information System (INIS)

    We present a model for the trapping of particles with finite inertia in the microscale viscous steady streaming flow of hydrodynamic tweezers. Devices containing a square array and an offset array of cylindrical posts of radius 25 µm were fabricated. As water is oscillated at small amplitude (s < 5 µm) and audible frequency (5000 Hz), highly symmetric microeddies form causing the fluid and particles suspended in the fluid to transport through the device. We image the flows by using 0.5 µm radius fluorescent polystyrene particles, and demonstrate trapping with larger 5 µm radius polystyrene particles. The streaming flow fields are simulated numerically using a fast analytic-numeric approach, and inertial particle motion is determined using the well-known Maxey–Riley equation for small Stokes number (St) particle motion. The St-dependent period-averaged particle velocity is used to describe the effects of inertia on particle trapping locations. We find the St-dependence of trapping location depends on the underlying symmetry of the flow. Only traps located near eddy centers are affected by particle inertia. (paper)

  14. On chip single-cell separation and immobilization using optical tweezers and thermosensitive hydrogel.

    Science.gov (United States)

    Arai, Fumihito; Ng, Chinaik; Maruyama, Hisataka; Ichikawa, Akihiko; El-Shimy, Haitham; Fukuda, Toshio

    2005-12-01

    A novel approach appropriate for rapid separation and immobilization of a single cell by concomitantly utilizing laser manipulation and locally thermosensitive hydrogelation is proposed in this paper. We employed a single laser beam as optical tweezers for separating a target cell and locating it adjacent to a fabricated, transparent micro heater. Simultaneously, the target cell is immobilized or partially entrapped by heating the thermosensitive hydrogel with the micro heater. The state of the thermosensitive hydrogel can be switched from sol to gel and gel to sol by controlling the temperature through heating and cooling by the micro heater. After other unwanted cells are removed by the high-speed cleaning flow in the microchannel, the entrapped cell is successfully isolated. It is possible to collect the immobilized target cell for analysis or culture by switching off the micro heater and releasing the cell from the entrapment. We demonstrated that the proposed approach is feasible for rapid manipulation, immobilization, cleaning, isolation and extraction of a single cell. The experimental results are shown here. PMID:16286972

  15. Uncoiling mechanism of Klebsiella pneumoniae type 3 pili measured by using optical tweezers

    Science.gov (United States)

    Chen, Feng-Jung; Chan, Chia-Han; Liu, Kuo-Liang; Huang, Ying-Jung; Peng, Hwei-Ling; Chang, Hwan-You; Yew, Tri-Rung; Hsu, Ken Y.; Hsu, Long

    2007-09-01

    Pili are bacterial appendages that play many important roles in bacterial behaviors, physiology and interaction with hosts. Via pili, bacteria are able to adhere to, migrate onto, and colonize on host cells, mechanically. Different from the most studied type 1 and P type pili, which are rigid and thick with an average of 6~7 nm in diameter, type 3 pili are relatively tiny (3-5 nm in diameter) and flexible, and their biophysical properties remains unclear. By using optical tweezers, we found that the elongation processes of type 3 pili are divided into three phases: (1) elastic elongation, (2) uncoiling elongation, and (3) intrinsic elongation, separately. Besides, the uncoiling force of the recombinant pili displayed on the surface of E. coli [pmrkABCD V1F] is measured 20 pN in average stronger than that of E. coli [pmrkABCD V1]. This suggests that pilin MrkF is involved in determining the mechanical properties of the type 3 pili.

  16. Optical tweezers reveal a dynamic mechanical response of cationic peptide-DNA complexes

    Science.gov (United States)

    Lee, Amy; Zheng, Tai; Sucayan, Sarah; Chou, Szu-Ting; Tricoli, Lucas; Hustedt, Jason; Kahn, Jason; Mixson, A. James; Seog, Joonil

    2013-03-01

    Nonviral carriers have been developed to deliver nucleic acids by forming nanoscale complexes; however, there has been limited success in achieving high transfection efficiency. Our hypothesis is that a factor affecting gene delivery efficiency is the mechanical response of the condensed complex. To begin to test this hypothesis, we directly measured the mechanical properties of DNA-carrier complexes using optical tweezers. Histidine-lysine (HK) polymer, Asparagine-lysine (NK) polymer and poly-L-lysine were used to form complexes with a single DNA molecule. As carriers were introduced, a sudden decrease in DNA extension occurrs at a force level which is defined as critical force (Fc). Fc is carrier and concentration dependent. Pulling revealed reduction in DNA extension length for HK-DNA complexes. The characteristics of force profiles vary by agent and can be dynamically manipulated by changes in environmental conditions such as ionic strength of the buffer as well as pH. Heparin can remove cationic reagents which are otherwise irreversibly bound to DNA. The implications for optimizing molecular interactions to enhance transfection efficiency will be discussed.

  17. Stereoscopic particle tracking for 3D touch, vision and closed-loop control in optical tweezers

    International Nuclear Information System (INIS)

    Force measurement in an interactive 3D micromanipulation system can allow the user to make delicate adjustments, and to explore surfaces with touch as well as vision. We present a system to achieve this on the micron scale using stereoscopic particle tracking combined with holographic optical tweezers, which can track particles with nanometre accuracy. 2D tracking of particles in each of the stereo images gives 3D positions for each particle. This takes less than 200 µs per image pair, using a 1D 'symmetry transform' applied to each row and column of a 2D image, which can maintain tracking of particles throughout the 10 µm axial range. The only parameters required are the geometry of the imaging system, and therefore there is no need to recalibrate for different particle sizes or refractive indices. Consequently, we can calculate the force exerted by the optical trap in real time at 1 kilohertz, allowing us to implement a force-feedback interface (with a loop rate of 400 Hz). In combination with our OpenGL hologram calculation engine, the system has a closed-loop bandwidth of 20 Hz. This allows us to stabilize trapped particles axially through active feedback, cancelling out some Brownian motion. For the weak traps we use here (spring constant k≈2 pN µm−1), this results in a threefold increase in axial stiffness. We demonstrate the 3D interface by probing an oil droplet, mapping out its surface in the y–z plane

  18. Determination of femto Newton forces and fluid viscosity using optical tweezers: application to Leishmania amazonensis

    Science.gov (United States)

    Fontes, Adriana; Giorgio, Selma; de Castro, Archimedes B., Jr.; Neto, Vivaldo M.; Pozzo, Liliana d. Y.; Marques, Gustavo P.; Barbosa, Luiz C.; Cesar, Carlos L.

    2005-03-01

    The objective of this research is to use the displacements of a polystyrene microsphere trapped by an optical tweezers (OT) as a force transducer in mechanical measurements in life sciences. To do this we compared the theoretical optical and hydrodynamic models with experimental data under a broad variation of parameters such as fluid viscosity, refractive index, drag velocity and wall proximities. The laser power was measured after the objective with an integration sphere because normal power meters do not provide an accurate measurement for beam with high numerical apertures. With this careful laser power determination the plot of the optical force (calculated by the particle displacement) versus hydrodynamic force (calculated by the drag velocity) under very different conditions shows an almost 45 degrees straight line. This means that hydrodynamic models can be used to calibrate optical forces and vice-versa. With this calibration we observed the forces of polystyrene bead attached to the protozoa Leishmania amazonensis, responsible for a serious tropical disease. The force range is from 200 femto Newtons to 4 pico Newtons and these experiments shows that OT can be used for infection mechanism and chemotaxis studies in parasites. The other application was to use the optical force to measure viscosities of few microliters sample. Our result shows 5% accuracy measurements.

  19. Space-time-wavelength mapping: a new approach for electronic control of optical tweezers

    CERN Document Server

    Rahman, Shah; Zhao, Qiancheng; Atasever, Tuva; Boyraz, Ozdal

    2015-01-01

    We present a new approach for electronic control of optical tweezers. The key technique, called 'space-time-wavelength mapping', involves time-domain modulation which is translated onto spatial domain by diffraction and enables direct control of location and polarity of force hot-spots created by Lorentz force (gradient force). In this study 150 fs optical pulses are dispersed in time and space to achieve a focused elliptical beam that is ~20 {\\mu}m long and ~2 {\\mu}m wide. In order to manipulate the intensity gradient along the beam at the focal spot, we use an electro-optic modulator to modulate power spectral distribution of the femtosecond beam after temporal dispersion. The electro-optic modulator is supplied with a chosen RF waveform that dictates the manipulation of the power spectral distribution. By choosing the appropriate RF waveform, it is possible to create force fields for cell stretching and compression as well as multiple hot spots (of > 200 pN force) for attractive or repulsive forces. We pre...

  20. Force unfolding kinetics of RNA using optical tweezers. II. Modeling experiments

    CERN Document Server

    Manosas, M; Li, P T X; Smith, S B; Bustamante, C; Tinoco, I; Ritort, F

    2007-01-01

    By exerting mechanical force it is possible to unfold/refold RNA molecules one at a time. In a small range of forces, an RNA molecule can hop between the folded and the unfolded state with force-dependent kinetic rates. Here, we introduce a mesoscopic model to analyze the hopping kinetics of RNA hairpins in an optical tweezers setup. The model includes different elements of the experimental setup (beads, handles and RNA sequence) and limitations of the instrument (time lag of the force-feedback mechanism and finite bandwidth of data acquisition). We investigated the influence of the instrument on the measured hopping rates. Results from the model are in good agreement with the experiments reported in the companion article (1). The comparison between theory and experiments allowed us to infer the values of the intrinsic molecular rates of the RNA hairpin alone and to search for the optimal experimental conditions to do the measurements. We conclude that long handles and soft laser traps represent the best cond...

  1. Studying red blood cell agglutination by measuring membrane viscosity with optical tweezers

    Science.gov (United States)

    Fernandes, Heloise P.; Fontes, Adriana; de Thomaz, André A.; Barbosa, Luiz C.; Barjas-Castro, Maria L.; Cesar, Carlos L.

    2007-09-01

    The red blood cell (RBC) viscoelastic membrane contains proteins and glycoproteins embedded in a fluid lipid bilayer that are responsible for cell agglutination. Manipulating RBCs rouleaux with a double optical tweezers, we observed that the cells slide easily one over the others but are strongly connected by their edges. An explanation for this behavior could be the fact that when the cells slide one over the others, proteins are dragged through the membrane. It confers to the movement a viscous characteristic that is dependent of the velocity between the RBCs and justifies why is so easy to slide them apart. Therefore, in a first step of this work, by measuring the force as a function of the relative velocity between two cells, we confirmed this assumption and used this viscous characteristic of the RBC rouleaux to determine the apparent membrane viscosity of the cell. As this behavior is related to the proteins interactions, we can use the apparent membrane viscosity to obtain a better understanding about cell agglutination. Methods related to cell agglutination induced by antigen-antibody interactions are the basis of most of tests used in transfusion centers. Then, in a second step of this work, we measured the apparent membrane viscosity using antibodies. We observed that this methodology is sensitive to different kinds of bindings between RBCs. Better comprehension of the forces and bindings between RBCs could improve the sensibility and specificity of the hemagglutination reactions and also guides the development of new potentiator substances.

  2. Structural and Optoelectronic Properties of Cubic CsPbF3 for Novel Applications

    Institute of Scientific and Technical Information of China (English)

    G. Murtaza; Iftikhar Ahmad; M. Maqbool; H. A. Rahnamaye Aliabad; A. Afaq

    2011-01-01

    Chemical bonding as well as structural, electronic and optical properties of CsPbF3 are calculated using the highly accurate full potential linearized augmented plane-wave method within the framework of density functional theory (DFT). The calculated lattice constant is found to be in good agreement with the experimental results. The electron density plots reveal strong ionic bonding in Cs-F and strong covalent bonding in Pb-F. The calculations show that the material is a direct and wide bandgap semiconductor with a fundamental gap at the R-symmetry point. Optical properties such as the real and imaginary parts of the dielectric function, refractive index, extinction coefficient, reflectivity, optical conductivity and absorption coefficient are also calculated. Based on the calculated wide and direct bandgap, as well as other optical properties of the compound, it is predicted that CsPbF3 is suitable for optoelectronic devices and anti-reflecting coatings.%Chemical bonding as well as structural,electronic and optical properties of CsPbF3 are calculated using the highly accurate full potential linearized augmented plane-wave method within the framework of density functional theory (DFT).The calculated lattice constant is found to be in good agreement with the experimental results.The electron density plots reveal strong ionic bonding in Cs-F and strong covalent bonding in Pb-F.The calculations show that the material is a direct and wide bandgap semiconductor with a fundamental gap at the R-symmetry point.Optical properties such as the real and imaginary parts of the dielectric function,refractive index,extinction coefficient,reflectivity,optical conductivity and absorption coefficient are also calculated.Based on the calculated wide and direct bandgap,as well as other optical properties of the compound,it is predicted that CsPbF3 is suitable for optoelectronic devices and anti-reflecting coatings.Perovskites have gained high technological and fundamental importance

  3. Optoelectronic method for detection of cervical intraepithelial neoplasia and cervical cancer

    Science.gov (United States)

    Pruski, D.; Przybylski, M.; Kędzia, W.; Kędzia, H.; Jagielska-Pruska, J.; Spaczyński, M.

    2011-12-01

    The optoelectronic method is one of the most promising concepts of biophysical program of the diagnostics of CIN and cervical cancer. Objectives of the work are evaluation of sensitivity and specificity of the optoelectronic method in the detection of CIN and cervical cancer. The paper shows correlation between the pNOR number and sensitivity/specificity of the optoelectronic method. The study included 293 patients with abnormal cervical cytology result and the following examinations: examination with the use of the optoelectronic method — Truscreen, colposcopic examination, and histopathologic biopsy. Specificity of the optoelectronic method for LGSIL was estimated at 65.70%, for HGSIL and squamous cell carcinoma of cervix amounted to 90.38%. Specificity of the optoelectronic method used to confirm lack of cervical pathology was estimated at 78.89%. The field under the ROC curve for the optoelectronic method was estimated at 0.88 (95% CI, 0.84-0.92) which shows high diagnostic value of the test in the detection of HGSIL and squamous cell carcinoma. The optoelectronic method is characterised by high usefulness in the detection of CIN, present in the squamous epithelium and squamous cell carcinoma of cervix.

  4. Structural and optoelectronic properties of cubic perovskite RbPbF3

    Indian Academy of Sciences (India)

    K Ephraim Babu; N Murali; D Tirupathi Swamy; V Veeraiah

    2014-04-01

    The structural and optoelectronic properties of cubic perovskite RbPbF 3 are calculated using all electrons full potential linearized augmented plane wave (FP-LAPW) method. The calculated lattice constant is in good agreement with the experimental result. The calculated band structure shows a direct band gap of 3.07 eV. The contribution of different bands is analysed from the total and partial density of state curves. We identified hybridization of Pb , Pb states with F states in the valence bonding region. Calculations of the optical spectra, viz., the dielectric function, optical reflectivity, absorption coefficient, real part of optical conductivity, refractive index, extinction coefficient and electron energy loss are performed for the energy range of 0-30 eV. Based on the direct bandgap, as well as other optical properties of the compound, it is predicted that this material is useful for vacuum-ultraviolet-transparent (VUV-transparent) applications.

  5. The effect of plasmonic nanoparticles on the optoelectronic characteristics of CdTe nanowires.

    Science.gov (United States)

    Luo, Lin-Bao; Huang, Xiao-Li; Wang, Ming-Zheng; Xie, Chao; Wu, Chun-Yan; Hu, Ji-Gang; Wang, Li; Huang, Jian-An

    2014-07-01

    In this work, a simple strategy is proposed to improve the device performance of photodetector by modifying plasmonic nanoparticles onto the surface of semiconductors nanostructure. Both experimental analysis and theoretical simulation show that the plasmonic metal nanoparticles (AuNPs) exhibits obvious localized surface plasmon resonance (LSPR) which can trap incident light efficiently, leading to enhanced photocurrents and improved performance of photoelectronic devices. It is also observed that the AuNPs modified CdTeNW photodetector exhibit apparent sensitivity to 510 nm light, to which pure CdTeNWs is virtually blind. What is more, after AuNPs decoration, the response speed of the photodetector is increased substantially from 6.12 to 1.92 s. It is believed that this result will open up new doors for manipulating light and further improving the efficiency of semiconductor nanostructures based optoelectronic devices. PMID:24610773

  6. The method of testing of the attitude reference systems with optoelectronic sensors

    Science.gov (United States)

    Szelmanowski, Andrzej; Michalak, Slawomir

    2003-09-01

    What the paper deals with is the method of testing of the attitude reference systems with the coning excitation/motion applied. A theoretical description of the excitation at issue has been given and followed with a comparative analysis of the excitation generated in the UPG-48 station with a tilting platform. Experimental data of testing of the attitude and heading reference system AHRS LCR-92 system for the non-holonomical excitation/motion have been compared with results effected by some simulation-based tests of numerical models of the attitude and heading reference systems with the optoelectronic sensors. On the grounds of some numerical-simulation-effected findings gained with the AutoCAD packet, a concept of a coning-excitation-generating measuring station has been developed at the Air Force Institute of Technology and presented in this paper.

  7. Reconfigurable optoelectronic oscillator incorporating a double-coupling recirculating delay line

    Science.gov (United States)

    Li, Cheng-Xin; Chen, Fu-Shen; Zhang, Jia-Hong

    2014-07-01

    A reconfigurable optoelectronic oscillator (OEO) based on a double-coupling recirculating delay line (DC-RDL) is analyzed and experimentally demonstrated. In the proposed OEO, an incoherent two-tap microwave photonic filter is formed by an amplified spontaneous emission (ASE) source, a Mach-Zehnder modulator, a DC-RDL, and a polarization beam splitter (PBS) to realize selection of the oscillation mode. Specifically, the incoherence is implemented using an ASE broadband laser source and a DC-RDL, and the high sidemode suppression performance can be achieved by employing the dual-loops system between the dual output of the DC-RDL and the PBS. A detailed theoretical analysis is provided and is verified by the experiment. The single-sideband phase noise, the frequency tunability, and the long-term stability of the generated microwave signal are investigated. In addition, the frequency independent of the phase noise is also experimentally observed.

  8. Spectroscopic diagnostics of defect and interface effects on carrier dynamics in semiconductor optoelectronics

    Science.gov (United States)

    Scofield, A. C.; Hudson, A. I.; Liang, B. L.; Wells, N. P.; Huffaker, D. L.; Lotshaw, W. T.

    2016-05-01

    We use steady-state and time-resolved spectroscopy to evaluate optoelectronic material quality and obtain detailed information about carrier generation, transport, and relaxation in semiconductor devices and test structures. This report focuses on time-resolved and steady-state photoluminescence of III-V reference heterostructures at temperatures between 4K and 300K in order to investigate the mechanisms limiting carrier lifetime and to develop the capability to provide actionable feedback to research-and-development efforts for improvement and optimization of material properties and/or device performance. We combine the results of photoluminescence experiments with model-based analyses and simulations of carrier relaxation to assess the impacts of defects and interface quality on the relaxation dynamics of photo-generated carriers in double heterostructure test vehicles grown by MOCVD and MBE.

  9. A Long-Term View on Perovskite Optoelectronics.

    Science.gov (United States)

    Docampo, Pablo; Bein, Thomas

    2016-02-16

    Recently, metal halide perovskite materials have become an exciting topic of research for scientists of a wide variety of backgrounds. Perovskites have found application in many fields, starting from photovoltaics and now also making an impact in light-emitting applications. This new class of materials has proven so interesting since it can be easily solution processed while exhibiting materials properties approaching the best inorganic optoelectronic materials such as GaAs and Si. In photovoltaics, in only 3 years, efficiencies have rapidly increased from an initial value of 3.8% to over 20% in recent reports for the commonly employed methylammonium lead iodide (MAPI) perovskite. The first light emitting diodes and light-emitting electrochemical cells have been developed already exhibiting internal quantum efficiencies exceeding 15% for the former and tunable light emission spectra. Despite their processing advantages, perovskite optoelectronic materials suffer from several drawbacks that need to be overcome before the technology becomes industrially relevant and hence achieve long-term application. Chief among these are the sensitivity of the structure toward moisture and crystal phase transitions in the device operation regime, unreliable device performance dictated by the operation history of the device, that is, hysteresis, the inherent toxicity of the structure, and the high cost of the employed charge selective contacts. In this Account, we highlight recent advances toward the long-term viability of perovskite photovoltaics. We identify material decomposition routes and suggest strategies to prevent damage to the structure. In particular, we focus on the effect of moisture upon the structure and stabilization of the material to avoid phase transitions in the solar cell operating range. Furthermore, we show strategies to achieve low-cost chemistries for the development of hole transporters for perovskite solar cells, necessary to be able to compete with other

  10. Observation of plasmon-induced optical field enhancement near a pair of partially metal covered dielectric spheres manipulated by optical tweezers

    Science.gov (United States)

    Zhdanov, Alexander G.; Fedyanin, Andrey A.; Rao, Satish; Kreuzer, Mark; Ballint, Stefan; Petrov, Dmitri

    2009-05-01

    Optical tweezers technique combined with local confocal luminescence spectroscopy is suggested as a tool for investigation of local optical fields. Utilizing this method plasmon-enhanced optical fields inside a pair of dielectric 2 μm spheres partially covered by 70 nm silver nanoparticles are visualized via field enhanced luminescence of rhodamine dye solution. Positions of the particles are controlled with submicrometer accuracy by two optical traps formed by strongly focused laser beams with λ=980nm. A supplementary beam from CW laser with λ=532nm provided for luminescence excitation is also focused into the sample cavity just to the trapping area. In order to obtain spatial filtering of the signal and separate luminescence signal from an area near the spheres pin-hole based confocal system is designed. The focal volume available for luminescence signal collection turns out to be approximately 3μm x 3 μm x 5 μm. Since optical field is enhanced in the region near plasmon-active 2 μm spheres the enhancement of luminescence intensity is observed. Collective plasmonic effects in two-particle measurements are also considered.

  11. Digital optical computers at the optoelectronic computing systems center

    Science.gov (United States)

    Jordan, Harry F.

    1991-01-01

    The Digital Optical Computing Program within the National Science Foundation Engineering Research Center for Opto-electronic Computing Systems has as its specific goal research on optical computing architectures suitable for use at the highest possible speeds. The program can be targeted toward exploiting the time domain because other programs in the Center are pursuing research on parallel optical systems, exploiting optical interconnection and optical devices and materials. Using a general purpose computing architecture as the focus, we are developing design techniques, tools and architecture for operation at the speed of light limit. Experimental work is being done with the somewhat low speed components currently available but with architectures which will scale up in speed as faster devices are developed. The design algorithms and tools developed for a general purpose, stored program computer are being applied to other systems such as optimally controlled optical communication networks.

  12. A nonlinear optoelectronic filter for electronic signal processing

    Science.gov (United States)

    Loh, William; Yegnanarayanan, Siva; Ram, Rajeev J.; Juodawlkis, Paul W.

    2014-01-01

    The conversion of electrical signals into modulated optical waves and back into electrical signals provides the capacity for low-loss radio-frequency (RF) signal transfer over optical fiber. Here, we show that the unique properties of this microwave-photonic link also enable the manipulation of RF signals beyond what is possible in conventional systems. We achieve these capabilities by realizing a novel nonlinear filter, which acts to suppress a stronger RF signal in the presence of a weaker signal independent of their separation in frequency. Using this filter, we demonstrate a relative suppression of 56 dB for a stronger signal having a 1-GHz center frequency, uncovering the presence of otherwise undetectable weaker signals located as close as 3.5 Hz away. The capabilities of the optoelectronic filter break the conventional limits of signal detection, opening up new possibilities for radar and communication systems, and for the field of precision frequency metrology. PMID:24402418

  13. Modifying the Optoelectronic Properties of Rubrene by Strain

    Science.gov (United States)

    Sharifzadeh, Sahar; Ramasubramaniam, Ashwin

    Rubrene crystals are promising organic electronic and optoelectronic materials due to their high charge carrier mobility. Recent studies have shown that the electronic properties of rubrene films can be tuned by substrate-induced strain, suggesting a new route towards the design of more efficient devices. Here, we present a first-principles density functional theory and many-body perturbation theory analysis of strain-induced changes to the mechanical, electronic, and optical properties of rubrene crystals. With an applied strain that is consistent with experiment, we predict changes of hole motilities in excellent agreement with electrical conductivity measurements. Furthermore, we predict that the optical absorption and nature of low-energy excitons within the crystal can be tuned by an applied strain as low as 1%. This work utilized resources at the Center for Nanoscale Materials, supported by the U.S. Department of Energy under Contract No. DE-AC02-06CH11357.

  14. Design and Radiation Assessment of Optoelectronic Transceiver Circuits for ITER

    CERN Document Server

    Leroux, P; Van Uffelen, M; Steyaert, M

    2008-01-01

    The presented work describes the design and characterization results of different electronic building blocks for a MGy gamma radiation tolerant optoelectronic transceiver aiming at ITER applications. The circuits are implemented using the 70GHz fT SiGe HBT in a 0.35μm BiCMOS technology. A VCSEL driver circuit has been designed and measured up to a TID of 1.6 MGy and up to a bit rate of 622Mbps. No significant degradation is seen in the eye opening of the output signal. On the receiver side, both a 1GHz, 3kΩ transimpedance and a 5GHz Cherry-Hooper amplifier with over 20dB voltage gain have been designed.

  15. Elastic, Optoelectronic and Thermal Properties of Boron Phosphide

    Directory of Open Access Journals (Sweden)

    S. Daoud

    2014-01-01

    Full Text Available Elastic, mechanical, optoelectronic and some thermal properties of boron phosphide (BP in its structure zincblende phase has been performed using the pseudopotential combined with the plane wave method. The plane-wave pseudopotential approach to the density-functional theory within the local density approximation (LDA implemented in Abinit code is used. The elastic stiffness and compliance constants, bulk modulus, shear modulus, zener anisotropy factor, young's modulus, internal strain parameter, poisson's ratio, sound velocity for directions within the important crystallographic planes, Debye temperature, melting point, refractive index, plasmon energy, force constants, lattice energy, band gap energy, homopolar energy, heteropolar energy, ionicity and dielectric constant are obtained and analyzed in comparison with the available data.

  16. Low-bandgap, monolithic, multi-bandgap, optoelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Wanlass, Mark W.; Carapella, Jeffrey J.

    2016-01-05

    Low bandgap, monolithic, multi-bandgap, optoelectronic devices (10), including PV converters, photodetectors, and LED's, have lattice-matched (LM), double-heterostructure (DH), low-bandgap GaInAs(P) subcells (22, 24) including those that are lattice-mismatched (LMM) to InP, grown on an InP substrate (26) by use of at least one graded lattice constant transition layer (20) of InAsP positioned somewhere between the InP substrate (26) and the LMM subcell(s) (22, 24). These devices are monofacial (10) or bifacial (80) and include monolithic, integrated, modules (MIMs) (190) with a plurality of voltage-matched subcell circuits (262, 264, 266, 270, 272) as well as other variations and embodiments.

  17. Low-bandgap, monolithic, multi-bandgap, optoelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Wanlass, Mark W.; Carapella, Jeffrey J.

    2016-03-22

    Low bandgap, monolithic, multi-bandgap, optoelectronic devices (10), including PV converters, photodetectors, and LED's, have lattice-matched (LM), double-heterostructure (DH), low-bandgap GaInAs(P) subcells (22, 24) including those that are lattice-mismatched (LMM) to InP, grown on an InP substrate (26) by use of at least one graded lattice constant transition layer (20) of InAsP positioned somewhere between the InP substrate (26) and the LMM subcell(s) (22, 24). These devices are monofacial (10) or bifacial (80) and include monolithic, integrated, modules (MIMs) (190) with a plurality of voltage-matched subcell circuits (262, 264, 266, 270, 272) as well as other variations and embodiments.

  18. Photonics and optoelectronics of 2D semiconductor transition metal dichalcogenides

    Science.gov (United States)

    Mak, Kin Fai; Shan, Jie

    2016-04-01

    Recent advances in the development of atomically thin layers of van der Waals bonded solids have opened up new possibilities for the exploration of 2D physics as well as for materials for applications. Among them, semiconductor transition metal dichalcogenides, MX2 (M = Mo, W; X = S, Se), have bandgaps in the near-infrared to the visible region, in contrast to the zero bandgap of graphene. In the monolayer limit, these materials have been shown to possess direct bandgaps, a property well suited for photonics and optoelectronics applications. Here, we review the electronic and optical properties and the recent progress in applications of 2D semiconductor transition metal dichalcogenides with emphasis on strong excitonic effects, and spin- and valley-dependent properties.

  19. High-speed switching characteristics of integrated optoelectronic crossbar switch

    Science.gov (United States)

    Gouin, Francois L.; Almeida, Carlos; Callender, Claire L.; Robitaille, Lucie; Noad, Julian P.

    1999-04-01

    Optoelectronic (OE) switching is a promising approach for routing signals in fiber optic networks. Recently, the integration of a 4 X 4 MSM array with optical surface waveguides has been reported. This technique greatly simplifies the packaging of an OE switch. The on-chip polyimide optical waveguides perform the optical signal distribution to a matrix of MSMs which are responsible for the switching operation itself. Photoresponse bandwidths exceeding 4 GHz have been demonstrated. Another important characteristic of a switch is the switching speed since it determines the reconfiguration time. Mechanical and thermal optical waveguide switches offer switching speeds of the order of milliseconds which is sufficient for network traffic management but too slow for packet switching. We report measurements on the switching characteristics of a 4 X 4 optoelectronic switch performed in both the frequency and time domain. In the time domain, the individual crosspoints exhibit a rise time of 3 ns. However, a sizeable overshoot and ringing settles only after 35 ns. This constitutes the reconfiguration time at present. This is confirmed by measurements in the frequency domain of the electrical transmission from control line to output line. The 3-dB switching bandwidth is a few hundred megahertz. The 35 ns reconfiguration time indicates that it is already suitable for packet switching in a 10 Mb/s network. Switching speed measurements on individual MSMs suggests that modifications to the switch circuit could improve the switching time. The switch could also find application as a component in the wavelength conversion circuit of a WDM fiber optic network.

  20. Power spectrum analysis for optical tweezers. II: Laser wavelength dependence of parasitic filtering, and how to achieve high bandwidth

    DEFF Research Database (Denmark)

    Berg-Sørensen, Kirstine; Peterman, Erwin J G; Weber, Tom; Schmidt, Christoph F; Flyvbjerg, Henrik

    2006-01-01

    the high transparency of silicon to near-infrared light. A simple model that accounts for this phenomenon is here solved for frequencies up to 100 kHz and for laser wavelengths between 750 and 1064 nm. The solution is applied to experimental data in the same range, and is demonstrated to give this......In a typical optical tweezers detection system, the position of a trapped object is determined from laser light impinging on a quadrant photodiode. When the laser is infrared and the photodiode is of silicon, they can act together as an unintended low-pass filter. This parasicit effect is due to...