Sample records for based optoelectronic tweezers

  1. Optoelectronic tweezers for medical diagnostics (United States)

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


    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.

  2. Phototransistor-based optoelectronic tweezers for dynamic cell manipulation in cell culture media. (United States)

    Hsu, Hsan-yin; Ohta, Aaron T; Chiou, Pei-Yu; Jamshidi, Arash; Neale, Steven L; Wu, Ming C


    Optoelectronic tweezers (OET), based on light-induced dielectrophoresis, has been shown as a versatile tool for parallel manipulation of micro-particles and cells (P. Y. Chiou, A. T. Ohta and M. C. Wu, Nature, 2005, 436, 370-372). However, the conventional OET device cannot operate in cell culture media or other high-conductivity physiological buffers due to the limited photoconductivity of amorphous silicon. In this paper, we report a new phototransistor-based OET (Ph-OET). Consisting of single-crystalline bipolar junction transistors, the Ph-OET has more than 500x higher photoconductivity than amorphous silicon. Efficient cell trapping of live HeLa and Jurkat cells in Phosphate Buffered Saline (PBS) and Dulbecco's Modified Eagle's Medium (DMEM) has been demonstrated using a digital light projector, with a cell transport speed of 33 microm/sec, indicating a force of 14.5 pN. Optical concentration of cells and real-time control of individually addressable cell arrays have also been realized. Precise control of separation between two cells has also been demonstrated. We envision a new platform for single cell studies using Ph-OET.

  3. 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


    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.

  4. Manipulating and assembling metallic beads with Optoelectronic Tweezers (United States)

    Zhang, Shuailong; Juvert, Joan; Cooper, Jonathan M.; Neale, Steven L.


    Optoelectronic tweezers (OET) or light-patterned dielectrophoresis (DEP) has been developed as a micromanipulation technology for controlling micro- and nano-particles with applications such as cell sorting and studying cell communications. Additionally, the capability of moving small objects accurately and assembling them into arbitrary 2D patterns also makes OET an attractive technology for microfabrication applications. In this work, we demonstrated the use of OET to manipulate conductive silver-coated Poly(methyl methacrylate) (PMMA) microspheres (50 μm diameter) into tailored patterns. It was found that the microspheres could be moved at a max velocity of 3200 μm/s, corresponding to 4.2 nano-newton (10-9 N) DEP force, and also could be positioned with high accuracy via this DEP force. The underlying mechanism for this strong DEP force is shown by our simulations to be caused by a significant increase of the electric field close to the particles, due to the interaction between the field and the silver shells coating the microspheres. The associated increase in electrical gradient causes DEP forces that are much stronger than any previously reported for an OET device, which facilitates manipulation of the metallic microspheres efficiently without compromise in positioning accuracy and is important for applications on electronic component assembling and circuit construction.

  5. Micromanipulation of InP lasers with optoelectronic tweezers for integration on a photonic platform. (United States)

    Juvert, Joan; Zhang, Shuailong; Eddie, Iain; Mitchell, Colin J; Reed, Graham T; Wilkinson, James S; Kelly, Anthony; Neale, Steven L


    The integration of light sources on a photonic platform is a key aspect of the fabrication of self-contained photonic circuits with a small footprint that does not have a definitive solution yet. Several approaches are being actively researched for this purpose. In this work we propose optoelectronic tweezers for the manipulation and integration of light sources on a photonic platform and report the positional and angular accuracy of the micromanipulation of standard Fabry-Pérot InP semiconductor laser die. These lasers are over three orders of magnitude bigger in volume than any previously assembled with optofluidic techniques and the fact that they are industry standard lasers makes them significantly more useful than previously assembled microdisk lasers. We measure the accuracy to be 2.5 ± 1.4 µm and 1.4 ± 0.4° and conclude that optoelectronic tweezers are a promising technique for the micromanipulation and integration of optoelectronic components in general and semiconductor lasers in particular.

  6. Biaxial crystal-based optical tweezers

    DEFF Research Database (Denmark)

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


    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 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


    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. Optoelectronic tweezers for the measurement of the relative stiffness of erythrocytes (United States)

    Neale, Steven L.; Mody, Nimesh; Selman, Colin; Cooper, Jonathan M.


    In this paper we describe the first use of Optoelectronic Tweezers (OET), an optically controlled micromanipulation method, to measure the relative stiffness of erythrocytes in mice. Cell stiffness is an important measure of cell health and in the case of erythrocytes, the most elastic cells in the body, an increase in cell stiffness can indicate pathologies such as type II diabetes mellitus or hypertension (high blood pressure). OET uses a photoconductive device to convert an optical pattern into and electrical pattern. The electrical fields will create a dipole within any polarisable particles in the device, such as cells, and non-uniformities of the field can be used to place unequal forces onto each side of the dipole thus moving the particle. In areas of the device where there are no field gradients, areas of constant illumination, the force on each side of the dipole will be equal, keeping the cell stationary, but as there are opposing forces on each side of the cell it will be stretched. The force each cell will experience will differ slightly so the stretching will depend on the cells polarisability as well as its stiffness. Because of this a relative stiffness rather than absolute stiffness is measured. We show that with standard conditions (20Vpp, 1.5MHz, 10mSm-1 medium conductivity) the cell's diameter changes by around 10% for healthy mouse erythrocytes and we show that due to the low light intensities required for OET, relative to conventional optical tweezers, multiple cells can be measured simultaneously.

  9. Self-Locking Optoelectronic Tweezers for Single-Cell and Microparticle Manipulation across a Large Area in High Conductivity Media. (United States)

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


    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.

  10. Fractal zone plate beam based optical tweezers (United States)

    Cheng, Shubo; Zhang, Xinyu; Ma, Wenzhuo; Tao, Shaohua


    We demonstrate optical manipulation with an optical beam generated by a fractral zone plate (FZP). The experimental results show that the FZP beam can simultaneously trap multiple particles positioned in different focal planes of the FZP beam, owing to the multiple foci and self-reconstruction property of the FZP beam. The FZP beam can also be used to construct three-dimensional optical tweezers for potential applications. PMID:27678305

  11. Progress of Si-based Optoelectronic Devices

    Institute of Scientific and Technical Information of China (English)

    PENG Ying-cai; FU Guang-sheng; WANG Ying-long; SHANG Yong


    Si-based optoelectronics is becoming a very active research area due to its potential applications to optical communications. One of the major goals of this study is to realize ali-Si optoelectronic integrated circuit. This is due to the fact that Si- based optoelectronic technology can be compatible with Si microelectronic technology. If Si-based optoelectronic devices and integrated circuits can be achieved,it will lead to a new informational technological revolution. In the article, the current developments of this exciting field are mainly reviewed in the recent years. The involved contents are the realization of various Si-based optoelectronic devices, such as light-emitting diodes,optical waveguides devices, Si photonic bandgap crystals,and Si laser,etc. Finally, the developed tendency of all-Si optoelectronic integrated technology are predicted in the near future.

  12. Design and synthesis of novel tweezer anion receptors based on deoxycholic acid

    Institute of Scientific and Technical Information of China (English)

    Xing Li Liu; Zhi Gang Zhao; Shu Hua Chen


    A novel type of molecular tweezer receptors based on deoxycholic acid has been designed and synthesized and their binding properties were examined by UV-vis spectral titration. These molecular tweezers showed a high selectivity toward F- over Cl-,Br-, I-, AcO-, H2PO4-.

  13. Vortex-based line beam optical tweezers (United States)

    Cheng, Shubo; Tao, Shaohua


    A vortex-based line beam, which has a straight-line shape of intensity and possesses phase gradient along the line trajectory is developed and applied for optical manipulation in this paper. The intensity and phase distributions of the beam in the imaging plane of the Fourier transform are analytically studied. Simulation results show that the length of the line and phase gradient possessed by a vortex-based line beam are dependent on the topological charge and the azimuthal proportional constant. A superposition of multiple phase-only holograms with elliptical azimuthal phases can be used to generate an array of vortex-based line beams. Optical trapping with the vortex-based line beams has been implemented. Furthermore, the automatic transportation of microparticles along the line trajectory perpendicular to the optical axis is realized with an array of the beams. The generation method for the vortex-based line beam is simple. The beam would have potential applications in fields such as optical trapping, laser machining, and so on.

  14. III-Nitride Based Optoelectronics (United States)


    c • N =5x1011 cm𔃼 LU -, FT ac v A A A - -3.5 \\/\\/\\ : VB -4.0 V \\ N- N N • - I 1 • Length (nm) 50...GaAs/AlGaAs based npn structures," Appl. Phys. Lett., vol. 70, pp. 2876- 2878, May 1997. 102. J. M. Shah , Y.-L. Li, Th. Gessmann, and E. F. Schubert...Ning, Phys. Rev. B 74, 155308 (2006). 105. Z.-M. Liao, K.-J. Liu, J.-M. Zhang, J. Xu, and D.-P. Yu, Phys. Lett. A 367, 207 (2007). 106. J. M. Shah , Y

  15. Optoelectronic date acquisition system based on FPGA (United States)

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


    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.

  16. Bulky melamine-based Zn-porphyrin tweezer as a CD probe of molecular chirality. (United States)

    Petrovic, Ana G; Vantomme, Ghislaine; Negrón-Abril, Yashira L; Lubian, Elisa; Saielli, Giacomo; Menegazzo, Ileana; Cordero, Roselynn; Proni, Gloria; Nakanishi, Koji; Carofiglio, Tommaso; Berova, Nina


    The transfer of chirality from a guest molecule to an achiral host is the subject of significant interest especially when, upon chiral induction, the chiroptical response of the host/guest complex can effectively report the absolute configuration (AC) of the guest. For more than a decade, dimeric metalloporphyrin hosts (tweezers) have been successfully applied as chirality probes for determination of the AC for a wide variety of chiral synthetic compounds and natural products. The objective of this study is to investigate the utility of a new class of melamine-bridged Zn-porphyrin tweezers as sensitive AC reporters. A combined approach based on an experimental CD analysis and a theoretical prediction of the prevailing interporphyrin helicity demonstrates that these tweezers display favorable properties for chiral recognition. Herein, we discuss the application of the melamine-bridged tweezer to the chiral recognition of a diverse set of chiral guests, such as 1,2-diamines, α-amino-esters and amides, secondary alcohols, and 1,2-amino-alcohols. The bulky periphery and the presence of a rigid porphyrin linkage lead, in some cases, to a more enhanced CD sensitivity than that reported earlier with other tweezers.

  17. Fiber based optical tweezers for simultaneous in situ force exertion and measurements in a 3D polyacrylamide gel compartment. (United States)

    Ti, Chaoyang; Thomas, Gawain M; Ren, Yundong; Zhang, Rui; Wen, Qi; Liu, Yuxiang


    Optical tweezers play an important role in biological applications. However, it is difficult for traditional optical tweezers based on objective lenses to work in a three-dimensional (3D) solid far away from the substrate. In this work, we develop a fiber based optical trapping system, namely inclined dual fiber optical tweezers, that can simultaneously apply and measure forces both in water and in a 3D polyacrylamide gel matrix. In addition, we demonstrate in situ, non-invasive characterization of local mechanical properties of polyacrylamide gel by measurements on an embedded bead. The fiber optical tweezers measurements agree well with those of atomic force microscopy (AFM). The inclined dual fiber optical tweezers provide a promising and versatile tool for cell mechanics study in 3D environments.

  18. Terahertz biochip based on optoelectronic devices (United States)

    Lu, Ja-Yu; Chen, Li-Jin; Kao, Tzeng-Fu; Chang, Hsu-Hao; Liu, An-Shyi; Yu, Yi-Chun; Wu, Ruey-Beei; Liu, Wei-Sheng; Chyi, Jen-Inn; Pan, Ci-Ling; Tsai, Ming-Cheng; Sun, Chi-Kuang


    The accurate detection of minute amounts of chemical and biological substances has been a major goal in bioanalytical technology throughout the twentieth century. Fluorescence dye labeling detection remains the effective analysis method, but it modifies the surroundings of molecules and lowering the precision of detection. An alternative label free detecting tool with little disturbance of target molecules is highly desired. Theoretical calculations and experiments have demonstrated that many biomolecules have intrinsic resonance due to vibration or rotation level transitions, allowing terahertz (THz)-probing technique as a potential tool for the label-free and noninvasive detection of biomolecules. In this paper, we first ever combined the THz optoelectronic technique with biochip technology to realize THz biosensing. By transferring the edge-coupled photonic transmitter into a thin glass substrate and by integrating with a polyethylene based biochip channel, near field THz detection of the biomolecules is demonstrated. By directly acquiring the absorption micro-spectrum in the THz range, different boiomecules can then be identified according to their THz fingerprints. For preliminary studies, the capability to identity different illicit drug powders is successfully demonstrated. This novel biochip sensing system has the advantages including label-free detection, high selectivity, high sensitivity, ease for sample preparation, and ease to parallel integrate with other biochip functionality modules. Our demonstrated detection capability allows specifying various illicit drug powders with weight of nano-gram, which also enables rapid identification with minute amounts of other important molecules including DNA, biochemical agents in terrorism warfare, explosives, viruses, and toxics.

  19. Integral optoelectronic switch based on DMOS-transistors

    Directory of Open Access Journals (Sweden)

    Politanskyy L. F.


    Full Text Available The characteristics of optoelectronic couples photodiodes-DMOS-transistor are studied in the paper. There was developed a mathematical model of volt-ampere characteristic of the given optoelectronic couple which allows to determine interrelation of its electric parameters with constructive and electrophysical parameters of photodiodes and DMOS-transistors. There was suggested a construction of integral optoelectronic switch, based on DMOS-transistors on the silicon with dielectric insulation structures (SDIS. Possible is the optic control of executive devices, connected both to the source and drain circuits of the switching transistor.

  20. Oscillating optical tweezer-based 3-D confocal microrheometer for investigating the intracellular micromechanics and structures (United States)

    Ou-Yang, H. D.; Rickter, E. A.; Pu, C.; Latinovic, O.; Kumar, A.; Mengistu, M.; Lowe-Krentz, L.; Chien, S.


    Mechanical properties of living biological cells are important for cells to maintain their shapes, support mechanical stresses and move through tissue matrix. The use of optical tweezers to measure micromechanical properties of cells has recently made significant progresses. This paper presents a new approach, the oscillating optical tweezer cytorheometer (OOTC), which takes advantage of the coherent detection of harmonically modulated particle motions by a lock-in amplifier to increase sensitivity, temporal resolution and simplicity. We demonstrate that OOTC can measure the dynamic mechanical modulus in the frequency range of 0.1-6,000 Hz at a rate as fast as 1 data point per second with submicron spatial resolution. More importantly, OOTC is capable of distinguishing the intrinsic non-random temporal variations from random fluctuations due to Brownian motion; this capability, not achievable by conventional approaches, is particular useful because living systems are highly dynamic and often exhibit non-thermal, rhythmic behavior in a broad time scale from a fraction of a second to hours or days. Although OOTC is effective in measuring the intracellular micromechanical properties, unless we can visualize the cytoskeleton in situ, the mechanical property data would only be as informative as that of "Blind men and the Elephant". To solve this problem, we take two steps, the first, to use of fluorescent imaging to identify the granular structures trapped by optical tweezers, and second, to integrate OOTC with 3-D confocal microscopy so we can take simultaneous, in situ measurements of the micromechanics and intracellular structure in living cells. In this paper, we discuss examples of applying the oscillating tweezer-based cytorheometer for investigating cultured bovine endothelial cells, the identification of caveolae as some of the granular structures in the cell as well as our approach to integrate optical tweezers with a spinning disk confocal microscope.

  1. Magnetometer Based on Optoelectronic Microwave Oscillator (United States)

    Maleki, Lute; Strekalov, Dmitry; Matsko, Andrey


    proposed instrument, intended mainly for use as a magnetometer, would include an optoelectronic oscillator (OEO) stabilized by an atomic cell that could play the role of a magnetically tunable microwave filter. The microwave frequency would vary with the magnetic field in the cell, thereby providing an indication of the magnetic field. The proposed magnetometer would offer a combination of high accuracy and high sensitivity, characterized by flux densities of less than a picotesla. In comparison with prior magnetometers, the proposed magnetometer could, in principle, be constructed as a compact, lightweight instrument: It could fit into a package of about 10 by 10 by 10 cm and would have a mass <0.5 kg. As described in several prior NASA Tech Briefs articles, an OEO is a hybrid of photonic and electronic components that generates highly spectrally pure microwave radiation, and optical radiation modulated by the microwave radiation, through direct conversion between laser light and microwave radiation in an optoelectronic feedback loop. As used here, "atomic cell" signifies a cell containing a vapor, the constituent atoms of which can be made to undergo transitions between quantum states, denoted hyperfine levels, when excited by light in a suitable wavelength range. The laser light must be in this range. The energy difference between the hyperfine levels defines the microwave frequency. In the proposed instrument (see figure), light from a laser would be introduced into an electro-optical modulator (EOM). Amplitude-modulated light from the exit port of the EOM would pass through a fiber-optic splitter having two output branches. The light in one branch would be sent through an atomic cell to a photodiode. The light in the other branch would constitute the microwave-modulated optical output. Part of the light leaving the atomic cell could also be used to stabilize the laser at a frequency in the vicinity of the desired hyperfine or other quantum transition. The

  2. Magnetometer Based on the Opto-Electronic Oscillator (United States)

    Matsko, Andrey B.; Strekalov, Dmitry; Maleki, Lute


    We theoretically propose and discuss properties of two schemes of an all-optical self-oscillating magnetometer based on an opto-electronic oscillator stabilized with an atomic vapor cell. Proof of the principle DC magnetic field measurements characterized with 2 x 10(exp -7) G sensitivity and 1 - 1000 mG dynamic range in one of the schemes are demonstrated.

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

    Institute of Scientific and Technical Information of China (English)


    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.

  4. Determining the structure-mechanics relationships of dense microtubule networks with confocal microscopy and magnetic tweezers-based microrheology. (United States)

    Yang, Yali; Valentine, Megan T


    The microtubule (MT) cytoskeleton is essential in maintaining the shape, strength, and organization of cells. Its spatiotemporal organization is fundamental for numerous dynamic biological processes, and mechanical stress within the MT cytoskeleton provides an important signaling mechanism in mitosis and neural development. This raises important questions about the relationships between structure and mechanics in complex MT structures. In vitro, reconstituted cytoskeletal networks provide a minimal model of cell mechanics while also providing a testing ground for the fundamental polymer physics of stiff polymer gels. Here, we describe our development and implementation of a broad tool kit to study structure-mechanics relationships in reconstituted MT networks, including protocols for the assembly of entangled and cross-linked MT networks, fluorescence imaging, microstructure characterization, construction and calibration of magnetic tweezers devices, and mechanical data collection and analysis. In particular, we present the design and assembly of three neodymium iron boron (NdFeB)-based magnetic tweezers devices optimized for use with MT networks: (1) high-force magnetic tweezers devices that enable the application of nano-Newton forces and possible meso- to macroscale materials characterization; (2) ring-shaped NdFeB-based magnetic tweezers devices that enable oscillatory microrheology measurements; and (3) portable magnetic tweezers devices that enable direct visualization of microscale deformation in soft materials under applied force.

  5. Synthesis and Anion Recognition of Novel Molecular Tweezer Receptors Based on Carbonyl Thiosemicarbazide for Fluoride Ions

    Institute of Scientific and Technical Information of China (English)

    WEI,Wei; ZHANG,You-Ming; WEI,Tai-Bao


    Three title compounds have been designed and synthesized in high yields as novel anion receptors, which show a higher selectivity for F- than other halide ions. The binding properties for fluoride ions of the receptors have been examined by UV-Vis and 1H NMR spectroscopy, indicating that a 1 : 1 stoichiometry complex is formed between the receptors and fluoride ions through hydrogen bonding interactions in DMSO solution. In addition, because these receptors have more binding points, they have better binding properties for anions than the molecular tweezer receptors based on thiourea we reported last time.

  6. Optical tweezers and non-ratiometric fluorescent-dye-based studies of respiration in sperm mitochondria (United States)

    Chen, Timothy; Shi, Linda Z.; Zhu, Qingyuan; Chandsawangbhuwana, Charlie; Berns, Michael W.


    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.

  7. 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)


    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.

  8. 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...... usefulness is illustrated in specific application examples. Optical traps enable contact-less, all-optical manipulation of microscopic objects. Over the last decades, this laser-based micro-manipulation tool has facilitated numerous exciting discoveries within biology and physics, and it is today regarded...

  9. Photodetectors based on heterostructures for optoelectronic applications (United States)

    Nabet, Bahram; Cola, Adriano; Cataldo, Andrea; Chen, Xiying; Quaranta, Fabio


    In this work we describe a family of optical devices based on heterojunction and heterodimensional structures and we investigate their static and dynamic properties. Such devices are good candidates, due to their high performance, for utilization as the sensing element for the realization of sensors in the fields of telecommunications, remote sensing, LIDAR and medical imaging. First, we present a Heterostructure Metal-Semiconductor-Metal (HMSM) photodetectors that employ a uniformly doped GaAs/AlGaAs heterojunction for the dual purpose of barrier height enhancement and creating an internal electric field that aids in the transport and collection of the photogenerated electrons. In this first family of devices, two doping levels are compared showing the direct effect of the aiding field due to modulation doping. Subsequently, we analyze a novel Resonant-Cavity-Enhanced (RCE) HMSM photodetector in which a Distributed Bragg Reflector (DBR) is employed in order to reduce the thickness of the absorption layer thus achieving good responsivity and high speed as well as wavelength selectivity. Current-voltage, current-temperature, photocurrent spectra, high-speed time response, and on-wafer frequency domain measurements point out the better performance of this last family of detectors, as they can operate in tens of Giga-Hertz range with low dark current and high responsivity. Particularly, the I-V curves show a very low dark current (around 10 picoamps at operative biases); C-V measurements highlight the low geometrical capacitance values; the photocurrent spectrum shows a clear peak at 850 nm wavelength, while time response measurements give a 3 dB bandwidth of about 30 GHz. Small signal model based on frequency domain data is also extracted in order to facilitate future photoreceiver design. Furthermore, two-dimensional numerical simulations have been carried out in order to predict the electrical properties of these detectors. Combination of very low dark current and

  10. Design and synthesis of novel chiral molecular tweezers based on deoxycholic acid

    Institute of Scientific and Technical Information of China (English)

    Zhi Gang Zhao; Xing Li Liu; Yi Zhong


    A novel type of chiral molecular tweezers has been designed and synthesized by using deoxycholic acid as backbone and ethanoyl and the chiral unsymmetrical urea unit as arms. Their structures were characterized by 1H NMR, IR, MS spectra and elemental analysis. These molecular tweezers showed good binding ability for neutral molecules and chiral molecules.

  11. Optoelectronics Devices Based on Zinc Oxide Thin Films and Nanostructures


    Chu, Sheng


    Optoelectronics devices based on ZnO thin films and nanostructures are discussed in this dissertation. A ZnO homojunction LED was demonstrated. Sb-doped p-type ZnO and Ga-doped n-type ZnO on Si (100) substrate were used for the LED device. After achieving ohmic contacts on both types of ZnO, the device showed rectifying current-voltage (I-V) characteristics. Under forward bias, the device successfully showed ultraviolet emissions. The emission properties were analyzed and the emission was con...

  12. Prediction of Silicon-Based Layered Structures for Optoelectronic Applications (United States)

    Luo, Wei; Ma, Yanming; Gong, Xingao; Xiang, Hongjun; CCMG Team


    A method based on the particle swarm optimization (PSO) algorithm is presented to design quasi-two-dimensional (Q2D) materials. With this development, various single-layer and bi-layer materials in C, Si, Ge, Sn, and Pb were predicted. A new Si bi-layer structure is found to have a much-favored energy than the previously widely accepted configuration. Both single-layer and bi-layer Si materials have small band gaps, limiting their usages in optoelectronic applications. Hydrogenation has therefore been used to tune the electronic and optical properties of Si layers. We discover two hydrogenated materials of layered Si8H2andSi6H2 possessing quasi-direct band gaps of 0.75 eV and 1.59 eV, respectively. Their potential applications for light emitting diode and photovoltaics are proposed and discussed. Our study opened up the possibility of hydrogenated Si layered materials as next-generation optoelectronic devices.

  13. 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


    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.

  14. 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


    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.

  15. Microscopic theory of semiconductor-based optoelectronic devices (United States)

    Iotti, Rita C.; Rossi, Fausto


    Since the seminal paper by Esaki and Tsu, semiconductor-based nanometric heterostructures have been the subject of impressive theoretical and experimental activity due to their high potential impact in both fundamental research and device technology. The steady scaling down of typical space and time scales in quantum optoelectronic systems inevitably leads to a regime in which the validity of the traditional Boltzmann transport theory cannot be taken for granted and a more general quantum-transport description is imperative. In this paper, we shall review state-of-the-art approaches used in the theoretical modelling, design and optimization of optoelectronic quantum devices. The primary goal is to provide a cohesive treatment of basic quantum-transport effects, able to explain and predict the performances of new-generation semiconductor devices. With this aim, we shall review and discuss a fully three-dimensional microscopic treatment of time-dependent as well as steady-state quantum-transport phenomena, based on the density matrix formalism. This will allow us to introduce in a quite natural way the separation between coherent and incoherent processes. Starting with this general theoretical framework, we shall analyse two different types of quantum devices, namely periodically repeated structures and quantum systems with open boundaries. For devices within the first class, we will show how a proper use of periodic boundary conditions allows us to reproduce and predict their current-voltage characteristics without resorting to phenomenological parameters. For the second class of devices, we will address the relevant issue of a quantum treatment of charge transport in systems with open boundaries (electrical contacts) when studying and simulating an at least two-terminal device.

  16. Steerable optical tweezers for ultracold atom studies


    Roberts, Kris O.; McKellar, Thomas; Fekete, Julia; Rakonjac, Ana; Deb, Amita B.; Kjærgaard, Niels


    We report on the implementation of an optical tweezer system for controlled transport of ultracold atoms along a narrow, static confinement channel. The tweezer system is based on high-efficiency acousto-optical deflectors and offers two-dimensional control over beam position. This opens up the possibility for tracking the transport channel when shuttling atomic clouds along the guide, forestalling atom spilling. Multiple clouds can be tracked independently by time-shared tweezer beams addres...

  17. Quantifying the DNA binding characteristics of ruthenium based threading intercalator Λ Λ -P with optical tweezers (United States)

    Bryden, Nicholas; McCauley, Micah; Westerlund, Fredrik; Lincoln, Per; Rouzina, Ioulia; Williams, Mark; Paramanathan, Thayaparan

    Utilizing optical tweezers, biophysics researchers have been able to study drug-DNA interactions on the single molecule level. Binuclear ruthenium complexes are a particular type of drug molecule that have been found to have potential cancer-fighting qualities, due to their high binding affinity and low dissociation rates. These complexes are threading intercalators, meaning that they must thread their bulky side chains through DNA base pairs to allow the central planar moiety to intercalate between the bases. In this study, we explored the binding properties of the binuclear ruthenium complex, ΛΛ -P (ΛΛ -[µ-bidppz(phen)4Ru2]4+) . A single DNA molecule is held at a constant force and the ΛΛ -P solution introduced to the system in varying concentrations until equilibrium is reached. DNA extension data at various concentrations of ΛΛ -P recorded as a function of time provide the DNA binding kinetics and equilibrium binding affinity. Preliminary data analysis suggests that ΛΛ -P exhibits fast binding kinetics compared to the very similar ΔΔ -P. These complexes have the same chemical structure and only differ in their chirality, which suggests that the left handed (ΛΛ) threading moieties require less DNA structural distortion for threading compared with the right handed (ΔΔ) threading moieties.

  18. Toward silicon-based longwave integrated optoelectronics (LIO) (United States)

    Soref, Richard


    The vision of longwave silicon photonics articulated in the Journal of Optics A, vol. 8, pp 840-848, 2006 has now come into sharper focus. There is evidence that newly designed silicon-based optoelectronic circuits will operate at any wavelength within the wide 1.6 to 200 μm range. Approaches to that LWIR operation are reviewed here. A long-range goal is to manufacture LWIR OEIC chips in a silicon foundry by integrating photonics on-chip with CMOS, bipolar, or BiCMOS micro-electronics. A principal LWIR application now emerging is the sensing of chemical and biological agents with an OE laboratory-on-a-chip. Regarding on-chip IR sources, the hybrid evanescent-wave integration of III-V interband-cascade lasers and quantum-cascade lasers on silicon (or Ge/Si) waveguides is a promising technique, although an alternative all-group-IV solution is presently taking shape in the form of silicon-based Ge/SiGeSn band-to-band and inter-subband lasers. There is plenty of room for creativity in developing a complete suite of LWIR components. Materials modification, device innovation, and scaling of waveguide dimensions are needed to implement microphotonic, plasmonic and photonic-crystal LWIR devices, both active and passive. Such innovation will likely lead to significant LIO applications.

  19. MOF-based electronic and opto-electronic devices. (United States)

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


    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.

  20. EDFA-based coupled opto-electronic oscillator and its phase noise (United States)

    Salik, Ertan; Yu, Nan; Tu, Meirong; Maleki, Lute


    EDFA-based coupled opto-electronic oscillator (COEO), an integrated optical and microwave oscillator that can generate picosecond optical pulses, is presented. the phase noise measurements of COEO show better performance than synthesizer-driven mode-locked laser.

  1. New materials based on carbazole for optoelectronic device applications:Theoretical investigation

    Institute of Scientific and Technical Information of China (English)

    K.Hasnaoui; H.Zgou; M.Hamidi; M.Bouachrine


    A quantum-chemical investigation on the structural and optoelectronic properties of two materials based on carbazole is carried out.The purpose is to display the effect of grafting the fluorine atoms on their optoelectronic and pbysico-chemical properties.In addition to solubility in the polar solvents and the modification in geometric parameters,the substitution of fluorine destabilizes the HOMO and LUMO levels,decreases the band gap energy and raises conjugation length.These properties suggest the substituted fluorine compound as a good candidate for optoelectronic applications.

  2. Integrated Graphene-Based Optoelectronic Devices Used for Ultrafast Optical-THz Photodetectors, Modulators and Emitters (United States)


    AFRL-RV-PS- AFRL-RV-PS- TR-2015-0083 TR-2015-0083 INTEGRATED GRAPHENE -BASED OPTOELECTRONIC DEVICES USED FOR ULTRAFAST OPTICAL-THZ PHOTODETECTORS...From - To) 7 Nov 2011 – 12 Feb 2012 4. TITLE AND SUBTITLE Integrated Graphene -Based Optoelectronic Devices Used for Ultrafast Optical-THz...quasiparticles in graphene electrons, phlasmons and electron-hole pairs with the ultimate goal to convert them into or be extracted from terahertz

  3. 25th anniversary article: carbon nanotube- and graphene-based transparent conductive films for optoelectronic devices. (United States)

    Du, Jinhong; Pei, Songfeng; Ma, Laipeng; Cheng, Hui-Ming


    Carbon nanotube (CNT)- and graphene (G)-based transparent conductive films (TCFs) are two promising alternatives for commonly-used indium tin oxide-based TCFs for future flexible optoelectronic devices. This review comprehensively summarizes recent progress in the fabrication, properties, modification, patterning, and integration of CNT- and G-TCFs into optoelectronic devices. Their potential applications and challenges in optoelectronic devices, such as organic photovoltaic cells, organic light emitting diodes and touch panels, are discussed in detail. More importantly, their key characteristics and advantages for use in these devices are compared. Despite many challenges, CNT- and G-TCFs have demonstrated great potential in various optoelectronic devices and have already been used for some products like touch panels of smartphones. This illustrates the significant opportunities for the industrial use of CNTs and graphene, and hence pushes nanoscience and nanotechnology one step towards practical applications.

  4. Optical tweezers and surface plasmon resonance combination system based on the high numerical aperture lens (United States)

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


    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.

  5. Electronic and optoelectronic nano-devices based on carbon nanotubes. (United States)

    Scarselli, M; Castrucci, P; De Crescenzi, M


    The discovery and understanding of nanoscale phenomena and the assembly of nanostructures into different devices are among the most promising fields of material science research. In this scenario, carbon nanostructures have a special role since, in having only one chemical element, they allow physical properties to be calculated with high precision for comparison with experiment. Carbon nanostructures, and carbon nanotubes (CNTs) in particular, have such remarkable electronic and structural properties that they are used as active building blocks for a large variety of nanoscale devices. We review here the latest advances in research involving carbon nanotubes as active components in electronic and optoelectronic nano-devices. Opportunities for future research are also identified.

  6. Standard Cell-Based Implementation of a Digital Optoelectronic Neural-Network Hardware (United States)

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


    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.

  7. A novel single fiber optical tweezers based on light-induced thermal effect (United States)

    Zhang, Yu; Liu, Zhihai; Liang, Peibo; Zhang, Yaxun; Zhao, Enming; Yang, Jun; Yuan, Libo


    We present and demonstrate a novel single fiber optical tweezers which can trap and launch (clean) a target polystyrene (PS) microsphere (diameter~10μm) with independent control by using two wavelengths beams: 980nm and 1480nm. We employ 980nm laser beam to trap the target PS microsphere by molding the fiber tip into a special tapered-shape; and we employ 1480nm laser beam to launch the trapped PS microsphere with a certain velocity by using the thermophoresis force generated from the thermal effect due to the high absorption of the 1480nm laser beams in water. When the launching force is smaller than the trapping force, the PS microsphere will be trapped near the fiber tip, and the launching force will blow away other PS microspheres in the workspace realizing the cleaning function; When the launching force is larger than the trapping force, the trapped PS microsphere will be launched away from the fiber tip with a certain velocity and towards a certain direction, realizing the launching function. This PS microsphere launching and cleaning functions expanded new features of single fiber optical tweezers, providing for the possibility of more practical applications in the micro manipulation research fields.

  8. Molecular clips and tweezers hosting neutral guests. (United States)

    Hardouin-Lerouge, Marie; Hudhomme, Piétrick; Sallé, Marc


    Intense current interest in supramolecular chemistry is devoted to the construction of molecular assemblies displaying controlled molecular motion associated to recognition. On this ground, molecular clips and tweezers have focused an increasing attention. This tutorial review points out the recent advances in the construction of always more sophisticated molecular clips and tweezers, illustrating their remarkably broad structural variety and focusing on their binding ability towards neutral guests. A particular attention is brought to recent findings in dynamic molecular tweezers whose recognition ability can be regulated by external stimuli. Porphyrin-based systems will not be covered here as this very active field has been recently reviewed.

  9. Optical tweezers for confocal microscopy (United States)

    Hoffmann, A.; Meyer zu Hörste, G.; Pilarczyk, G.; Monajembashi, S.; Uhl, V.; Greulich, K. O.


    In confocal laser scanning microscopes (CLSMs), lasers can be used for image formation as well as tools for the manipulation of microscopic objects. In the latter case, in addition to the imaging lasers, the light of an extra laser has to be focused into the object plane of the CLSM, for example as optical tweezers. Imaging as well as trapping by optical tweezers can be done using the same objective lens. In this case, z-sectioning for 3D imaging shifts the optical tweezers with the focal plane of the objective along the optical axis, so that a trapped object remains positioned in the focal plane. Consequently, 3D imaging of trapped objects is impossible without further measures. We present an experimental set-up keeping the axial trapping position of the optical tweezers at its intended position whilst the focal plane can be axially shifted over a distance of about 15 μm. It is based on fast-moving correctional optics synchronized with the objective movement. First examples of application are the 3D imaging of chloroplasts of Elodea densa (Canadian waterweed) in a vigorous cytoplasmic streaming and the displacement of zymogen granules in pancreatic cancer cells (AR42 J).

  10. Tracking control strategy for the optoelectronic system on the flexible suspended platform based on backstepping method (United States)

    Yu, Wei; Ma, Jiaguang; Xiao, Jing


    To improve the optoelectronic tracking ability and rope-hanged platform attitude stability, against the interact effect between rope-hanged platform and optoelectronic system during system tracking process, the optoelectronic system fixed on rope hanged platform simplified dynamic model, according to the system's Lagrange dynamic model, was established. Backstepping method was employed to design an integrated controller for both optoelectronic system azimuth direction steering and platform attitude stabilizing. To deal with model's uncertainty and disturbance, a sliding mode controller form based exponential reaching law was adopted to structure the integrated controller. Simulation experiments simulated an optoelectronic system with 600mm caliber telescope, whose inertia fluctuation is 6%. The maximal control moment is 15Nm. And the external disturbance and internal friction effected together. When the line of sight(LOS) azimuth angular input is a step signal with 1rad amplitude, the response's overshoot is 6%, and the response time is 6.2s, and the steady state error is less than 4×10-4rad. When the input is a sinusoidal signal of 0.2rad amplitude with 0.0318Hz frequency, the LOS azimuth angular error amplitude is 5. 6×10-4rad. It is concluded that the controller designed in this article has excellent ability and can ensure the system's stability.

  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


    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. Surface modes of a sessile water drop: an optical tweezer based study. (United States)

    Ghosh, Shankar; Sharma, Prerna; Bhattacharya, S


    A high-precision method to study the dynamics of two-fluid interfaces using an optical tweezer and a phase-sensitive detection technique are described. The disturbances set up at the interface are studied by analyzing the motion of an optically trapped particle in the bulk of the fluid, i.e., away from the interface. The usefulness of the technique is demonstrated for the well-known problem of a horizontally vibrated sessile liquid drop. The vibrational modes of the liquid drop excited by sinusoidally vibrating the support in a horizontal plane appear as resonances in the motion of the trapped particle. The nature of the resonance is studied in detail by measuring the real part, the imaginary part, and the phase response of the motion of the particle as a function of the "effective" size of the liquid drop. Excellent quantitative agreement with the theoretically predicted values of the eigenfrequencies and damping of the surface modes is obtained.

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

    Directory of Open Access Journals (Sweden)

    Benpeng Zhu


    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.

  14. Micro-particle manipulation by single beam acoustic tweezers based on hydrothermal PZT thick film (United States)

    Zhu, Benpeng; Xu, Jiong; Li, Ying; Wang, Tian; Xiong, Ke; Lee, Changyang; Yang, Xiaofei; Shiiba, Michihisa; Takeuchi, Shinichi; Zhou, Qifa; Shung, K. Kirk


    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. PMID:27014504

  15. Surface modes of a sessile water drop: An optical tweezer based study (United States)

    Ghosh, Shankar; Sharma, Prerna; Bhattacharya, S.


    A high-precision method to study the dynamics of two-fluid interfaces using an optical tweezer and a phase-sensitive detection technique are described. The disturbances set up at the interface are studied by analyzing the motion of an optically trapped particle in the bulk of the fluid, i.e., away from the interface. The usefulness of the technique is demonstrated for the well-known problem of a horizontally vibrated sessile liquid drop. The vibrational modes of the liquid drop excited by sinusoidally vibrating the support in a horizontal plane appear as resonances in the motion of the trapped particle. The nature of the resonance is studied in detail by measuring the real part, the imaginary part, and the phase response of the motion of the particle as a function of the "effective" size of the liquid drop. Excellent quantitative agreement with the theoretically predicted values of the eigenfrequencies and damping of the surface modes is obtained.

  16. 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


    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.

  17. Development and applications of an optical tweezer-based microrheometer: case studies of biomaterials and living cells (United States)

    Wang, Jing; Yalcin, Huseyin; Lengel, Angela; Hewitt, Corey; Ou-Yang, H. Daniel


    The investigation of mechanical properties of living biological cells and biomaterials is challenging because they are inhomogeneous and anisotropic at microscopic scales, and often time-dependent over a broad time scale. Through three case studies of biomaterials and living cells, we demonstrate that a novel, oscillating optical tweezer-based imaging microrheometer developed recently in our laboratory has overcome many technical barriers posed by the complexity of biological systems. In this paper, we present the working principle, system setup and calibration of the imaging microrheometer, and report the groundbreaking results of the three applications: gelation dynamics of cross-linkable hyaluronan acid (HA) hydrogels; Mechanical in-homogeneity and anisotropy in purified microtubule networks; and effects of drug treatment and temperature variation on the mechanical properties of in vitro human alveolar epithelial cells. In each case, micro beads inserted in the materials, or attached to the cell membrane were used as probes for optical trapping. The probe particle was set into a forced harmonic oscillation by oscillating optical tweezers. Position sensing optics and phase lock-in signal processing allow the determination of the amplitude and phase shift of the particle motion at high sensitivity. The complex mechanical modulus G * is then calculated from the amplitude and the phase shift. The rheometer system is capable of measuring dynamic local mechanical moduli in the broad frequency range of 1.3-1000 Hz at a sampling rate of 2 data point per second across a wide dynamic range (1~20,000 dyne/cm2). Integration of the rheometer system with spinning disk confocal microscopy enables the study of micromechanical properties and the microstructure of the sample simultaneously. Combination of dual-axis, piezo-electric activated mirror and 2-D position sensing detector gives the rheometer system the capability of investigating mechanical anisotropy in highly

  18. Steerable optical tweezers for ultracold atom studies. (United States)

    Roberts, K O; McKellar, T; Fekete, J; Rakonjac, A; Deb, A B; Kjærgaard, N


    We report on the implementation of an optical tweezer system for controlled transport of ultracold atoms along a narrow, static confinement channel. The tweezer system is based on high-efficiency acousto-optic deflectors and offers two-dimensional control over beam position. This opens up the possibility for tracking the transport channel when shuttling atomic clouds along it, forestalling atom spilling. Multiple clouds can be tracked independently by time-shared tweezer beams addressing individual sites in the channel. The deflectors are controlled using a multichannel direct digital synthesizer, which receives instructions on a submicrosecond time scale from a field-programmable gate array. Using the tweezer system, we demonstrate sequential binary splitting of an ultracold 87Rb cloud into 2(5) clouds.

  19. Optoelectronic studies on heterocyclic bases of deoxyribonucleic acid for DNA photonics. (United States)

    El-Diasty, Fouad; Abdel-Wahab, Fathy


    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.

  20. Effect of annealing over optoelectronic properties of graphene based transparent electrodes (United States)

    Yadav, Shriniwas; Kaur, Inderpreet


    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.

  1. Thickness dependence on the optoelectronic properties of multilayered GaSe based photodetector (United States)

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


    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 × 1010 cm Hz1/2 W-1 at 532 nm laser wavelength, underscoring that GaSe is a promising p-type 2D material for photodetection applications in the visible spectrum.

  2. Fluorene-based macromolecular nanostructures and nanomaterials for organic (opto)electronics. (United States)

    Xie, Ling-Hai; Yang, Su-Hui; Lin, Jin-Yi; Yi, Ming-Dong; Huang, Wei


    Nanotechnology not only opens up the realm of nanoelectronics and nanophotonics, but also upgrades organic thin-film electronics and optoelectronics. In this review, we introduce polymer semiconductors and plastic electronics briefly, followed by various top-down and bottom-up nano approaches to organic electronics. Subsequently, we highlight the progress in polyfluorene-based nanoparticles and nanowires (nanofibres), their tunable optoelectronic properties as well as their applications in polymer light-emitting devices, solar cells, field-effect transistors, photodetectors, lasers, optical waveguides and others. Finally, an outlook is given with regard to four-element complex devices via organic nanotechnology and molecular manufacturing that will spread to areas such as organic mechatronics in the framework of robotic-directed science and technology.

  3. InP-Based Heterostructure Design and Growth for Semiconductor Nanomembrane Optoelectronics on Si and on Flexible Substrates (United States)


    AFRL-AFOSR-UK-TR-2014-0015 InP-based heterostructure design and growth for semiconductor nanomembrane optoelectronics on Si and...TITLE AND SUBTITLE InP-based heterostructure design and growth for semiconductor nanomembrane optoelectronics on Si and on flexible substrates...on the realization of ultracompact microcavity lasers directly integrated on silicon. Using a stamp-assisted transfer-printing technology, silicon

  4. Ge-Photodetectors for Si-Based Optoelectronic Integration

    Directory of Open Access Journals (Sweden)

    Sungjoo Lee


    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.

  5. Towards Silicon-Based Longwave Integrated Optoelectronics (LIO) (United States)


    buried SiO2 layer etched away locally under the silicon rib: (a) solid rib, (b) slotted rib. The slotted silicon rib has the feature of very high...heterostructures offer brighter prospects than SiGe for IV-IV lasing. The Si-based GeSn /SiGeSn and Ge/SiGeSn heterostructures offer higher gain, less strain...serpentine paths are again used, and the CB analytes flow inside a narrow slot of width λ/20 etched into the length of the folded Group IV waveguide

  6. 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:; 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)


    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.

  7. Optical tweezers: wideband microrheology

    CERN Document Server

    Preece, Daryl; Tassieri, Manlio; Evans, R M L; Gibson, Graham M; Padgett, Miles J; Cooper, Jonathan M


    Microrheology is a branch of rheology having the same principles as conventional bulk rheology, but working on micron length scales and micro-litre volumes. Optical tweezers have been successfully used with Newtonian fluids for rheological purposes such as determining fluid viscosity. Conversely, when optical tweezers are used to measure the viscoelastic properties of complex fluids the results are either limited to the material's high-frequency response, discarding important information related to the low-frequency behavior, or they are supplemented by low-frequency measurements performed with different techniques, often without presenting an overlapping region of clear agreement between the sets of results. We present a simple experimental procedure to perform microrheological measurements over the widest frequency range possible with optical tweezers. A generalised Langevin equation is used to relate the frequency-dependent moduli of the complex fluid to the time-dependent trajectory of a probe particle as...

  8. Quantum limited particle sensing in optical tweezers

    CERN Document Server

    Tay, Jian Wei; Bowen, Warwick P


    Particle sensing in optical tweezers systems provides information on the position, velocity and force of the specimen particles. The conventional quadrant detection scheme is applied ubiquitously in optical tweezers experiments to quantify these parameters. In this paper we show that quadrant detection is non-optimal for particle sensing in optical tweezers and propose an alternative optimal particle sensing scheme based on spatial homodyne detection. A formalism for particle sensing in terms of transverse spatial modes is developed and numerical simulations of the efficacy of both quadrant and spatial homodyne detection are shown. We demonstrate that an order of magnitude improvement in particle sensing sensitivity can be achieved using spatial homodyne over quadrant detection.

  9. Photon management of GaN-based optoelectronic devices via nanoscaled phenomena (United States)

    Tsai, Yu-Lin; Lai, Kun-Yu; Lee, Ming-Jui; Liao, Yu-Kuang; Ooi, Boon S.; Kuo, Hao-Chung; He-Hau, Jr.


    Photon management is essential in improving the performances of optoelectronic devices including light emitting diodes, solar cells and photo detectors. Beyond the advances in material growth and device structure design, photon management via nanoscaled phenomena have also been demonstrated as a promising way for further modifying/improving the device performance. The accomplishments achieved by photon management via nanoscaled phenomena include strain-induced polarization field management, crystal quality improvement, light extraction/harvesting enhancement, radiation pattern control, and spectrum management. In this review, we summarize recent development, challenges and underlying physics of photon management in GaN-based light emitting diodes and solar cells.

  10. Multi-Axis Force/Torque Sensor Based on Simply-Supported Beam and Optoelectronics


    Noh, Yohan; Bimbo, Joao; Sareh, Sina; Wurdemann, Helge; Fraś, Jan; Chathuranga, Damith Suresh; Liu, Hongbin; Housden, James; Althoefer, Kaspar; Rhode, Kawal


    This paper presents a multi-axis force/torque sensor based on simply-supported beam and optoelectronic technology. The sensor’s main advantages are: (1) Low power consumption; (2) low-level noise in comparison with conventional methods of force sensing (e.g., using strain gauges); (3) the ability to be embedded into different mechanical structures; (4) miniaturisation; (5) simple manufacture and customisation to fit a wide-range of robot systems; and (6) low-cost fabrication and assembly of s...

  11. Photon management of GaN-based optoelectronic devices via nanoscaled phenomena

    KAUST Repository

    Tsai, Yu-Lin


    Photon management is essential in improving the performances of optoelectronic devices including light emitting diodes, solar cells and photo detectors. Beyond the advances in material growth and device structure design, photon management via nanoscaled phenomena have also been demonstrated as a promising way for further modifying/improving the device performance. The accomplishments achieved by photon management via nanoscaled phenomena include strain-induced polarization field management, crystal quality improvement, light extraction/harvesting enhancement, radiation pattern control, and spectrum management. In this review, we summarize recent development, challenges and underlying physics of photon management in GaN-based light emitting diodes and solar cells. (C) 2016 Elsevier Ltd. All rights reserved.

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

    DEFF Research Database (Denmark)

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


    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...

  13. High-Q wavelength division multiplexed optoelectronic oscillator based on a cascaded multi-loop topology (United States)

    Charalambous, Georgios; Hasanuzzaman, G. K. M.; Perentos, Andreas; Iezekiel, Stavros


    A WDM optoelectronic oscillator (OEO) based on a cascaded optical multi-loop configuration and multiple photodiodes is proposed and demonstrated experimentally. By employing up to three lasers widely separated in wavelength along with two cascaded multi-loop fiber sections and two photodiodes, we demonstrate OEO topologies that scale up to six effective loops revealing an ultra-high quality factor in excess of 1010 and a phase noise performance down to -119 dBc/Hz at 10 kHz offset

  14. Graphene-Boron Nitride Heterostructure Based Optoelectronic Devices for On-Chip Optical Interconnects (United States)

    Gao, Yuanda

    Graphene has emerged as an appealing material for a variety of optoelectronic applications due to its unique electrical and optical characteristics. In this thesis, I will present recent advances in integrating graphene and graphene-boron nitride (BN) heterostructures with confined optical architectures, e.g. planar photonic crystal (PPC) nanocavities and silicon channel waveguides, to make this otherwise weakly absorbing material optically opaque. Based on these integrations, I will further demonstrate the resulting chip-integrated optoelectronic devices for optical interconnects. After transferring a layer of graphene onto PPC nanocavities, spectral selectivity at the resonance frequency and orders-of-magnitude enhancement of optical coupling with graphene have been observed in infrared spectrum. By applying electrostatic potential to graphene, electro-optic modulation of the cavity reflection is possible with contrast in excess of 10 dB. And furthermore, a novel and complex modulator device structure based on the cavity-coupled and BN-encapsulated dual-layer graphene capacitor is demonstrated to operate at a speed of 1.2 GHz. On the other hand, an enhanced broad-spectrum light-graphene interaction coupled with silicon channel waveguides is also demonstrated with ?0.1 dB/?m transmission attenuation due to graphene absorption. A waveguide-integrated graphene photodetector is fabricated and shown 0.1 A/W photoresponsivity and 20 GHz operation speed. An improved version of a similar photodetector using graphene-BN heterostructure exhibits 0.36 A/W photoresponsivity and 42 GHz response speed. The integration of graphene and graphene-BN heterostructures with nanophotonic architectures promises a new generation of compact, energy-efficient, high-speed optoelectronic device concepts for on-chip optical communications that are not yet feasible or very difficult to realize using traditional bulk semiconductors.

  15. An opto-electronic joint detection system based on DSP aiming at early cervical cancer screening (United States)

    Wang, Weiya; Jia, Mengyu; Gao, Feng; Yang, Lihong; Qu, Pengpeng; Zou, Changping; Liu, Pengxi; Zhao, Huijuan


    The cervical cancer screening at a pre-cancer stage is beneficial to reduce the mortality of women. An opto-electronic joint detection system based on DSP aiming at early cervical cancer screening is introduced in this paper. In this system, three electrodes alternately discharge to the cervical tissue and three light emitting diodes in different wavelengths alternately irradiate the cervical tissue. Then the relative optical reflectance and electrical voltage attenuation curve are obtained by optical and electrical detection, respectively. The system is based on DSP to attain the portable and cheap instrument. By adopting the relative reflectance and the voltage attenuation constant, the classification algorithm based on Support Vector Machine (SVM) discriminates abnormal cervical tissue from normal. We use particle swarm optimization to optimize the two key parameters of SVM, i.e. nuclear factor and cost factor. The clinical data were collected on 313 patients to build a clinical database of tissue responses under optical and electrical stimulations with the histopathologic examination as the gold standard. The classification result shows that the opto-electronic joint detection has higher total coincidence rate than separate optical detection or separate electrical detection. The sensitivity, specificity, and total coincidence rate increase with the increasing of sample numbers in the training set. The average total coincidence rate of the system can reach 85.1% compared with the histopathologic examination.

  16. Quantum computation architecture using optical tweezers

    DEFF Research Database (Denmark)

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


    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....

  17. Optically efficient InAsSb nanowires for silicon-based mid-wavelength infrared optoelectronics (United States)

    Zhuang, Q. D.; Alradhi, H.; Jin, Z. M.; Chen, X. R.; Shao, J.; Chen, X.; Sanchez, Ana M.; Cao, Y. C.; Liu, J. Y.; Yates, P.; Durose, K.; Jin, C. J.


    InAsSb nanowires (NWs) with a high Sb content have potential in the fabrication of advanced silicon-based optoelectronics such as infrared photondetectors/emitters and highly sensitive phototransistors, as well as in the generation of renewable electricity. However, producing optically efficient InAsSb NWs with a high Sb content remains a challenge, and optical emission is limited to 4.0 μm due to the quality of the nanowires. Here, we report, for the first time, the success of high-quality and optically efficient InAsSb NWs enabling silicon-based optoelectronics operating in entirely mid-wavelength infrared. Pure zinc-blende InAsSb NWs were realized with efficient photoluminescence emission. We obtained room-temperature photoluminescence emission in InAs NWs and successfully extended the emission wavelength in InAsSb NWs to 5.1 μm. The realization of this optically efficient InAsSb NW material paves the way to realizing next-generation devices, combining advances in III-V semiconductors and silicon.

  18. Design and Fabrication of a Monolithic Optoelectronic Integrated Circuit Chip Based on CMOS Compatible Technology

    Institute of Scientific and Technical Information of China (English)

    GUO Wei-Feng; ZHAO Yong; WANG Wan-Jun; SHAO Hai-Feng; YANG Jian-Yi; JIANG Xiao-Qing


    A monolithic optoelectronic integrated circuit chip on a silicon-on-insulator is designed and fabricated based on complementary metal oxide semiconductor compatible technology.The chip integrates an optical Mach-Zehnder modulator (MZM) and a CMOS driving circuit with the amplification function.Test results show that the extinction ratio of the MZM is close to 20dB and the small-signal gain of the CMOS driving circuit is about 26.9dB.A 50m V 10 MHz sine wave signal is amplified by the driving circuit,and then drives the MZM successfully.%A monolithic optoelectronic integrated circuit chip on a silicon-on-insulator is designed and fabricated based on complementary metal oxide semiconductor compatible technology. The chip integrates an optical Mach-Zehnder modulator (MZM) and a CMOS driving circuit with the amplification function. Test results show that the extinction ratio of the MZM is close to 20 dB and the small-signal gain of the CMOS driving circuit is about 26.9dB. A 50mV 10MHz sine wave signal is amplified by the driving circuit, and then drives the MZM successfully.

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

    Directory of Open Access Journals (Sweden)

    Cimrová Vĕra


    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.

  20. Quantum dot-based organic-inorganic hybrid materials for optoelectronic applications (Conference Presentation) (United States)

    Lee, Kwang-Sup


    Our recent research involves the design, characterization and testing of devices constituting low bandgap conjugated polymers, surface-engineered quantum dots (QDs), carbon nanotube (CNT)-QDs, QDs decorated nanowires, and QD coupled conjugated polymers. The resulting hybrid materials can be used for facilitating the charge/energy transfer and enhancing the charge carrier mobility in highly efficient optoelectronic and photonic devices. Exploiting the full potential of quantum dots (QDs) in optoelectronic devices require efficient mechanisms for transfer of energy or electrons produced in the optically excited QDs. We propose semiconducting π-conjugated molecules as ligands to achieve energy or charge transfer. The hybridization of p-type π-conjugated molecules to the surface of n-type QDs can induce distinct luminescence and charge transport characteristics due to energy and/or charge transfer effects. QDs and π-conjugated molecule hybrids with controlled luminescent properties can be used for new active materials for light-emitting diodes and flexible displays. In addition, such hybrid systems with enhanced charge transfer efficiency can be used for nanoscale photovoltaic devices. We have also explored single nanoparticle based electronics using QDs and π-conjugated molecule hybrids with molecular-scale n-p or n-insulating (ins)-p-heterojunction structures.

  1. Phase Noise Analysis of Clock Recovery Based on an Optoelectronic Phase-Locked Loop (United States)

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


    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 employed in the loop. The effects of loop time delay and the laser transfer function are included in the stochastic differential equations describing the system, and a detailed timing jitter analysis of this type of optoelectronic CR for high-speed optical-time-division-multiplexing systems is performed. 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 VCO are more relaxed for the extracted optical clock (lasers's output) signal.

  2. Chaotic communication in radio-over-fiber transmission based on optoelectronic feedback semiconductor lasers. (United States)

    Lin, Fan-Yi; Tsai, Meng-Chiao


    Performance of chaotic communication in radio-over-fiber (ROF) transmission based on optoelectronic feedback semiconductor lasers is studied numerically. The chaotic carrier is generated by optoelectronic feedback semiconductor lasers, where chaotic communication is realized by synchronizing a receiver laser with a transmitter laser. Transmission quality of different message encoding schemes, including additive chaos modulation (ACM) and on-off shift keying (OOSK), are investigated and compared. In this study, the dispersion and nonlinearity effects in the fiber transmission module and the amplified spontaneous emission noise from the optical amplifiers are considered. In the wireless channel, effects of additive white Gaussian noise, multipath, and path loss are included. To quantitatively study the performance of this chaotic communication system in the ROF transmission, bit-error-rates (BER) of different transmission lengths, message bit-rates, and signal-to-noise ratios are studied. The optimal launched power and message strength that minimize the BER while assuring effective communication security are discussed. While the ACM scheme is shown to perform better in a fiber only configuration, the OOSK scheme shows better immunity to the random effects and waveform distortions presented in the wireless channel.

  3. Physics of optical tweezers. (United States)

    Nieminen, Timo A; Knöner, Gregor; Heckenberg, Norman R; Rubinsztein-Dunlop, Halina


    We outline the basic principles of optical tweezers as well as the fundamental theory underlying optical tweezers. The optical forces responsible for trapping result from the transfer of momentum from the trapping beam to the particle and are explained in terms of the momenta of incoming and reflected or refracted rays. We also consider the angular momentum flux of the beam in order to understand and explain optical torques. In order to provide a qualitative picture of the trapping, we treat the particle as a weak positive lens and the forces on the lens are shown. However, this representation does not provide quantitative results for the force. We, therefore, present results of applying exact electromagnetic theory to optical trapping. First, we consider a tightly focused laser beam. We give results for trapping of spherical particles and examine the limits of trappability in terms of type and size of the particles. We also study the effect of a particle on the beam. This exact solution reproduces the same qualitative effect as when treating the particle as a lens where changes in the convergence or divergence and in the direction of the trapping beam result in restoring forces acting on the particle. Finally, we review the fundamental theory of optical tweezers.

  4. Final report on LDRD project 52722 : radiation hardened optoelectronic components for space-based applications.

    Energy Technology Data Exchange (ETDEWEB)

    Hargett, Terry W. (L& M Technologies, Inc.); Serkland, Darwin Keith; Blansett, Ethan L.; Geib, Kent Martin; Sullivan, Charles Thomas; Hawkins, Samuel D.; Wrobel, Theodore Frank; Keeler, Gordon Arthur; Klem, John Frederick; Medrano, Melissa R.; Peake, Gregory Merwin; Karpen, Gary D.; Montano, Victoria A. (L& M Technologies, Inc.)


    This report describes the research accomplishments achieved under the LDRD Project 'Radiation Hardened Optoelectronic Components for Space-Based Applications.' The aim of this LDRD has been to investigate the radiation hardness of vertical-cavity surface-emitting lasers (VCSELs) and photodiodes by looking at both the effects of total dose and of single-event upsets on the electrical and optical characteristics of VCSELs and photodiodes. These investigations were intended to provide guidance for the eventual integration of radiation hardened VCSELs and photodiodes with rad-hard driver and receiver electronics from an external vendor for space applications. During this one-year project, we have fabricated GaAs-based VCSELs and photodiodes, investigated ionization-induced transient effects due to high-energy protons, and measured the degradation of performance from both high-energy protons and neutrons.

  5. Integrated Silicon Optoelectronics

    CERN Document Server

    Zimmermann, Horst K


    Integrated Silicon Optoelectronics synthesizes topics from optoelectronics and microelectronics. The book concentrates on silicon as the major base of modern semiconductor devices and circuits. Starting from the basics of optical emission and absorption, as well as from the device physics of photodetectors, the aspects of the integration of photodetectors in modern bipolar, CMOS, and BiCMOS technologies are discussed. Detailed descriptions of fabrication technologies and applications of optoelectronic integrated circuits are included. The book, furthermore, contains a review of the newest state of research on eagerly anticipated silicon light emitters. In order to cover the topics comprehensively, also included are integrated waveguides, gratings, and optoelectronic power devices. Numerous elaborate illustrations facilitate and enhance comprehension. This extended edition will be of value to engineers, physicists, and scientists in industry and at universities. The book is also recommended to graduate student...

  6. Multi-Axis Force/Torque Sensor Based on Simply-Supported Beam and Optoelectronics (United States)

    Noh, Yohan; Bimbo, Joao; Sareh, Sina; Wurdemann, Helge; Fraś, Jan; Chathuranga, Damith Suresh; Liu, Hongbin; Housden, James; Althoefer, Kaspar; Rhode, Kawal


    This paper presents a multi-axis force/torque sensor based on simply-supported beam and optoelectronic technology. The sensor’s main advantages are: (1) Low power consumption; (2) low-level noise in comparison with conventional methods of force sensing (e.g., using strain gauges); (3) the ability to be embedded into different mechanical structures; (4) miniaturisation; (5) simple manufacture and customisation to fit a wide-range of robot systems; and (6) low-cost fabrication and assembly of sensor structure. For these reasons, the proposed multi-axis force/torque sensor can be used in a wide range of application areas including medical robotics, manufacturing, and areas involving human–robot interaction. This paper shows the application of our concept of a force/torque sensor to flexible continuum manipulators: A cylindrical MIS (Minimally Invasive Surgery) robot, and includes its design, fabrication, and evaluation tests. PMID:27869689

  7. Optoelectronic multiplexer for digital data processing based on lipid crystal pixels and optical fiber elements (United States)

    Pérez, I.; Pena, J. M. S.; Torres, J. C.; Manzanares, R.; Marcos, C.; Vázquez, C.


    In this work, we present an optoelectronic digital multiplexer 4:1 based on a multipixel nematic liquid crystal cell. This device uses two optical control signals to select one among four possible optical data inputs. These data signals are generated by four red LEDs, which are guided through plastic optical fiber towards liquid crystal pixels. For our purpose, only four pixels of the cell will be used to modulate the optical signal across them. Each pixel will be addressed by a square waveform coming from the conditioning circuit managed by a microcontroller system. The electronic control allows the multiplexer to work as as simple two input logical gates such as AND, NAND, OR, NOR, XOR and XNOR. The operation time of the device is limited by the response time of LC cell that is in the millisecond range.

  8. Multi-Axis Force/Torque Sensor Based on Simply-Supported Beam and Optoelectronics

    Directory of Open Access Journals (Sweden)

    Yohan Noh


    Full Text Available This paper presents a multi-axis force/torque sensor based on simply-supported beam and optoelectronic technology. The sensor’s main advantages are: (1 Low power consumption; (2 low-level noise in comparison with conventional methods of force sensing (e.g., using strain gauges; (3 the ability to be embedded into different mechanical structures; (4 miniaturisation; (5 simple manufacture and customisation to fit a wide-range of robot systems; and (6 low-cost fabrication and assembly of sensor structure. For these reasons, the proposed multi-axis force/torque sensor can be used in a wide range of application areas including medical robotics, manufacturing, and areas involving human–robot interaction. This paper shows the application of our concept of a force/torque sensor to flexible continuum manipulators: A cylindrical MIS (Minimally Invasive Surgery robot, and includes its design, fabrication, and evaluation tests.

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

    CERN Document Server

    Kotsifaki, Domna G; Lagoudakis, Pavlos G


    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...

  10. Organic optoelectronics

    CERN Document Server

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


    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

  11. Design of optoelectronic imaging system with high resolution and large field-of-view based on dual CMOS (United States)

    Cheng, Hanglin; Hao, Qun; Hu, Yao; Cao, Jie; Wang, Shaopu; Li, Lin


    With the advantages of high resolution, large field of view and compacted size, optoelectronic imaging sensors are widely used in many fields, such as robot's navigation, industrial measurement and remote sensing. Many researchers pay more attention to improve the comprehensive performances of imaging sensors, including large field of view (FOV), high resolution, compact size and high imaging efficiency, etc. One challenge is the tradeoff between high resolution and large field of view simultaneously considering compacted size. In this paper, we propose an optoelectronic imaging system combining the lenses of short focal length and long focal length based on dual CMOS to simulate the characters of human eyes which observe object within large FOV in high resolution. We design and optimize the two lens, the lens of short focal length is used to search object in a wide field and the long one is responsible for high resolution imaging of the target area. Based on a micro-CMOS imaging sensor with low voltage differential transmission technology-MIPI (Mobile Industry Processor Interface), we design the corresponding circuits to realize collecting optical information with high speed. The advantage of the interface is to help decreasing power consumption, improving transmission efficiency and achieving compacted size of imaging sensor. Meanwhile, we carried out simulations and experiments to testify the optoelectronic imaging system. The results show that the proposed method is helpful to improve the comprehensive performances of optoelectronic imaging sensors.

  12. Growth and fabrication of gallium nitride and indium gallium nitride-based optoelectronic devices (United States)

    Berkman, Erkan Acar

    In this study, heteroepitaxial growth of III-Nitrides was performed by metalorganic chemical vapor deposition (MOCVD) technique on (0001) Al 2O3 substrates to develop GaN and InxGa1-x N based optoelectronic devices. Comprehensive experimental studies on emission and relaxation mechanisms of InxGa1-xN quantum wells (QWs) and InxGa 1-xN single layers were performed. The grown films were characterized by x-ray diffraction (XRD), Hall Effect measurements, photoluminescence measurements (PL) and transmission electron microscopy (TEM). An investigation on the effect of number and width of QWs on PL emission properties of InxGa 1-xN single QWs and multi-quantum wells (MQW) was conducted. The experimental results were explained by the developed theoretical bandgap model. The study on the single layer InxGa1-xN films within and beyond critical layer thickness (CLT) demonstrated that thick InxGa 1-xN films display simultaneous presence of strained and (partially) relaxed layers. The In incorporation into the lattice was observed to be dependent on the strain state of the film. The findings on InxGa1-xN QWs and single layers were implemented in the development of InxGa1-xN based LEDs and photodiodes, respectively. The as-grown samples were fabricated using conventional lithography techniques into various optoelectronic devices including long wavelength LEDs, dichromatic monolithic white LEDs, and p-i-n photodiodes. Emission from InxGa1-xN/GaN MQW LEDs at wavelengths as long as 625nm was demonstrated. This is one of the longest peak emission wavelengths reported for MOCVD grown InxGa1-xN MQW structures. Dichromatic white emission in LEDs was realized by utilizing two InGaN MQW active regions emitting at complementary wavelengths. InGaN p-i-n photodiodes operating at various regions of the visible spectrum tailored by the i-layer properties were developed. This was achieved by the novel approach of employing InxGa1-xN in all layers of the p-i-n photodiodes, enabling nearly

  13. Optoelectronic characterization of the curing process of thermoset-based composites (United States)

    Cusano, A.; Breglio, G.; Giordano, M.; Calabrò, A.; Cutolo, A.; Nicolais, L.


    In this paper, the optoelectronic characterization of the polymerization process of thermoset-based composites is described. As is well known, in the last decade, these kinds of material in the light of their low weight/mechanical strength ratio have been widely used in many industrial areas such as automotive, aeronautic and aerospace. Because of the dependence of their properties on the manufacturing stage, real-time monitoring of the curing process has been indicated as the key point for improving the quality and reducing manufacturing process costs. In fact, in situ identification of the status of the processed material would allow the implementation of an on-line control of the manufacturing stage, leading to the transformation of the classical process in a real scientific operation. Based on this line of argument, a less-contact optical technique has been used to monitor the refractive index variation of an epoxy-based resin due to the polymerization process. Starting from preliminary experimental results, a fibre optic sensor has been designed and developed in order to perform in situ cure monitoring by refractive index measurement. A theoretical model has been developed and validated by comparison with calorimetric characterization.

  14. Lipid Bilayer-Integrated Optoelectronic Tweezers for Nanoparticle Manipulations (United States)


    Wu, M. C. Nano Lett. 2009, 9, 2921−2925. (25) Cremer , P. S.; Boxer, S. G. J. Phys. Chem. B 1999, 103, 2554− 2559. (26) Groves, J. T. Science 1997... Martin , A.; Forster, R. J.; Keyes, T. E. Soft Matter 2012, 8, 8743. (33) Ba, H.; Rodríguez-Fernańdez, J.; Stefani, F. D.; Feldmann, J. Nano Lett. 2010

  15. Polarization multiplexed dual-loop optoelectronic oscillator based on stimulated Brillouin scattering (United States)

    Han, Xiuyou; Ma, Liang; Shao, Yuchen; Ye, Qing; Gu, Yiying; Zhao, Mingshan


    A polarization multiplexed dual-loop optoelectronic oscillator (OEO) based on stimulated Brillouin scattering (SBS) is theoretically analyzed and experimentally demonstrated. The narrow bandwidth of SBS gain spectrum is utilized to implement the phase modulation to intensity modulation conversion and select the oscillation mode of the OEO. The polarization multiplexed dual-loop is constructed to suppress the side modes with Vernier effect. The output frequency of the OEO can be tuned by changing the frequency of the signal or the pump light wave. With the polarization multiplexed dual-loop the side-mode suppression ratio (SMSR) of 45 dB is achieved at 10 GHz. The generated oscillation frequency is tuned from 4 GHz to 16 GHz by changing the frequency of the signal light wave. The phase noise decreases with the power increase of the signal light wave when it is under the threshold of SBS. By adjusting the polarization state of the light wave, the influence of the power distribution between the long loop and the short loop on the phase noise of the OEO is investigated. The results show that more power in the long loop is helpful to suppress the near end phase noise.

  16. Silicon-based optoelectronic integrated circuit for label-free bio/chemical sensor. (United States)

    Song, Junfeng; Luo, Xianshu; Kee, Jack Sheng; Han, Kyungsup; Li, Chao; Park, Mi Kyoung; Tu, Xiaoguang; Zhang, Huijuan; Fang, Qing; Jia, Lianxi; Yoon, Yong-Jin; Liow, Tsung-Yang; Yu, Mingbin; Lo, Guo-Qiang


    We demonstrate a silicon-based optoelectronic integrated circuit (OEIC) for label-free bio/chemical sensing application. Such on-chip OEIC sensor system consists of optical grating couplers for vertical light coupling into silicon waveguides, a thermal-tunable microring as a tunable filter, an exposed microring as an optical label-free sensor, and a Ge photodetector for a direct electrical readout. Different from the conventional wavelength-scanning method, we adopt low-cost broadband ASE light source, together with the on-chip tunable filter to generate sliced light source. The effective refractive index change of the sensing microring induced by the sensing target is traced by scanning the supplied electrical power applied onto the tracing microring, and the detected electrical signal is read out by the Ge photodetector. For bulk refractive index sensing, we demonstrate using such OEIC sensing system with a sensitivity of ~15 mW/RIU and a detection limit of 3.9 μ-RIU, while for surface sensing of biotin-streptavidin, we obtain a surface mass sensitivity of S(m) = ~192 µW/ng·mm(-2) and a surface detection limit of 0.3 pg/mm(2). The presented OEIC sensing system is suitable for point-of-care applications.

  17. Transverse load sensing based on a dual-frequency optoelectronic oscillator. (United States)

    Kong, Fanqi; Li, Wangzhe; Yao, Jianping


    We propose and experimentally demonstrate a fiber-optic sensor implemented based on a dual-frequency optoelectronic oscillator (OEO) for transverse load sensing. In the OEO loop, a phase-shifted fiber Bragg grating (PS-FBG) is employed to which a transverse load is applied to introduce a birefringence to create two orthogonally polarized notches, which leads to the generation of two oscillating frequencies. The beat frequency between the two oscillating frequencies is a function of the load force applied to the PS-FBG. The proposed sensor is experimentally demonstrated. The sensitivity and the minimal detectable load are measured to be as high as ~9.73 GHz/(N/mm) and 2.06×10(-4) N/mm, respectively. The high-frequency purity and stability of the generated microwave signal by the OEO permit extremely reliable and high-accuracy measurement. The frequency interrogation allows the system to operate at an ultra-high speed. In addition, the sensing signal is insensitive to the variations of both the environmental temperature and the optical carrier wavelength.

  18. Multi-Beam Optical Tweezers


    Glückstad, Jesper; Eriksen, Rene Lynge; Hanson, Steen Grüner


    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 angular orientation of a plurality of micro-objects may be individually controlled.A set of multi-beam electromagnetic tweezers is provided comprising a multi-beam generator for emission of a plurality of ...

  19. Optical tweezers absolute calibration

    CERN Document Server

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


    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...

  20. Steps towards silicon optoelectronics

    CERN Document Server

    Starovoytov, A


    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...

  1. Rationally designed donor-acceptor scheme based molecules for applications in opto-electronic devices. (United States)

    Subash Sundar, T; Sen, R; Johari, P


    Several donor (D)-acceptor (A) based molecules are rationally designed by adopting three different schemes in which the conjugation length, strength of the donor and acceptor moieties, and planarity of the molecules are varied. These variations are made by introducing a π-conjugated linkage unit, terminating the ends of the moieties by different electron donating and accepting functional groups, and fusing the donor and acceptor moieties, respectively. Our DFT and TDDFT based calculations reveal that using the above-mentioned design schemes, the electronic and optical properties of the D-A based molecules can be largely tuned. While introduction of a linkage and fusing of moieties enhance the π-π interaction, addition of electron donating groups (-CH3, -OH, and -NH2) and electron accepting groups (-CF3, -CN, -NO2, and -NH3(+)) varies the strength of the donor and acceptor moieties. These factors lead to modulation of the HOMO and LUMO energy levels and facilitate the engineering of the HOMO-LUMO gap and the optical gap over a wide range of ∼0.7-3.7 eV. Moreover, on the basis of calculated ionization potential and reorganization energy, most of the investigated molecules are predicted to be air stable and to exhibit high electron mobility, with the possibility of the presence of ambipolar characteristics in a few of them. The results of our calculations not only demonstrate the examined molecules to be the potential materials for organic opto-electronic devices, but also establish an understanding of the composition-structure-property correlation, which will provide guidelines for designing and synthesizing new materials of choice.

  2. Narrow-linewidth photonic microwave generation based on an optically injected 1550 nm VCSEL subject to optoelectronic feedback (United States)

    Liang, Qing; Fan, Li; Yang, Ji-Yun; Wang, Zhen-Zhen; Wu, Zheng-Mao; Xia, Guang-Qiong


    High-quality photonic microwave generation is experimentally demonstrated based on the period-one (P1) dynamical state output from an optically injected 1550 nm vertical-cavity surface-emitting laser (1550 nm-VCSEL) subject to optoelectronic negative feedback. The experimental results show that, under suitable injection condition, the 1550 nm-VCSEL can generate a photonic microwave signal with single sideband optical spectrum structure, but the linewidth of the microwave signal is relatively wide (on the order of MHz). After further introducing optoelectronic negative feedback, the linewidth of the microwave signal can be narrowed two orders of magnitude to 105.7 kHz. Furthermore, for the case that the feedback strength is set at an optimized value, the frequency of the microwave signal can be tuned continuously within a certain range through simply adjusting the injection strength.

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

    DEFF Research Database (Denmark)

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


    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...

  4. Two-UAV Intersection Localization System Based on the Airborne Optoelectronic Platform. (United States)

    Bai, Guanbing; Liu, Jinghong; Song, Yueming; Zuo, Yujia


    To address the limitation of the existing UAV (unmanned aerial vehicles) photoelectric localization method used for moving objects, this paper proposes an improved two-UAV intersection localization system based on airborne optoelectronic platforms by using the crossed-angle localization method of photoelectric theodolites for reference. This paper introduces the makeup and operating principle of intersection localization system, creates auxiliary coordinate systems, transforms the LOS (line of sight, from the UAV to the target) vectors into homogeneous coordinates, and establishes a two-UAV intersection localization model. In this paper, the influence of the positional relationship between UAVs and the target on localization accuracy has been studied in detail to obtain an ideal measuring position and the optimal localization position where the optimal intersection angle is 72.6318°. The result shows that, given the optimal position, the localization root mean square error (RMS) will be 25.0235 m when the target is 5 km away from UAV baselines. Finally, the influence of modified adaptive Kalman filtering on localization results is analyzed, and an appropriate filtering model is established to reduce the localization RMS error to 15.7983 m. Finally, An outfield experiment was carried out and obtained the optimal results: σ B = 1.63 × 10 - 4 ( ° ) , σ L = 1.35 × 10 - 4 ( ° ) , σ H = 15.8 ( m ) , σ s u m = 27.6 ( m ) , where σ B represents the longitude error, σ L represents the latitude error, σ H represents the altitude error, and σ s u m represents the error radius.

  5. Optical tweezers principles and applications

    CERN Document Server

    Jones, Philip; Volpe, Giovanni


    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, 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...

  6. Telemedicine optoelectronic biomedical data processing system (United States)

    Prosolovska, Vita V.


    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.

  7. Design and test of optoelectronic system of alignment control based on CCD camera (United States)

    Anisimov, A. G.; Gorbachyov, A. A.; Krasnyashchikh, A. V.; Pantushin, A. N.; Timofeev, A. N.


    In this work, design, implementation and test of a system intended for positioning of the elements of turbine units relative to the line of shaft with high precision, are discussed. A procedure of the conversion of coordinates from the instrument system into the system connected with the practical position of the axis of turbine has been devised. It is shown that optoelectronic systems of aligment built by autoreflexive scheme can be used for high precision measurements.

  8. Nanowire Optoelectronics

    Directory of Open Access Journals (Sweden)

    Wang Zhihuan


    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.

  9. Features of the piezo-phototronic effect on optoelectronic devices based on wurtzite semiconductor nanowires. (United States)

    Yang, Qing; Wu, Yuanpeng; Liu, Ying; Pan, Caofeng; Wang, Zhong Lin


    The piezo-phototronic effect, a three way coupling effect of piezoelectric, semiconductor and photonic properties in non-central symmetric semiconductor materials, utilizing the piezo-potential as a "gate" voltage to tune the charge transport/generation/recombination and modulate the performance of optoelectronic devices, has formed a new field and attracted lots of interest recently. The mechanism was verified in various optoelectronic devices such as light emitting diodes (LEDs), photodetectors and solar cells etc. The fast development and dramatic increasing interest in the piezo-phototronic field not only demonstrate the way the piezo-phototronic effects work, but also indicate the strong need for further research in the physical mechanism and potential applications. Furthermore, it is important to distinguish the contribution of the piezo-phototronic effect from other factors induced by external strain such as piezoresistance, band shifting or contact area change, which also affect the carrier behaviour and device performance. In this perspective, we review our recent progress on piezo-phototronics and especially focus on pointing out the features of piezo-phototronic effect in four aspects: I-V characteristics; c-axis orientation; influence of illumination; and modulation of carrier behaviour. Finally we proposed several criteria for describing the contribution made by the piezo-phototronic effect to the performance of optoelectronic devices. This systematic analysis and comparison will not only help give an in-depth understanding of the piezo-phototronic effect, but also work as guide for the design of devices in related areas.

  10. Coaxial Atomic Force Microscope Tweezers

    CERN Document Server

    Brown, K A; Westervelt, R M


    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.

  11. Multi-Beam Optical Tweezers

    DEFF Research Database (Denmark)


    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 angular...... orientation of a plurality of micro-objects may be individually controlled.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...

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


    Bandar Ali Al-Asbahi; Mohammad Hafizuddin Haji Jumali; Chi Chin Yap; Muhamad Mat Salleh


    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 emis...

  13. HoloHands: Kinect Control of Optical Tweezers

    CERN Document Server

    McDonald, Craig; McDougall, Craig; McGloin, David


    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.

  14. Fused thiophene-based conjugated polymers and their use in optoelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Facchetti, Antonio; Marks, Tobin J; Takai, Atsuro; Seger, Mark; Chen, Zhihua


    The present teachings relate to certain polymeric compounds and their use as organic semiconductors in organic and hybrid optical, optoelectronic, and/or electronic devices such as photovoltaic cells, light emitting diodes, light emitting transistors, and field effect transistors. The disclosed compounds can provide improved device performance, for example, as measured by power conversion efficiency, fill factor, open circuit voltage, field-effect mobility, on/off current ratios, and/or air stability when used in photovoltaic cells or transistors. The disclosed compounds can have good solubility in common solvents enabling device fabrication via solution processes.

  15. Nanoelectronic devices and measurements toward nanocrystal-based optoelectronics and DNA sequencing with solid-state nanopores (United States)

    Willis, Lauren J.

    Nanoelectronics are critical to exploring nanoscale materials: including nanocrystals, which could revolutionize optoelectronics, and DNA, which could revolutionize medicine. Our suspended silicon nitride membranes combined with electron beam lithography and transmission electron microscopy have been essential to our device fabrication and measurements. Nanocyrstal-based optoelectronics have garnered much interest, and thus new ways of increasing their transport are constantly being researched. We used ligand exchanges to decrease the interparticle spacing of nanocrystal films, which is known to augment transport. Using gaps only a few nanoparticles-wide, we measured transport and found that current could be controlled with annealing, hydrazine treatment, and voltage-sweeping. Annealing destroyed the insulating ligand surrounding each nanocrystal and allowed the particles to move closer. This usually increased the photocurrent, without significantly increasing the dark current. However, this was ineffective on sub-monolayers. Hydrazine was similar, except it replaced the ligand, rather than destroying it, and it was effective on sub-monolayers; however, it caused a large increase in the dark current as well as the photocurrent. Sweeping the voltage overnight could increase or decrease the photocurrent of a sample depending on whether the sample was illuminated or in the dark, corresponding to traps being emptied or filled. In addition to nanocrystals, our devices were used in solution to sense DNA. We fabricated nanelectrodes and nanowires next to nanopores and showed DNA translocations ionically. We also developed methods to make the pores hydrophilic without the use of piranha; we instead used rapid thermal annealing, heated ozone treatments, and oxygen/hydrogen plasmas. While high rates of device failure was a challenge, recommendations for future experiments are presented, including grounding of all equipment and an extreme focus on sample cleanliness. We have

  16. Electronic and optoelectronic devices based on chirality-enriched wafer-scale single-wall carbon nanotube thin films (United States)

    Gao, Weilu; He, Xiaowei; Xie, Lijuan; Zhang, Qi; Haroz, Erik; Doorn, Stephen K.; Kono, Junichiro


    The unique and rich material properties of single-wall carbon nanotubes (SWCNTs) make them attractive for nano-electronic and optoelectronic applications. Slight changes in tube diameter and wrapping angle, defined by the chirality indices (n, m), can dramatically modify the bandstructure, which can be utilized for designing devices with tailored properties. However, it remains to be a challenge to fabricate macroscopic, single-chirality devices. Here, we introduce a simple way of producing chirality-enriched wafer-scale SWCNT films by combining recently developed solution-based polymer-modified sorting method and vacuum filtration. The produced thin films can be easily transferred onto any substrate to have a CMOS compatible wafer. We fabricated a transistor of (6,5)-enriched SWCNTs with an on/off ratio >103. Large-scale photothermoelectric-effect-based and photovoltaic-effect-based photodetectors made of (6,6)- and (6,5)-enriched films, respectively, will also be discussed.

  17. High frequency optoelectronic oscillators based on the optical feedback of semiconductor mode-locked laser diodes. (United States)

    Haji, Mohsin; Hou, Lianping; Kelly, Anthony E; Akbar, Jehan; Marsh, John H; Arnold, John M; Ironside, Charles N


    Optical self seeding feedback techniques can be used to improve the noise characteristics of passively mode-locked laser diodes. External cavities such as fiber optic cables can increase the memory of the phase and subsequently improve the timing jitter. In this work, an improved optical feedback architecture is proposed using an optical fiber loop delay as a cavity extension of the mode-locked laser. We investigate the effect of the noise reduction as a function of the loop length and feedback power. The well known composite cavity technique is also implemented for suppressing supermode noise artifacts presented due to harmonic mode locking effects. Using this method, we achieve a record low radio frequency linewidth of 192 Hz for any high frequency (>1 GHz) passively mode-locked laser to date (to the best of the authors' knowledge), making it promising for the development of high frequency optoelectronic oscillators.

  18. Photonic Nanojet in Optical Tweezers

    CERN Document Server

    Neves, Antonio Alvaro Ranha


    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...

  19. Single-molecule phenyl-acetylene-macrocycle-based optoelectronic switch functioning as a quantum-interference-effect transistor. (United States)

    Hsu, Liang-Yan; Rabitz, Herschel


    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.

  20. Plasmon enhanced optical tweezers with gold-coated black silicon (United States)

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


    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.

  1. 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


    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...

  2. Optical tweezers for free-solution label-free single bio-molecule studies (United States)

    Kotnala, Abhay; Al-Balushi, Ahmed A.; Gordon, Reuven


    Nanoaperture based trapping has developed as a significant tool among the various optical tweezer systems for trapping of very small particles down to the single nanometer range. The double nanohole aperture based trap provides a method for efficient, highly-sensitive, label-free, low-cost, free-solution single molecule trapping and detection. We use the double nanohole tweezer to understand biomolecular phenomena like protein unfolding, binding, structural conformation of DNA, protein-DNA interactions, and protein small molecule interactions.

  3. Nano-light-emitting-diodes based on InGaN mesoscopic structures for energy saving optoelectronics (United States)

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


    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.

  4. Local electric field measurements by optical tweezers

    Directory of Open Access Journals (Sweden)

    G. Pesce


    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.

  5. Experimental research and analysis of three-finger micro-tweezers

    Institute of Scientific and Technical Information of China (English)

    HUANG Wen-hao; XING Hao


    A new type of three-finger micro-tweezer driven by electro-static force was developed for stable manipulation and assembly of micro devices. The whole system consists of micro-tweezers and a specially designed high frequency AC power supply. The free end of the fingers closes and opens with the increase and decrease of the voltage. The tweezers can grasp and manipulate micro objects at size from 30~100 μm. A quantitative simulation method based on boundarx element method(BEM) and equation of energy conservation is introduced to analyze the non-linear behaviors of the tweezer closure. The simulation results agree well with the experimental data.

  6. Phase noise analysis of a 10-GHz optical injection-locked vertical-cavity surface-emitting laser-based optoelectronic oscillator (United States)

    Coronel, Juan; Varón, Margarita; Rissons, Angélique


    The optical injection locking (OIL) technique is proposed to reduce the phase noise of a carrier generated for a vertical-cavity surface-emitting laser (VCSEL)-based optoelectronic oscillator. The OIL technique permits the enhancement of the VCSEL direct modulation bandwidth as well as the stabilization of the optical noise of the laser. A 2-km delay line, 10-GHz optical injection-locked VCSEL-based optoelectronic oscillator (OILVBO) was implemented. The internal noise sources of the optoelectronic oscillator components were characterized and analyzed to understand the noise conversion of the system into phase noise in the oscillator carrier. The implemented OILVBO phase noise was -105.7 dBc/Hz at 10 kHz from the carrier; this value agrees well with the performed simulated analysis. From the computed and measured phase noise curves, it is possible to infer the noise processes that take place inside the OILVBO. As a second measurement of the oscillation quality, a time-domain analysis was done through the Allan's standard deviation measurement, reported for first time for an optoelectronic oscillator using the OIL technique.

  7. Computer simulation of the collision frequency of two particles in optical tweezers

    Institute of Scientific and Technical Information of China (English)

    Xu Sheng-Hua; Li Yin-Mei; Lou Li-Ren; Sun Zhi-Wei


    Optical tweezers have been successfully used in the study of colloid science. In most applications people are concerned with the behaviour of a single particle held in the optical tweezers. Recently, the ability of the optical tweezers to simultaneously hold two particles has been used to determine the stability ratio of colloidal dispersion. This new development stimulates the efforts to explore the characteristics of a two-particle system in the optical tweezers.An infinite spherical potential well has been used to estimate the collision frequency for two particles in the optical trap based on a Monte Carlo simulation. In this article, a more reasonable harmonic potential, commonly accepted for the optical tweezers, is adopted in a Monte Carlo simulation of the collision frequency. The effect of hydrodynamic interaction of particles in the trap is also considered. The simulation results based on this improved model show quantitatively that the collision frequency drops down sharply at first and then decreases slowly as the distance between the two particles increases. The simulation also shows how the collision frequency is related to the stiffness of the optical tweezers.

  8. An introduction to optoelectronic sensors

    CERN Document Server

    Tajani, Antonella; Cutolo, Antonello


    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

  9. First-principles study of the optoelectronic properties and photovoltaic absorber layer efficiency of Cu-based chalcogenides (United States)

    Sarmadian, N.; Saniz, R.; Partoens, B.; Lamoen, D.


    Cu-based chalcogenides are promising materials for thin-film solar cells with more than 20% measured cell efficiency. Using first-principles calculations based on density functional theory, the optoelectronic properties of a group of Cu-based chalcogenides Cu2-II-IV-VI4 is studied. They are then screened with the aim of identifying potential absorber materials for photovoltaic applications. The spectroscopic limited maximum efficiency (SLME) introduced by Yu and Zunger [Phys. Rev. Lett. 108, 068701 (2012)] is used as a metric for the screening. After constructing the current-voltage curve, the SLME is calculated from the maximum power output. The role of the nature of the band gap, direct or indirect, and also of the absorptivity of the studied materials on the maximum theoretical power conversion efficiency is studied. Our results show that Cu2II-GeSe4 with II = Cd and Hg, and Cu2-II-SnS4 with II = Cd, Hg, and Zn have a higher theoretical efficiency compared with the materials currently used as absorber layer.

  10. 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: [Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom)


    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.

  11. Automated multi-parametric sorting of micron-sized particles via multi-trap laser tweezers (United States)

    Kaputa, Daniel S.

    The capabilities of laser tweezers have rapidly expanded since the first demonstration by Ashkin and co-workers in 1970 of the ability to trap particles using optical energy. Laser tweezers have been used to measure piconewton forces in many biological and material science application, sort bacteria, measure DNA bond strength, and even perform microsurgery. The laser tweezers system developed for this dissertation foreshadows the next generation of laser tweezer systems that provide automated particle sorted based upon multiple criteria. Many laser tweezer sorting applications today entail the operator sorting cells from a bulk sample, one by one. This dissertation demonstrates the technologies of pattern recognition and image processing that allow for an entire microscope slide to be sorted without any operator intervention. We already live in an automated world where the cars we drive are built by machines instead of humans. The technology is there, and the only factors limiting the advancements of fully automated biological instrumentation is the lack of developers with the appropriate knowledge sets. This dissertation introduces the concept of sorting particles via a multi-parametric approach where several parameters such as size, fluorescence, and Raman spectra are used as sorting criteria. Since the advent of laser tweezers, several groups have demonstrated the ability to sort cells and other particle by size, or by fluorescence, or by any other parameter, but to our knowledge there does not exist a laser tweezer sorting system that can sort particles based upon multiple parameters. Sorting via a single parameter can be a severe limitation as the method lacks the robustness and class specificity that exists when sorting based upon multiple parameters. Simply put, it makes more sense to determine the worth of a baseball card by considering it's condition as well as it's age, rather then solely upon its condition. By adding another parameter such as the name of

  12. 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


    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.

  13. A DNA tweezer-actuated enzyme nanoreactor. (United States)

    Liu, Minghui; Fu, Jinglin; Hejesen, Christian; Yang, Yuhe; Woodbury, Neal W; Gothelf, Kurt; Liu, Yan; Yan, Hao


    The functions of regulatory enzymes are essential to modulating cellular pathways. Here we report a tweezer-like DNA nanodevice to actuate the activity of an enzyme/cofactor pair. A dehydrogenase and NAD(+) cofactor are attached to different arms of the DNA tweezer structure and actuation of enzymatic function is achieved by switching the tweezers between open and closed states. The enzyme/cofactor pair is spatially separated in the open state with inhibited enzyme function, whereas in the closed state, enzyme is activated by the close proximity of the two molecules. The conformational state of the DNA tweezer is controlled by the addition of specific oligonucleotides that serve as the thermodynamic driver (fuel) to trigger the change. Using this approach, several cycles of externally controlled enzyme inhibition and activation are successfully demonstrated. This principle of responsive enzyme nanodevices may be used to regulate other types of enzymes and to introduce feedback or feed-forward control loops.

  14. Characterising Conical Refraction Optical Tweezers

    CERN Document Server

    McDonald, Craig; Rafailov, Edik; McGloin, David


    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.

  15. Fiber-integrated optical nano-tweezer based on a bowtie-aperture nano-antenna at the apex of a SNOM tip. (United States)

    El Eter, Ali; Hameed, Nyha M; Baida, Fadi I; Salut, Roland; Filiatre, Claudine; Nedeljkovic, Dusan; Atie, Elie; Bole, Samuel; Grosjean, Thierry


    We propose a new concept of fiber-integrated optical nano-tweezer on the basis of a single bowtie-aperture nano-antenna (BNA) fabricated at the apex of a metal-coated SNOM tip. We demonstrate 3D optical trapping of 0.5 micrometer latex beads with input power which does not exceed 1 mW. Optical forces induced by the BNA on tip are then analyzed numerically. They are found to be 10(3) times larger than the optical forces of a circular aperture of the same area. Such a fiber nanostructure provides a new path for manipulating nano-objects in a compact, flexible and versatile architecture and should thus open promising perspectives in physical, chemical and biomedical domains.

  16. Numerical study of the properties of optical vortex array laser tweezers. (United States)

    Kuo, Chun-Fu; Chu, Shu-Chun


    Chu et al. constructed a kind of Ince-Gaussian modes (IGM)-based vortex array laser beams consisting of p x p embedded optical vortexes from Ince-Gaussian modes, IG(e)(p,p) modes [Opt. Express 16, 19934 (2008)]. Such an IGM-based vortex array laser beams maintains its vortex array profile during both propagation and focusing, and is applicable to optical tweezers. This study uses the discrete dipole approximation (DDA) method to study the properties of the IGM-based vortex array laser tweezers while it traps dielectric particles. This study calculates the resultant force exerted on the spherical dielectric particles of different sizes situated at the IGM-based vortex array laser beam waist. Numerical results show that the number of trapping spots of a structure light (i.e. IGM-based vortex laser beam), is depended on the relation between the trapped particle size and the structure light beam size. While the trapped particle is small comparing to the beam size of the IGM-based vortex array laser beams, the IGM-based vortex array laser beams tweezers are suitable for multiple traps. Conversely, the tweezers is suitable for single traps. The results of this study is useful to the future development of the vortex array laser tweezers applications.

  17. State-of-the-art Sn2+-based ternary oxides as photocatalysts for water splitting: electronic structures and optoelectronic properties

    KAUST Repository

    Noureldine, Dalal


    Developing visible light responsive metal oxide photocatalysts is a challenge that must be conquered to achieve high efficiency for water splitting or hydrogen evolution reactions. Valence band engineering is possible by forming ternary oxides using the combination of a metal cation with an s2d10 electronic configuration and a transition metal oxide with a d0 configuration. Many (Sn2+, Bi3+, Pb2+)-based ternary metal oxide photocatalysts have been reported for hydrogen and/or oxygen evolution under visible irradiation. Sn2+-based materials have attracted particular attention because tin is inexpensive, abundant and more environmentally friendly than lead or bismuth. In this review, we provide a fruitful library for Sn2+-based photocatalysts that have been reported to evolve hydrogen using sacrificial reagents, including SnNb2O6, Sn2Nb2O7, SnTaxNb2−xO6, SnTa2O6, Sn2Ta2O7, SnWO4 (α and β phases), SnSb2O6·nH2O, and Sn2TiO4. The synthesis method used in the literature and the resultant morphology and crystal structure of each compound are discussed. The density functional theory (DFT) calculations of the electronic structure and density of states are provided, and the consequent optoelectronic properties such as band gap, nature of the bandgap, dielectric constant, and effective masses are summarized. This review will help highlight the main challenges for Sn2+-based materials.

  18. Enhanced multi-hop operation using hybrid optoelectronic router with time-to-live-based selective forward error correction. (United States)

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


    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.

  19. Integrated terahertz optoelectronics (United States)

    Liang, Guozhen; Wang, Qi Jie


    Currently, terahertz (THz) optical systems are based on bulky free-space optics. This is due to the lack of a common platform onto which different THz components, e.g., source, waveguide, modulator and detector, can be monolithically integrated. With the development of THz quantum cascade laser (QCL), it has been realized that the QCL chip may be such a platform for integrated THz photonics. Here, we report our recent works where the THz QCL is integrated with passive or optoelectronic components. They are: 1) integrated graphene modulator with THz QCL achieving 100% modulation depth and fast speed; 2) phase-locked THz QCL with integrated plasmonic waveguide and subwavelength antennas realizing dynamically widely tunable polarizations.

  20. Integrated silicon optoelectronics

    CERN Document Server

    Zimmermann, Horst


    'Integrated Silicon Optoelectronics'assembles optoelectronics and microelectronics The book concentrates on silicon as the major basis of modern semiconductor devices and circuits Starting from the basics of optical emission and absorption and from the device physics of photodetectors, the aspects of the integration of photodetectors in modern bipolar, CMOS, and BiCMOS technologies are discussed Detailed descriptions of fabrication technologies and applications of optoelectronic integrated circuits are included The book, furthermore, contains a review of the state of research on eagerly expected silicon light emitters In order to cover the topic of the book comprehensively, integrated waveguides, gratings, and optoelectronic power devices are included in addition Numerous elaborate illustrations promote an easy comprehension 'Integrated Silicon Optoelectronics'will be of value to engineers, physicists, and scientists in industry and at universities The book is also recommendable for graduate students speciali...

  1. 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;


    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...

  2. Fiber optical tweezers for microscale and nanoscale particle manipulation and force sensing (United States)

    Liu, Yuxiang


    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

  3. The supramolecular design of low-dimensional carbon nano-hybrids encoding a polyoxometalate-bis-pyrene tweezer. (United States)

    Modugno, Gloria; Syrgiannis, Zois; Bonasera, Aurelio; Carraro, Mauro; Giancane, Gabriele; Valli, Ludovico; Bonchio, Marcella; Prato, Maurizio


    A novel bis-pyrene tweezer anchored on a rigid polyoxometalate scaffold fosters a unique interplay of hydrophobic and electrostatic supramolecular interactions, to shape carbon nanostructures (CNSs)-based extended architectures.

  4. Siloxane-based photonic structures and their application in optic and optoelectronic devices (United States)

    Pudiš, Dušan; Šušlik, Łuboš; Jandura, Daniel; Goraus, Matej; Figurová, Mária; Martinček, Ivan; Gašo, Peter


    Polymer based photonics brings simple and cheap solutions often with interesting results. We present capabilities of some siloxanes focusing on polydimethylsiloxane (PDMS) with unique mechanical and optical properties. In combination of laser lithography technologies with siloxane embossing we fabricate different grating structures with one- and two-dimensional symmetry. Concept of PDMS based thin membranes with patterned surface as an effective diffraction element for modification of radiation pattern diagram of light emitting diodes is here shown. Also the PDMS was used as an alternative material for fabrication of complicated waveguide with implemented Bragg grating. For lab-on-chip applications, we patterned PDMS microstructures for microfluidic and micro-optic devices.

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

    Directory of Open Access Journals (Sweden)

    Gary Zaiats


    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.

  6. Laser tweezers Raman spectroscopy of single cells (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.

  7. Optoelectronics circuits manual

    CERN Document Server

    Marston, R M


    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.

  8. 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


    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

  9. A bioanalytical microsystem for protein and DNA sensing based on a monolithic silicon optoelectronic transducer

    Energy Technology Data Exchange (ETDEWEB)

    Misiakos, K [Microelectronics Institute, NCSR ' Demokritos' , 15310, Athens (Greece); Petrou, P S [Immunoassay Lab., I/R-RP, NCSR ' Demokritos' , 15310, Athens (Greece); Kakabakos, S E [Immunoassay Lab., I/R-RP, NCSR ' Demokritos' , 15310, Athens (Greece); Ruf, H H [Fraunhofer Institute of Biomedical Engineering (IBMT) and University of Saarland, 66386, St Ingbert (Germany); Ehrentreich-Foerster, E [Department of Molecular Bioanalytics and Bioelectronics, Fraunhofer Institute for Biomedical Engineering, D-14558 Nuthetal (Germany); Bier, F F [Department of Molecular Bioanalytics and Bioelectronics, Fraunhofer Institute for Biomedical Engineering, D-14558 Nuthetal (Germany)


    A bioanalytical microsystem that is based on a monolithic silicon optical transducer and a microfluidic module and it is appropriate for real-time sensing of either DNA or protein analytes is presented. The optical transducer monolithically integrates silicon avalanche diodes as light sources, silicon nitride optical fibers and detectors and efficiently intercouples these optical elements through a self-alignment technique. After hydrophilization and silanization of the transducer surface, the biomolecular probes are immobilized through physical adsorption. Detection is performed through reaction of the immobilized biomolecules with gold nanoparticle labeled counterpart molecules. The binding of these molecules within the evanescent field at the surface of the optical fiber cause attenuated total reflection of the waveguided modes and reduction of the detector photocurrent. Using the developed microsystem, determination of single nucleotide polymorphism (SNP) in the gene of the human phenol sulfotransferase SULT1A1 was achieved. Full-matching hybrid resulted in 4-5 times higher signals compared to the mismatched hybrid after hybridization and dissociation processes. The protein sensing abilities of the developed microsystem were also investigated through a non-competitive assay for the determination of the MB isoform of creatine kinase enzyme (CK-MB) that is a widely used cardiac marker.

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

    Directory of Open Access Journals (Sweden)

    Annamaria Panniello


    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.

  11. Optoelectronic Properties of Color-Tunable Mixed Ligand-Based Light-Emitting Zinc Complexes (United States)

    Singh, Devender; Bhagwan, Shri; Saini, Raman Kumar; Tanwar, Vijeta; Nishal, Vandna


    A series of mixed ligand-based zinc complexes (Zn1-Zn5); [(8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn1), [(5-chloro-8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn2), [(5,7-dichloro-8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn3), [(2-methyl-8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn4) and [(5,7-dimethyl-8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn5) were synthesized and characterized. The photophysical properties of zinc complexes were examined by ultraviolet-visible absorption and photoluminescence emission spectroscopy. All prepared metal complexes produced intense luminescence on excitation with a UV light source. In this study, the color-tunable characteristics of metal complexes were investigated by introducing the electron-donating and electron-withdrawing groups on the 8-hydroxyquinoline ligand. The emission spectra of metal complexes showed emission wavelength at 500 nm for [ZnHBI(q)], 509 nm for [ZnHBI(Clq)], 504 nm for [Zn(HBI)(Cl2q)], 496 nm for [ZnHBI (Meq)] and 573 nm for [ZnHBI(Me2Q)] materials. A temperature-dependent PL spectrum was used to study the emission profile of zinc complex and observed that variation in the temperature altered the position and the intensity of emission peak. The synthesized metal complex also exhibited good thermal stability (>300°C). Photophysical characteristics of color-tunable light-emitting zinc complexes suggested that these materials could be efficiently used for emissive display device applications.

  12. Roughness sensor based on a compact optoelectronic emitter-receiver modules (United States)

    Will, Matthias; Brodersen, Olaf; Steinke, Arndt


    In construction and manufacturing the surface roughness and their control plays a major role. The mechanical test probes are used in many applications, because the advantage of the higher resolution of optical systems often plays no role. But in all cases the measurement systems were uses outside of fabrication processes due to the complex and expensive equipment. To overcome these we developed a roughness sensor suitable for an automated control of machined surfaces. The sensor is able to handle high throughput and parallel systems is due to the low cost available. Our solution is compact stand-alone sensors that can be simple integrated in existing systems like machine tools or transport systems. The sensor is based on a diode laser, focusing optics and a special silicon photo diode array in a stable housing. The single-mode VCSEL at 670 nm emission wavelength is focused on the surface of the sample at distance of 5mm. The light was reflected from the test surface and detected with an 8-channel photodiode array. The position of the main reflex allows an optimization of the sensor distance to the surface. During the movement of the sample with a known velocity roughness depended signals over time were recorded at 8 cannels. This allows a detection of the angular distribution of the scattered light in combination of position dependent refection. It was shown here that we be able to achieve resolution below the spot diameter (30μm FWHM). We verify the sensor capabilities for real world applications on drilled samples with typical roughness variations in micro meter range.

  13. Theory of optical-tweezers forces near a plane interface

    DEFF Research Database (Denmark)

    Dutra, Rafael de Sousa; Neto, P. A. Maia; Nussenzveig, H. M.


    Optical-tweezers experiments in molecular and cell biology often take place near the surface of the microscope slide that defines the bottom of the sample chamber. There, as elsewhere, force measurements require forcecalibrated tweezers. In bulk, one can calculate the tweezers force from first...

  14. Micro magnetic tweezers for nanomanipulation inside live cells.

    NARCIS (Netherlands)

    A.H. de Vries; G.E. Krenn; R. van Driel; J.S. Kanger


    This study reports the design, realization, and characterization of a multi-pole magnetic tweezers that enables us to maneuver small magnetic probes inside living cells. So far, magnetic tweezers can be divided into two categories: I), tweezers that allow the exertion of high forces but consist of o

  15. Micro Magnetic Tweezers for Nanomanipulation Inside Live Cells

    NARCIS (Netherlands)

    Vries, de Anthony H.B.; Krenn, Bea E.; Driel, van Roel; Kanger, Johannes S.


    This study reports the design, realization, and characterization of a multi-pole magnetic tweezers that enables us to maneuver small magnetic probes inside living cells. So far, magnetic tweezers can be divided into two categories: I), tweezers that allow the exertion of high forces but consist of o

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

  17. Designing single-beam multitrapping acoustical tweezers

    CERN Document Server

    Silva, Glauber T


    The concept of a single-beam acoustical tweezer device which can simultaneously trap microparticles at different points is proposed and demonstrated through computational simulations. The device employs an ultrasound beam produced by a circular focused transducer operating at 1 MHz in water medium. The ultrasound beam exerts a radiation force that may tweeze suspended microparticles in the medium. Simulations show that the acoustical tweezer can simultaneously trap microparticles in the pre-focal zone along the beam axis, i.e. between the transducer surface and its geometric focus. As acoustical tweezers are fast becoming a key instrument in microparticle handling, the development of acoustic multitrapping concept may turn into a useful tool in engineering these devices.

  18. Dielectric thin-films by ion-beam sputtering deposition for III-V based infrared optoelectronic imaging (United States)

    Nguyen, Jean

    The growing technological industry is demanding the development of powerful and smaller devices. Dielectric thin-films can play an important role to help push towards achieving these goals. However, their advantage of high-quality material and low material costs compared to bulk can only be achieved with consideration of the technique, conditions, and parameters. The sensitivity makes every step in the process extremely important, beginning from substrate preparation to the first initial layers of growth and ending with the testing/modeling of the devices. Further, not all applications want bulk-like properties, so the ability to adjust and fine tune the material characteristics opens up a wide range of opportunities with the advancements and can drive the power of the devices to an ultimate level. This work provides the motivation, theoretical basis, and experimental results for performance enhancement of optoelectronic devices through the use of high-quality dielectric thin-films by ion-beam sputtering deposition (IBSD). The advantages and disadvantages to this technique are demonstrated and compared to others. The optimization processes, relationships, and motivation of using seven different thin-film materials have been detailed and provided. Using IBSD, the performance improvements were demonstrated on infrared lasers and detectors. For lasers, a 170% increase in maximum output power was achieved using near-0% percent anti-reflection coatings (AR) and near-100% high-reflection (HR) coatings. Following, wide tunability was achieved by using the structures in an external cavity laser system, showing nearly a three-fold improvement in tuning range. Also, structurally robust lasers were achieved with a custom-tailored HR structure designed for damage resistance to high output power density operation, showing over 14W of peak output power for MOCVD lasers. For infrared photodetectors, over a 4 orders of magnitude decrease in current density and zero-bias resistance

  19. Rotation of microscopic propellers in laser tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Galajda, Peter; Ormos, Pal [Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, PO Box 521, H-6701 (Hungary)


    Particles of helical shape trapped in laser tweezers are rotated by light, independently of its polarization state. Light scattering by such propeller-like particles generates the momentum to drive the rotation. The efficiency of the rotation depends on the geometry of the particles. We used photopolymerization of light curing resins to create micrometre-size rotors with different shapes. The rotation of such particles was studied: the effect of shape and size on the rotation, as well as on the stability of the position in the laser tweezers.

  20. Thermal gradient induced tweezers for the manipulation of particles and cells (United States)

    Chen, Jiajie; Cong, Hengji; Loo, Fong-Chuen; Kang, Zhiwen; Tang, Minghui; Zhang, Haixi; Wu, Shu-Yuen; Kong, Siu-Kai; Ho, Ho-Pui


    Optical tweezers are a well-established tool for manipulating small objects. However, their integration with microfluidic devices often requires an objective lens. More importantly, trapping of non-transparent or optically sensitive targets is particularly challenging for optical tweezers. Here, for the first time, we present a photon-free trapping technique based on electro-thermally induced forces. We demonstrate that thermal-gradient-induced thermophoresis and thermal convection can lead to trapping of polystyrene spheres and live cells. While the subject of thermophoresis, particularly in the micro- and nano-scale, still remains to be fully explored, our experimental results have provided a reasonable explanation for the trapping effect. The so-called thermal tweezers, which can be readily fabricated by femtosecond laser writing, operate with low input power density and are highly versatile in terms of device configuration, thus rendering high potential for integration with microfluidic devices as well as lab-on-a-chip systems.

  1. Optoelectronic Oscillators for Communication Systems (United States)

    Romeira, Bruno; Figueiredo, José

    We introduce and report recent developments on a novel five port optoelectronic voltage controlled oscillator consisting of a resonant tunneling diode (RTD) optical-waveguide integrated with a laser diode. The RTD-based optoelectronic oscillator (OEO) has both optical and electrical input and output ports, with the fifth port allowing voltage control. The RTD-OEO locks to reference radio-frequency (RF) sources by either optical or electrical injection locking techniques allowing remote synchronization, eliminating the need of impedance matching between traditional RF oscillators. RTD-OEO functions include generation, amplification and distribution of RF carriers, clock recovery, carrier recovery, modulation and demodulation and frequency synthesis. Self-injection locking operation modes, where small portions of the output electrical/optical signals are fed back into the electrical/optical input ports, are also proposed. The self-phase locked loop configuration can give rise to low-noise high-stable oscillations, not limited by the RF source performance and with no need of external optoelectronic conversion.

  2. Reconfigurable Integrated Optoelectronics

    Directory of Open Access Journals (Sweden)

    Richard Soref


    Full Text Available 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 some of them changeable in function. Reconfiguration is provided by electrical control signals to the electro-optical building blocks. We illustrate these modules in detail and discuss 3D ROEIC chips for the highest-performance signal processing. We present examples of our module theory for RPIC optical lattice filters already constructed, and we propose new ROEICs for directed optical logic, large-scale matrix switching, and 2D beamsteering of a phased-array microwave antenna. In general, large-scale-integrated ROEICs will enable significant applications in computing, quantum computing, communications, learning, imaging, telepresence, sensing, RF/microwave photonics, information storage, cryptography, and data mining.

  3. Exact theory of optical tweezers and its application to absolute calibration

    DEFF Research Database (Denmark)

    Dutra, Rafael de Sousa; Viana, Nathan B.; Maia Neto, Paulo A.


    Optical tweezers have become a powerful tool for basic and applied research in cell biology. Here, we describe an experimentally verified theory for the trapping forces generated by optical tweezers based on first principles that allows absolute calibration. For pedagogical reasons, the steps...... that led to the development of the theory over the past 15 years are outlined. The results are applicable to a broad range of microsphere radii, from the Rayleigh regime to the ray optics one, for different polarizations and trapping heights, including all commonly employed parameter domains. Protocols...

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

    KAUST Repository

    Ziani, Ahmed


    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.

  5. Nanotube electronics and optoelectronics

    Directory of Open Access Journals (Sweden)

    Phaedon Avouris


    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.

  6. Semiconductor opto-electronics

    CERN Document Server

    Moss, TS; Ellis, B


    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

  7. Optoelectronic packaging: A review

    Energy Technology Data Exchange (ETDEWEB)

    Carson, R.F.


    Optoelectronics and photonics hold great potential for high data-rate communication and computing. Wide using in computing applications was limited first by device technologies and now suffers due to the need for high-precision, mass-produced packaging. The use of phontons as a medium of communication and control implies a unique set of packaging constraints that was not present in traditional telecommunications applications. The state-of-the-art in optoelectronic packaging is now driven by microelectric techniques that have potential for low cost and high volume manufacturing.

  8. Airy acoustical-sheet spinner tweezers (United States)

    Mitri, F. G.


    The Airy acoustical beam exhibits parabolic propagation and spatial acceleration, meaning that the propagation bending angle continuously increases before the beam trajectory reaches a critical angle where it decays after a propagation distance, without applying any external bending force. As such, it is of particular importance to investigate its properties from the standpoint of acoustical radiation force, spin torque, and particle dynamics theories, in the development of novel particle sorting techniques and acoustically mediated clearing systems. This work investigates these effects on a two-dimensional (2D) circular absorptive structure placed in the field of a nonparaxial Airy "acoustical-sheet" (i.e., finite beam in 2D), for potential applications in surface acoustic waves and acousto-fluidics. Based on the characteristics of the acoustic field, the beam is capable of manipulating the circular cylindrical fluid cross-section and guides it along a transverse or parabolic trajectory. This feature of Airy acoustical beams could lead to a unique characteristic in single-beam acoustical tweezers related to acoustical sieving, filtering, and removal of particles and cells from a section of a small channel. The analysis developed here is based on the description of the nonparaxial Airy beam using the angular spectrum decomposition of plane waves in close association with the partial-wave series expansion method in cylindrical coordinates. The numerical results demonstrate the ability of the nonparaxial Airy acoustical-sheet beam to pull, propel, or accelerate a particle along a parabolic trajectory, in addition to particle confinement in the transverse direction of wave propagation. Negative or positive radiation force and spin torque causing rotation in the clockwise or the anticlockwise direction can occur depending on the nondimensional parameter ka (where k is the wavenumber and a is the radius) and the location of the cylinder in the beam. Applications in

  9. 100 gigasamples per second 12 bits optoelectronic analog-to-digital converter design and implementation based on cellular polyphase-sampling architecture (United States)

    Villa-Angulo, Carlos

    The next generation digital information systems such as high performance computers, multigigabit/sec communication networks, distributed sensors, three dimensional digital imaging systems etc, will require analog-to-digital converters (ADCs) with high sampling rates exceeding 10 Gigasamples per second (GSPS) and high bit resolution of at least 10 bits. Such performance criteria are difficult to achieve with silicon electronics technology because the switching speeds peak at about 10-20GHz. Also, timing jitters, amplitude fluctuations, phase noise, thermal noise, and harmonic distortion, all contribute to reductions in ADC bit resolution as sampling rate increases. Photonics ADCs are rapidly emerging as the enabling technologies for high-performance digital signal processing systems. For this technology, high optical pulses repetition rate (in the order of GHz) with low time jitter and pulse width in the femtoseconds regime are the major attractive characteristics of optical sources. In this dissertation work, a novel 102.4 GSPS 12-bit optoelectronic analog-to-digital converter architecture that is based on a Cellular Polyphase-Sampling architecture is introduced. First, a 102.4 GHz all-optical clock was designed and implemented using a femtosecond laser source and passive optical components. Second, a novel optoelectronic architecture for optical sampling and parallel demultiplexing of different phases (polyphase) of an input analog signal is presented. The optoelectronic sampling and demultiplexing architecture is composed by 20 optoelectronic subcircuit referred as "OE-Cell"; these have been designed and implemented using optical passive components and InGaAs PIN photodiodes. A unique feature of this approach is that the optically sampled RF signal always remains in the electrical domain and thus eliminates the need for electrical-to-optical and optical-to-electrical conversions. The electrical-in to electrical-out transfer functions of the sampling and

  10. Piezoelectric-transducer-based optoelectronic frequency synchronizer for control of pulse delay in a femtosecond passively mode-locked Ti:sapphire laser. (United States)

    Un, Gong-Ru; Chang, Yung-Cheng; Liu, Tze-An; Pan, Ci-Ling


    We propose a piezoelectric transducer-(PZT-) based optoelectronic frequency synchronizer to control simultaneously change in the repetition rate, the relative pulse delay, and the phase noise of a passively mode-locked femtosecond Ti:sapphire laser with an intracavity saturable Bragg reflector absorber with respect to an electronic frequency reference. An optoelectronic phase-locked-loop-based PZT feedback controller with a proportional, integral, and differential (PID) circuit and a tunable voltage regulator is designed to achieve frequency synchronization, phase-noise suppression, and delay-time tuning. When the controlling voltage is tuned from -2.6 to 2.6 V, the maximum pulse-delay range, tuning slope, and tuning resolution of the laser pulse-train are 11.3 ns, 2.3 ps/mV, and 1.2 ps, respectively. Setting the gain constant of the PID circuit at 10 or larger causes the delay-time tuning function to be linearly proportional to the controlling voltage. In the delay-time tuning mode the uncorrelated single-side-band phase-noise density of the frequency-synchronized laser is approximately -120 dBc/Hz at an offset frequency of 5 kHz, which is only 7 dBc/Hz higher than that of the electrical frequency reference. The proposed system also supports linear,continuous switching,and programmable control of the delay time of Ti:sapphire laser pulses when they are frequency synchronized to external reference clocks.

  11. 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. (United States)

    Cassinelli, A; Chavel, P; Desmulliez, M P


    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 array to monolithically integrate photodetectors and modulators on the same chip, providing compact, high-bandwidth intrachip optoelectronic interconnects. We have modeled the operation of the monolithic processor, clearly showing system-performance improvement.

  12. Independent trapping and manipulation of microparticles using dexterous acoustic tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Courtney, Charles R. P., E-mail: [Department of Mechanical Engineering, University of Bath, Bath (United Kingdom); Demore, Christine E. M.; Wu, Hongxiao; Cochran, Sandy [Institute of Medical Science and Technology, University of Dundee, Dundee (United Kingdom); Grinenko, Alon; Wilcox, Paul D.; Drinkwater, Bruce W. [Department of Mechanical Engineering, University of Bristol, Bristol (United Kingdom)


    An electronically controlled acoustic tweezer was used to demonstrate two acoustic manipulation phenomena: superposition of Bessel functions to allow independent manipulation of multiple particles and the use of higher-order Bessel functions to trap particles in larger regions than is possible with first-order traps. The acoustic tweezers consist of a circular 64-element ultrasonic array operating at 2.35 MHz which generates ultrasonic pressure fields in a millimeter-scale fluid-filled chamber. The manipulation capabilities were demonstrated experimentally with 45 and 90-μm-diameter polystyrene spheres. These capabilities bring the dexterity of acoustic tweezers substantially closer to that of optical tweezers.

  13. Exploring unconventional capabilities of holographic tweezers (United States)

    Hernandez, R. J.; Pagliusi, P.; Provenzano, C.; Cipparrone, G.


    We report an investigation of manipulation and trapping capabilities of polarization holographic tweezers. A polarization gradient connected with a modulation of the ellipticity shows an optical force related to the polarization of the light that can influence optically isotropic particles. While in the case of birefringent particles an unconventional trapping in circularly polarized fringes is observed. A liquid crystal emulsion has been adopted to investigate the capabilities of the holographic tweezers. The unusual trapping observed for rotating bipolar nematic droplets has suggested the involvement of the lift hydrodynamic force responsible of the Magnus effect, originating from the peculiar optical force field. We show that the Magnus force which is ignored in the common approach can contribute to unconventional optohydrodynamic trapping and manipulation.

  14. 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


    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...

  15. New approaches in the design of magnetic tweezers-current magnetic tweezers (United States)

    Bessalova, Valentina; Perov, Nikolai; Rodionova, Valeria


    The main advantages of the magnetic tweezers are the low price and simplicity of use. However the range of their application is reduced due to shortcomings like, for example, the remanent induction of the core and interaction between ferromagnetic cores. We present the new design of magnetic tweezers-Current Magnetic Tweezers (CMT) that allow particle manipulation by means of the magnetic field generated by the electric currents flowing through the non-magnetic wires. Arranging wires in different geometric shapes allows the particle movement either in two or three dimensions. Forces acting on the magnetic particles with the magnetic moment of 2·10-11 A m2 at distances up to 1 mm had been experimentally measured. It is established that a current of about 1 A at a 1 mm distance generates force of (approximately) 3 pN which is consistent with theoretical estimates.

  16. Photonics and Optoelectronics (United States)


    DARPA NNI/NNCO BRI (2D Materials & Devices Beyond Graphene – planning phase) LRIR PIs Szep – RY: PICS Quantum Information...vertically from plasmonic filters into Si CMOS image sensor diodes via PMMA dielectric and SiNx vertical light couplers - •Designed and implemented signal...model) Future: Metasurfaces/ Meta Photonics, Quantum Integrated Nanophotonics, Ultra Low Power, Graphene Optoelectronics

  17. Graphene Photonics and Optoelectronics


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


    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, ...

  18. Actin and myosin regulate cytoplasm stiffness in plant cells: a study using optical tweezers. (United States)

    van der Honing, Hannie S; de Ruijter, Norbert C A; Emons, Anne Mie C; Ketelaar, Tijs


    Here, we produced cytoplasmic protrusions with optical tweezers in mature BY-2 suspension cultured cells to study the parameters involved in the movement of actin filaments during changes in cytoplasmic organization and to determine whether stiffness is an actin-related property of plant cytoplasm. Optical tweezers were used to create cytoplasmic protrusions resembling cytoplasmic strands. Simultaneously, the behavior of the actin cytoskeleton was imaged. After actin filament depolymerization, less force was needed to create cytoplasmic protrusions. During treatment with the myosin ATPase inhibitor 2,3-butanedione monoxime, more trapping force was needed to create and maintain cytoplasmic protrusions. Thus, the presence of actin filaments and, even more so, the deactivation of a 2,3-butanedione monoxime-sensitive factor, probably myosin, stiffens the cytoplasm. During 2,3-butanedione monoxime treatment, none of the tweezer-formed protrusions contained filamentous actin, showing that a 2,3-butanedione monoxime-sensitive factor, probably myosin, is responsible for the movement of actin filaments, and implying that myosin serves as a static cross-linker of actin filaments when its motor function is inhibited. The presence of actin filaments does not delay the collapse of cytoplasmic protrusions after tweezer release. Myosin-based reorganization of the existing actin cytoskeleton could be the basis for new cytoplasmic strand formation, and thus the production of an organized cytoarchitecture.

  19. Perovskite Materials: Solar Cell and Optoelectronic Applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Bin [ORNL; Geohegan, David B [ORNL; Xiao, Kai [ORNL


    Hybrid organometallic trihalide perovskites are promising candidates in the applications for next-generation, high-performance, low-cost optoelectronic devices, including photovoltaics, light emitting diodes, and photodetectors. Particularly, the solar cells based on this type of materials have reached 22% lab scale power conversion efficiency in only about seven years, comparable to the other thin film photovoltaic technologies. Hybrid perovskite materials not only exhibit superior optoelectronic properties, but also show many interesting physical properties such as ion migration and defect physics, which may allow the exploration of more device functionalities. In this article, the fundamental understanding of the interrelationships between crystal structure, electronic structure, and material properties is discussed. Various chemical synthesis and processing methods for superior device performance in solar cells and optoelectronic devices are reviewed.

  20. Tweezer dexterity aptitude of dental students. (United States)

    Lundergan, William P; Soderstrom, Elizabeth J; Chambers, David W


    The rationale for using the Perceptual Ability Test (PAT) as a component in admissions decisions for dental schools is that candidates vary in an underlying aptitude that is predictive of degree of success in technique course performance and perhaps in clinical performance. There have been periodic attempts to identify tests that more directly measure manual dexterity aptitude that would supplement the predictive power of admissions decisions. Previous research has demonstrated that a commercially available "speeded" tweezer dexterity test (Johnson O'Connor Test #32022) is not associated with performance in dental school or dental practice. Our research investigated both Test #32022 and Test #18 that measure both speed and accuracy as potential predictors of dental school performance in technical and clinical courses. This article reports the results of a longitudinal, comparative study of tweezer dexterity scores for students at the University of the Pacific School of Dentistry during their first and last quarters in school. The goals of the study were to 1) evaluate the correlation between beginning students' scores on two different types of tweezer dexterity tests; 2) compare dental students' scores to normative data for the general population; 3) determine the effect of a dental curriculum on students' performance on Test #18; and 4) evaluate the two tests as potential dental school admission screening instruments in comparison to the PAT. Fifty first-quarter students were tested from a class of 134. Forty-nine of these students were retested on Test #18 during their final quarter. The predictor value of the initial scores for the two dexterity tests was assessed for seven outcome measures reflecting student technique performance. Analysis showed a significant correlation (r=0.318, ptests. The difference between the norm mean (41.58) and the dental student mean for Test #18 (40.42) was not significant (p>0.05). The correlation between the first and final

  1. Trends in optoelectronic perimeter security sensors (United States)

    Szustakowski, Mieczyslaw; Ciurapinski, Wiesław M.; Zyczkowski, Marek


    New trends in development of optoelectronic and radar systems with mixed technologies for detection, identification and visualization for critical infrastructure protection are presented. Network-based communication as well as new algorithms of intelligent vision surveillance and image fusion is described.

  2. 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


    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.

  3. Polymer optoelectronic structures for retinal prosthesis. (United States)

    Gautam, Vini; Narayan, K S


    This commentary highlights the effectiveness of optoelectronic properties of polymer semiconductors based on recent results emerging from our laboratory, where these materials are explored as artificial receptors for interfacing with the visual systems. Organic semiconductors based polymer layers in contact with physiological media exhibit interesting photophysical features, which mimic certain natural photoreceptors, including those in the retina. The availability of such optoelectronic materials opens up a gateway to utilize these structures as neuronal interfaces for stimulating retinal ganglion cells. In a recently reported work entitled "A polymer optoelectronic interface provides visual cues to a blind retina," we utilized a specific configuration of a polymer semiconductor device structure to elicit neuronal activity in a blind retina upon photoexcitation. The elicited neuronal signals were found to have several features that followed the optoelectronic response of the polymer film. More importantly, the polymer-induced retinal response resembled the natural response of the retina to photoexcitation. These observations open up a promising material alternative for artificial retina applications.

  4. TweezPal - Optical tweezers analysis and calibration software (United States)

    Osterman, Natan


    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: Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, 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

  5. Microrheology of concentrated DNA solutions using optical tweezers

    Indian Academy of Sciences (India)

    Arun S Rajkumar; B M Jaffar Ali


    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.

  6. Fluorinated porphyrin tweezer: a powerful reporter of absolute configuration for erythro and threo diols, amino alcohols, and diamines. (United States)

    Li, Xiaoyong; Tanasova, Marina; Vasileiou, Chrysoula; Borhan, Babak


    A general and sensitive nonempirical protocol to determine the absolute configurations of erythro and threo diols, amino alcohols, and diamines is reported. Binding of diols to the porphyrin tweezer system is greatly enhanced by increasing the Lewis acidity of the metalloporphyrin. Supramolecular complexes formed between the porphyrin tweezer host and chiral substrates exhibited exciton-coupled bisignate CD spectra with predictable signs based on the substituents on the chiral center. The working model suggests that the observed helicity of the porphyrin tweezer is dictated via steric differentiation experienced by the porphyrin ring bound to each chiral center. A variety of erythro and threo substrates were investigated to verify this chiroptical method. Their absolute configurations were unequivocally determined, and thus a general mnemonic is provided for the assignment of chirality.

  7. Optoelectronics of Molecules and Polymers

    CERN Document Server

    Moliton, André


    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...

  8. Materials for optoelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Shiang, Joseph John; Smigelski, Jr., Paul Michael


    Energy efficient optoelectronic devices include an electroluminescent layer containing a polymer made up of structural units of formula I and II; ##STR00001## wherein R.sup.1 and R.sup.2 are independently C.sub.22-44 hydrocarbyl, C.sub.22-44 hydrocarbyl containing one or more S, N, O, P, or Si atoms, oxaalkylaryl, or a combination thereof; R.sup.3 and R.sup.4 are independently H, C.sub.1-44 hydrocarbyl or C.sub.1-44 hydrocarbyl containing one or more S, N, O, P, or Si atoms, or R.sup.3 and R.sup.4, taken together, form a C.sub.2-10 monocyclic or bicyclic ring containing up to three S, N, O, P, or Si heteroatoms; and X is S, Se, or a combination thereof.

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

    KAUST Repository

    Khan, Jafar Iqbal


    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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Raman sorting and identification of single living micro-organisms with optical tweezers (United States)

    Xie, Changan; Chen, De; Li, Yong-Qing


    We report on a novel technique for sorting and identification of single biological cells and food-borne bacteria based on laser tweezers and Raman spectroscopy (LTRS). With this technique, biological cells of different physiological states in a sample chamber were identified by their Raman spectral signatures and then they were selectively manipulated into a clean collection chamber with optical tweezers through a microchannel. As an example, we sorted the live and dead yeast cells into the collection chamber and validated this with a standard staining technique. We also demonstrated that bacteria existing in spoiled foods could be discriminated from a variety of food particles based on their characteristic Raman spectra and then isolated with laser manipulation. This label-free LTRS sorting technique may find broad applications in microbiology and rapid examination of food-borne diseases.

  11. Multiscale modeling of nanostructured ZnO based devices for optoelectronic applications: Dynamically-coupled structural fields, charge, and thermal transport processes (United States)

    Abdullah, Abdulmuin; Alqahtani, Saad; Nishat, Md Rezaul Karim; Ahmed, Shaikh; SIU Nanoelectronics Research Group Team

    Recently, hybrid ZnO nanostructures (such as ZnO deposited on ZnO-alloys, Si, GaN, polymer, conducting oxides, and organic compounds) have attracted much attention for their possible applications in optoelectronic devices (such as solar cells, light emitting and laser diodes), as well as in spintronics (such as spin-based memory, and logic). However, efficiency and performance of these hybrid ZnO devices strongly depend on an intricate interplay of complex, nonlinear, highly stochastic and dynamically-coupled structural fields, charge, and thermal transport processes at different length and time scales, which have not yet been fully assessed experimentally. In this work, we study the effects of these coupled processes on the electronic and optical emission properties in nanostructured ZnO devices. The multiscale computational framework employs the atomistic valence force-field molecular mechanics, models for linear and non-linear polarization, the 8-band sp3s* tight-binding models, and coupling to a TCAD toolkit to determine the terminal properties of the device. A series of numerical experiments are performed (by varying different nanoscale parameters such as size, geometry, crystal cut, composition, and electrostatics) that mainly aim to improve the efficiency of these devices. Supported by the U.S. National Science Foundation Grant No. 1102192.

  12. 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:; 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)


    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.

  13. MatLab program for precision calibration of optical tweezers (United States)

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


    Optical tweezers are used as force transducers in many types of experiments. The force they exert in a given experiment is known only after a calibration. Computer codes that calibrate optical tweezers with high precision and reliability in the ( x, y)-plane orthogonal to the laser beam axis were written in MatLab (MathWorks Inc.) and are presented here. 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. First, cross-talk between channels in 2D position measurements is tested for, and eliminated if detected. Then, the Lorentzian power spectrum that results from the Einstein-Ornstein-Uhlenbeck theory, is fitted to the low-frequency part of the experimental spectrum in order to obtain an initial guess for parameters to be fitted. Finally, a more complete theory is fitted, a theory that optionally accounts for the frequency dependence of the hydrodynamic drag force and hydrodynamic interaction with a nearby cover slip, for effects of finite sampling frequency (aliasing), for effects of anti-aliasing filters in the data acquisition electronics, and for unintended "virtual" filtering caused by the position detection system. Each of these effects can be left out or included as the user prefers, with user-defined parameters. Several tests are applied to the experimental data during calibration to ensure that the data comply with the theory used for their interpretation: Independence of x- and y-coordinates, Hooke's law, exponential distribution of power spectral values, uncorrelated Gaussian scatter of residual values. Results are given with statistical errors and covariance matrix. Program summaryTitle of program: tweezercalib Catalogue identifier: ADTV Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland. Program Summary URL: Computer for

  14. Design of Fresnel Lens-Type Multi-Trapping Acoustic Tweezers

    Directory of Open Access Journals (Sweden)

    You-Lin Tu


    Full Text Available In this paper, acoustic tweezers which use beam forming performed by a Fresnel zone plate are proposed. The performance has been demonstrated by finite element analysis, including the acoustic intensity, acoustic pressure, acoustic potential energy, gradient force, and particle distribution. The acoustic tweezers use an ultrasound beam produced by a lead zirconate titanate (PZT transducer operating at 2.4 MHz and 100 Vpeak-to-peak in a water medium. The design of the Fresnel lens (zone plate is based on air reflection, acoustic impedance matching, and the Fresnel half-wave band (FHWB theory. This acoustic Fresnel lens can produce gradient force and acoustic potential wells that allow the capture and manipulation of single particles or clusters of particles. Simulation results strongly indicate a good trapping ability, for particles under 150 µm in diameter, in the minimum energy location. This can be useful for cell or microorganism manipulation.

  15. Computational toolbox for optical tweezers in geometrical optics

    CERN Document Server

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


    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.

  16. Manipulation on human red blood cells with femtosecond optical tweezers

    Institute of Scientific and Technical Information of China (English)

    Ming Zhou; Haifeng Yang; Jianke Di; Enlan Zhao


    Different types of femtosecond optical tweezers have become a powerful tool in the modern biological field. However, how to control the irregular targets, including biological cells, using femtosecond optical tweezers remains to be explored. In this study, human red blood cells (hRBCs) are manipulated with femtosecond optical tweezers, and their states under different laser powers are investigated. The results indicate that optical potential traps only can capture the edge of hRBCs under the laser power from 1.4 to 2.8 mW, while it can make hRBCs turn over with the laser power more than 2.8 roW. It is suggested that femtosecond optical tweezers could not only manipulate biological cells, but also subtly control its states by adjusting the laser power.

  17. Grating-flanked plasmonic coaxial apertures for efficient fiber optical tweezers. (United States)

    Saleh, Amr A E; Sheikhoelislami, Sassan; Gastelum, Steven; Dionne, Jennifer A


    Subwavelength plasmonic apertures have been foundational for direct optical manipulation of nanoscale specimens including sub-100 nm polymeric beads, metallic nanoparticles and proteins. While most plasmonic traps result in two-dimensional localization, three-dimensional manipulation has been demonstrated by integrating a plasmonic aperture on an optical fiber tip. However, such 3D traps are usually inefficient since the optical mode of the fiber and the subwavelength aperture only weakly couple. In this paper we design more efficient optical-fiber-based plasmonic tweezers combining a coaxial plasmonic aperture with a plasmonic grating coupler at the fiber tip facet. Using full-field finite difference time domain analysis, we optimize the grating design for both gold and silver fiber-based coaxial tweezers such that the optical transmission through the apertures is maximized. With the optimized grating, we show that the maximum transmission efficiency increases from 2.5% to 19.6% and from 1.48% to 16.7% for the gold and silver structures respectively. To evaluate their performance as optical tweezers, we calculate the optical forces and the corresponding trapping potential on dielectric particles interacting with the apertures. We demonstrate that the enahncement in the transmission translates into an equivalent increase in the optical forces. Consequently, the optical power required to achieve stable optical trapping is significantly reduced allowing for efficient localization and 3D manipulation of sub-30 nm dielectric particles.

  18. Miniaturized Optical Tweezers Through Fiber-End Microfabrication

    KAUST Repository

    Liberale, Carlo


    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.

  19. Independent trapping and manipulation of microparticles using dexterous acoustic tweezers


    Courtney, Charles R. P.; Demore, Christine E. M.; Wu, Hongxiao; Grinenko, Alon; Wilcox, Paul D.; Cochran, Sandy; Drinkwater, Bruce W.


    An electronically controlled acoustic tweezer was used to demonstrate two acoustic manipulation phenomena: superposition of Bessel functions to allow independent manipulation of multiple particles and the use of higher-order Bessel functions to trap particles in larger regions than is possible with first-order traps. The acoustic tweezers consist of a circular 64-element ultrasonic array operating at 2.35 MHz which generates ultrasonic pressure fields in a millimeter-scale fluid-filled chambe...

  20. Optical manipulation of lipid and polymer nanotubes with optical tweezers (United States)

    Reiner, Joseph E.; Kishore, Rani; Pfefferkorn, Candace; Wells, Jeffrey; Helmerson, Kristian; Howell, Peter; Vreeland, Wyatt; Forry, Samuel; Locascio, Laurie; Reyes-Hernandez, Darwin; Gaitan, Michael


    Using optical tweezers and microfluidics, we stretch either the lipid or polymer membranes of liposomes or polymersomes, respectively, into long nanotubes. The membranes can be grabbed directly with the optical tweezers to produce sub-micron diameter tubes that are several hundred microns in length. We can stretch tubes up to a centimeter in length, limited only by the travel of our microscope stage. We also demonstrate the cross linking of a pulled polymer nanotube.

  1. Single Bessel tractor-beam tweezers

    CERN Document Server

    Mitri, F G


    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.

  2. Power spectrum analysis for optical tweezers

    DEFF Research Database (Denmark)

    Berg-Sørensen, K.; Flyvbjerg, H.


    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...... error bars and correlations, for the best such chi(2) fit in a given frequency range. We use these functions to determine the information content of various parts of the power spectrum, and find, at odds with lore, much information at relatively high frequencies. Applying the method to real data, we...... the 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...

  3. Eukaryotic membrane tethers revisited using magnetic tweezers (United States)

    Hosu, Basarab G.; Sun, Mingzhai; Marga, Françoise; Grandbois, Michel; Forgacs, Gabor


    Membrane nanotubes, under physiological conditions, typically form en masse. We employed magnetic tweezers (MTW) to extract tethers from human brain tumor cells and compared their biophysical properties with tethers extracted after disruption of the cytoskeleton and from a strongly differing cell type, Chinese hamster ovary cells. In this method, the constant force produced with the MTW is transduced to cells through super-paramagnetic beads attached to the cell membrane. Multiple sudden jumps in bead velocity were manifest in the recorded bead displacement-time profiles. These discrete events were interpreted as successive ruptures of individual tethers. Observation with scanning electron microscopy supported the simultaneous existence of multiple tethers. The physical characteristics, in particular, the number and viscoelastic properties of the extracted tethers were determined from the analytic fit to bead trajectories, provided by a standard model of viscoelasticity. Comparison of tethers formed with MTW and atomic force microscopy (AFM), a technique where the cantilever-force transducer is moved at constant velocity, revealed significant differences in the two methods of tether formation. Our findings imply that extreme care must be used to interpret the outcome of tether pulling experiments performed with single molecular techniques (MTW, AFM, optical tweezers, etc). First, the different methods may be testing distinct membrane structures with distinct properties. Second, as soon as a true cell membrane (as opposed to that of a vesicle) can attach to a substrate, upon pulling on it, multiple nonspecific membrane tethers may be generated. Therefore, under physiological conditions, distinguishing between tethers formed through specific and nonspecific interactions is highly nontrivial if at all possible.

  4. Stable optical trapping and sensitive characterization of nanostructures using standing-wave Raman tweezers (United States)

    Wu, Mu-Ying; Ling, Dong-Xiong; Ling, Lin; Li, William; Li, Yong-Qing


    Optical manipulation and label-free characterization of nanoscale structures open up new possibilities for assembly and control of nanodevices and biomolecules. Optical tweezers integrated with Raman spectroscopy allows analyzing a single trapped particle, but is generally less effective for individual nanoparticles. The main challenge is the weak gradient force on nanoparticles that is insufficient to overcome the destabilizing effect of scattering force and Brownian motion. Here, we present standing-wave Raman tweezers for stable trapping and sensitive characterization of single isolated nanostructures with a low laser power by combining a standing-wave optical trap with confocal Raman spectroscopy. This scheme has stronger intensity gradients and balanced scattering forces, and thus can be used to analyze many nanoparticles that cannot be measured with single-beam Raman tweezers, including individual single-walled carbon nanotubes (SWCNT), graphene flakes, biological particles, SERS-active metal nanoparticles, and high-refractive semiconductor nanoparticles. This would enable sorting and characterization of specific SWCNTs and other nanoparticles based on their increased Raman fingerprints.

  5. Stable optical trapping and sensitive characterization of nanostructures using standing-wave Raman tweezers (United States)

    Wu, Mu-ying; Ling, Dong-xiong; Ling, Lin; Li, William; Li, Yong-qing


    Optical manipulation and label-free characterization of nanoscale structures open up new possibilities for assembly and control of nanodevices and biomolecules. Optical tweezers integrated with Raman spectroscopy allows analyzing a single trapped particle, but is generally less effective for individual nanoparticles. The main challenge is the weak gradient force on nanoparticles that is insufficient to overcome the destabilizing effect of scattering force and Brownian motion. Here, we present standing-wave Raman tweezers for stable trapping and sensitive characterization of single isolated nanostructures with a low laser power by combining a standing-wave optical trap with confocal Raman spectroscopy. This scheme has stronger intensity gradients and balanced scattering forces, and thus can be used to analyze many nanoparticles that cannot be measured with single-beam Raman tweezers, including individual single-walled carbon nanotubes (SWCNT), graphene flakes, biological particles, SERS-active metal nanoparticles, and high-refractive semiconductor nanoparticles. This would enable sorting and characterization of specific SWCNTs and other nanoparticles based on their increased Raman fingerprints. PMID:28211526

  6. Terahertz optoelectronics with surface plasmon polariton diode. (United States)

    Vinnakota, Raj K; Genov, Dentcho A


    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.

  7. Optoelectronic and Photovoltaic Performances of Pyridine Based Monomer and Polymer Capped ZnO Dye-Sensitized Solar Cells. (United States)

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


    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.

  8. Electro-physical characteristics of MIS structures with HgTe- based single quantum wells for optoelectronics devices (United States)

    Dzyadukh, S.; Nesmelov, S.; Voitsekhovskii, A.; Gorn, D.


    The paper presents brief research results of the admittance of metal-insulator- semiconductor (MIS) structures based on Hg1-xCdxTe grown by molecular-beam epitaxy (MBE) method including single HgCdTe/HgTe/HgCdTe quantum wells (QW) in the surface layer. The thickness of a quantum well was 5.6 nm, and the composition of barrier layers with the thickness of 35 nm was close to 0.65. Measurements were conducted in the range of temperatures from 8 to 200 K. It is shown that for structure with quantum well based on HgTe capacitance and conductance oscillations in the strong inversion are observed. Also it is assumed these oscillations are related with the recharging of quantum levels in HgTe.

  9. A Nanomembrane-Based Bandgap-Tunable Germanium Microdisk Using Lithographically-Customizable Biaxial Strain for Silicon-Compatible Optoelectronics

    CERN Document Server

    Sukhdeo, David S; Kang, Ju-Hyung; Brongersma, Mark L; Saraswat, Krishna C


    Strain engineering has proven to be vital for germanium-based photonics, in particular light emission. However, applying a large permanent biaxial strain to germanium has been a challenge. We present a simple, CMOS-compatible technique to conveniently induce a large, spatially homogenous strain in microdisks patterned within ultrathin germanium nanomembranes. Our technique works by concentrating and amplifying a pre-existing small strain into the microdisk region. Biaxial strains as large as 1.11% are observed by Raman spectroscopy and are further confirmed by photoluminescence measurements, which show enhanced and redshifted light emission from the strained microdisks. Our technique allows the amount of biaxial strain to be customized lithographically, allowing the bandgaps of different microdisks to be independently tuned in a single mask process. Our theoretical calculations show that this platform can deliver substantial performance improvements, including a >200x reduction in the lasing threshold, to bia...

  10. Study of photoresponsivity in optoelectronic devices based on single crystal β-Ga2O3 epitaxial layers (United States)

    Horng, Ray-Hua; Ravadgar, Parvaneh


    Single crystal β-Ga2O3 epitaxial layers have been prepared on c-axis (0001) sapphire substrates using metalorganic chemical vapor deposition technique at relatively low temperature. Post-annealing of β-Ga2O3 single crystals up to 800 °C does not affect the crystallinity, explored by x-ray diffraction, showing that β-Ga2O3 epitaxial layers are highly (-201) oriented. Metal-semiconductor-metal devices are fabricated on single crystals to study their photoresponsivity. A significant improvement in performance of post annealed-based devices is observed, attributed to point defect reduction. Annealing of as-grown samples results to a significant decrease in both oxygen and gallium vacancies, which are sources of current leakage.

  11. Opto-electronic properties of a TiO2/PS/mc-Si heterojunction based solar cell (United States)

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


    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.

  12. Constructing Dual Beam Optical Tweezers for Undergraduate Biophysics Research (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.

  13. Traceable assembly of microparts using optical tweezers (United States)

    Kim, Jung-Dae; Hwang, Sun-Uk; Lee, Yong-Gu


    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.

  14. Optical Tweezers Analysis of Double-Stranded DNA Denaturation in the Presence of Urea (United States)

    Zhu, Chunli; Li, Jing


    Urea is a kind of denaturant prone to form hydrogen bonds with the electronegative centers of the nitrogenous bases, threatening the stability of hydrogen bonds between DNA base pairs. In this paper, the stability and stiffness of DNA double helix influenced by urea are investigated at single-molecule level using optical tweezers. Experimental results show that DNA's double helix stability and stiffness both decrease with increasing urea concentration. In addition, the re-forming of ruptured hydrogen bonds between the base pairs is blocked by urea as the tension on DNA is released.

  15. Organic ferroelectric opto-electronic memories

    Directory of Open Access Journals (Sweden)

    Kamal Asadi


    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.

  16. 3D coordinate measurement system based on optoelectronic scanning%基于光电扫描的三维坐标测量系统

    Institute of Scientific and Technical Information of China (English)

    端木琼; 杨学友; 邾继贵; 杨凌辉; 叶声华


    WMPS is a novel coordinate measuring system based on optoelectronic scanning. When it works, laser-stations are distributed around the workspace, and the scanning signals cover the entire area. Location sensors use these signals to obtain the bearing angles to multiple stations, and calculate the spatial cooradinate. Compared with other measuring systems, it is suitable for on-field large-scale measurements because of its robust parallel measurement capability, strong anti-interference and good ease-to-use. According to the requirements of digital assembly, the components and structure of this system were introduced, the measuring principal was derived by geometry relationship and the metrology model was also given. At last, a complete prototype platform was built. The measuring results show that the repeatability accuracy of angle measurement is higher than 5 arc-seconds and the coordinate deviation is less than 0.5 mm in 5mx5mx3m area.%wMPS测量系统是一种新型的基于光电扫描的坐标测量系统,当系统工作时,激光测站分布在测量空间四周,扫描信号覆盖整个工作空间,位置传感器通过扫描信号测量与多个测站之间的方位角计算三维坐标.与其他测量系统相比,具有能够同时跟踪测量多个目标、抗干扰能力强、自动化程度高、简单易用等特点,适用于现场条件下的大尺寸测量.针对数字化装配的需求,介绍了系统的组成及结构,通过几何关系推导出系统的测量原理,给出了测量的几何模型,搭建了完整的验证平台.测量结果表明:系统的角度测量重复性精度优于5”,坐标测量精度优于0.5mm.

  17. Simple Optoelectronic Feedback in Microwave Oscillators (United States)

    Maleki, Lute; Iltchenko, Vladimir


    A proposed method of stabilizing microwave and millimeter-wave oscillators calls for the use of feedback in optoelectronic delay lines characterized by high values of the resonance quality factor (Q). The method would extend the applicability of optoelectronic feedback beyond the previously reported class of optoelectronic oscillators that comprise two-port electronic amplifiers in closed loops with high-Q feedback circuits.

  18. Magnetic tweezers for manipulation of magnetic particles in single cells (United States)

    Ebrahimian, H.; Giesguth, M.; Dietz, K.-J.; Reiss, G.; Herth, S.


    Magnetic tweezers gain increasing interest for applications in biology. Here, a setup of magnetic tweezers is introduced using micropatterned conducting lines on transparent glass slides. Magnetic particles of 1 μm diameter were injected in barley cell vacuoles using a microinject system under microscopic control. Time dependent tracking of the particles after application of a magnetic field was used to determine the viscosity of vacuolar sap in vivo relative to water and isolated vacuolar fluid. The viscosity of vacuolar sap in cells was about 2-fold higher than that of extracted vacuolar fluid and 5 times higher than that of water.

  19. Optoelectronic implementation of multilayer perceptron and Hopfield neural networks (United States)

    Domanski, Andrzej W.; Olszewski, Mikolaj K.; Wolinski, Tomasz R.


    In this paper we present an optoelectronic implementation of two networks based on multilayer perceptron and the Hopfield neural network. We propose two different methods to solve a problem of lack of negative optical signals that are necessary for connections between layers of perceptron as well as within the Hopfield network structure. The first method applied for construction of multilayer perceptron was based on division of signals into two channels and next to use both of them independently as positive and negative signals. The second one, applied for implementation of the Hopfield model, was based on adding of constant value for elements of matrix weight. Both methods of compensation of lack negative optical signals were tested experimentally as optoelectronic models of multilayer perceptron and Hopfield neural network. Special configurations of optical fiber cables and liquid crystal multicell plates were used. In conclusion, possible applications of the optoelectronic neural networks are briefly discussed.

  20. System of Optoelectronic Sensors for Breath Analysis

    Directory of Open Access Journals (Sweden)

    Mikołajczyk Janusz


    Full Text Available The paper describes an integrated laser absorption system as a potential tool for breath analysis for clinical diagnostics, online therapy monitoring and metabolic disorder control. The sensors operate basing on cavity enhanced spectroscopy and multi-pass spectroscopy supported by wavelength modulation spectroscopy. The aspects concerning selection of operational spectral range and minimization of interference are also discussed. Tests results of the constructed devices collected with reference samples of biomarkers are also presented. The obtained data provide an opportunity to analyse applicability of optoelectronic sensors in medical screening.

  1. Research on optical multistage butterfly interconnection and optoelectronic logic operations (United States)

    Sun, De-Gui; Wang, Na-Xin; He, Li-Ming; Xu, Mai; Liang, Guo-Dong; Zheng, Jie

    We briefly study butterfly interconnection construction and propose an experimental approach to implementing multistage butterfly interconnection networks by using a special interconnection grating with the reflection ladder structure and liquid crystal light valves (LCLVs), and implementing the optical butterfly interconnections and primary optical digital logic operations. With this foundation, we analyse and discuss the features of the approach by computer simulations. In terms of our theoretical analyses, we improve the ring-circuit approach, based on the reflection ladder structure gratings, into a more suitable form based on transmission gratings, and we substitute the LCLVs with optoelectronic switches. Finally we give the experimental results of both the transmission grating and optoelectronic switches.

  2. Effect of Surface Layer on Electromechanical Stability of Tweezers and Cantilevers Fabricated from Conductive Cylindrical Nanowires (United States)

    Keivani, Maryam; Koochi, Ali; Sedighi, Hamid M.; Abadyan, Mohamadreza; Farrokhabadi, Amin; Shahedin, Abed Moheb


    Herein, the impact of surface layer on the stability of nanoscale tweezers and cantilevers fabricated from nanowires with cylindrical cross section is studied. A modified continuum based on the Gurtin-Murdoch surface elasticity is applied for incorporating the presence of surface layer. Considering the cylindrical geometry of the nanowire, the presence of the Coulomb attraction and dispersion forces are incorporated in the derived formulations. Three different approaches, i.e. numerical differential quadrature method (DQM), an approximated homotopy perturbation method (HPM) and developing lumped parameter model (LPM) have been employed to solve the governing equations. The impact of surface layer on the instability of the system is demonstrated.

  3. Numerical and Experimental Study of Optoelectronic Trapping on Iron-Doped Lithium Niobate Substrate

    Directory of Open Access Journals (Sweden)

    Michela Gazzetto


    Full Text Available Optoelectronic tweezers (OET are a promising technique for the realization of reconfigurable systems suitable to trap and manipulate microparticles. In particular, dielectrophoretic (DEP forces produced by OET represent a valid alternative to micro-fabricated metal electrodes, as strong and spatially reconfigurable electrical fields can be induced in a photoconductive layer by means of light-driven phenomena. In this paper we report, and compare with the experimental data, the results obtained by analyzing the spatial configurations of the DEP-forces produced by a 532 nm laser beam, with Gaussian intensity distribution, impinging on a Fe-doped Lithium Niobate substrate. Furthermore, we also present a promising preliminary result for water-droplets trapping, which could open the way to the application of this technique to biological samples manipulation.

  4. Crystalline Molybdenum Oxide Thin-Films for Application as Interfacial Layers in Optoelectronic Devices

    DEFF Research Database (Denmark)

    Fernandes Cauduro, André Luis; dos Reis, Roberto; Chen, Gong


    The ability to control the interfacial properties in metal-oxide thin films through surface defect engineering is vital to fine-tune their optoelectronic properties and thus their integration in novel optoelectronic devices. This is exemplified in photovoltaic devices based on organic, inorganic...

  5. Mid-infrared Semiconductor Optoelectronics

    CERN Document Server

    Krier, Anthony


    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...

  6. Nanofabrication of Hybrid Optoelectronic Devices (United States)

    Dibos, Alan Michael

    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 applications. First, we show that combining a single strip of conjugated polymer and inorganic nanowire can yield a nanoscale solar cell, and modeling of optical absorption and exciton diffusion in this device can provide insight into the efficiency of charge separation. Second, we use an on-chip nanowire light emitting diode to pump a colloidal quantum dot coupled to a silver waveguide. The resulting device is an electro-optic single plasmon source. Finally, we transfer diamond waveguides onto near-field avalanche photodiodes fabricated from GaAs. Embedded in the diamond waveguides are nitrogen vacancy color centers, and the mapping of emission from these single-photon sources is demonstrated using our on-chip detectors, eliminating the need for external photodetectors on an optical table. These studies show the promise of hybrid optoelectronic devices at the nanoscale with applications in alternative energy, optical communication, and quantum optics.

  7. Scanning probe and optical tweezer investigations of biomolecular interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rigby-Singleton, Shellie


    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

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

    CERN Document Server

    Protopopov, Vladimir


    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...

  9. Optoelectronics Research Center (United States)


    PLTZ and PLT using Chlorine Baseed Gases , in the Symposium on Ferroelectric Thin Films," Spring Meeting, Materials Research Society, San Francisco, CA...tanintdpsinlnndsea15 tinutins of (a) at low current levels showing the reduction of switching voltage optical pulse ( inse ) showing optical threshold

  10. The Measurement of Displacement and Optical Force in Multi-Optical Tweezers

    Institute of Scientific and Technical Information of China (English)

    LING Lin; GUO Hong-Lian; HUANG Lu; QU E; LI Zhao-Lin; LI Zhi-Yuan


    We set up a system of multiple optical tweezers based on a spatial light modulator, and measured the displacement and optical force of the trapped particles simultaneously. All of the trapped particles can be clearly imaged in three dimensions by several CCDs. The displacement is obtained by calculating the gray weighted centroid in the trapped particle's image. The stiffness of the trapped particles in the optical traps is measured by oscillating the sample stage in a triangular wave based on Stokes fluid dynamics. The optical force of each trapped particle can be calculated by the measured displacement and stiffness.%We set up a system of multiple optical tweezers based on a spatial light modulator,and measured the displacement and optical force of the trapped particles simultaneously.All of the trapped particles can be clearly imaged in three dimensions by several CCDs.The displacement is obtained by calculating the gray weighted centroid in the trapped particle's image.The stiffness of the trapped particles in the optical traps is measured by oscillating the sample stage in a triangular wave based on Stokes fluid dynamics.The optical force of each trapped particle can be calculated by the measured displacement and stiffness.

  11. Magnetic and optoelectronic properties of gold nanocluster-thiophene assembly. (United States)

    Qin, Wei; Lohrman, Jessica; Ren, Shenqiang


    Nanohybrids consisting of Au nanocluster and polythiophene nanowire assemblies exhibit unique thermal-responsive optical behaviors and charge-transfer controlled magnetic and optoelectronic properties. The ultrasmall Au nanocluster enhanced photoabsorption and conductivity effectively improves the photocurrent of nanohybrid based photovoltaics, leading to an increase of power conversion efficiency by 14 % under AM 1.5 illumination. In addition, nanohybrids exhibit electric field controlled spin resonance and magnetic field sensing behaviors, which open up the potential of charge-transfer complex system where the magnetism and optoelectronics interact.

  12. A class of fascinating optoelectronic materials: Triarylboron compounds

    Institute of Scientific and Technical Information of China (English)


    Triarylboron compounds are significant optoelectronic materials due to their excellent emissive and electron-transport properties,and could be applied in organic light-emitting diodes as emissive and/or electron-transport layers.Triarylboron compounds have vacant pπ orbital and have received increasing interest as fluoride ion and cyanide ion sensors utilizing specific Lewis acid-base interaction.This review summarizes their structural characteristics,optical properties and applications in chemosensors for anions and optoelectronic devices developed in recent years and discusses the problems and prospects.

  13. 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


    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.

  14. 2D semiconductor optoelectronics (United States)

    Novoselov, Kostya

    The advent of graphene and related 2D materials has recently led to a new technology: heterostructures based on these atomically thin crystals. The paradigm proved itself extremely versatile and led to rapid demonstration of tunnelling diodes with negative differential resistance, tunnelling transistors, photovoltaic devices, etc. By taking the complexity and functionality of such van der Waals heterostructures to the next level we introduce quantum wells engineered with one atomic plane precision. Light emission from such quantum wells, quantum dots and polaritonic effects will be discussed.

  15. Reconfigurable Optical Interconnections Using Dynamic Optoelectronic Holograms (United States)

    Schulze, Elmar


    Increasing complexity and processing speed of electronic circuits and a high device density have led to serious problems in electrical interconnections. Their limitations arise from their signal transmission capacity. power consumption. crosstalk. and reliability. Optical links may solve such problems by offering high data rates of several gigabits per second. large fanouts of up to 100 loads. good reliability and less power expenditure. Optical fibers, integrated optical waveguides or free-space transmission links may be applicable. For the free-space links, lenses. mirrors and holograms can be used to guide the light waves. In this paper, reconfigurable optical interconnection schemes are proposed and described which are based on optoelectronic holograms. Their interference patterns can be changed dynamically. To establish connections as free-space links, the light beams emitted from even hundreds of light sources are imaged onto an array of small dynamic holograms. Their interference patterns are optically and electronically controllable. These holograms diffract and focus each of the incident light beams individually onto the receiving photo-diodes. By changing the hologram interference patterns dynamically. an optical switch is obtained. It renders the establishment of reconfigurable optical interconnections. As optoelectronic holograms very-high-resolution spatial light modulators are proposed.

  16. New Results with the Opto-Electronic Oscillators (OEO) (United States)

    Yao, S.; Maleki, L.


    A new class of oscillators based on photonic devices is presented. These opto-electronic oscillators (OEOs) generate microwave oscillation by converting continuous energy from a light source using a feedback circuit which includes a delay element, an electro-optic switch, and a photodetctor.

  17. Stabilizing an optoelectronic microwave oscillator with photonic filters (United States)

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


    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.

  18. Lasers and optoelectronics fundamentals, devices and applications

    CERN Document Server

    Maini, Anil K


    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

  19. Anion-π aromatic neutral tweezers complexes: are they stable in polar solvents? (United States)

    Sánchez-Lozano, Marta; Otero, Nicolás; Hermida-Ramón, Jose M; Estévez, Carlos M; Mandado, Marcos


    The impact of the solvent environment on the stabilization of the complexes formed by fluorine (T-F) and cyanide (T-CN) substituted tweezers with halide anions has been investigated theoretically. The study was carried out using computational methodologies based on density functional theory (DFT) and symmetry adapted perturbation theory (SAPT). Interaction energies were obtained at the M05-2X/6-31+G* level. The obtained results show a large stability of the complexes in solvents with large dielectric constant and prove the suitability of these molecular tweezers as potential hosts for anion recognition in solution. A detailed analysis of the effects of the solvent on the electron withdrawing ability of the substituents and its influence on the complex stability has been performed. In particular, the interaction energy in solution was split up into intermonomer and solvent-complex terms. In turn, the intermonomer interaction energy was partitioned into electrostatic, exchange, and polarization terms. Polar resonance structures in T-CN complexes are favored by polar solvents, giving rise to a stabilization of the intermonomer interaction, the opposite is found for T-F complexes. The solvent-complex energy increases with the polarity of the solvent in T-CN complexes, nonetheless the energy reaches a maximum and then decreases slowly in T-F complexes. An electron density analysis was also performed before and after complexation, providing an explanation to the trends followed by the interaction energies and their different components in solution.

  20. A modular system architecture for agile assembly of nanocomponents using optical tweezers (United States)

    Balijepalli, Arvind; LeBrun, Thomas; Gagnon, Cedric; Lee, Yong-Gu; Dagalakis, Nicholas


    In order to realize the flexibility optical trapping offers as a nanoassembly tool, we need to develop natural and intuitive interfaces to assemble large quantities of nanocomponents quickly and cheaply. We propose a system to create such an interface that is scalable, inter-changeable and modular. Several prototypes are described, starting with simple interfaces that control a single trap in the optical tweezers instrument using a 3-dimensional Phantom haptic device. A networkbased approach is adopted early on, and a modular prototype is then described in detail. In such a design, individual modules developed on different platforms work independently and communicate with each other through a common language interface using the Neutral Messaging Language (NML) communication protocol. A natural user interface is implemented that can be used to create and manipulate traps interactively like in a CAD program. Modules such as image processing and automatic assembly are also added to help simplify routine assembly tasks. Drawing on lessons learned from the prototypes, a new system specification is formulated to better integrate the modules. Finally, conclusions are drawn on the overall viability and future of network-based systems for nanoassembly using optical tweezers.

  1. Determination of motility forces on isolated chromosomes with laser tweezers. (United States)

    Khatibzadeh, Nima; Stilgoe, Alexander B; Bui, Ann A M; Rocha, Yesenia; Cruz, Gladys M; Loke, Vince; Shi, Linda Z; Nieminen, Timo A; Rubinsztein-Dunlop, Halina; Berns, Michael W


    Quantitative determination of the motility forces of chromosomes during cell division is fundamental to understanding a process that is universal among eukaryotic organisms. Using an optical tweezers system, isolated mammalian chromosomes were held in a 1064 nm laser trap. The minimum force required to move a single chromosome was determined to be ≈ 0.8-5 pN. The maximum transverse trapping efficiency of the isolated chromosomes was calculated as ≈ 0.01-0.02. These results confirm theoretical force calculations of ≈ 0.1-12 pN to move a chromosome on the mitotic or meiotic spindle. The verification of these results was carried out by calibration of the optical tweezers when trapping microspheres with a diameter of 4.5-15 µm in media with 1-7 cP viscosity. The results of the chromosome and microsphere trapping experiments agree with optical models developed to simulate trapping of cylindrical and spherical specimens.

  2. Construction of an optical tweezer for nanometer scale rheology

    Indian Academy of Sciences (India)

    A Raghu; Sharath Ananthamurthy


    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.

  3. A guide to magnetic tweezers and their applications (United States)

    Sarkar, Rupa; Rybenkov, Valentin


    Magnetic force spectroscopy is a rapidly developing single molecule technique that found numerous applications at the interface of physics and biology. Since the invention of the first magnetic tweezers, a number of modifications were incorporated into the approach that helped relieve the limitations of the original design and amplified its strengths. Inventive molecular biology solutions further advanced the technique by expanding its possible applications. In its present form, the method can be applied to single molecules and live cells without resorting to intense sample irradiation, can be easily multiplexed, accommodates multiple DNAs, displays impressive resolution, and allows a remarkable ease in stretching and twisting macromolecules. In this review, we describe the architecture of magnetic tweezers, key requirements to the experimental design and analysis of data, and outline several applications of the method that illustrate its versatility.

  4. Microwave Assisted Synthesis of Carbamate-type Molecular Tweezers Based on Hyodeoxycholic Acid and Their Recognition on Halogen Anions%氨基甲酸酯型猪去氧胆酸分子钳的微波合成及其对卤素阴离子的识别

    Institute of Scientific and Technical Information of China (English)

    曾碧涛; 周黎军; 李相彪; 赵先明; 赵志刚


    Five novel carbamate-type molecular tweezers (4a ~ 4e) based on hyodeoxycholic acid were synthesized using hyodeoxycholic acid as spacer to bridge different aromatic amines under microwave irradiation. The structures were characterized by ' H NMR, IR, MS and elemental analysis. The recognition properties of 4 on halogen anions were investigated by UV-Vis titration method. The results showed that 4 not only formed 1 :1 complex with halogen anions, but also exhibited good selectivity for halogen anions with selective sequence of I- > Br- > Cl-.%在微波辐射条件下,以猪去氧胆酸为隔离基,芳香胺为手臂,通过三光气桥连,合成了五个新型猪去氧胆酸分子钳(4a~4e),其结构经1H NMR,IR,MS和元素分析表征.紫外光谱滴定法的研究结果表明,4对卤素阴离子均具有良好的识别能力,选择顺序依次为I-> Br-> Cl-;主客体之间形成1∶1型超分子配合物,识别作用的主要推动力为氢键.

  5. Dynamic array generation and pattern formation for optical tweezers

    DEFF Research Database (Denmark)

    Mogensen, P.C.; Glückstad, J.


    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....

  6. Electromagnetic tweezers with independent force and torque control (United States)

    Jiang, Chang; Lionberger, Troy A.; Wiener, Diane M.; Meyhofer, Edgar


    Magnetic tweezers are powerful tools to manipulate and study the mechanical properties of biological molecules and living cells. In this paper we present a novel, bona fide electromagnetic tweezer (EMT) setup that allows independent control of the force and torque applied via micrometer-sized magnetic beads to a molecule under study. We implemented this EMT by combining a single solenoid that generates force (f-EMT) with a set of four solenoids arranged into a symmetric quadrupole to generate torque (τ-EMT). To demonstrate the capability of the tweezers, we attached optically asymmetric Janus beads to single, tethered DNA molecules. We show that tension in the piconewton force range can be applied to single DNA molecules and the molecule can simultaneously be twisted with torques in the piconewton-nanometer range. Furthermore, the EMT allows the two components to be independently controlled. At various force levels applied to the Janus bead, the trap torsional stiffness can be continuously changed simply by varying the current magnitude applied to the τ-EMT. The flexible and independent control of force and torque by the EMT makes it an ideal tool for a range of measurements where tensional and torsional properties need to be studied simultaneously on a molecular or cellular level.

  7. Theory of optical-tweezers forces near a plane interface (United States)

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


    Optical-tweezers experiments in molecular and cell biology often take place near the surface of the microscope slide that defines the bottom of the sample chamber. There, as elsewhere, force measurements require force-calibrated tweezers. In bulk, one can calculate the tweezers force from first principles, as recently demonstrated. Near the surface of the microscope slide, this absolute calibration method fails because it does not account for reverberations from the slide of the laser beam scattered by the trapped microsphere. Nor does it account for evanescent waves arising from total internal reflection of wide-angle components of the strongly focused beam. In the present work we account for both of these phenomena. We employ Weyl's angular spectrum representation of spherical waves in terms of real and complex rays and derive a fast-converging recursive series of multiple reflections that describes the reverberations, including also evanescent waves. Numerical simulations for typical setup parameters evaluate these effects on the optical force and trap stiffness, with emphasis on axial trapping. Results are in good agreement with available experimental data. Thus, absolute calibration now applies to all situations encountered in practice.

  8. Optoelectronic properties of natural cyanin dyes. (United States)

    Calzolari, A; Varsano, D; Ruini, A; Catellani, A; Tel-Vered, R; Yildiz, H B; Ovits, O; Willner, I


    An integrated theoretical/experimental study of the natural cyanin dye is presented in terms of its structural and optoelectronic properties for different gas-phase and prototypical device configurations. Our microscopic analysis reveals the impact of hydration and hydroxylation reactions, as well as of the attached sugar, on ground and optically excited states, and it illustrates the visible-light harvesting capability of the dye. Our optical experiments at different and controlled pH concentrations allow for a direct comparison with theoretical results. We analyze the many different contributions to photocurrent of the various portions of a prototypical device and, as a proof of principle, we propose the addition of specific ligands to control the increase of the photocurrent yield in the cyanin-based electrochemical device.

  9. Seeing smells: development of an optoelectronic nose

    Directory of Open Access Journals (Sweden)

    Kenneth S. Suslick


    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.

  10. 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


    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.

  11. Organic optoelectronics:materials,devices and applications

    Institute of Scientific and Technical Information of China (English)

    LIU Yi; CUI Tian-hong


    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.

  12. 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


    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.

  13. Design and Synthesis of Novel Molecular Tweezers Derived from Chenodeoxycholic Acid

    Institute of Scientific and Technical Information of China (English)

    Zhi Gang ZHAO; Qi Ming MU; Shu Hua CHEN


    A novel type of chiral molecular tweezers has been designed and synthesized by using chenodeoxy cholic acid as spacer and the aromatic compounds as arm. Their structures were characterized by 1HNMR, IR, MS spectra and elemental analysis. These chiral molecular tweezers showed good enantioselectivity for D-amino acid methyl esters.

  14. Linear microrheology with optical tweezers of living cells 'is not an option'! (United States)

    Tassieri, Manlio


    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.

  15. Rapid feedback control and stabilization of an optical tweezers with a budget microcontroller (United States)

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


    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.

  16. Design of a wavelength-tunable optical tweezer using a graded-index multimode optical fiber

    CERN Document Server

    Mobini, Esmaeil


    A wavelength-tunable Optical Fiber Tweezer (OFT) based on a Graded Index Multimode Fiber (GIMF) with a flat endface is proposed. It is shown that the design can support a trapping position which is far from the tip of the GIMF compared with other common optical tweezing methods, hence reducing the possibility of a contact between the trapped particle and the fiber tip. Moreover, because of the wavelength dependence of the GIMF design parameters such the Numerical Aperture (NA), the trapping position can become wavelength-dependent. Therefore, the trapping position can be tuned over a long range using a common wave-length tunable laser. The proposed OFT differs from previous fiber-based demonstrations by using a flat-endface fiber making the fabrication and experiment quite easier than previously proposed tapered-endface OFTs.

  17. Energy Landscape of Alginate-Epimerase Interactions Assessed by Optical Tweezers and Atomic Force Microscopy.

    Directory of Open Access Journals (Sweden)

    Armend Gazmeno Håti

    Full Text Available Mannuronan C-5 epimerases are a family of enzymes that catalyze epimerization of alginates at the polymer level. This group of enzymes thus enables the tailor-making of various alginate residue sequences to attain various functional properties, e.g. viscosity, gelation and ion binding. Here, the interactions between epimerases AlgE4 and AlgE6 and alginate substrates as well as epimerization products were determined. The interactions of the various epimerase-polysaccharide pairs were determined over an extended range of force loading rates by the combined use of optical tweezers and atomic force microscopy. When studying systems that in nature are not subjected to external forces the access to observations obtained at low loading rates, as provided by optical tweezers, is a great advantage since the low loading rate region for these systems reflect the properties of the rate limiting energy barrier. The AlgE epimerases have a modular structure comprising both A and R modules, and the role of each of these modules in the epimerization process were examined through studies of the A- module of AlgE6, AlgE6A. Dynamic strength spectra obtained through combination of atomic force microscopy and the optical tweezers revealed the existence of two energy barriers in the alginate-epimerase complexes, of which one was not revealed in previous AFM based studies of these complexes. Furthermore, based on these spectra estimates of the locations of energy transition states (xβ, lifetimes in the absence of external perturbation (τ0 and free energies (ΔG# were determined for the different epimerase-alginate complexes. This is the first determination of ΔG# for these complexes. The values determined were up to 8 kBT for the outer barrier, and smaller values for the inner barriers. The size of the free energies determined are consistent with the interpretation that the enzyme and substrate are thus not tightly locked at all times but are able to relocate

  18. A simple optical tweezers for trapping polystyrene particles (United States)

    Shiddiq, Minarni; Nasir, Zulfa; Yogasari, Dwiyana


    Optical tweezers is an optical trap. For decades, it has become an optical tool that can trap and manipulate any particle from the very small size like DNA to the big one like bacteria. The trapping force comes from the radiation pressure of laser light which is focused to a group of particles. Optical tweezers has been used in many research areas such as atomic physics, medical physics, biophysics, and chemistry. Here, a simple optical tweezers has been constructed using a modified Leybold laboratory optical microscope. The ocular lens of the microscope has been removed for laser light and digital camera accesses. A laser light from a Coherent diode laser with wavelength λ = 830 nm and power 50 mW is sent through an immersion oil objective lens with magnification 100 × and NA 1.25 to a cell made from microscope slides containing polystyrene particles. Polystyrene particles with size 3 μm and 10 μm are used. A CMOS Thorlabs camera type DCC1545M with USB Interface and Thorlabs camera lens 35 mm are connected to a desktop and used to monitor the trapping and measure the stiffness of the trap. The camera is accompanied by camera software which makes able for the user to capture and save images. The images are analyzed using ImageJ and Scion macro. The polystyrene particles have been trapped successfully. The stiffness of the trap depends on the size of the particles and the power of the laser. The stiffness increases linearly with power and decreases as the particle size larger.

  19. pH microprobe manipulated in microchannels using optical tweezers (United States)

    Sinclair, Gavin S.; Klauke, Norbert; Monaghan, Paul; Padgett, Miles J.; Cooper, Jon


    SNARF-1 fluorochrome was used to functionalize 3μm diameter latex spheres making them sensitive to the pH of their environment, manifested as a change in their fluorescence. The fluorescence emission at 580nm was excited using a filtered xenon arc lamp at 515nm. A solution of functionalized latex spheres was placed between gold microelectrodes in a microfluidic channel. Optical tweezers were used to trap and manipulate the spheres in the vicinity of the microelectrodes, to map out the pH profile in the electrolyte solution, induced by passing 20 microsecond transient current pulses through the microelectrodes.

  20. Piezophototronic Effect in Single-Atomic-Layer MoS 2 for Strain-Gated Flexible Optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wenzhuo [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta GA 30332-0245 USA; Wang, Lei [Department of Electrical Engineering, Columbia University, New York NY 10027 USA; Yu, Ruomeng [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta GA 30332-0245 USA; Liu, Yuanyue [National Renewable Energy Laboratory (NREL), Golden CO 80401 USA; Wei, Su-Huai [National Renewable Energy Laboratory (NREL), Golden CO 80401 USA; Hone, James [Department of Mechanical Engineering, Columbia University, New York NY 10027 USA; Wang, Zhong Lin [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta GA 30332-0245 USA; Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, 100083 Beijing China


    Strain-gated flexible optoelectronics are reported based on monolayer MoS2. Utilizing the piezoelectric polarization created at metal-MoS2 interface to modulate the separation/transport of photogenerated carriers, the piezophototronic effect is applied to implement atomic-layer-thick phototransistor. Coupling between piezoelectricity and photogenerated carriers may enable the development of novel optoelectronics.

  1. Progress on the optoelectronic functional organic crystals

    Institute of Scientific and Technical Information of China (English)


    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 ma-terials, make them attractive candidates for optoelectronic devices. Single crystal with definite struc-ture 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 crys-tals. In this paper, we will emphatically introduce the progress in optoelectronic functional organic crystals and some correlative principle.

  2. Progress on the optoelectronic functional organic crystals

    Institute of Scientific and Technical Information of China (English)

    WANG Huan; XIE ZengQi; Ma YuGuang; Shen JiaCong


    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.

  3. Opto-Electronic Oscillator and its Applications (United States)

    Yao, X. S.; Maleki, L.


    We present the theoretical and experimental results of a new class of microwave oscillators called opto-electronic oscillators (OEO). We discuss techniques of achieving high stability single mode operation and demonstrate the applications of OEO in photonic communication systems.

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

    CERN Document Server

    Kotnala, Abhay


    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.

  5. Robert Feulgen Prize Lecture. Laser tweezers and multiphoton microscopes in life sciences. (United States)

    König, K


    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.

  6. 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


    @@ 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.

  7. Opto-electronics on Single Nanowire Quantum Dots



    An important goal for nanoscale opto-electronics is the transfer of single electron spin states into single photon polarization states (and vice versa), thereby interfacing quantum transport and quantum optics. Such an interface enables new experiments in the field of quantum information processing. Single and entangled photon-pair generation can be used for quantum cryptography. Furthermore, photons can be used in the readout of a quantum computer based on electron spins. Semiconducting nano...

  8. Organic semiconductors as candidates for advanced optoelectronic devices:


    Bratina, Gvido; Hudej, Robert


    Organic semiconductors are gaining an increasing attention due to their promise of novel optoelectronic devices. The main attraction of these materials stems from their potential integration with flexible materials, which would result in ultrathin flexible multicolor displays. Basic electronic properties of typical representatives of organic semiconductors are reviewed. The operation of a light-emitting device based on organic semiconductors is fundamentally different from its inorganic count...

  9. Radiation effects in optoelectronic devices. [Review

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, C.E.; Wiczer, J.J.


    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. Highly Conductive Transparent Organic Electrodes with Multilayer Structures for Rigid and Flexible Optoelectronics


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


    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 b...

  11. Metamaterial mirrors in optoelectronic devices

    KAUST Repository

    Esfandyarpour, Majid


    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.

  12. Metal oxides for optoelectronic applications. (United States)

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


    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.

  13. Metal oxides for optoelectronic applications (United States)

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


    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. Widrow-cellular neural network and optoelectronic implementation (United States)

    Bal, Abdullah

    A new type of optoelectronic cellular neural network has been developed by providing the capability of coefficients adjusment of cellular neural network (CNN) using Widrow based perceptron learning algorithm. The new supervised cellular neural network is called Widrow-CNN. Despite the unsupervised CNN, the proposed learning algorithm allows to use the Widrow-CNN for various image processing applications easily. Also, the capability of CNN for image processing and feature extraction has been improved using basic joint transform correlation architecture. This hardware application presents high speed processing capability compared to digital applications. The optoelectronic Widrow-CNN has been tested for classic CNN feature extraction problems. It yields the best results even in case of hard feature extraction problems such as diagonal line detection and vertical line determination.

  15. Use of optical tweezers to probe epithelial mechanosensation (United States)

    Resnick, Andrew


    Cellular mechanosensation mechanisms have been implicated in a variety of disease states. Specifically in renal tubules, the primary cilium and associated mechanosensitive ion channels are hypothesized to play a role in water and salt homeostasis, with relevant disease states including polycystic kidney disease and hypertension. Previous experiments investigating ciliary-mediated cellular mechanosensation have used either fluid flow chambers or micropipetting to elicit a biological response. The interpretation of these experiments in terms of the ``ciliary hypothesis'' has been difficult due the spatially distributed nature of the mechanical disturbance-several competing hypotheses regarding possible roles of primary cilium, glycocalyx, microvilli, cell junctions, and actin cytoskeleton exist. I report initial data using optical tweezers to manipulate individual primary cilia in an attempt to elicit a mechanotransduction response-specifically, the release of intracellular calcium. The advantage of using laser tweezers over previous work is that the applied disturbance is highly localized. I find that stimulation of a primary cilium elicits a response, while stimulation of the apical surface membrane does not. These results lend support to the hypothesis that the primary cilium mediates transduction of mechanical strain into a biochemical response in renal epithelia.

  16. Research on Active Disturbance Rejection Control of Optoelectronic Tracking System Based on Mobile Platform%机动平台光电跟踪系统的自抗扰控制研究

    Institute of Scientific and Technical Information of China (English)

    刘翔; 包启亮


    针对机动平台光电跟踪系统跟踪目标需具备较强动态抗扰能力的问题,提出了一种将包含了非线性跟踪微分器、扩张状态观测器、非线性状态误差反馈三个环节的结构完整的自抗扰控制器用于光电跟踪伺服系统的速度环的思路。针对某单轴稳定转台设计了二阶自抗扰控制器,并进行了仿真研究。结果表明,该控制器对外扰变化及系统模型不确定性具有良好的鲁棒性和适应性,且能有效抑制系统中存在的非线性因素的影响。%Optoelectronic tracking systems based on mobile platform should have stronger dynamic anti-disturbance ability for tracking target accurately. Full-structured active disturbance rejection controller(ADRC) which includes nonlinear track- ing differentiation(NTD), extended state observer(ESO) and nonlinear state error feedback(NLSEF), is applied to the speed-loop of an optoelectronic tracking system. On basis of analyzing its principle of active disturbance rejection, a two-or- der ADRC for a single-axis stabilized turntable is designed. The results of simulation show that ADRC has fine robustness and adaptability versus external disturbance variation and model uncertainty. It can inhibit the effect of nonlinear factors ex- isting in system. Using ADRC can improve the shortage of anti-disturbance ability in current control technique for speed- loop. It achieves a better speed response without overshooting. Compared with the traditional PI controller, the stable track ing and disturbance rejection abilities have obviously improved.

  17. Colloidal quantum dot materials for infrared optoelectronics (United States)

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


    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.

  18. Hybrid optoelectronic device with multiple bistable outputs (United States)

    Costazo-Caso, Pablo A.; Jin, Yiye; Gelh, Michael; Granieri, Sergio; Siahmakoun, Azad


    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.

  19. Optoelectronic microdevices for combined phototherapy (United States)

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


    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.

  20. Patterning of conjugated polymers for organic optoelectronic devices. (United States)

    Xu, Youyong; Zhang, Fan; Feng, Xinliang


    Conjugated polymers have been attracting more and more attention because they possess various novel electrical, magnetical, and optical properties, which render them useful in modern organic optoelectronic devices. Due to their organic nature, conjugated polymers are light-weight and can be fabricated into flexible appliances. Significant research efforts have been devoted to developing new organic materials to make them competitive with their conventional inorganic counterparts. It is foreseeable that when large-scale industrial manufacture of the devices made from organic conjugated polymers is feasible, they would be much cheaper and have more functions. On one hand, in order to improve the performance of organic optoelectronic devices, it is essential to tune their surface morphologies by techniques such as patterning. On the other hand, patterning is the routine requirement for device processing. In this review, the recent progress in the patterning of conjugated polymers for high-performance optoelectronic devices is summarized. Patterning based on the bottom-up and top-down methods are introduced. Emerging new patterning strategies and future trends for conventional patterning techniques are discussed.

  1. Web-Enabled Optoelectronic Particle-Fallout Monitor (United States)

    Lineberger, Lewis P.


    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.

  2. Power spectrum analysis with least-squares fitting: Amplitude bias and its elimination, with application to optical tweezers and atomic force microscope cantilevers

    DEFF Research Database (Denmark)

    Nørlykke, Simon F.; Flyvbjerg, Henrik


    Optical tweezers and atomic force microscope (AFM) cantilevers are often calibrated by fitting their experimental power spectra of Brownian motion. We demonstrate here that if this is done with typical weighted least-squares methods, the result is a bias of relative size between -2/n and + 1/n...... on the value of the fitted diffusion coefficient. Here, n is the number of power spectra averaged over, so typical calibrations contain 10%-20% bias. Both the sign and the size of the bias depend on the weighting scheme applied. Hence, so do length-scale calibrations based on the diffusion coefficient....... The fitted value for the characteristic frequency is not affected by this bias. For the AFM then, force measurements are not affected provided an independent length-scale calibration is available. For optical tweezers there is no such luck, since the spring constant is found as the ratio...

  3. Graphene and Two-Dimensional Materials for Optoelectronic Applications

    Directory of Open Access Journals (Sweden)

    Andreas Bablich


    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.

  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


    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. 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


    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.

  6. Automated transportation of single cells using robot-tweezer manipulation system. (United States)

    Hu, Songyu; Sun, Dong


    Manipulation of biological cells becomes increasingly important in biomedical engineering to address challenge issues in cell-cell interaction, drug discovery, and tissue engineering. Significant demand for both accuracy and productivity in cell manipulation highlights the need for automated cell transportation with integrated robotics and micro/nano manipulation technologies. Optical tweezers, which use highly focused low-power laser beams to trap and manipulate particles at micro/nanoscale, have emerged as an essential tool for manipulating single cells. In this article, we propose to use a robot-tweezer manipulation system to solve the problem of automatic transportation of biological cells, where optical tweezers function as special robot end effectors. Dynamics equation of the cell in optical tweezers is analyzed. A closed-loop controller is designed for transporting and positioning cells. Experiments are performed on live cells to demonstrate the effectiveness of the proposed approach in effective cell positioning.

  7. 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


    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.

  8. Microrheology with Optical Tweezers of gel-like materials 'is not an option'!

    CERN Document Server

    Tassieri, Manlio


    Optical tweezers have been successfully adopted as exceptionally sensitive transducers for microrheology studies of complex 'fluids'. Despite the general trend, a similar approach cannot be adopted for microrheology studies of 'gel-like' materials, e.g. living cells.

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

    CERN Document Server

    Andersson, Magnus


    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...

  10. Contemporary optoelectronics materials, metamaterials and device applications

    CERN Document Server

    Sukhoivanov, Igor


    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.

  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


    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. Combined holographic-mechanical optical tweezers: Construction, optimization, and calibration

    Energy Technology Data Exchange (ETDEWEB)

    Hanes, Richard D. L.; Jenkins, Matthew C.; Egelhaaf, Stefan U. [Condensed Matter Physics Laboratory, Heinrich-Heine University, 40225 Duesseldorf (Germany)


    A spatial light modulator (SLM) and a pair of galvanometer-mounted mirrors (GMM) were combined into an optical tweezers setup. This provides great flexibility as the SLM creates an array of traps, which can be moved smoothly and quickly with the GMM. To optimize performance, the effect of the incidence angle on the SLM with respect to phase and intensity response was investigated. Although it is common to use the SLM at an incidence angle of 45 deg., smaller angles give a full 2{pi} phase shift and an output intensity which is less dependent on the magnitude of the phase shift. The traps were calibrated using an active oscillatory technique and a passive probability distribution method.

  13. Speckle Optical Tweezers: Micromanipulation with Random Light Fields

    CERN Document Server

    Volpe, Giorgio; Callegari, Agnese; Volpe, Giovanni; Gigan, Sylvain


    Current optical manipulation techniques rely on carefully engineered setups and samples. Although similar conditions are routinely met in research laboratories, it is still a challenge to manipulate microparticles when the environment is not well controlled and known a priori, since optical imperfections and scattering limit the applicability of this technique to real-life situations, such as in biomedical or microfluidic applications. Nonetheless, scattering of coherent light by disordered structures gives rise to speckles, random diffraction patterns with well-defined statistical properties. Here, we experimentally demonstrate how speckle fields can become a versatile tool to efficiently perform fundamental optical manipulation tasks such as trapping, guiding and sorting. We anticipate that the simplicity of these "speckle optical tweezers" will greatly broaden the perspectives of optical manipulation for real-life applications.

  14. Dynamic properties of bacterial pili measured by optical tweezers

    CERN Document Server

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


    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...

  15. Optical tweezers formed by pure phase pupil filter (United States)

    Lv, Wei; You, Chenglong; Wang, Mei; Yun, Maojin


    The focusing properties of vector beams have attracted great attention and quickly became the subject of extensive worldwide research due to their applications in lithography, optical storage, microscopy, material processing, and optical trapping. Focusing properties of the radially polarized beam and generalized cylindrical vector beams in high numerical aperture system with designed pure phase filter are analyzed in detail by using vector Debye diffraction theory. By utilizing diffractive optical element to partly change the polarization of vector beams, the energy density of light field in the vicinity of focus is studied by the numerical analysis. Numerical simulation result shows that optical bubbles can be obtained by changing the composition and polarization of the incident beams. At last, optical tweezers are constituted by two optical bubbles around the focus.

  16. Investigating collagen self-assembly with optical tweezers microrheology (United States)

    Forde, Nancy; Shayegan, Marjan; Altindal, Tuba

    Collagen is the fundamental structural protein in vertebrates. Assembled from individual triple-helical proteins to make strong fibres, collagen is a beautiful example of a hierarchical self-assembling system. Using optical tweezers to perform microrheology measurements, we explore the dynamics of interactions between collagens responsible for their self-assembly and examine the development of heterogeneous mechanics during assembly into fibrillar gels. Telopeptides, short non-helical regions that flank the triple helix, have long been known to facilitate fibril self-assembly. We find that their removal not only slows down fibril nucleation but also results in a significant frequency-dependent reduction in the elastic modulus of collagens in solution. We interpret these results in terms of a model in which telopeptides facilitate transient intermolecular interactions, which enhance network connectivity in solution and lead to more rapid assembly in fibril-forming conditions. Current address: Department of Physics, McGill University.

  17. Novedosa pinza lumínica New light tweezer

    Directory of Open Access Journals (Sweden)

    M. Bernstein


    Full Text Available Se presenta la primera pinza adaptada a la novedosa tecnología lumínica, mediante diodo ultrabrillante, sin cables ni fibra óptica, a fin de lograr la adecuada iluminación de cavidades oscuras de difícil acceso, y que gracias a su cobertura aislante y su punta libre, permite la cauterización bajo buena iluminación de vasos sangrantes distales, sin lesionar sitios de apoyo accidental de sus ramas.Introducing the first tweezer adjusted to the newest lighting technology though ultra-bright diode, without cables nor optical fiber to obtain the proper illumination of dark and hard acces caves, and thanks to its insulating cover, and its free point allows the cauterization under good illumination of bloody vasels without injurying sites of accidental supports of its branches.

  18. Electromagnetic Theory for Microwaves and Optoelectronics

    CERN Document Server

    Zhang, Keqian


    This book is a first year graduate text on electromagnetic fields and waves. At the same time it serves as a useful reference for researchers and engineers in the areas of microwaves and optoelectronics. Following the presentation of the physical and mathematical foundations of electromagnetic theory, the book discusses the field analysis of electromagnetic waves confined in material boundaries, or so-called guided waves, electromagnetic waves in the dispersive media and anisotropic media, Gaussian beams and scalar diffraction theory. The theories and methods presented in the book are foundations of wireless engineering, microwave and millimeter wave techniques, optoelectronics and optical fiber communication.

  19. III-V compound SC for optoelectronic devices

    Directory of Open Access Journals (Sweden)

    Sudha Mokkapati


    Full Text Available III-V compound semiconductors (SC have played a crucial role in the development of optoelectronic devices for a broad range of applications. Major applications of InP or GaAs based III-V compound SC are devices for optical fiber communications, infrared and visible LEDs/LDs and high efficiency solar cells. GaN based compounds are extremely important for short wavelength light emitters used in solid state lighting systems. We review the important device applications of various III-V compound SC materials.

  20. III-V Semiconductor Quantum Well Lasers and Related Optoelectronic Devices (On Silicon). Oxide-Defined Semiconductor Quantum Well Lasers and Optoelectrnic Devices: A1-Based III-V Native Oxides (United States)


    lateral direction. guide layer. The effect of the optical waveguide is shown by the The laser fabrication begins with the deposition on the manipulate photons around a "chip," e.g., The laser fabrication begins with the patterning of for optoelectronic integrated circuits (OEICs), a

  1. Optoelectronic line transmission an introduction to fibre optics

    CERN Document Server

    Tricker, Raymond L


    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

  2. 三维物场多重分数傅里叶变换全息图光电再现实验研究%Optoelectronic Reconstruction of Three-Dimensional Scenes Based on Multiple Fractional-Fourier-Transform Holograms

    Institute of Scientific and Technical Information of China (English)

    郑华东; 代林茂; 王涛; 于瀛洁


    Optoelectronic reconstruction experiment is carried out for holographic display of three-dimensional (3D)scene based on multiple fractional Fourier transform (FrFT). By setting different fractional orders according to different diffraction distances, multiple fractional Fourier transform in each object plane is calculated and superposed to the whole complex amplitude. The amplitude-type and phase-type holograms are obtained by encoding the whole complex amplitude in hologram plane. In order to suppress the speckle noise, a pseudorandom phase factor is added to object planes in calculating sequential holograms. An experimental system is set up for optoelectronic reconstruction based on phase-type liquid crystal spatial light modulator (LC-SLM). Speckle index and correlation coefficient between the reconstructed images from single hologram and sequential holograms are analyzed. The experimental results show that, by calculating sequential holograms of 3D object and reconstructing with phase-type LC-SLM, the speckle noise and conjugate image can be well suppressed and the quality of reconstructed image is improved significantly.%对基于多重分数傅里叶变换(FrFT)的三维(3D)物场计算全息图进行光电再现实验研究.根据分数阶与衍射距离的关系,对不同物面分别设置不同的分数阶,分别计算得到各层物面在全息面的复振幅并进行叠加,对其进行编码分别得到分数傅里叶变换振幅型全息图和相息图.同时在计算3D物场的全息图时,在物波面加入不同的随机相位因子,得到3D物场的序列全息图,实现对再现影像中散斑噪声的抑制.构建了基于相位型液晶空间光调制器的全息光电再现系统,对单幅全息图和序列全息图的光电再现像的散斑指数、互相关系数进行分析.实验结果表明,通过计算3D物场的分数傅里叶变换序列相息图,可有效地抑制3D物场全息光电再现时的共轭像和散斑噪声,提高再现像的质量.

  3. Novel single-cell functional analysis of red blood cells using laser tweezers Raman spectroscopy: application for sickle cell disease. (United States)

    Liu, Rui; Mao, Ziliang; Matthews, Dennis L; Li, Chin-Shang; Chan, James W; Satake, Noriko


    Laser tweezers Raman spectroscopy was used to characterize the oxygenation response of single normal adult, sickle, and cord blood red blood cells (RBCs) to an applied mechanical force. Individual cells were subjected to different forces by varying the laser power of a single-beam optical trap, and the intensities of several oxygenation-specific Raman spectral peaks were monitored to determine the oxygenation state of the cells. For all three cell types, an increase in laser power (or mechanical force) induced a greater deoxygenation of the cell. However, sickle RBCs deoxygenated more readily than normal RBCs when subjected to the same optical forces. Conversely, cord blood RBCs were able to maintain their oxygenation better than normal RBCs. These results suggest that differences in the chemical or mechanical properties of fetal, normal, and sickle cells affect the degree to which applied mechanical forces can deoxygenate the cell. Populations of normal, sickle, and cord RBCs were identified and discriminated based on this mechanochemical phenomenon. This study demonstrates the potential application of laser tweezers Raman spectroscopy as a single-cell, label-free analytical tool to characterize the functional (e.g., mechanical deformability, oxygen binding) properties of normal and diseased RBCs.

  4. GaAs optoelectronic neuron arrays (United States)

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


    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.

  5. Using optoelectronic sensors in the system PROTEUS (United States)

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


    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.

  6. Photoemission from optoelectronic materials and their nanostructures

    CERN Document Server

    Ghatak, Kamakhya Prasad; Bhattacharya, Sitangshu


    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..

  7. A remarkable effect of N,N-diethylamino functionality on the optoelectronic properties of a salicylimine-based probe for Al(3+). (United States)

    Neeraj; Kumar, Ajit; Kumar, Virendra; Prajapati, Rahul; Asthana, Sharad Kumar; Upadhyay, K K; Zhao, Jianzhang


    A new live-cell permeable, fluorescent probe comprised of a simple salicylimine-based Schiff base (SA1) has been developed for Al3+ with nano-molar sensitivity in aqueous media. SA1 was synthesized through a simple structural modification of a recently reported receptor SA2 by the incorporation of the N,Ndiethylamino (DEA) group as a fine controllable unit. This modification affects the performance of SA1 remarkably in terms of its sensitivity, water compatibility and efficiency as well as its mechanistic aspect. The presence of the DEA group in SA1 led to its dual channel emission due to the TICT state and at the same time its hydrophobic nature was also responsible for controlling the strong hydration of Al3+ ions in aqueous media which ultimately led to the high sensitivity of SA1 for Al3+. The structure of SA1 was confirmed by single crystal X-ray diffraction and its binding with Al3+ was studied in detail using UVvisible, fluorescence and 1H NMR spectral studies along with mass determination. The effort of getting a single crystal of Al3+–SA1 led to single crystals of Cl−/NO3 − complexes of protonated SA1 which were fully characterized by their XRD studies.

  8. Selectively Transparent and Conducting Photonic Crystals and their Potential to Enhance the Performance of Thin-Film Silicon-Based Photovoltaics and Other Optoelectronic Devices (United States)

    O'Brien, Paul G.


    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

  9. Enhanced fabrication process of zinc oxide nanowires for optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    García Núñez, C., E-mail: [Grupo de Electrónica y Semiconductores, Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Pau, J.L.; Ruíz, E.; García Marín, A.; García, B.J.; Piqueras, J. [Grupo de Electrónica y Semiconductores, Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Shen, G.; Wilbert, D.S.; Kim, S.M.; Kung, P. [Department of Electrical and Computer Engineering, the University of Alabama, Tuscaloosa, AL 35487 (United States)


    Zinc oxide (ZnO) nanowires (NWs) based ultraviolet (UV) sensors have been fabricated using different assembly techniques to form functional structures, aiming at the improvement of the performance of NW-based sensors for optoelectronic applications. NWs with diameters and lengths varying between 90–870 nm and 2–20 μm, respectively, were synthesized by controlling the growth conditions in a chemical vapor transport system. Optical properties of NWs were studied by means of transmission spectroscopy. Electrical properties of single ZnO NW-based sensors were analyzed in dark and under UV illumination (at photon wavelength of λ < 370 nm) as a function of the NW diameter. Results of the study indicate that reduction of the NW diameter below 200 nm leads to an improvement of the photocurrent (at λ < 370 nm) up to 10{sup 2} μA and a decrease of the decay time around 150 s. These enhancements may help to improve the performance of ZnO-based optoelectronic devices. - Highlights: • ZnO nanowires (NWs) with diameters 90–870 nm were grown by chemical vapor transport. • ZnO NWs showed strong absorption in the UV range. • Different assembly techniques were tested for preparing ZnO NW-based UV sensors. • Sensor photoresponses were around 10{sup 3} A/W. • Reducing NW diameter below 200 nm improved sensor photosensitivity.

  10. Simulation and analysis of the axicon tipped optical fiber tweezers based on FDTD%基于FDTD对尖端为轴锥体的光纤光镊的模拟分析

    Institute of Scientific and Technical Information of China (English)



    Based on the conservation of momentum and using the finite difference time domain (FDTD) method, we calculated and simulated the optimal angle of the axicon tip as a function of the working distance and the dependence of axial optical force on tip angle of tapered optical fiber. The result show that with the increasing working distance, the optimal axicon tip angle grows, while the trapping force changed differently. The simulation results are in good agreement with the experiment observation.%基于动量守恒,采用时域有限差分法(FDTD),仿真模拟了光纤光镊轴锥角和工作距离关系及捕获力大小和轴锥角的关系.结果表明工作距离和捕获力的大小和轴锥角度的大小有着密切的关系.模拟结果与其它相关文件报道的实验结果基本相符合.

  11. Effect of Top-Region Area of Flat-Top Pyramid Patterned Sapphire Substrate on the Optoelectronic Performance of GaN-Based Light-Emitting Diodes

    Directory of Open Access Journals (Sweden)

    Hsu-Hung Hsueh


    Full Text Available The flat-top pyramid patterned sapphire substrates (FTP-PSSs have been prepared for the growth of GaN epilayers and the fabrication of lateral-type light-emitting diodes (LEDs with an emission wavelength of approximately 470 nm. Three kinds of FTP-PSSs, which were denoted as FTP-PSS-A, FTP-PSS-B, and FTP-PSS-C, respectively, were formed through the sequential wet etching processes. The diameters of circle areas on the top regions of these three FTP-PSSs were 1, 2, and 3 μm, respectively. Based on the X-ray diffraction results, the full-width at half-maximum values of rocking curves at (002 plane for the GaN epilayers grown on conventional sapphire substrate (CSS, FTP-PSS-A, FTP-PSS-B, and FTP-PSS-C were 412, 238, 346, and 357 arcsec, while these values at (102 plane were 593, 327, 352, and 372 arcsec, respectively. The SpeCLED-Ratro simulation results reveal that the LED prepared on FTP-PSS-A has the highest light extraction efficiency than that of the other devices. At an injection current of 350 mA, the output powers of LEDs fabricated on CSS, FTP-PSS-A, FTP-PSS-B, and FTP-PSS-C were 157, 254, 241, and 233 mW, respectively. The results indicate that both the crystal quality of GaN epilayer and the light extraction of LED can be improved via the use of FTP-PSS, especially for the FTP-PSS-A.

  12. WARRP Core: Optoelectronic Implementation of Network-Router Deadlock-Handling Mechanisms. (United States)

    Pinkston, T M; Raksapatcharawong, M; Choi, Y


    The wormhole adaptive recovery-based routing via pre-emption(WARRP) core optoelectronic chip, which integrates coredeadlock-handling circuitry for a fully adaptive deadlock-freemultiprocessor network router, is presented. This chip demonstratesprimarily the integration of complex deadlock-recovery circuitry andfree-space optoelectronic input-output on a monolithicGaAs-based chip. The design and implementation of thefirst-generation, bit-serial, torus-connected chip that uses 1400transistors and six light-emitting diode-photodetector pairs is presented.

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

  14. Optoelectronic Devices Based on Novel Semiconductor Structures (United States)


    generation are the Nd:YAG beam at 1.0642 ptm and the idler beam from a master oscillator/power oscillator ( MOPO ) pumped by a frequency-tripled Nd:YAG...matched DFG (see Fig. a 72 1). In order to achieve phase-matching, the 1.0642-ptm pump beam and idler beam from the MOPO system are ordinary and...frequency for the MOPO beam (idler), which is given by Avi (1) 4L [no) , (o) ] where n,(,o°) and n(0°) are the indices of refraction for the ordinary

  15. Coupled Optoelectronic Oscillators:. Application to Low-Jitter Pulse Generation (United States)

    Yu, N.; Tu, M.; Maleki, L.


    Actively mode-locked Erbium-doped fiber lasers (EDFL) have been studied for generating stable ultra-fast pulses ( 5 GHz) [1,2]. These devices can be compact and environmentally stable, quite suitable for fiber-based high-data-rate communications and optical ultra-fast analog-to-digital conversions (ADC) [3]. The pulse-to-pulse jitter of an EDFL-based pulse generator will be ultimately limited by the phase noise of the mode-locking microwave source (typically electronic frequency synthesizers). On the other hand, opto-electronic oscillators (OEO) using fibers have been demonstrated to generate ultra-low phase noise microwaves at 10 GHz and higher [4]. The overall phase noise of an OEO can be much lower than commercially available synthesizers at the offset-frequency range above 100 Hz. Clearly, ultra-low jitter pulses can be generated by taking advantage of the low phase noise of OEOs. In this paper, we report the progress in developing a new low-jitter pulse generator by combing the two technologies. In our approach, the optical oscillator (mode-locked EDFL) and the microwave oscillator (OEO) are coupled through a common Mach-Zehnder (MZ) modulator, thus named coupled opto-electronic oscillator (COEO) [5]. Based on the results of previous OEO study, we can expect a 10 GHz pulse train with jitters less than 10 fs.

  16. Mechanics of protein-DNA interaction studied with ultra-fast optical tweezers (United States)

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


    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.

  17. Optoelectronic sensor device for monitoring ethanol concentration in winemaking applications (United States)

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


    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.

  18. Improved antireflection coated microspheres for biological applications of optical tweezers (United States)

    Ferro, Valentina; Sonnberger, Aaron; Abdosamadi, Mohammad K.; McDonald, Craig; Schäffer, Erik; McGloin, David


    The success of optical tweezers in cellular biology1 is in part due to the wide range of forces that can be applied, from femto- to hundreds of pico-Newtons; nevertheless extending the range of applicable forces to the nanoNewton regime opens access to a new set of phenomena that currently lie beyond optical manipulation. A successful approach to overcome the conventional limits on trapping forces involves the optimization of the trapped probes. Jannasch et al.2 demonstrated that an anti-reflective shell of nanoporous titanium dioxide (aTiO2, nshell = 1.75) on a core particle made out of titanium dioxide in the anatase phase (cTiO2, ncore = 2.3) results in trappable microspheres capable to reach forces above 1 nN. Here we present how the technique can be further improved by coating the high refractive index microspheres with an additional anti-reflective shell made out of silica (SiO2). This external shell not only improves the trap stability for microspheres of different sizes, but also enables the use of functionalization techniques already established for commercial silica beads in biological experiments. We are also investigating the use of these new microspheres as probes to measure adhesion forces between intercellular adhesion molecule 1 (ICAM-1) and lymphocyte function-associated antigen 1 (LFA-1) in effector T-Cells and will present preliminary results comparing standard and high-index beads.

  19. Toward automated formation of microsphere arrangements using multiplexed optical tweezers (United States)

    Rajasekaran, Keshav; Bollavaram, Manasa; Banerjee, Ashis G.


    Optical tweezers offer certain advantages such as multiplexing using a programmable spatial light modulator, flexibility in the choice of the manipulated object and the manipulation medium, precise control, easy object release, and minimal object damage. However, automated manipulation of multiple objects in parallel, which is essential for efficient and reliable formation of micro-scale assembly structures, poses a difficult challenge. There are two primary research issues in addressing this challenge. First, the presence of stochastic Langevin force giving rise to Brownian motion requires motion control for all the manipulated objects at fast rates of several Hz. Second, the object dynamics is non-linear and even difficult to represent analytically due to the interaction of multiple optical traps that are manipulating neighboring objects. As a result, automated controllers have not been realized for tens of objects, particularly with three dimensional motions with guaranteed collision avoidances. In this paper, we model the effect of interacting optical traps on microspheres with significant Brownian motions in stationary fluid media, and develop simplified state-space representations. These representations are used to design a model predictive controller to coordinate the motions of several spheres in real time. Preliminary experiments demonstrate the utility of the controller in automatically forming desired arrangements of varying configurations starting with randomly dispersed microspheres.

  20. Materials for optoelectronic devices, OEICs and photonics

    Energy Technology Data Exchange (ETDEWEB)

    Schloetterer, H.; Quillec, M.; Greene, P.D.; Bertolotti, M. (eds.)


    The aim of the contributors in this volume is to give a current overview on the basic properties of nonlinear optical materials for optoelectronics and integrated optics. They provide a cross-linkage between different materials (III-V, II-VI, Si-Ge, etc.), various sample dimensions (from bulk crystals to quantum dots), and a range of techniques from growth (LPE to MOMBE) and for processing from surface passivation to ion beams. Major growth techniques and materials are discussed, including the sophisticated technologies required to exploit the exciting properties of low dimensional semiconductors. These proceedings will prove an invaluable guide to the current state of optoelectronic materials development, as well as indicating the growth techniques that will be in use around the year 2000.

  1. Optoelectronic Devices Advanced Simulation and Analysis

    CERN Document Server

    Piprek, Joachim


    Optoelectronic devices transform electrical signals into optical signals and vice versa by utilizing the sophisticated interaction of electrons and light within micro- and nano-scale semiconductor structures. Advanced software tools for design and analysis of such devices have been developed in recent years. However, the large variety of materials, devices, physical mechanisms, and modeling approaches often makes it difficult to select appropriate theoretical models or software packages. This book presents a review of devices and advanced simulation approaches written by leading researchers and software developers. It is intended for scientists and device engineers in optoelectronics, who are interested in using advanced software tools. Each chapter includes the theoretical background as well as practical simulation results that help to better understand internal device physics. The software packages used in the book are available to the public, on a commercial or noncommercial basis, so that the interested r...

  2. Inactivation of Spores of Bacillus Species by Wet Heat: Studies on Single Spores Using Laser Tweezers Taman Spectroscopy (United States)


    germination using phase contrast and fluorescence microscopy, Raman spectroscopy and optical tweezers, Nature Protocols , (04 2011): . doi: 05/11...multiple individual spores [ Nature Protocols , 6, 625 (2011)]. (1e) We developed a multiple-trap laser tweezers Raman spectroscopy (LTRS) array for

  3. Intriguing Optoelectronic Properties of Metal Halide Perovskites. (United States)

    Manser, Joseph S; Christians, Jeffrey A; Kamat, Prashant V


    A new chapter in the long and distinguished history of perovskites is being written with the breakthrough success of metal halide perovskites (MHPs) as solution-processed photovoltaic (PV) absorbers. The current surge in MHP research has largely arisen out of their rapid progress in PV devices; however, these materials are potentially suitable for a diverse array of optoelectronic applications. Like oxide perovskites, MHPs have ABX3 stoichiometry, where A and B are cations and X is a halide anion. Here, the underlying physical and photophysical properties of inorganic (A = inorganic) and hybrid organic-inorganic (A = organic) MHPs are reviewed with an eye toward their potential application in emerging optoelectronic technologies. Significant attention is given to the prototypical compound methylammonium lead iodide (CH3NH3PbI3) due to the preponderance of experimental and theoretical studies surrounding this material. We also discuss other salient MHP systems, including 2-dimensional compounds, where relevant. More specifically, this review is a critical account of the interrelation between MHP electronic structure, absorption, emission, carrier dynamics and transport, and other relevant photophysical processes that have propelled these materials to the forefront of modern optoelectronics research.

  4. Optoelectronic leak detection system for monitoring subsea structures (United States)

    Moodie, D.,; Costello, L.; McStay, D.


    Leak detection and monitoring on subsea structures is an area of increasing interest for the detection and monitoring of production and control fluids for the oil and gas industry. Current techniques such as capacitive (dielectric) based measurement or passive acoustic systems have limitations and we report here an optoelectronic solution based upon fluorescence spectroscopy to provide a permanent monitoring solution. We report here a new class of optoelectronic subsea sensor for permanent, real time monitoring of hydrocarbon production systems. The system is capable of detecting small leaks of production or hydraulic fluid (ppm levels) over distances of 4-5 meters in a subsea environment. Ideally systems designed for such applications should be capable of working at depths of up to 3000m unattended for periods of 20+ years. The system uses advanced single emitter LED technology to meet the challenges of lifetime, power consumption, spatial coverage and delivery of a cost effective solution. The system is designed for permanent deployment on Christmas tree (XT), subsea processing systems (SPS) and associated equipment to provide enhanced leak detection capability.

  5. Photonics and optoelectronics of two-dimensional materials beyond graphene (United States)

    Ponraj, Joice Sophia; Xu, Zai-Quan; Chander Dhanabalan, Sathish; Mu, Haoran; Wang, Yusheng; Yuan, Jian; Li, Pengfei; Thakur, Siddharatha; Ashrafi, Mursal; Mccoubrey, Kenneth; Zhang, Yupeng; Li, Shaojuan; Zhang, Han; Bao, Qiaoliang


    Apart from conventional materials, the study of two-dimensional (2D) materials has emerged as a significant field of study for a variety of applications. Graphene-like 2D materials are important elements of potential optoelectronics applications due to their exceptional electronic and optical properties. The processing of these materials towards the realization of devices has been one of the main motivations for the recent development of photonics and optoelectronics. The recent progress in photonic devices based on graphene-like 2D materials, especially topological insulators (TIs) and transition metal dichalcogenides (TMDs) with the methodology level discussions from the viewpoint of state-of-the-art designs in device geometry and materials are detailed in this review. We have started the article with an overview of the electronic properties and continued by highlighting their linear and nonlinear optical properties. The production of TIs and TMDs by different methods is detailed. The following main applications focused towards device fabrication are elaborated: (1) photodetectors, (2) photovoltaic devices, (3) light-emitting devices, (4) flexible devices and (5) laser applications. The possibility of employing these 2D materials in different fields is also suggested based on their properties in the prospective part. This review will not only greatly complement the detailed knowledge of the device physics of these materials, but also provide contemporary perception for the researchers who wish to consider these materials for various applications by following the path of graphene.

  6. Semiconductor laser amplifier and its optoelectronic properties for application in lightwave communication systems (United States)

    Luc, V. V.; Eliseev, Petr G.; Man'ko, M. A.; Tsotsoriya, M. V.


    Output power and fiber-to-fiber gain along with infernal gain of the active element and optoelectronic signal curves at different values of input power versus pumping current are measured for the amplifier modules on the base of AR-coated InGaAsP/InP BH diodes. It is shown that diagnostics of the amplifier module oper''ation regime may be performed by voltage measurements and the optoelectronic signal can be used to monitor optical information passage in the regenerator device or for the distributed access the data transmitted in the lightwave comrnunicat ion systems. I.

  7. Sub-THz photonic frequency conversion using optoelectronic transistors for future fully coherent access network systems (United States)

    Otsuji, Taiichi; Sugawara, Kenta; Tamamushi, Gen; Dobroiu, Adrian; Suemitsu, Tetsuya; Ryzhii, Victor; Iwatsuki, Katsumi; Kuwano, Shigeru; Kani, Jun-ichi; Terada, Jun


    This paper reviews advances in sub-THz photonic frequency conversion using optoelectronic transistors for future fully coherent access network systems. Graphene-channel field effect transistors (G-FETs) and InP-based high electron mobility transistors (inP-HEMT) are experimentally examined as photonic frequency converters. Optoelectronic properties and three-terminal functionalities of the G-FETs and InP-HEMTs are exploited to perform single-chip photonic double-mixing operation over the 120 GHz wireless communication band. A single transistor can photomix the optical subcarriers to generate LO and mix down the RF data on the sub-THz carrier to the IF band.

  8. A new switching parameter varying optoelectronic delayed feedback model with computer simulation (United States)

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


    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.

  9. Computations of radiation force using the translational addition theorem: Applications to acoustical tweezers

    CERN Document Server

    Baggio, André L; Silva, Glauber T


    This work proposes a method to compute both axial and transverse radiation forces produced by an ultrasound beam of arbitrary wavefront based on the partial-wave expansion (PWE) and the translational addition theorem for spherical wave functions. The major advantage of using the addition theorem is the computation of acoustic radiation force for a wide variety of beams which satisfy the Helmholtz equation without the need of numerical quadrature schemes. The PWE method is applied to calculate the radiation force exerted on a silicone-oil droplet suspended in water. The force is produced by a single-beam acoustical tweezer composed by a spherically focused transducer with driving frequency of 3.1 MHz and F-number of 1.6. The droplet can be positioned anywhere in the host medium. The radiation force is analyzed in the Rayleigh and resonant scattering regimes. The obtained results in the Rayleigh scattering regime are compared to those calculated with Gor'kov's radiation force theory. It turns out to be that bot...

  10. Determining the specificity of monoclonal antibody HPT-101 to tau-peptides with optical tweezers. (United States)

    Stangner, Tim; Wagner, Carolin; Singer, David; Angioletti-Uberti, Stefano; Gutsche, Christof; Dzubiella, Joachim; Hoffmann, Ralf; Kremer, Friedrich


    Optical tweezers-assisted dynamic force spectroscopy is employed to investigate specific receptor-ligand interactions on the level of single binding events. In particular, we analyze binding of the phosphorylation-specific monoclonal antibody (mAb) HPT-101 to synthetic tau-peptides with two potential phosphorylation sites (Thr231 and Ser235), being the most probable markers for Alzheimer's disease. Whereas the typical interpretation of enzyme-linked immunosorbent assay (ELISA) suggests that this monoclonal antibody binds exclusively to the double-phosphorylated tau-peptide, we show here by DFS that the specificity of only mAb HPT-101 is apparent. In fact, binding occurs also to each sort of monophosphorylated peptide. Therefore, we characterize the unbinding process by analyzing the measured rupture force distributions, from which the lifetime of the bond without force τ0, its characteristic length xts, and the free energy of activation ΔG are extracted for the three mAb/peptide combinations. This information is used to build a simple theoretical model to predict features of the unbinding process for the double-phosphorylated peptide purely based on data on the monophosphorylated ones. Finally, we introduce a method to combine binding and unbinding measurements to estimate the relative affinity of the bonds. The values obtained for this quantity are in accordance with ELISA, showing how DFS can offer important insights about the dynamic binding process that are not accessible with this common and widespread assay.

  11. Simple horizontal magnetic tweezers for micromanipulation of single DNA molecules and DNA-protein complexes. (United States)

    McAndrew, Christopher P; Tyson, Christopher; Zischkau, Joseph; Mehl, Patrick; Tuma, Pamela L; Pegg, Ian L; Sarkar, Abhijit


    We report the development of a simple-to-implement magnetic force transducer that can apply a wide range of piconewton (pN) scale forces on single DNA molecules and DNA-protein complexes in the horizontal plane. The resulting low-noise force-extension data enable very high-resolution detection of changes in the DNA tether's extension: ~0.05 pN in force and DNA in near equilibrium conditions through the wide range of forces by ramping the force from low to high and back again, and observing minimal hysteresis in the molecule's force response. Using a calibration technique based on Stokes' drag law, we have confirmed our force measurements from DNA force-extension experiments obtained using the fluctuation-dissipation theorem applied to transverse fluctuations of the magnetic microsphere. We present data on the force-distance characteristics of a DNA molecule complexed with histones. The results illustrate how the tweezers can be used to study DNA binding proteins at the single molecule level.

  12. Optical disassembly of cellular clusters by tunable ‘tug-of-war’ tweezers (United States)

    Bezryadina, Anna S; Preece, Daryl C; Chen, Joseph C; Chen, Zhigang


    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 the 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. PMID:27818838

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

    CERN Document Server

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


    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.

  14. Manipulation of cells with laser microbeam scissors and optical tweezers: a review (United States)

    Greulich, Karl Otto


    The use of laser microbeams and optical tweezers in a wide field of biological applications from genomic to immunology is discussed. Microperforation is used to introduce a well-defined amount of molecules into cells for genetic engineering and optical imaging. The microwelding of two cells induced by a laser microbeam combines their genetic outfit. Microdissection allows specific regions of genomes to be isolated from a whole set of chromosomes. Handling the cells with optical tweezers supports investigation on the attack of immune systems against diseased or cancerous cells. With the help of laser microbeams, heart infarction can be simulated, and optical tweezers support studies on the heartbeat. Finally, laser microbeams are used to induce DNA damage in living cells for studies on cancer and ageing.

  15. Hong-Ou-Mandel atom interferometry in tunnel-coupled optical tweezers (United States)

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


    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.

  16. Temperature-dependent conformations of a membrane supported zinc porphyrin tweezer by 2D fluorescence spectroscopy. (United States)

    Widom, Julia R; Lee, Wonbae; Perdomo-Ortiz, Alejandro; Rappoport, Dmitrij; Molinski, Tadeusz F; Aspuru-Guzik, Alán; Marcus, Andrew H


    We studied the equilibrium conformations of a zinc porphyrin tweezer composed of two carboxylphenyl-functionalized zinc tetraphenyl porphyrin subunits connected by a 1,4-butyndiol spacer, which was suspended inside the amphiphilic regions of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) liposomes. By combining phase-modulation two-dimensional fluorescence spectroscopy (2D FS) with linear absorbance and fluorimetry, we determined that the zinc porphyrin tweezer adopts a mixture of folded and extended conformations in the membrane. By fitting an exciton-coupling model to a series of data sets recorded over a range of temperatures (17-85 °C) and at different laser center wavelengths, we determined that the folded form of the tweezer is stabilized by a favorable change in the entropy of the local membrane environment. Our results provide insights toward understanding the balance of thermodynamic factors that govern molecular assembly in membranes.

  17. Shape deformations of giant unilamellar vesicles with a laser tweezer array (United States)

    Losert, Wolfgang; Poole, Cory; Bradford, Peter; English, Doug


    Vesicles are phospholipid bilayers that form a surface enclosing a volume of water or solution. They are of importance as model systems to study cells, as well as having practical applications such as containers for performing nanochemistry and facilitating drug delivery. Their properties have been studied for decades. Using a holographic laser tweezer array (LTA), which converts a single laser beam into many laser tweezer points, we stretch the vesicles in controlled ways from several points at once, measuring each force applied. Here, we present data on shape deformations of simple, spherical vesicles and on membrane fracture.

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

    CERN Document Server

    Kotsifaki, Domna G; Lagoudakis, Pavlos G


    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 (CW) 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, the effective trapping quality factor, and observe an exponential distance dependence of the trapping force from the nanostructures, expected from the evanescent plasmon field.

  19. Single and dual fiber nano-tip optical tweezers: trapping and analysis

    CERN Document Server

    Decombe, Jean-Baptiste; Fick, Jochen


    An original optical tweezers using one or two chemically etched fiber nano-tips is developed. We demonstrate optical trapping of 1 micrometer polystyrene spheres at optical powers down to 2 mW. Harmonic trap potentials were found in the case of dual fiber tweezers by analyzing the trapped particle position fluctuations. The trap stiffness was deduced using three different models. Consistent values of up to 1 fN/nm were found. The stiffness linearly decreases with decreasing light intensity and increasing fiber tip-to-tip distance.

  20. Observing Nanometre Scale Particles with Light Scattering for Manipulation Using Optical Tweezers

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jin-Hua; Qu Lian-Jie; Yao Kun; ZHONG Min-Cheng; LI Yin-Mei


    Nanometre-scale particles can be manipulated using optical tweezers,but cannot be directly observed.We Drasent a simple method that nanoparticles can be directly observed using optical tweezers combined with dark field microscopy.A laser beam perpendicular to a tightly focused laser beam for trap illuminates specimen and does not enter objective,nanoparticles in focal plane all can be directly observed in dark field because of light scattering.It is implemented that the polystyrene beads of diameter 100nm can be directly observed and trapped.

  1. Laser applications in the electronics and optoelectronics industry in Japan (United States)

    Washio, Kunihiko


    This paper explains current status and technological trends in laser materials processing applications in electronics and optoelectronics industry in Japan. Various laser equipment based on solid state lasers or gas lasers such as excimer lasers or CO2 lasers has been developed and applied in manufacturing electronic and optoelectronic devices to meet the strong demands for advanced device manufacturing technologies for high-performance, lightweight, low power-consumption portable digital electronic appliances, cellular mobile phones, personal computers, etc. Representative applications of solid-state lasers are, opaque and clear defects repairing of photomasks for LSIs and LCDs, trimming of thick-film chip resistors and low resistance metal resistors, laser cutting and drilling of thin films for high-pin count semiconductor CSP packages, laser patterning of thin-film amorphous silicon solar cells, and laser welding of electronic components such as hard-disk head suspensions, optical modules, miniature relays and lithium ion batteries. Compact and highly efficient diode- pumped and Q-switched solid-state lasers in second or third harmonic operation mode are now being increasingly incorporated in various laser equipment for fine material processing. Representative applications of excimer lasers are, sub-quarter micron design-rule LSI lithography and low- temperature annealing of poly-silicon TFT LCD.

  2. Optoelectronic scanning system upgrade by energy center localization methods (United States)

    Flores-Fuentes, W.; Sergiyenko, O.; Rodriguez-Quiñonez, J. C.; Rivas-López, M.; Hernández-Balbuena, D.; Básaca-Preciado, L. C.; Lindner, L.; González-Navarro, F. F.


    A problem of upgrading an optoelectronic scanning system with digital post-processing of the signal based on adequate methods of energy center localization is considered. An improved dynamic triangulation analysis technique is proposed by an example of industrial infrastructure damage detection. A modification of our previously published method aimed at searching for the energy center of an optoelectronic signal is described. Application of the artificial intelligence algorithm of compensation for the error of determining the angular coordinate in calculating the spatial coordinate through dynamic triangulation is demonstrated. Five energy center localization methods are developed and tested to select the best method. After implementation of these methods, digital compensation for the measurement error, and statistical data analysis, a non-parametric behavior of the data is identified. The Wilcoxon signed rank test is applied to improve the result further. For optical scanning systems, it is necessary to detect a light emitter mounted on the infrastructure being investigated to calculate its spatial coordinate by the energy center localization method.

  3. Ultrasensitive optoelectronic sensors for nitrogen oxides and explosives detection (United States)

    Wojtas, J.; Bielecki, Z.; Stacewicz, T.; Mikolajczyk, J.


    The article describes application of cavity enhanced absorption spectroscopy (CEAS) for detection of nitrogen oxides and vapours of explosives. The oxides are important greenhouse gases that are of large influence on environment, living organisms and human health. These compounds are also markers of some human diseases as well as they are emitted by commonly used explosives. Therefore sensitive nitrogen oxides sensors are of great importance for many applications, e. g. for environment protection (air monitoring), for medicine investigation (analyzing of exhaled air) and finally for explosives detection. In the Institute of Optoelectronics MUT different types of optoelectronic sensors employing CEAS were developed. They were designed to measure trace concentration of nitrogen dioxide, nitric oxide, and nitrous oxide. The sensors provide opportunity for simultaneous measurement of these gases concentration at ppb level. Their sensitivity is comparable with sensitivities of instruments based on other methods, e.g. gas chromatography or mass spectrometry. Our sensors were used for some explosives detection as well. The experiment showed that the sensors provide possibility to detect explosive devices consisting of nitroglycerine, ammonium nitrate, TNT, PETN, RDX and HMX.

  4. Nanomaterials for Electronics and Optoelectronics (United States)

    Koehne, Jessica E.; Meyyappan, M.


    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.

  5. Characterisation of coated aerosols using optical tweezers and neutron reflectometry (United States)

    Jones, S. H.; Ward, A.; King, M. D.


    Thin organic films are believed to form naturally on the surface of aerosols [1,2] and influence aerosol properties. Cloud condensation nuclei formation and chemical reactions such as aerosol oxidation are effected by the presence of thin films [3]. There is a requirement to characterise the physical properties of both the core aerosol and its organic film in order to fully understand the contribution of coated aerosols to the indirect effect. Two complementary techniques have been used to study the oxidation of thin organic films on the surface of aerosols; laser optical tweezers and neutron reflectometry. Micron sized polystyrene beads coated in oleic acid have been trapped in air using two counter propagating laser beams. Polystyrene beads are used as a proxy for solid aerosol. The trapped aerosol is illuminated with a white LED over a broadband wavelength range and the scattered light collected to produce a Mie spectrum [4]. Analysis of the Mie spectrum results in determination of the core polystyrene bead radius, the oleic acid film thickness and refractive index dispersion of the core and shell [5]. A flow of ozone gas can then be introduced into the aerosol environment to oxidise the thin film of oleic acid and the reaction followed by monitoring the changes in the Mie spectrum. The results demonstrate complete removal of the oleic acid film. We conclude that the use of a counter propagating optical trap combined with white light Mie spectroscopy can be used to study a range of organic films on different types of aerosols and their oxidation reactions. Neutron reflectometry has been used as a complementary technique to study the oxidation of monolayer films at the air-water interface in order to gain information on reaction kinetics. The oxidation of an oleic acid film at the air-water interface by the common tropospheric oxidant ozone has been studied using a Langmuir trough. Results indicate complete removal of the oleic acid film with ozone in agreement

  6. Dynamic properties of bacterial pili measured by optical tweezers (United States)

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


    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.

  7. Substrate-dependent cell elasticity measured by optical tweezers indentation (United States)

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


    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).

  8. Oxide Heteroepitaxy for Flexible Optoelectronics. (United States)

    Bitla, Yugandhar; Chen, Ching; Lee, Hsien-Chang; Do, Thi Hien; Ma, Chun-Hao; Qui, Le Van; Huang, Chun-Wei; Wu, Wen-Wei; Chang, Li; Chiu, Po-Wen; Chu, Ying-Hao


    The emerging technological demands for flexible and transparent electronic devices have compelled researchers to look beyond the current silicon-based electronics. However, fabrication of devices on conventional flexible substrates with superior performance are constrained by the trade-off between processing temperature and device performance. Here, we propose an alternative strategy to circumvent this issue via the heteroepitaxial growth of transparent conducting oxides (TCO) on the flexible mica substrate with performance comparable to that of their rigid counterparts. With the examples of ITO and AZO as a case study, a strong emphasis is laid upon the growth of flexible yet epitaxial TCO relying muscovite's superior properties compared to those of conventional flexible substrates and its compatibility with the present fabrication methods. Besides excellent optoelectro-mechanical properties, an additional functionality of high-temperature stability, normally lacking in the current state-of-the-art transparent flexitronics, is provided by these heterostructures. These epitaxial TCO electrodes with good chemical and thermal stabilities as well as mechanical durability can significantly contribute to the field of flexible, light-weight, and portable smart electronics.

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

    CERN Document Server

    bin M Yusoff, Abdul Rashid


    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-

  10. In-situ nanochemistry for optoelectronics (United States)

    Kim, Won Jin

    This thesis describes recent results on simple methods to arrange nanosize objects such as semiconductor nanocrystals, noble metal nanoparticles, and upconversion nanophosphors by means of top-down processes. Specific focus is directed towards approaches to produce predefined patterns of various nanostructure materials using optical lithography for direct writing of films for optoelectronic and electronic devices. To obtain photo-patternability, the nanostructure materials [for example semiconductor nanocrystals (CdSe, CdTe, PbSe), metallic nanoparticles (Ag), upconversion nanophosphors (Er3+/Yb 3+ or Tm3+/Yb3+ co-doped NaYF4 ), and transparent conducting oxide nanoparticles (ITO, ZnO)] were functionalized by incorporation of the functional ligand t-butoxycarbonyl (t-BOC) which has an acid-labile moiety. The t-BOC group undergoes a cleavage, when subjected to UV irradiation in the presence of a photo acid generator (PAG) to releases isobutene and carbon dioxide. Depending on the need of the application, either the exposed regions (negative pattern) or the non-exposed regions (positive pattern) could be developed from the exposed films by appropriate solvent selection. The photo exposed regions of the film are rendered hydrophilic due to the degradation of the t-BOC, the un-exposed regions remain hydrophobic. This solubility change in the QDs is the basis of their patternablity. The un-exposed regions can be removed to obtain the negative pattern by washing with hydrophobic solvents, whereas the exposed regions can be selectively removed to obtain positive pattern by washing with hydrophilic solvents. This change in the surface chemistry results in the ability to photo-pattern the various nanostructure materials where desired for a number of optoelectronic device geometries. We demonstrate that the ultimate resolution (linewidth and spacing) of this technique is below submicron. Details on technological aspects concerning nanoparticle patterning as well as practical

  11. Statistical conjugated polymers comprising optoelectronically distinct units. (United States)

    Hollinger, Jon; Sun, Jing; Gao, Dong; Karl, Dominik; Seferos, Dwight S


    Poly(3-heptylselenophene)-stat-poly(3-hexylthiophene) is synthesized and characterized in terms of its crystallinity and performance in an organic photovoltaic (OPV) cell. Despite the random distribution of units along the polymer main chain, the material is semi-crystalline, as demonstrated by differential scanning calorimetry and wide-angle X-ray diffraction. Thin-film absorption suggests an increased compatibility than seen with 3-hexylselenophene monomer. Optoelectronic properties are an average of the two homopolymers, and OPV performance is enhanced by a broadened absorption profile and a favorable morphology.

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

    NARCIS (Netherlands)

    Horst, Astrid van der


    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

  13. Multifunctional single beam acoustic tweezer for non-invasive cell/organism manipulation and tissue imaging (United States)

    Lam, Kwok Ho; Li, Ying; Li, Yang; Lim, Hae Gyun; Zhou, Qifa; Shung, Koping Kirk


    Non-contact precise manipulation of single microparticles, cells, and organisms has attracted considerable interest in biophysics and biomedical engineering. Similar to optical tweezers, acoustic tweezers have been proposed to be capable of manipulating microparticles and even cells. Although there have been concerted efforts to develop tools for non-contact manipulation, no alternative to complex, unifunctional tweezer has yet been found. Here we report a simple, low-cost, multifunctional single beam acoustic tweezer (SBAT) that is capable of manipulating an individual micrometer scale non-spherical cell at Rayleigh regime and even a single millimeter scale organism at Mie regime, and imaging tissue as well. We experimentally demonstrate that the SBAT with an ultralow f-number (f# = focal length/aperture size) could manipulate an individual red blood cell and a single 1.6 mm-diameter fertilized Zebrafish egg, respectively. Besides, in vitro rat aorta images were collected successfully at dynamic foci in which the lumen and the outer surface of the aorta could be clearly seen. With the ultralow f-number, the SBAT offers the combination of large acoustic radiation force and narrow beam width, leading to strong trapping and high-resolution imaging capabilities. These attributes enable the feasibility of using a single acoustic device to perform non-invasive multi-functions simultaneously for biomedical and biophysical applications.

  14. Measurements of displacement and trapping force on micron-sized particles in optical tweezers system

    Institute of Scientific and Technical Information of China (English)

    郭红莲; 姚新程; 李兆霖; 程丙英; 韩学海; 张道中


    A high-stability optical tweezers equipped with a high-precision measurement system of displacement and force is set up. The results show that this combination can be used to carry out quantitative measurements of small displacements and forces for micron-sized spheres. The precision of measurements has reached nanometers and piconewtons, respectively.

  15. Optical tweezers in concentrated colloidal dispersions : Manipulating and imaging individual particles

    NARCIS (Netherlands)

    Vossen, Dirk Leo Joep


    Using a laser beam that is focused down to a diffraction-limited spot, particles with a size ranging from several nanometers up to tens of micrometers can be trapped and manipulated. This technique, known as "optical tweezers" or "optical trapping", has been used in a wide variety of (interdisciplin

  16. Research Advances: Nanoscale Molecular Tweezers; Cinnamon as Pesticide?; Recently Identified Dietary Sources of Antioxidants (United States)

    King, Angela G.


    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 .

  17. Modelling and studies of the spectral response of some optoelectronic components (United States)

    Albino, André; Bortoli, Daniele; Tlemçani, Mouhaydine; Joyce, António


    Solar radiation takes in today's world, an increasing importance. Different devices are used to carry out spectral and integrated measurements of solar radiation. Thus the sensors can be divided into the fallow types: Calorimetric, Thermomechanical, Thermoelectric and Photoelectric. The first three categories are based on components converting the radiation to temperature (or heat) and then into electrical quantity. On the other hand, the photoelectric sensors are based on semiconductor or optoelectronic elements that when irradiated change their impedance or generate a measurable electric signal. The response function of the sensor element depends not only on the intensity of the radiation but also on its wavelengths. The radiation sensors most widely used fit in the first categories, but thanks to the reduction in manufacturing costs and to the increased integration of electronic systems, the use of the photoelectric-type sensors became more interesting. In this work we present a study of the behavior of different optoelectronic sensor elements. It is intended to verify the static response of the elements to the incident radiation. We study the optoelectronic elements using mathematical models that best fit their response as a function of wavelength. As an input to the model, the solar radiation values are generated with a radiative transfer model. We present a modeling of the spectral response sensors of other types in order to compare the behavior of optoelectronic elements with other sensors currently in use.

  18. Optoelectronic pH Meter: Further Details (United States)

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


    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.

  19. 拉曼镊子结合多元统计方法分析两种人体滴虫的差异性%Investigation of Biochemical Diversity of Two Species of Trichomonads Based on Raman Tweezers Combined with Multistatistical Analysis

    Institute of Scientific and Technical Information of China (English)

    黄庶识; 赖钧灼; 梁裕芬; 韦俊彬


    应用单细胞激光拉曼光谱分析技术,对不同来源的阴道毛滴虫和口腔毛滴虫的拉曼光谱数据进行减背景、平滑、基线校正、归一化等处理后做主成分分析(PCA)和辨别函数分析(DFA)等多元统计分析.平均光谱和PCA分析结果表明,阴道毛滴虫和口腔毛滴虫差异最为明显是 1002 cm峰,其次,差异相关性最大的还有9个拉曼谱峰785,888,979,1127,1287,1317,1364,1446和1465 cm,其中4个峰来自核酸,6个峰归属于蛋白质信号峰,反映两种滴虫的蛋白质、核酸的相对含量差异较大,可以通过PCA方法鉴别两种毛滴虫的差异.由于口腔毛滴虫或阴道毛滴虫虫株间差异并不明显,应用PCA结合DFA多元统计学方法,在保留原有数据信息基础上,通过扩大组间差异,缩小组内差距,同种毛滴虫虫株间在一定程度得到区分.口腔毛滴虫4个虫株之间有12个峰是差异最大的谱峰,阴道毛滴虫4个虫株之间有14个峰是差异最大,反映了两种毛滴虫虫株之间核酸、蛋白质、脂类及糖类等生物大分子组成相对含量差异.此外,根据DFA中虫株间欧氏距离聚类,可以确知虫株之间的差异.%To investigate the biochemical components and structure between two species of trichomonads, a Raman tweezers was used to collect Raman spectra of single Trichomonas tenax and Trichomonas vaginalis cells taken from different patients, in which multiple statistical analysis, principal component analyses(PCA) and discriminant function analysis(DFA), were applied to distinguish the biological diversity between tow species of trichomonads and among their strains statistically. A laser beam was introduced into a sample pool on the stage of an inverted microscopy to form an optical trap, a uniform trichomonad with vitality was trapped randomly in water and the Raman scatter was collected, subsequently, Raman data were background-subtracted smoothed, baselined, normalized, PCA, DFA and hierarchical

  20. Fullerene recognition with molecular tweezers made up of efficient buckybowls: a dispersion-corrected DFT study. (United States)

    Josa, Daniela; Rodríguez-Otero, Jesús; Cabaleiro-Lago, Enrique M


    In 2007, Sygula and co-workers introduced a novel type of molecular tweezers with buckybowl pincers that have attracted the substantial interest of researchers due to their ideal architecture for recognizing fullerenes by concave-convex π∙∙∙π interactions (A. Sygula et al., J. Am. Chem. Soc., 2007, 129, 3842). Although in recent years some modifications have been performed on these original molecular tweezers to improve their ability for catching fullerenes, very few improvements were achieved to date. For that reason, in the present work a series of molecular tweezers have been devised and their supramolecular complexes with C60 studied at the B97-D2/TZVP//SCC-DFTB-D and B97-D2/TZVP levels. Three different strategies have been tested: (1) changing the corannulene pincers to other buckybowls, (2) replacing the tetrabenzocyclooctatetraene tether by a buckybowl, and (3) adding methyl groups on the molecular tweezers. According to the results, all the three approaches are effective, in such a way that a combination of the three strategies results in buckycatchers with complexation energies (with C60) up to 2.6 times larger than that of the original buckycatcher, reaching almost -100 kcal mol(-1). The B97-D2/TZVP//SCC-DFTB-D approach can be a rapid screening tool for testing new molecular tweezers. However, since this approach does not reproduce correctly the deformation energy and this energy represents an important contribution to the total complexation energy of complexes, subsequent higher-level re-optimization is compulsory to achieve reliable results (the full B97-D2/TZVP level is used herein). This re-optimization could be superfluous when quite rigid buckycatchers are studied.

  1. Optoelectronic sensors for subsea oil and gas production (United States)

    McStay, D.; Shiach, G.; Nolan, A.; McAvoy, S.


    The potential for optoelectronic sensor technology to provide the monitoring and control systems required for advanced subsea hydrocarbon production management is described. The utilisation of optoelectronic sensor technology to produce a new class of subsea Christmas Tree with in-built enhanced production monitoring and control systems as well as effective environmental monitoring systems is reported.

  2. Synthesis and Opto-electronic Properties of a Red-Emitting Heteroleptic Platinum Complex Using Pyrazol-based Diketone Derivative as Ancillary Ligand%Synthesis and Opto-electronic Properties of a Red-Emitting Heteroleptic Platinum Complex Using Pyrazol-based Diketone Derivative as Ancillary Ligand

    Institute of Scientific and Technical Information of China (English)

    邓继勇; 王亚飞; 李小双; 倪美君; 刘明; 刘煜; 雷钢铁; 朱美香; 朱卫国


    A red-emitting heteroleptic cyclometalated platinum(II) complex containing an ancillary ligand of pyra- zol-based diketone derivative was synthesized. Its optophysical and electroluminescent properties were studied. Compared to the reported (piq)Pt(acac) complex, this platinum(II) complex exhibited a blue-shifted UV absorption band at 300--450 nm, a low LUMO energy level and improved electroluminescent property. Using this platinum(II) complex as a single doping emitter and a blend of ploy(9,9-dioctylfluorene) and 2-tert-butylphenyl-5-phenyl- 1,3,4-oxadiazole as a host matrix, the fabricated polymer light-emitting devices displayed saturated red emission with a peak at 648 um and a shoulder at 601 nm. Furthermore, the emission quenching of the platinum(II) complex was significantly suppressed in these devices at high current density due to an introduction of the non-planar pyra- zol group into the ancillary ligand.

  3. Spatially resolved optoelectronic characterization of perovskite lead iodide nanostructures (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.

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

    Institute of Scientific and Technical Information of China (English)

    Bingkun ZHOU


    @@ 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.

  5. Optoelectronic properties of higher acenes, their BN analogue and substituted derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Armaković, Stevan, E-mail: [University of Novi Sad, Faculty of Sciences, Department of Physics, Trg Dositeja Obradovića 4, 21000, Novi Sad (Serbia); Armaković, Sanja J. [University of Novi Sad, Faculty of Sciences, Department of Chemistry, Biochemistry and Environmental Protection, Trg Dositeja Obradovića 3, 21000, Novi Sad (Serbia); Holodkov, Vladimir [Educons University, Faculty of Sport and Tourism - TIMS, Radnička 30a, 21000, Novi Sad (Serbia); Pelemiš, Svetlana [University of East Sarajevo, Faculty of Technology, Karakaj bb, 75400, Zvornik, Republic of Srpska, Bosnia and Herzegovina (Bosnia and Herzegovina)


    We have investigated optoelectronic properties of higher acenes: pentacene, hexacene, heptacene, octacene, nonacene, decacene and their boron-nitride (BN) analogues, within the framework of density functional theory (DFT). We have also investigated the optoelectronic properties of acenes modified by BN substitution. Calculated optoelectronic properties encompasses: oxidation and reduction potentials, electron and hole reorganization energies and energy difference between excited first singlet and triplet states ΔE(S{sub 1}−T{sub 1}). Oxidation and reduction potentials indicate significantly better stability of BN analogues, comparing with their all-carbon relatives. Although higher acenes possess lower electron and hole reorganization energies, with both best values much lower than 0.1 eV, their BN analogues also have competitive values of reorganization energies, especially for holes for which reorganization energy is also lower than 0.1 eV. On the other hand ΔE(S{sub 1}−T{sub 1}) is much better for BN analogues, having values that indicate that BN analogues are possible applicable for thermally activated delayed fluorescence. - Highlights: • Optoelectronic properties of structures based on higher acenes have been investigated. • Oxidation and reduction potentials together with reorganization energies are calculated. • TADF is analyzed through calculation of ΔE(S{sub 1}−T{sub 1}), which is much better for BN analogues. • Reorganization energies of acenes improve with the increase of number of benzene rings.

  6. Experimental phase diagram of negatively supercoiled DNA measured by magnetic tweezers and fluorescence (United States)

    Vlijm, Rifka; Mashaghi, Alireza; Bernard, Stéphanie; Modesti, Mauro; Dekker, Cees


    The most common form of DNA is the well-known B-structure of double-helix DNA. Many processes in the cell, however, exert force and torque, inducing structural changes to the DNA that are vital to biological function. Virtually all DNA in cells is in a state of negative supercoiling, with a DNA structure that is complex. Using magnetic tweezers combined with fluorescence imaging, we here study DNA structure as a function of negative supercoiling at the single-molecule level. We classify DNA phases based on DNA length as a function of supercoiling, down to a very high negative supercoiling density σ of -2.5, and forces up to 4.5 pN. We characterize plectonemes using fluorescence imaging. DNA bubbles are visualized by the binding of fluorescently labelled RPA, a eukaryotic single-strand-binding protein. The presence of Z-DNA, a left-handed form of DNA, is probed by the binding of Zα77, the minimal binding domain of a Z-DNA-binding protein. Without supercoiling, DNA is in the relaxed B-form. Upon going toward negative supercoiling, plectonemic B-DNA is being formed below 0.6 pN. At higher forces and supercoiling densities down to about -1.9, a mixed state occurs with plectonemes, multiple bubbles and left-handed L-DNA. Around σ = -1.9, a buckling transition occurs after which the DNA end-to-end length linearly decreases when applying more negative turns, into a state that we interpret as plectonemic L-DNA. By measuring DNA length, Zα77 binding, plectoneme and ssDNA visualisation, we thus have mapped the co-existence of many DNA structures and experimentally determined the DNA phase diagram at (extreme) negative supercoiling.The most common form of DNA is the well-known B-structure of double-helix DNA. Many processes in the cell, however, exert force and torque, inducing structural changes to the DNA that are vital to biological function. Virtually all DNA in cells is in a state of negative supercoiling, with a DNA structure that is complex. Using magnetic tweezers

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


    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 (United States)

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


    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. Experimental phase diagram of negatively supercoiled DNA measured by magnetic tweezers and fluorescence. (United States)

    Vlijm, Rifka; Mashaghi, Alireza; Bernard, Stéphanie; Modesti, Mauro; Dekker, Cees


    The most common form of DNA is the well-known B-structure of double-helix DNA. Many processes in the cell, however, exert force and torque, inducing structural changes to the DNA that are vital to biological function. Virtually all DNA in cells is in a state of negative supercoiling, with a DNA structure that is complex. Using magnetic tweezers combined with fluorescence imaging, we here study DNA structure as a function of negative supercoiling at the single-molecule level. We classify DNA phases based on DNA length as a function of supercoiling, down to a very high negative supercoiling density σ of -2.5, and forces up to 4.5 pN. We characterize plectonemes using fluorescence imaging. DNA bubbles are visualized by the binding of fluorescently labelled RPA, a eukaryotic single-strand-binding protein. The presence of Z-DNA, a left-handed form of DNA, is probed by the binding of Zα77, the minimal binding domain of a Z-DNA-binding protein. Without supercoiling, DNA is in the relaxed B-form. Upon going toward negative supercoiling, plectonemic B-DNA is being formed below 0.6 pN. At higher forces and supercoiling densities down to about -1.9, a mixed state occurs with plectonemes, multiple bubbles and left-handed L-DNA. Around σ = -1.9, a buckling transition occurs after which the DNA end-to-end length linearly decreases when applying more negative turns, into a state that we interpret as plectonemic L-DNA. By measuring DNA length, Zα77 binding, plectoneme and ssDNA visualisation, we thus have mapped the co-existence of many DNA structures and experimentally determined the DNA phase diagram at (extreme) negative supercoiling.

  10. 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....

  11. Optoelectronic circuits in nanometer CMOS technology

    CERN Document Server

    Atef, Mohamed


    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...

  12. Tracking of Single Quantum Dot Labeled EcoRV Sliding along DNA Manipulated by Double Optical Tweezers


    Biebricher, Andreas; Wende, Wolfgang; Escudé, Christophe; Pingoud, Alfred; Desbiolles, Pierre


    Fluorescence microscopy provides a powerful method to directly observe single enzymes moving along a DNA held in an extended conformation. In this work, we present results from single EcoRV enzymes labeled with quantum dots which interact with DNA manipulated by double optical tweezers. The application of quantum dots facilitated accurate enzyme tracking without photobleaching whereas the tweezers allowed us to precisely control the DNA extension. The labeling did not affect the biochemical a...

  13. Communications with chaotic optoelectronic systems cryptography and multiplexing (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.

  14. Research of Opto-electronic Match in Long-distance Laser Ranging System Based on APD%基于APD的远程激光测距系统光电匹配研究

    Institute of Scientific and Technical Information of China (English)



    针对主动式红外弱光检测,本文研究如何提高和稳定雪崩光电二极管APD电路增益,及其光电匹配参数.该方法根据APD增益或噪声与反向偏压分别呈指数或线性关系,采用温度补偿电路稳定APD偏压,通过调整串联稳压管获得接近APD的温度系数,使器件工作点接近其击穿电压,获得超100倍的增益.采用交流耦合的本级负反馈低电压低噪声NPN晶体管电路,提高频响和晶体管截止频率fT.在保持电路稳定性的前提下,电压增益可提高到原来的2~3倍,光电系统灵敏度提高23 dB以上.功率激光二极管LD的PN结温度变化导致波长漂移,难与极窄带宽匹配.抑制背景辐射的干涉滤光片带宽介于10~15 nm为宜.%Aimed at active weak IR detection, how to get the stable high gain from Avalanche Photodiode (APD) circuits and its opto-electronic matching characters are researched. The methods are relation with APD exponent gain and linear noise with its reverse bias voltage. It gets closed to temperature coefficient by serial Zener diodes and always-stable bias voltage to APD near break voltage at real PN junction temperature, and is over 100 times gain with temperature complement circuits. Transistor cut-off frequency and its response are increased by NPN type transistor with an improved a.c. couple low noise and low voltage supplier negative feedback circuits. The system voltage gain enhances 2 to 3 times,and opto-electronic sensitivity rises over 23 dB. Because PN junction temperature of power LD changes causes wavelength drift, it is very difficult to match extremely narrow bandwidth interference filters. So the interference filter bandwidth between 10 and 15 nm is available for background radiation depression.

  15. Neural Network for Image-to-Image Control of Optical Tweezers (United States)

    Decker, Arthur J.; Anderson, Robert C.; Weiland, Kenneth E.; Wrbanek, Susan Y.


    A method is discussed for using neural networks to control optical tweezers. Neural-net outputs are combined with scaling and tiling to generate 480 by 480-pixel control patterns for a spatial light modulator (SLM). The SLM can be combined in various ways with a microscope to create movable tweezers traps with controllable profiles. The neural nets are intended to respond to scattered light from carbon and silicon carbide nanotube sensors. The nanotube sensors are to be held by the traps for manipulation and calibration. Scaling and tiling allow the 100 by 100-pixel maximum resolution of the neural-net software to be applied in stages to exploit the full 480 by 480-pixel resolution of the SLM. One of these stages is intended to create sensitive null detectors for detecting variations in the scattered light from the nanotube sensors.

  16. Probing the structural dynamics of proteins and nucleic acids with optical tweezers. (United States)

    Ritchie, Dustin B; Woodside, Michael T


    Conformational changes are an essential feature of most molecular processes in biology. Optical tweezers have emerged as a powerful tool for probing conformational dynamics at the single-molecule level because of their high resolution and sensitivity, opening new windows on phenomena ranging from folding and ligand binding to enzyme function, molecular machines, and protein aggregation. By measuring conformational changes induced in a molecule by forces applied by optical tweezers, new insight has been gained into the relationship between dynamics and function. We discuss recent advances from studies of how structure forms in proteins and RNA, including non-native structures, fluctuations in disordered proteins, and interactions with chaperones assisting native folding. We also review the development of assays probing the dynamics of complex protein-nucleic acid and protein-protein assemblies that reveal the dynamic interactions between biomolecular machines and their substrates.

  17. 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


    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...

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

    CERN Document Server

    Baresch, Diego; Marchiano, Régis


    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...

  19. Organic component vapor pressures and hygroscopicities of aqueous aerosol measured by optical tweezers


    Cai, Chen; Stewart, David J.; Reid, Jonathan P; Zhang, Yun Hong; Ohm, Peter; Dutcher, Cari S.; Clegg, Simon L.


    Measurements of the hygroscopic response of aerosol and the particle-to-gas partitioning of semivolatile organic compounds are crucial for providing more accurate descriptions of the compositional and size distributions of atmospheric aerosol. Concurrent measurements of particle size and composition (inferred from refractive index) are reported here using optical tweezers to isolate and probe individual aerosol droplets over extended timeframes. The measurements are shown to allow accurate re...

  20. 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.

  1. Raman Tweezers as a Diagnostic Tool of Hemoglobin-Related Blood Disorders

    Directory of Open Access Journals (Sweden)

    Giulia Rusciano


    Full Text Available This review presents the development of a Raman Tweezers system for detecting hemoglobin-related blood disorders at a single cell level. The study demonstrates that the molecular fingerprint insight provided by Raman analysis holds great promise for distinguishing between healthy and diseased cells in the field of biomedicine. Herein a Raman Tweezers system has been applied to investigate the effects of thalassemia, a blood disease quite diffuse in the Mediterranean Sea region. By resonant excitation of hemoglobin Raman bands, we examined the oxygenation capability of normal, alpha- and beta-thalassemic erythrocytes. A reduction of this fundamental red blood cell function, particularly severe for beta-thalassemia, has been found. Raman spectroscopy was also used to draw hemoglobin distribution inside single erythrocytes; the results confirmed the characteristic anomaly (target shape, occurring in thalassemia and some other blood disorders. The success of resonance Raman spectroscopy for thalassemia detection reported in this review provide an interesting starting point to explore the application of a Raman Tweezers system in the analysis of several blood disorders.

  2. Opto-electronic devices from block copolymers and their oligomers.

    NARCIS (Netherlands)

    Hadziioannou, G


    This paper presents research activities towards the development of polymer materials and devices for optoelectronics, An approach to controlling the conjugation length and transferring the luminescence properties of organic molecules to polymers through black copolymers containing well-defined conju

  3. Optoelectronic Infrastructure for RF/Optical Phased Arrays Project (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 array...

  4. Optoelectronic Infrastructure for RF/Optical Phased Arrays Project (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...

  5. Architectural and performance considerations for a 10(7)-instruction/sec optoelectronic central processing unit. (United States)

    Arrathoon, R; Kozaitis, S


    Architectural considerations for a multiple-instruction, single-data-based optoelectronic central processing unit operating at 10(7) instructions per second are detailed. Central to the operation of this device is a giant fiber-optic content-addressable memory in a programmable logic array configuration. The design includes four instructions and emphasizes the fan-in and fan-out capabilities of optical systems. Interconnection limitations and scaling issues are examined.

  6. Metal-dielectric hybrid surfaces as integrated optoelectronic interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Narasimhan, Vijay K.; Hymel, Thomas M.; Lai, Ruby A.; Cui, Yi


    An optoelectronic device has a hybrid metal-dielectric optoelectronic interface including an array of nanoscale dielectric resonant elements (e.g., nanopillars), and a metal film disposed between the dielectric resonant elements and below a top surface of the resonant elements such that the dielectric resonant elements protrude through the metal film. The device may also include an anti-reflection coating. The device may further include a metal film layer on each of the dielectric resonant elements.

  7. Optoelectronic device with nanoparticle embedded hole injection/transport layer (United States)

    Wang, Qingwu [Chelmsford, MA; Li, Wenguang [Andover, MA; Jiang, Hua [Methuen, MA


    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.

  8. Functionalization of Semiconductor Nanomaterials for Optoelectronic Devices And Components (United States)


    AFRL-OSR-VA-TR-2015-0069 FUNCTIONALIZATIONS OF SEMICONDUCTOR NANOMATERIALS FOR OPTOELECTROINC DEVEICE AND Omar Manasreh UNIVERSITY OF ARKANSAS Final...Functionalization of semiconductor nanomaterials for optoelectronic devices and components 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-10-1-0136 5c. PROGRAM...Distribution A 13. SUPPLEMENTARY NOTES None 14. ABSTRACT Various semiconductor nanomaterials were functionalized for optoelectronic devices, such

  9. Emissive polymeric materials for optoelectronic devices (United States)

    Shiang, Joseph John; Chichak, Kelly Scott; Cella, James Anthony; Lewis, Larry Neil; Janora, Kevin Henry


    Polymers including at least one structural unit derived from a compound of formula I or including at least one pendant group of formula II may be used in optoelectronic devices ##STR00001## wherein R.sup.1, R.sup.3, R.sup.4 and R.sup.6 are independently hydrogen, alkyl, alkoxy, oxaalkyl, alkylaryl, aryl, arylalkyl, heteroaryl, substituted alkyl; substituted alkoxy, substituted oxaalkyl, substituted alkylaryl, substituted aryl, substituted arylalkyl, or substituted heteroaryl; R.sup.1a is hydrogen or alkyl; R.sup.2 is alkylene, substituted alkylene, oxaalkylene, CO, or CO.sub.2; R.sup.2a is alkylene; R.sup.5 is independently at each occurrence hydrogen, alkyl, alkylaryl, aryl, arylalkyl, alkoxy, carboxy, substituted alkyl; substituted alkylaryl, substituted aryl, substituted arylalkyl, or substituted alkoxy, X is halo, triflate, --B(OR.sup.1a).sub.2, or ##STR00002## located at the 2, 5- or 2, 7-positions; and L is derived from phenylpyridine, tolylpyridine, benzothienylpyridine, phenylisoquinoline, dibenzoquinozaline, fluorenylpyridine, ketopyrrole, 2-(1-naphthyl)benzoxazole)), 2-phenylbenzoxazole, 2-phenylbenzothiazole, coumarin, thienylpyridine, phenylpyridine, benzothienylpyridine, 3-methoxy-2-phenylpyridine, thienylpyridine, phenylimine, vinylpyridine, pyridylnaphthalene, pyridylpyrrole, pyridylimidazole, phenylindole, derivatives thereof or combinations thereof.

  10. Assessment of dental plaque by optoelectronic methods (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.


    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.

  11. Research progress of low-dimensional perovskites: synthesis, properties and optoelectronic applications (United States)

    Min, Xinzhe; Pengchen, Zhu; Gu, Shuai; Jia, Zhu


    The lead halide-based perovskites, for instance, CH3NH3PbX3 and CsPbX3 (X = Cl, Br, I), have received a lot of attention. Compared with bulk materials, low-dimensional perovskites have demonstrated a range of unique optical, electrical and mechanical properties, which enable wide applications in solar cells, lasers and other optoelectronic devices. In this paper, we provide a summary of the research progress of the low-dimensional perovskites in recent years, from synthesis methods, basic properties to their optoelectronic applications. Project jointly supported by the State Key Program for Basic Research of China (No. 2015CB659300), the National Natural Science Foundation of China (Nos. 11321063, 11574143), the Natural Science Foundation of Jiangsu Province (Nos. BK20150056, BK20151079), the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), and the Fundamental Research Funds for the Central Universities.

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

    Directory of Open Access Journals (Sweden)

    Eng Png Ching


    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.

  13. Modeling and optoelectronic realization of an artificial cortex (United States)

    Pashaie, Ramin

    codes and cortical topological computational maps. Next step in this research is seeking suitable enabling technologies, such as electronics and optics, for hardware implementation of these cortical models. It is a general consensus that realization of parallelism and massive interconnections can be done far better in optics compared to electronics. Nevertheless, one can exploit optoelectronic methodologies that combine the benefits of optics with flexibilities of electronics. An innovative optoelectronic approach is taking advantage of the optical mechanism of a special type of stimulable storage phosphor, the so called electron trapping materials. Our analytical modelings and experimental works reveal that the equilibrium state luminescence of this material can be controlled to generate a variety of different nonlinear behaviors including quasi-quadratic responses that can be used for generation of quadratic return maps. Combining this versatility with the state-of-the-art high speed spatial light modulators and CCD cameras, large arrays of quadratic return maps can be accommodated in a thin film of electron trapping material. Another approach which is investigated in this dissertation is based on using the recently developed digital microelectromechanic spatial light modulators. These modulators can control the exposure precisely. We show that a closed loop of such a spatial light modulator and a CCD camera can be used to build an optoelectronic machine suitable for parallel recursive computations similar to our cortical models.

  14. High throughput optoelectronic smart pixel systems using diffractive optics (United States)

    Chen, Chih-Hao


    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

  15. 泽尼克多项式校正全息阵列光镊像差的实验研究%Aberrations in holographic array optical tweezers corrected with Zernike polynomials

    Institute of Scientific and Technical Information of China (English)

    刘伟伟; 任煜轩; 高红芳; 孙晴; 王自强; 李银妹


    像差会影响光镊对粒子的捕获效果.全息阵列光镊中,像差不仅来自光学元件,由特定算法设计的光阱相位片也会在光路中引入像差.本文通过液晶空间光调制器加载泽尼克多项式相位图,对全息阵列光镊中由光栅透镜组型算法引起的像差进行校正.结果显示:利用三阶泽尼克多项式可有效消除光路中由光栅透镜组型算法引起的慧差,使得捕获2“m聚苯乙烯小球的阵列光阱刚度提高了约40%;对比不同项的像差校正结果发现,全息阵列光镊中由算法引起的慧差与光学元件引起的像差一样,也会对阵列光阱的捕获效果产生较大影响;同时根据一阶像差校正结果可得光栅透镜组型算法对于一阶泽尼克像差具有鲁棒性.实验结果表明,对全息阵列光镊中由算法引起的像差进行校正,对于提高光阱的捕获效果和深化对算法特性的认识都具有重要意义.%Aberrations will degrade trapping performance of optical tweezers. In the holographic optical tweezers, aberrations originate not only from optical elements but also from holographic phase hologram of optical traps designed by a certain algorithna. We utilize a spatial light modulator to imprint Zernike polynomials phase hologram for correcting some certain aberrations in holographic array optical tweezers which are caused by grating and lens algorithm. The results show that thirdorder Zernike term can effectively correct coma due to the algorithm in the optical train, and the trap stiffness for 2 tm microns diameter polystyrene beads can reach 40%. Further comparison between different Zernike term aberration correction effects demonstrates that coma caused by grating and lens algorithm in the holographic array optical tweezer has the same serious influence on tweezer trapping performance as the aberrations originating from optical elements. Meanwhile, based on firstorder Zernike term

  16. Molecular doping of single-walled carbon nanotube transistors: optoelectronic study (United States)

    Zhang, Jiangbin; Emelianov, Aleksei V.; Bakulin, Artem A.; Bobrinetskiy, Ivan I.


    Single-walled carbon nanotubes (SWCNT) are a promising material for future optoelectronic applications, including flexible electrodes and field-effect transistors. Molecular doping of carbon nanotube surface can be an effective way to control the electronic structure and charge dynamics of these material systems. Herein, two organic semiconductors with different energy level alignment in respect to SWCNT are used to dope the channel of the SWCNT-based transistor. The effects of doping on the device performance are studied with a set of optoelectronic measurements. For the studied system, we observed an opposite change in photo-resistance, depending on the type (electron donor vs electron acceptor) of the dopants. We attribute this effect to interplay between two effects: (i) the change in the carrier concentration and (ii) the formation of trapping states at the SWCNT surface. We also observed a modest 4 pA photocurrent generation in the doped systems, which indicates that the studied system could be used as a platform for multi-pulse optoelectronic experiments with photocurrent detection.

  17. The Search for Sub-Bandgap Optoelectronic Response in Silicon Hyperdoped with Gold (United States)

    Mailoa, Jonathan; Akey, Austin; Mathews, Jay; Hutchinson, David; Simmons, Christie; Sullivan, Joseph; Winkler, Mark; Recht, Dan; Persans, Peter; Warrender, Jeffrey; Aziz, Michael; Buonassisi, Tonio


    Deep-level dopants have been long known as the lifetime-killer in microelectronic devices. Nevertheless, it has been shown that deep-level donor can facilitate strong absorption of light with energy below the semiconductor bandgap. Due to this strong sub-bandgap absorption, it is possible to engineer silicon devices exhibiting sub-bandgap optoelectronic response, such as silicon-based infrared photodetectors and intermediate-band solar cells. In this work, we show the optoelectronic response of silicon doped with a gold concentration surpassing the equilibrium solubility limit (gold-hyperdoped silicon, Au:Si). We fabricated Au:Si by ion implantation followed by nanosecond pulse laser melting, achieving a gold dopant concentration of over 1019 cm-3. UV-VIS spectrophotometry was performed to measure sub-bandgap light absorption in the Au:Si layer. Our samples with the highest gold concentration have 10-15% absorption of sub-bandgap light. We will present and discuss the sub-bandgap optoelectronic response of this gold-doped silicon.

  18. Synthesis and optoelectronic properties of quaternary GaInAsSb alloy nanosheets (United States)

    Chen, Xinliang; Li, Honglai; Qi, Zhaoyang; Yang, Tiefeng; Yang, Yankun; Hu, Xuelu; Zhang, Xuehong; Zhu, Xiaoli; Zhuang, Xiujuan; Hu, Wei; Pan, Anlian


    Quasi-one-dimensional (1D) nanostructures have been extensively explored for electronic and optoelectronic devices on account of their unique morphologies and versatile physical properties. Here, we report the successful synthesis of GaInAsSb alloy nanosheets by a simple chemical vapor deposition method. The grown GaInAsSb alloy nanosheets are pure zinc-blende single crystals, which show nanosize-induced extraordinary optoelectronic properties as compared with bulk materials. μ-Raman spectra exhibit a multi-mode phonon vibration behavior with clear frequency shifts under varied laser power. Photoluminescence measurements reveal a strong light emission in the near-infrared region (1985 nm), and the obtained Varshni thermal coefficients α and β are smaller than those of the bulk counterparts due to the size confinement effect. In addition, photodetectors (PDs) based on these single-alloy nanosheets were constructed for the first time. The PDs show a strong response in the near-infrared region with the external quantum efficiency of 8.05 × 104%, and the responsivity of 0.675 × 103 A W-1. These novel nanostructures would make contributions to the study of fundamental physical phenomena in quasi-1D nanomaterial systems and can be potential building blocks for optoelectronic and quantum devices.

  19. Solution growth of single crystal methylammonium lead halide perovskite nanostructures for optoelectronic and photovoltaic applications. (United States)

    Fu, Yongping; Meng, Fei; Rowley, Matthew B; Thompson, Blaise J; Shearer, Melinda J; Ma, Dewei; Hamers, Robert J; Wright, John C; Jin, Song


    Understanding crystal growth and improving material quality is important for improving semiconductors for electronic, optoelectronic, and photovoltaic applications. Amidst the surging interest in solar cells based on hybrid organic-inorganic lead halide perovskites and the exciting progress in device performance, improved understanding and better control of the crystal growth of these perovskites could further boost their optoelectronic and photovoltaic performance. Here, we report new insights on the crystal growth of the perovskite materials, especially crystalline nanostructures. Specifically, single crystal nanowires, nanorods, and nanoplates of methylammonium lead halide perovskites (CH3NH3PbI3 and CH3NH3PbBr3) are successfully grown via a dissolution-recrystallization pathway in a solution synthesis from lead iodide (or lead acetate) films coated on substrates. These single crystal nanostructures display strong room-temperature photoluminescence and long carrier lifetime. We also report that a solid-liquid interfacial conversion reaction can create a highly crystalline, nanostructured MAPbI3 film with micrometer grain size and high surface coverage that enables photovoltaic devices with a power conversion efficiency of 10.6%. These results suggest that single-crystal perovskite nanostructures provide improved photophysical properties that are important for fundamental studies and future applications in nanoscale optoelectronic and photonic devices.

  20. Accuracy and feasibility of optoelectronic sensors for weed mapping in wide row crops. (United States)

    Andújar, Dionisio; Ribeiro, Ángela; Fernández-Quintanilla, César; Dorado, José


    The main objectives of this study were to assess the accuracy of a ground-based weed mapping system that included optoelectronic sensors for weed detection, and to determine the sampling resolution required for accurate weed maps in maize crops. The optoelectronic sensors were located in the inter-row area of maize to distinguish weeds against soil background. The system was evaluated in three maize fields in the early spring. System verification was performed with highly reliable data from digital images obtained in a regular 12 m × 12 m grid throughout the three fields. The comparison in all these sample points showed a good relationship (83% agreement on average) between the data of weed presence/absence obtained from the optoelectronic mapping system and the values derived from image processing software ("ground truth"). Regarding the optimization of sampling resolution, the comparison between the detailed maps (all crop rows with sensors separated 0.75 m) with maps obtained with various simulated distances between sensors (from 1.5 m to 6.0 m) indicated that a 4.5 m distance (equivalent to one in six crop rows) would be acceptable to construct accurate weed maps. This spatial resolution makes the system cheap and robust enough to generate maps of inter-row weeds.

  1. Electronic and optoelectronic materials and devices inspired by nature (United States)

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


    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.

  2. Photo-switchable tweezers illuminate pore-opening motions of an ATP-gated P2X ion channel. (United States)

    Habermacher, Chloé; Martz, Adeline; Calimet, Nicolas; Lemoine, Damien; Peverini, Laurie; Specht, Alexandre; Cecchini, Marco; Grutter, Thomas


    P2X receptors function by opening a transmembrane pore in response to extracellular ATP. Recent crystal structures solved in apo and ATP-bound states revealed molecular motions of the extracellular domain following agonist binding. However, the mechanism of pore opening still remains controversial. Here we use photo-switchable cross-linkers as 'molecular tweezers' to monitor a series of inter-residue distances in the transmembrane domain of the P2X2 receptor during activation. These experimentally based structural constraints combined with computational studies provide high-resolution models of the channel in the open and closed states. We show that the extent of the outer pore expansion is significantly reduced compared to the ATP-bound structure. Our data further reveal that the inner and outer ends of adjacent pore-lining helices come closer during opening, likely through a hinge-bending motion. These results provide new insight into the gating mechanism of P2X receptors and establish a versatile strategy applicable to other membrane proteins.

  3. Anion Recognition Using Novel and Colorimetric Tweezer Receptors:1,3-Phenylenedi(carbonylhydrazone) in Aqueous-organic Binary Solvents

    Institute of Scientific and Technical Information of China (English)

    ZHANG Youming; WANG Aixia; CAO Cheng; LENG Yanli; WEI Taibao


    Two novel artificial tweezer receptors 1,3-phenylenedi(carbonylhydrazone) derivatives with a symmetrical structure have been synthesized.Receptor 3a [1,3-di(salicylidenehydrazinocarbonyl)benzene] for anions (F-,CI-,Br-,I-,AcO-,HSO4-,H2PO-4,CIO-4) was investigated by UV-Vis spectroscopy in DMSO and even 85% DMSO-15% H2O binary solutions,respectively.Remarkable color changes from colorless to yellow were observed by the naked-eye upon addition of AcO-,F- and H2PO-4 to the solution of receptor 3a.The 1H NMR signals indicated that the receptor 3a underwent deprotonation after the addition of an excess of fluoride anion.In particular,the anion recognition was successfully applied to CH3COONa in 15% H20-85% DMSO.These findings were expected to be of significance for designing and developing novel color-based anion sensors operated in aqueous media.

  4. A polypeptide-DNA hybrid with selective linking capability applied to single molecule nano-mechanical measurements using optical tweezers. (United States)

    Moayed, Fatemeh; Mashaghi, Alireza; Tans, Sander J


    Many applications in biosensing, biomaterial engineering and single molecule biophysics require multiple non-covalent linkages between DNA, protein molecules, and surfaces that are specific yet strong. Here, we present a novel method to join proteins and dsDNA molecule at their ends, in an efficient, rapid and specific manner, based on the recently developed linkage between the protein StrepTactin (STN) and the peptide StrepTag II (ST). We introduce a two-step approach, in which we first construct a hybrid between DNA and a tandem of two STs peptides (tST). In a second step, this hybrid is linked to polystyrene bead surfaces and Maltose Binding Protein (MBP) using STN. Furthermore, we show the STN-tST linkage is more stable against forces applied by optical tweezers than the commonly used biotin-Streptavidin (STV) linkage. It can be used in conjunction with Neutravidin (NTV)-biotin linkages to form DNA tethers that can sustain applied forces above 65 pN for tens of minutes in a quarter of the cases. The method is general and can be applied to construct other surface-DNA and protein-DNA hybrids. The reversibility, high mechanical stability and specificity provided by this linking procedure make it highly suitable for single molecule mechanical studies, as well as biosensing and lab on chip applications.

  5. A polypeptide-DNA hybrid with selective linking capability applied to single molecule nano-mechanical measurements using optical tweezers.

    Directory of Open Access Journals (Sweden)

    Fatemeh Moayed

    Full Text Available Many applications in biosensing, biomaterial engineering and single molecule biophysics require multiple non-covalent linkages between DNA, protein molecules, and surfaces that are specific yet strong. Here, we present a novel method to join proteins and dsDNA molecule at their ends, in an efficient, rapid and specific manner, based on the recently developed linkage between the protein StrepTactin (STN and the peptide StrepTag II (ST. We introduce a two-step approach, in which we first construct a hybrid between DNA and a tandem of two STs peptides (tST. In a second step, this hybrid is linked to polystyrene bead surfaces and Maltose Binding Protein (MBP using STN. Furthermore, we show the STN-tST linkage is more stable against forces applied by optical tweezers than the commonly used biotin-Streptavidin (STV linkage. It can be used in conjunction with Neutravidin (NTV-biotin linkages to form DNA tethers that can sustain applied forces above 65 pN for tens of minutes in a quarter of the cases. The method is general and can be applied to construct other surface-DNA and protein-DNA hybrids. The reversibility, high mechanical stability and specificity provided by this linking procedure make it highly suitable for single molecule mechanical studies, as well as biosensing and lab on chip applications.

  6. History of modern optics ad optoelectronics development in China

    CERN Document Server

    Tian, Shouyun


    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.

  7. Measuring stall forces in vivo with optical tweezers through light momentum changes (United States)

    Mas, J.; Farré, A.; López-Quesada, C.; Fernández, X.; Martín-Badosa, E.; Montes-Usategui, M.


    The stall forces of processive molecular motors have been widely studied previously in vitro. Even so, in vivo experiments are required for determining the actual performance of each molecular motor in its natural environment. We report the direct measurement of light momentum changes in single beam optical tweezers as a suitable technique for measuring forces inside living cells, where few alternatives exist. The simplicity of this method, which does not require force calibration for each trapped object, makes it convenient for measuring the forces involved in fast dynamic biological processes such us intracellular traffic. Here we present some measurements of the stall force of processive molecular motors inside living Allium cepa cells.

  8. Laser-induced fusion of human embryonic stem cells with optical tweezers (United States)

    Chen, Shuxun; Cheng, Jinping; Kong, Chi-Wing; Wang, Xiaolin; Han Cheng, Shuk; Li, Ronald A.; Sun, Dong


    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.

  9. 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


    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.

  10. 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


    @@ 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.

  11. 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)


    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.

  12. Measurement of the total optical angular momentum transfer in optical tweezers

    CERN Document Server

    Parkin, S; Knoener, G; Nieminen, T A; Rubinsztein-Dunlop, H; Heckenberg, Norman R.; Knoener, Gregor; Nieminen, Timo A.; Parkin, Simon; Rubinsztein-Dunlop, Halina


    We describe a way to determine the total angular momentum, both spin and orbital, transferred to a particle trapped in optical tweezers. As an example an LG02 mode of a laser beam with varying degrees of circular polarisation is used to trap and rotate an elongated particle with a well defined geometry. The method successfully estimates the total optical torque applied to the particle. For this technique, there is no need to measure the viscous drag on the particle, as it is an optical measurement. Therefore, knowledge of the particle's size and shape, as well as the fluid's viscosity, is not required.

  13. Data on force-dependent structural changes of chromatin fibers measured with magnetic tweezers

    Directory of Open Access Journals (Sweden)

    Fan-Tso Chien


    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.

  14. Raman tweezers spectroscopy study of free radical induced oxidative stress leading to eryptosis (United States)

    Barkur, Surekha; Bankapur, Aseefhali; Chidangil, Santhosh


    Raman tweezers spectroscopy study of effect of free radicals was carried out on erythrocytes. We prepared hydroxyl radicals using Fenton reaction (which yields hydroxyl radicals). Raman spectra were acquired from single, trapped erythrocytes after supplementing with these free radicals. The changes in the Raman bands such as 1211 cm-1, 1224 cm-1, 1375 cm-1 indicate deoxygenation of red blood cells (RBCs). Our study shows that free radicals can induce oxidative stress on erythrocytes. The changes in the Raman spectra as well as shape of erythrocytes indicate that oxidative stress can trigger eryptosis in erythrocytes.

  15. Applications of HTSC films in hybrid optoelectronic devices (United States)

    Pavuna, Davor


    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.

  16. High bandgap III-V alloys for high efficiency optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Alberi, Kirstin; Mascarenhas, Angelo; Wanlass, Mark


    High bandgap alloys for high efficiency optoelectronics are disclosed. An exemplary optoelectronic device may include a substrate, at least one Al.sub.1-xIn.sub.xP layer, and a step-grade buffer between the substrate and at least one Al.sub.1-xIn.sub.xP layer. The buffer may begin with a layer that is substantially lattice matched to GaAs, and may then incrementally increase the lattice constant in each sequential layer until a predetermined lattice constant of Al.sub.1-xIn.sub.xP is reached.

  17. 77 FR 65713 - Certain Optoelectronic Devices for Fiber Optic Communications, Components Thereof, and Products... (United States)


    ... COMMISSION Certain Optoelectronic Devices for Fiber Optic Communications, Components Thereof, and Products... Singapore; and Avago Technologies U.S. Inc. of San Jose, California. Letters supplementing the complaint... the United States after importation of certain optoelectronic devices for fiber optic...

  18. Design of hybrid optical tweezers system for controlled three-dimensional micromanipulation (United States)

    Tanaka, Yoshio; Tsutsui, Shogo; Kitajima, Hiroyuki


    Three-dimensional (3D) micro/nano-manipulation using optical tweezers is a significant technique for various scientific fields ranging from biology to nanotechnology. For the dynamic handling of multiple/individual micro-objects in a true 3D working space, we present an improved hybrid optical tweezers system consisting of two multibeam techniques. These two techniques include the generalized phase contrast method with a spatial light modulator and the time-shared scanning method with a two-axis steering mirror and an electrically focus-tunable lens. Unlike our previously reported system that could only handle micro-objects in a two and half dimensional working space, the present system has high versatility for controlled manipulation of multiple micro-objects in a true 3D working space. The controlled rotation of five beads forming a pentagon, that of four beads forming a tetrahedron about arbitrary axes, and the fully automated assembly and subsequent 3D translation of micro-bead arrays are successfully demonstrated as part of the 3D manipulation experiment.

  19. Application of optical tweezers and excimer laser to study protoplast fusion (United States)

    Kantawang, Titirat; Samipak, Sompid; Limtrakul, Jumras; Chattham, Nattaporn


    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.

  20. Understanding local forces in electrophoretic ink systems: utilizing optical tweezers to explore electrophoretic display devices (United States)

    Wei, David L.; Dickinson, Mark R.; Smith, N.; Gleeson, Helen F.


    Optical tweezers can be used as a valuable tool to characterize electrophoretic display (EPD) systems. EPDs are ubiquitous with e-readers and are becoming a commonplace technology where reflective, low-power displays are required; yet the physics of some features crucial to their operation remains poorly defined. We utilize optical tweezers as a tool to understand the motion of charged ink particles within the devices and show that the response of optically trapped electrophoretic particles can be used to characterize electric fields within these devices. This technique for mapping the force can be compared to simulations of the electric field in our devices, thus demonstrating that the electric field itself is the sole governor of the particle motion in an individual-particle regime. By studying the individual-particle response to the electric field, we can then begin to characterize particle motion in `real' systems with many particles. Combining optical tweezing with particle tracking techniques, we can investigate deviations in many particle systems from the single-particle case.

  1. Chemotaxis study using optical tweezers to observe the strength and directionality of forces of Leishmania amazonensis (United States)

    Pozzo, Liliana d. Y.; Fontes, Adriana; de Thomaz, André A.; Barbosa, Luiz C.; Ayres, Diana C.; Giorgio, Selma; Cesar, Carlos L.


    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.

  2. A study of red blood cell deformability in diabetic retinopathy using optical tweezers (United States)

    Smart, Thomas J.; Richards, Christopher J.; Bhatnagar, Rhythm; Pavesio, Carlos; Agrawal, Rupesh; Jones, Philip H.


    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.

  3. Natural user interface as a supplement of the holographic Raman tweezers (United States)

    Tomori, Zoltan; Kanka, Jan; Kesa, Peter; Jakl, Petr; Sery, Mojmir; Bernatova, Silvie; Antalik, Marian; Zemánek, Pavel


    Holographic Raman tweezers (HRT) manipulates with microobjects by controlling the positions of multiple optical traps via the mouse or joystick. Several attempts have appeared recently to exploit touch tablets, 2D cameras or Kinect game console instead. We proposed a multimodal "Natural User Interface" (NUI) approach integrating hands tracking, gestures recognition, eye tracking and speech recognition. For this purpose we exploited "Leap Motion" and "MyGaze" low-cost sensors and a simple speech recognition program "Tazti". We developed own NUI software which processes signals from the sensors and sends the control commands to HRT which subsequently controls the positions of trapping beams, micropositioning stage and the acquisition system of Raman spectra. System allows various modes of operation proper for specific tasks. Virtual tools (called "pin" and "tweezers") serving for the manipulation with particles are displayed on the transparent "overlay" window above the live camera image. Eye tracker identifies the position of the observed particle and uses it for the autofocus. Laser trap manipulation navigated by the dominant hand can be combined with the gestures recognition of the secondary hand. Speech commands recognition is useful if both hands are busy. Proposed methods make manual control of HRT more efficient and they are also a good platform for its future semi-automated and fully automated work.

  4. Optical Tweezers Studies on Notch: Single-molecule Interaction Strength is Independent of Ligand Endocytosis (United States)

    Shergill, Bhupinder; Meloty-Kapella, Laurence; Musse, Abdiwahab A.; Weinmaster, Gerry; Botvinick, Elliot


    SUMMARY Notch signaling controls diverse cellular processes critical to development and disease. Cell surface ligands bind Notch on neighboring cells yet require endocytosis to activate signaling. The role ligand endocytosis plays in Notch activation has not been established. Here we integrate optical tweezers with cell biological and biochemical methods to test the prevailing model that ligand endocytosis facilitates recycling to enhance ligand interactions with Notch necessary to trigger signaling. Specifically, single-molecule measurements indicate that interference of ligand endocytosis and/or recycling does not alter the force required to rupture bonds formed between cells expressing the Notch ligand Delta-like1 (Dll1) and laser-trapped Notch1-beads. Together, our analyses eliminate roles for ligand endocytosis and recycling in Dll1-Notch1 interactions, and indicate that recycling indirectly affects signaling by regulating the accumulation of cell-surface ligand. Importantly, our study demonstrates the utility of optical tweezers to test a role for ligand endocytosis in generating cell-mediated mechanical force. PMID:22658935

  5. Intersatellite communications optoelectronics research at the Goddard Space Flight Center (United States)

    Krainak, Michael A.


    A review is presented of current optoelectronics research and development at the NASA Goddard Space Flight Center for high-power, high-bandwidth laser transmitters; high-bandwidth, high-sensitivity optical receivers; pointing, acquisition, and tracking components; and experimental and theoretical system modeling at the NASA Goddard Space Flight Center. Program hardware and space flight opportunities are presented.

  6. Opto-electronic properties of charged conjugated molecules

    NARCIS (Netherlands)

    Fratiloiu, S.


    The aim of this thesis is to provide fundamental insight into the nature and opto-electronic properties of charge carriers on conjugated oligomers and polymers. Electronic structure, optical absorption properties and distribution of charge carriers along the chains of different conjugated materials

  7. Simultaneous Thermoelectric and Optoelectronic Characterization of Individual Nanowires. (United States)

    Léonard, François; Song, Erdong; Li, Qiming; Swartzentruber, Brian; Martinez, Julio A; Wang, George T


    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.

  8. Optoelectronic Correlator Architecture for Shift Invariant Target Recognition

    CERN Document Server

    Monjur, Mehjabin S; Tripathi, Renu; Donoghue, John; Shahriar, M S


    In this paper, we present theoretical details and the underlying architecture of a hybrid optoelectronic correlator that correlates images using SLMs, detectors and VLSI chips. The proposed architecture bypasses the nonlinear material such as photorefractive polymer film by using detectors instead, and the phase information is yet conserved by the interference of plane waves with the images.

  9. 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


    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 ...

  10. Rapid and efficient synthesis of new chiral aromatic amide molecular tweezers under solvent-free conditions using microwave

    Institute of Scientific and Technical Information of China (English)

    Xiao Xiang Zhao; Zhi Gang Zhao; Xing Li Liu; Xiu Ming Wu


    An efficient and simple method for the synthesis of new chiral aromatic amide molecular tweezers by irradiation with microwave under solvent-free conditions has been developed.Its main advantages are short reaction times.good conversions and the environmentally friendly nature of the process.

  11. NAP1-Assisted Nucleosome Assembly on DNA Measured in Real Time by Single-Molecule Magnetic Tweezers

    NARCIS (Netherlands)

    Vlijm, R.; Smitshuijzen, J.S.J.; Lusser, A.; Dekker, C.


    While many proteins are involved in the assembly and (re)positioning of nucleosomes, the dynamics of protein-assisted nucleosome formation are not well understood. We study NAP1 (nucleosome assembly protein 1) assisted nucleosome formation at the single-molecule level using magnetic tweezers. This m

  12. Comparison of a high-speed camera and a quadrant detector for measuring displacements in optical tweezers (United States)

    Keen, S.; Leach, J.; Gibson, G.; Padgett, M. J.


    We compare the performance of a high-speed camera and a quadrant detector for measuring the displacement of micron-sized particles in optical tweezers. For trapping powers up to 100 mW, the standard deviation of the particle displacements measured by the two techniques shows excellent agreement. This comparison also provides a method for calibrating one technique against the other.

  13. RIR-MAPLE deposition of conjugated polymers and hybrid nanocomposites for application to optoelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Stiff-Roberts, Adrienne D.; Pate, Ryan; McCormick, Ryan; Lantz, Kevin R. [Department of Electrical and Computer Engineering, Duke University Box 90291, Durham, NC 27708-0291, 919-660-5560 (United States)


    Resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) is a variation of pulsed laser deposition that is useful for organic-based thin films because it reduces material degradation by selective absorption of infrared radiation in the host matrix. A unique emulsion-based RIR-MAPLE approach has been developed that reduces substrate exposure to solvents and provides controlled and repeatable organic thin film deposition. In order to establish emulsion-based RIR-MAPLE as a preferred deposition technique for conjugated polymer or hybrid nanocomposite optoelectronic devices, studies have been conducted to demonstrate the value added by the approach in comparison to traditional solution-based deposition techniques, and this work will be reviewed. The control of hybrid nanocomposite thin film deposition, and the photoconductivity in such materials deposited using emulsion-based RIR-MAPLE, will also be reviewed. The overall result of these studies is the demonstration of emulsion-based RIR-MAPLE as a viable option for the fabrication of conjugated polymer and hybrid nanocomposite optoelectronic devices that could yield improved device performance.

  14. Tunable Optical Tweezers for Wavelength-dependent Measurements (United States)


    nanoshells in addition to polystyrene and silica microspheres. A gold nanoshell is a small silica sphere coated with a thin, uni- form layer of gold.22 Based...on the overall size and the gold thickness, the nanoshell extinction resonance can be tuned from the visible to the infrared. We have trapped a range...Experimental extinction spectra of gold nanoshells in bulk (black dotted line) and polystyrene spheres in bulk (grey solid line) used in this study. The

  15. Computational design of surfaces, nanostructures and optoelectronic materials (United States)

    Choudhary, Kamal

    Properties of engineering materials are generally influenced by defects such as point defects (vacancies, interstitials, substitutional defects), line defects (dislocations), planar defects (grain boundaries, free surfaces/nanostructures, interfaces, stacking faults) and volume defects (voids). Classical physics based molecular dynamics and quantum physics based density functional theory can be useful in designing materials with controlled defect properties. In this thesis, empirical potential based molecular dynamics was used to study the surface modification of polymers due to energetic polyatomic ion, thermodynamics and mechanics of metal-ceramic interfaces and nanostructures, while density functional theory was used to screen substituents in optoelectronic materials. Firstly, polyatomic ion-beams were deposited on polymer surfaces and the resulting chemical modifications of the surface were examined. In particular, S, SC and SH were deposited on amorphous polystyrene (PS), and C2H, CH3, and C3H5 were deposited on amorphous poly (methyl methacrylate) (PMMA) using molecular dynamics simulations with classical reactive empirical many-body (REBO) potentials. The objective of this work was to elucidate the mechanisms by which the polymer surface modification took place. The results of the work could be used in tailoring the incident energy and/or constituents of ion beam for obtaining a particular chemistry inside the polymer surface. Secondly, a new Al-O-N empirical potential was developed within the charge optimized many body (COMB) formalism. This potential was then used to examine the thermodynamic stability of interfaces and mechanical properties of nanostructures composed of aluminum, its oxide and its nitride. The potentials were tested for these materials based on surface energies, defect energies, bulk phase stability, the mechanical properties of the most stable bulk phase, its phonon properties as well as with a genetic algorithm based evolution theory of

  16. Ultrafast properties of femtosecond-laser-ablated GaAs and its application to terahertz optoelectronics. (United States)

    Madéo, Julien; Margiolakis, Athanasios; Zhao, Zhen-Yu; Hale, Peter J; Man, Michael K L; Zhao, Quan-Zhong; Peng, Wei; Shi, Wang-Zhou; Dani, Keshav M


    We report on the first terahertz (THz) emitter based on femtosecond-laser-ablated gallium arsenide (GaAs), demonstrating a 65% enhancement in THz emission at high optical power compared to the nonablated device. Counter-intuitively, the ablated device shows significantly lower photocurrent and carrier mobility. We understand this behavior in terms of n-doping, shorter carrier lifetime, and enhanced photoabsorption arising from the ablation process. Our results show that laser ablation allows for efficient and cost-effective optoelectronic THz devices via the manipulation of fundamental properties of materials.

  17. Optoelectronic Recoded and Nonrecoded Trinary Signed-Digit Adder that uses Optical Correlation. (United States)

    Cherri, A K; Habib, M K; Alam, M S


    A symbolic-substitution-based optical numeric processor that uses recoded and nonrecoded trinary signed-digit (TSD) number representations is proposed. Also, we propose new joint spatial encodings for the TSD numbers that reduce the symbolic-substitution computation rules involved in the processor. Optoelectronic implementation of the proposed recoded adder is feasible. Also, the nonrecoded TSD addition can be performed optically in two steps. Both the proposed recoded and nonrecoded adders are more compact than a recently reported modified signed-digit counterpart and use fewer correlators and spatial light modulators.

  18. Carbon dots—Emerging light emitters for bioimaging, cancer therapy and optoelectronics

    KAUST Repository

    Hola, Katerina


    © 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.

  19. Reservoir computing with a slowly modulated mask signal for preprocessing using a mutually coupled optoelectronic system (United States)

    Tezuka, Miwa; Kanno, Kazutaka; Bunsen, Masatoshi


    Reservoir computing is a machine-learning paradigm based on information processing in the human brain. We numerically demonstrate reservoir computing with a slowly modulated mask signal for preprocessing by using a mutually coupled optoelectronic system. The performance of our system is quantitatively evaluated by a chaotic time series prediction task. Our system can produce comparable performance with reservoir computing with a single feedback system and a fast modulated mask signal. We showed that it is possible to slow down the modulation speed of the mask signal by using the mutually coupled system in reservoir computing.

  20. Silicon grating structures for optical fiber interfacing and III-V/silicon opto-electronic components (United States)

    Roelkens, Gunther; Vermeulen, Diedrik; Li, Yanlu; Muneeb, Muhammad; Hattasan, Nannicha; Ryckeboer, Eva; Deconinck, Yannick; Van Thourhout, Dries; Baets, Roel


    In this paper, we review our work on efficient, broadband and polarization independent interfaces between a silicon-on-insulator photonic IC and a single-mode optical fiber based on grating structures. The high alignment tolerance and the fact that the optical fiber interface is out-of-plane provide opportunities for easy packaging and wafer-scale testing of the photonic IC. Next to fiber-chip interfaces we will discuss the use of silicon grating structures in III-V on silicon optoelectronic components such as integrated photodetectors and microlasers.


    Institute of Scientific and Technical Information of China (English)


    In order for optical interconnection technologies to be incorporated into the next-generation parallel computers, new optoelectronic computer-aided design, integration, and packaging technologies must be investigated. One of the key issues in designing is the system volume, which is determined by maximum interconnection distance (MID) between PEs. A novel 2-D genetic algorithm was presented in this paper at the first time, and used to solve the placement of twin-butterfly multistage networks based on transmissive physical model. The experiment result shows that this algorithm case works better than other algorithm cases.

  2. Specification for a reconfigurable optoelectronic VLSI processor suitable for digital signal processing. (United States)

    Fey, D; Kasche, B; Burkert, C; Tschäche, O


    A concept for a parallel digital signal processor based on opticalinterconnections and optoelectronic VLSI circuits is presented. Itis shown that the proper combination of optical communication, architecture, and algorithms allows a throughput that outperformspurely electronic solutions. The usefulness of low-level algorithmsfrom the add-and-shift class is emphasized. These algorithms leadto fine-grain, massively parallel on-chip processor architectures withhigh demands for optical off-chip interconnections. A comparativeperformance analysis shows the superiority of a bit-serialarchitecture. This architecture is mapped onto an optoelectronicthree-dimensional circuit, and the necessary optical interconnectionscheme is specified.

  3. Absolute Position Total Internal Reflection Microscopy with an Optical Tweezer

    CERN Document Server

    Liu, Lulu; Rodriguez, Alejandro W; Capasso, Federico


    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.

  4. Flexible radio-frequency photonics: Optoelectronic frequency combs and integrated pulse shaping (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.

  5. Battlefield Lasers and Opto-electronics Systems (Review Paper

    Directory of Open Access Journals (Sweden)

    A. K. Maini


    Full Text Available During the last four decades or so, there has been an explosive growth in commercial, industrial, medical, scientific, technological, and above all, military usage of laser devices and systems. In fact, lasers have influenced every conceivable area of application during this period. While the expansion of non-military application spectrum of lasers is primarily driven by emergence of a large number of laser wavelengths followed by ever increasing power levels and reducing price tags at which those wavelengths could be generated, the military applications of lasers and related electro-optic devices have grown mainly because of technological maturity of the lasers that were born in the late 1960's and the early 1970's. Lasers have been used in various military applications since the early days of development that followed the invention of this magical device. There has been large scale proliferation of lasers and opto-electronic devices and systems for applications like range finding, target designation, target acquisition and tracking, precision guided munitions, etc. during 1970's and 1980's. These devices continue to improve in performance and find increased acceptance and usage in the contemporary battlefield scenario. Technological advances in optics, opto-electronics, and electronics, leading to more rugged, reliable, compact and efficient laser devices are largely responsible for making these indispensable in modern warfare. Past one decade or so has seen emergence of some new potential areas of usage. Some of these areas include rapid growth in the usage of lasers and opto-electronics devices and systems for electrooptic countermeasure (EOCM applications, test and evaluation systems that can perform online functionality checks on military opto-electronics systems and also their interoperability. In this paper, an overview of the current and emerging military applications of lasers and opto-electronics systems has been given with an outline

  6. Mapping and manipulating optoelectronic processes in emerging photovoltaic materials (United States)

    Leblebici, Sibel Yontz

    The goal of the work in this dissertation is to understand and overcome the limiting optoelectronic processes in emerging second generation photovoltaic devices. There is an urgent need to mitigate global climate change by reducing greenhouse gas emissions. Renewable energy from photovoltaics has great potential to reduce emissions if the energy to manufacture the solar cell is much lower than the energy the solar cell generates. Two emerging thin film solar cell materials, organic semiconductors and hybrid organic-inorganic perovskites, meet this requirement because the active layers are processed at low temperatures, e.g. 150 °C. Other advantages of these two classes of materials include solution processability, composted of abundant materials, strongly light absorbing, highly tunable bandgaps, and low cost. Organic solar cells have evolved significantly from 1% efficient devices in 1989 to 11% efficient devices today. Although organic semiconductors are highly tunable and inexpensive, the main challenges to overcome are the large exciton binding energies and poor understanding of exciton dynamics. In my thesis, I optimized solar cells based on three new solution processable azadipyrromethene-based small molecules. I used the highest performing molecule to study the effect of increasing the permittivity of the material by incorporating a high permittivity small molecule into the active layer. The studies on two model systems, small donor molecules and a polymer-fullerene bulk heterojunction, show that Frenkel and charge transfer exciton binding energies can be manipulated by controlling permittivity, which impacts the solar cell efficiency. Hybrid organic-inorganic perovskite materials have similar advantages to organic semiconductors, but they are not excitonic, which is an added advantage for these materials. Although photovoltaics based on hybrid halide perovskite materials have exceeded 20% efficiency in only a few years of optimization, the loss mechanisms

  7. Organic ferroelectric opto-electronic memories

    NARCIS (Netherlands)

    Asadi, K.; Li, M.; Blom, P.W.M.; Kemerink, M.; Leeuw, D.M. de


    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 ar


    Directory of Open Access Journals (Sweden)

    S. S. Kolasha


    Full Text Available Spacecraft optoelectronic modules traditionally have aluminum alloy or titanium alloy casing which substantial weight increases fuel consumption required to put them into orbit and, consequently, total cost of the project. Carbon fiber reinforced polymer based composite constructive materials is an efficient solution that allows reducing weight and dimensions of large optoelectronic modules 1,5–3 times and the coefficient of linear thermal expansion 15–20 times if compared with metals. Optical characteristic is a crucial feature of carbon-fibre-reinforced polymer that determines composite material interaction with electromagnetic emission within the optical range. This work was intended to develop a method to evaluate Carbon fiber reinforced polymer optoelectronic modules casing effect on lens scattering by computer simulation with Zemax application software package. Degrees of scattered, reflected and absorbed radiant flux effect on imaging quality are described here. The work included experimental study in order to determine bidirectional reflectance distribution function by goniometric method for LUP-0.1 carbon fabric check test pieces of EDT-69U epoxy binder with EPOFLEX-0.4 glue layer and 5056-3.5-23-A aluminium honeycomb filler. The scattered emission was registered within a hemisphere above the check test piece surface. Optical detection direction was determined with zenith (0º < θ < 90º and azimuth (0º < φ < 180º angles with 10° increment. The check test piece surface was proved to scatter emission within a narrow angle range (approximately 20° with clear directivity. Carbon fiber reinforced polymers was found to feature integrated reflectance coefficient 3 to 4 times greater than special coatings do. 

  9. Implementation and Tuning of an Optical Tweezers Force-Clamp Feedback System. (United States)

    Bugiel, Michael; Jannasch, Anita; Schäffer, Erik


    Feedback systems can be used to control the value of a system variable. In optical tweezers, active feedback is often implemented to either keep the position or tension applied to a single biomolecule constant. Here, we describe the implementation of the latter: an optical force-clamp setup that can be used to study the motion of processive molecular motors under a constant load. We describe the basics of a software-implemented proportional-integral-derivative (PID) controller, how to tune it, and how to determine its optimal feedback rate. Limitations, possible feed-forward applications, and extensions into two- and three-dimensional optical force clamps are discussed. The feedback is ultimately limited by thermal fluctuations and the compliance of the involved molecules. To investigate a particular mechanical process, understanding the basics and limitations of the feedback system will be helpful for choosing the proper feedback hardware, for optimizing the system parameters, and for the design of the experiment.

  10. Characterization of the mechanical properties of HL-1 cardiomyocytes with high throughput magnetic tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Chen, La; Maybeck, Vanessa; Offenhäusser, Andreas; Krause, Hans-Joachim [Institute of Bioelectronics (ICS-8/PGI-8), Forschungszentrum Jülich GmbH, 52425 Jülich (Germany)


    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.

  11. Calibration of trapping force and response function of optical tweezers in viscoelastic media

    DEFF Research Database (Denmark)

    Fischer, Mario; Berg-Sørensen, Kirstine


    , 594) is not possible as the viscoelastic properties of the bio-active medium are a priori unknown. Here, we present an approach that neither requires explicit assumptions about the size of the trapped particle nor about the viscoelastic properties of the medium. Instead, the interaction between...... the medium and the trapped particle is described in a general manner, through velocity and acceleration memory. Our method is applicable to general, at least locally homogeneous, viscoelastic media. The procedure combines active and passive approaches by the application of Onsager's regression hypothesis....... It allows extraction of the trapping stiffness kappa of the optical tweezers and of the response function chi(omega), which is the frequency-dependent effective inverse spring constant of the system. Finally, information about the viscoelastic properties of the medium may also be found. To test the method...

  12. Micro-rheology on (polymer-grafted) colloids using optical tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Gutsche, C; Elmahdy, M M; Kegler, K; Semenov, I; Stangner, T; Otto, O; Ueberschaer, O; Kremer, F [Institute of Experimental Physics I, Leipzig University, Linnestrasse 5, D-04103, Leipzig (Germany); Keyser, U F [Cavendish Laboratory, University of Cambridge, Cambridge, CB3 OHE (United Kingdom); Krueger, M; Rauscher, M [Max-Planck-Institut fuer Metallforschung, Heisenbergstrasse 3, D-70569 Stuttgart (Germany); Weeber, R; Harting, J [Institut fuer Computerphysik, Universitaet Stuttgart, Pfaffenwaldring 27, D-70569 Stuttgart (Germany); Kim, Y W [School of Physics, Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of); Lobaskin, V [Physics Department, Technical University Munich, D-85748 Garching (Germany); Netz, R R, E-mail: [Materials Research Laboratory, University of California at Santa Barbara, Santa Barbara, CA 93106 (United States)


    Optical tweezers are experimental tools with extraordinary resolution in positioning ({+-} 1 nm) a micron-sized colloid and in the measurement of forces ({+-} 50 fN) acting on it-without any mechanical contact. This enables one to carry out a multitude of novel experiments in nano- and microfluidics, of which the following will be presented in this review: (i) forces within single pairs of colloids in media of varying concentration and valency of the surrounding ionic solution, (ii) measurements of the electrophoretic mobility of single colloids in different solvents (concentration, valency of the ionic solution and pH), (iii) similar experiments as in (i) with DNA-grafted colloids, (iv) the nonlinear response of single DNA-grafted colloids in shear flow and (v) the drag force on single colloids pulled through a polymer solution. The experiments will be described in detail and their analysis discussed.

  13. Microfluidic platform combining droplets and magnetic tweezers: application to HER2 expression in cancer diagnosis (United States)

    Ferraro, Davide; Champ, Jérôme; Teste, Bruno; Serra, Marco; Malaquin, Laurent; Viovy, Jean-Louis; de Cremoux, Patricia; Descroix, Stephanie


    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.

  14. Optically-driven red blood cell rotor in linearly polarized laser tweezers

    Indian Academy of Sciences (India)

    Manas Khan; Samarendra K Mohanty; A K Sood


    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.

  15. Simultaneous detection of rotational and translational motion in optical tweezers by measurement of backscattered intensity

    CERN Document Server

    Roy, Basudev; Banerjee, Ayan


    We describe a simple yet powerful technique of simultaneously measuring both translational and rotational motion of mesoscopic particles in optical tweezers by measuring the backscattered intensity on a quadrant photodiode (QPD). While the measurement of translational motion by taking the difference of the backscattered intensity incident on adjacent quadrants of a QPD is well-known, we demonstrate that rotational motion can be measured very precisely by taking the difference between the diagonal quadrants. The latter measurement eliminates the translational component entirely, and leads to a detection sensitivity of around 50 mdeg at S/N of 2 for angular motion of a driven micro-rod. The technique is also able to resolve the translational and rotational Brownian motion components of the micro-rod in an unperturbed trap, and can be very useful in measuring translation-rotation coupling of micro-objects induced by hydrodynamic interactions.

  16. Tuning the size and configuration of nanocarbon microcapsules: aqueous method using optical tweezers (United States)

    Frusawa, Hiroshi; Matsumoto, Youei


    To date, optical manipulation techniques for aqueous dispersions have been developed that deposit and/or transport nanoparticles not only for fundamental studies of colloidal dynamics, but also for either creating photonic devices or allowing accurate control of liquids on micron scales. Here, we report that optical tweezers (OT) system is able to direct three-dimensional assembly of graphene, graphite, and carbon nanotubes (CNT) into microcapsules of hollow spheres. The OT technique facilitates both to visualize the elasticity of a CNT microcapsule and to arrange a triplet of identical graphene microcapsules in aqueous media. Furthermore, the similarity of swelling courses has been found over a range of experimental parameters such as nanocarbon species, the power of the incident light, and the suspension density. Thanks to the universality in evolutions of rescaled capsule size, we can precisely control the size of various nanocarbon microcapsules by adjusting the duration time of laser emission.

  17. Calibrating oscillation response of a piezo-stage using optical tweezers. (United States)

    Zhou, Jin-Hua; Li, Di; Hu, Xin-Yao; Zhong, Min-Cheng; Wang, Zi-Qiang; Gong, Lei; Liu, Wei-Wei; Li, Yin-Mei


    In optical tweezers, a piezo-stage (PZT) is widely used to precisely position samples for force clamp, calibrating optical trap and stretching DNA. For a trapped bead in solution, the oscillation response of PZT is vital for all kinds of applications. A coupling ratio, actual amplitude to nominal amplitude, can be calibrated by power spectral density during sinusoidal oscillations. With oscillation frequency increasing, coupling ratio decreases in both x- and y-directions, which is also confirmed by the calibration with light scattering of scanning two aligned beads on slide. Those oscillation responses are related with deformability of chamber and the intrinsic characteristics of PZT. If we take nominal amplitude as actual amplitude for sinusoidal oscillations at 50 Hz, the amplitude is overestimated ~2 times in x-direction and ~3 times in y-direction. That will lead to huge errors for subsequent calibrations.

  18. Pulse-train solutions and excitability in an optoelectronic oscillator (United States)

    Rosin, D. P.; Callan, K. E.; Gauthier, D. J.; Schöll, E.


    We study an optoelectronic time-delay oscillator with bandpass filtering for different values of the filter bandwidth. Our experiments show novel pulse-train solutions with pulse widths that can be controlled over a three-order-of-magnitude range, with a minimum pulse width of ~150 ps. The equations governing the dynamics of our optoelectronic oscillator are similar to the FitzHugh-Nagumo model from neurodynamics with delayed feedback in the excitable and oscillatory regimes. Using a nullclines analysis, we derive an analytical proportionality between pulse width and the low-frequency cutoff of the bandpass filter, which is in agreement with experiments and numerical simulations. Furthermore, the nullclines help to describe the shape of the waveforms.

  19. Research and Development of Electronic and Optoelectronic Materials in China

    Institute of Scientific and Technical Information of China (English)



    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.

  20. Electronics and optoelectronics of two-dimensional transition metal dichalcogenides. (United States)

    Wang, Qing Hua; Kalantar-Zadeh, Kourosh; Kis, Andras; Coleman, Jonathan N; Strano, Michael S


    The remarkable properties of graphene have renewed interest in inorganic, two-dimensional materials with unique electronic and optical attributes. Transition metal dichalcogenides (TMDCs) are layered materials with strong in-plane bonding and weak out-of-plane interactions enabling exfoliation into two-dimensional layers of single unit cell thickness. Although TMDCs have been studied for decades, recent advances in nanoscale materials characterization and device fabrication have opened up new opportunities for two-dimensional layers of thin TMDCs in nanoelectronics and optoelectronics. TMDCs such as MoS(2), MoSe(2), WS(2) and WSe(2) have sizable bandgaps that change from indirect to direct in single layers, allowing applications such as transistors, photodetectors and electroluminescent devices. We review the historical development of TMDCs, methods for preparing atomically thin layers, their electronic and optical properties, and prospects for future advances in electronics and optoelectronics.

  1. Indium phosphide nanowires and their applications in optoelectronic devices



    Group IIIA phosphide nanocrystalline semiconductors are of great interest among the important inorganic materials because of their large direct band gaps and fundamental physical properties. Their physical properties are exploited for various potential applications in high-speed digital circuits, microwave and optoelectronic devices. Compared to II–VI and I–VII semiconductors, the IIIA phosphides have a high degree of covalent bonding, a less ionic character and larger exciton diameters. In t...

  2. Accurate manufacturing and production of optoelectronic parts and modules (United States)

    Hannula, Tapio; Karioja, Pentti; Keraenen, Kimmo; Kopola, Harri K.; Malinen, Jouko; Ollila, Jyrki


    The trends in optoelectronic products are towards higher integration level of optics, electronics and mechanics. It means smaller dimensions and tighter packaging density. The precisions in component manufacturing and accuracies in module assemblings typically are in 10 to 50 micrometer range. Due to demands of the production in series of tens of thousands it means new type of know-how in production and assembling technologies.

  3. Adaptive Optoelectronic Eyes: Hybrid Sensor/Processor Architectures (United States)


    J.  Lange , C. von der Malsburg, R. P. Würtz, and W. Konen, “Distortion Invariant Object Recognition Adaptive Optoelectronic Eyes: Hybrid Sensor...Meeting, Dallas, Texas, (November, 1998). 17.  G. Sáry, G. Kovács, K. Köteles, G.  Benedek , J. Fiser, and I. Biederman, “Selectivity Variations in Monkey

  4. Optoelectronic and nonlinear optical processes in low dimensional semiconductors

    Indian Academy of Sciences (India)

    B P Singh


    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.

  5. Design, fabrication, and testing of an optoelectronic interface connectorized module (United States)

    Benoit, Jeffrey T.; Grzybowski, Richard R.; Rubino, Robert A.; Newman, Leon A.; Fields, Christopher V.; DiDomenico, John A.; Donofrio, Andrew J.


    As efforts to include fiber optic technology in aircraft flight control electronics have progressed, the need has arisen for a compact optoelectronic interface with an integral multipin optical connector. The United Technologies Research Center optoelectronic Connectorized Module (CM) was designed and built to satisfy this need. This paper will discuss the background, design, fabrication and testing of a completed Connectorized Module. The prototype CM is a four channel speed sensor interface that incorporates established ceramic multichip module (MCM-C) technology with optical emitters and detectors and a multipin fiber optic connector. This combination of technologies yields a compact and rugged interface module. In addition, the CM removes optical fibers, and their associated difficult to repair pigtails, from within the electronic control box. The CM achieves this because: it contains all necessary optoelectronic circuitry, has integral electrical and optical connectors, and is mounted directly on the electronic control box wall, not on an internal circuit board. Although this CM is a speed sensor interface, the flexible nature of MCM-C technology will enable a wide variety of sensor and data communication interfaces to be implemented.

  6. The Cellulose Nanofibers for Optoelectronic Conversion and Energy Storage

    Directory of Open Access Journals (Sweden)

    Yongfeng Luo


    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.

  7. Extreme Radiation Hardness and Space Qualification of AlGaN Optoelectronic Devices

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Ke-Xun; Balakrishnan, Kathik; Hultgren, Eric; Goebel, John; Bilenko, Yuri; Yang, Jinwei; Sun, Wenhong; Shatalov, Max; Hu, Xuhong


    Unprecedented radiation hardness and environment robustness are required in the new generation of high energy density physics (HEDP) experiments and deep space exploration. National Ignition Facility (NIF) break-even shots will have a neutron yield of 1015 or higher. The Europa Jupiter System Mission (EJSM) mission instruments will be irradiated with a total fluence of 1012 protons/cm2 during the space journey. In addition, large temperature variations and mechanical shocks are expected in these applications under extreme conditions. Hefty radiation and thermal shields are required for Si and GaAs based electronics and optoelectronics devices. However, for direct illumination and imaging applications, shielding is not a viable option. It is an urgent task to search for new semiconductor technologies and to develop radiation hard and environmentally robust optoelectronic devices. We will report on our latest systematic experimental studies on radiation hardness and space qualifications of AlGaN optoelectronic devices: Deep UV Light Emitting Diodes (DUV LEDs) and solarblind UV Photodiodes (PDs). For custom designed AlGaN DUV LEDs with a central emission wavelength of 255 nm, we have demonstrated its extreme radiation hardness up to 2x1012 protons/cm2 with 63.9 MeV proton beams. We have demonstrated an operation lifetime of over 26,000 hours in a nitrogen rich environment, and 23,000 hours of operation in vacuum without significant power drop and spectral shift. The DUV LEDs with multiple packaging styles have passed stringent space qualifications with 14 g random vibrations, and 21 cycles of 100K temperature cycles. The driving voltage, current, emission spectra and optical power (V-I-P) operation characteristics exhibited no significant changes after the space environmental tests. The DUV LEDs will be used for photoelectric charge management in space flights. For custom designed AlGaN UV photodiodes with a central response wavelength of 255 nm, we have demonstrated

  8. Contactless optoelectronic technique for monitoring epoxy cure. (United States)

    Cusano, A; Buonocore, V; Breglio, G; Calabrò, A; Giordano, M; Cutolo, A; Nicolais, L


    We describe a novel noninvasive optical technique to monitor the refractive-index variation in an epoxy-based resin that is due to the polymerization process. This kind of resin is widely used in polymer matrix composites. It is well known that the process of fabricating a thermoset-based composite involves mass and heat transfer coupled with irreversible chemical reactions that induce physical changes. To improve the quality and the reliability of these materials, monitoring the cure and optimization of the manufacturing process are of key importance. We discuss the basic operating principles of an optical system based on angle deflection measurements and present typical cure-monitoring results obtained from optical characterization. The method provides a flexible, high-sensitivity, material-independent, low-cost, noninvasive tool for monitoring real-time refractive-index variation.

  9. tweezercalib 2.1: Faster version of MatLab package for precise calibration of optical tweezers (United States)

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


    routines based on Refs. [1,2]. Statistical support for fit is given, with several plots facilitating inspection of consistency and quality of data and fit. Reasons for the new version:Recent progress in the field has demonstrated a better approximation of the formula for the theoretical power spectrum with corrections due to frequency dependence of motion and distance to a surface nearby. Summary of revisions:The expression for the theoretical power spectrum when accounting for corrections to Stokes law, P(f), has been updated to agree with a better approximation of the theoretical spectrum, as discussed in Ref. [4] The units of the kinematic viscosity applied in the program is now stated in the input window. Greek letters and exponents are inserted in the input window. The graphical output has improved: The figures now bear a meaningful title and four figures that test the quality of the fit are now combined in one figure with four parts. Restrictions: Data should be positions of bead doing Brownian motion while held by optical tweezers. For high precision in final results, data should be time series measured over a long time, with sufficiently high experimental sampling rate; The sampling rate should be well above the characteristic frequency of the trap, the so-called corner frequency. Thus, the sampling frequency should typically be larger than 10 kHz. The Fast Fourier Transform used works optimally when the time series contain 2 data points, and long measurement time is obtained with n>12-15. Finally, the optics should be set to ensure a harmonic trapping potential in the range of positions visited by the bead. The fitting procedure checks for harmonic potential. Running time:seconds ReferencesJ. Nocedal, Y.x. Yuan, Combining trust region and line search techniques, Technical Report OTC 98/04, Optimization Technology Center, 1998. W.H. Press, B.P. Flannery, S.A. Teukolsky, W.T. Vetterling, Numerical Recipes. The Art of Scientific Computing, Cambridge University Press

  10. Rare earth doped III-nitride semiconductors for spintronic and optoelectronic applications (Conference Presentation) (United States)

    Palai, Ratnakar


    Since last four decades the information and communication technologies are relying on the semiconductor materials. Currently a great deal of attention is being focused on adding spin degree-of-freedom into semiconductor to create a new area of solid-state electronics, called spintronics. In spintronics not only the current but also its spin state is controlled. Such materials need to be good semiconductors for easy integration in typical integrated circuits with high sensitivity to the spin orientation, especially room temperature ferromagnetism being an important desirable property. GaN is considered to be the most important semiconductor after silicon. It is widely used for the production of green, blue, UV, and white LEDs in full color displays, traffic lights, automotive lightings, and general room lighting using white LEDs. GaN-based systems also show promise for microwave and high power electronics intended for radar, satellite, wireless base stations and spintronic applications. Rare earth (Yb, Eu, Er, and Tm) doped GaN shows many interesting optoelectronic and magnetoptic properties e. g. sharp emission from UV through visible to IR, radiation hardness, and ferromagnetism. The talk will be focused on fabrication, optoelectronic (photoluminescence, cathodeluminescence, magnetic, and x-ray photoelectron spectroscopy) properties of some rare earth doped GaN and InGaN semiconductor nanostructures grown by plasma assisted molecular beam epitaxy (MBE) and future applications.


    Institute of Scientific and Technical Information of China (English)

    Qian-jin Zhao; Wen-hui Wu; Qiao-li Niu; Jun-biao Peng; Yiu-wing Mai


    A novel kind of hexa-armed fluorene-benzene copolymer based on a hexaazaisowurtzitane core was synthesized through Suzuki coupling polycondensation.The introduction of this bulky caged-core could not only enhance the photoluminescence quantum efficiency,but also improve the electroluminescence properties,especially suppress the common green-color emission of polyfluorenes(PFs)material during device operation.These features can be attributed to the successful suppression of PF's chain aggregation which profits from the introduction of the bulky hexaazaisowurtzitane core and the design of multi-armed architecture.

  12. New composite materials for optoelectronic applications (United States)

    Iovu, M. S.; Buzurniuc, S. A.; Verlan, V. I.; Culeac, I. P.; Nistor, Yu. H.


    The problem of obtaining low cost but efficient luminescent materials is still actually. Data concerning fabrication and luminescent properties of new composite materials on the base of thenoyltrifluoroacetone (TTA) of Europium(III) (Eu(TTA)3) and chalcogenide glasses doped with rare earth ions and polymers are presented. The visible emission spectra of the composites on the base of Eu(TTA)3 structured with phenantroline (Eu(TTA)3Phen) and copolymer from styrene and butylmethacrylate (1:1)(SBMA) under the excitation with N2-laser (λ=337 nm) contain sharp emission bands located at 354, 415, 580, 587, 590, 596, 611.4, 616.5, 621, 652, 690, 700, 713 nm. The nature of the observed emission bands and the possible mechanisms of the radiative electron transition in the investigated composite materials are discussed.

  13. I–II–V and I–III–IV half-Heusler compounds for optoelectronic applications: Comparative ab initio study

    Energy Technology Data Exchange (ETDEWEB)

    Kacimi, S.; Mehnane, H.; Zaoui, A., E-mail:


    Highlights: • TB-mBJ calculations were performed on 96 half-Heusler materials. • Several criteria were used to select candidates for optoelectronic applications. • Only six compounds fulfill these criteria. -- Abstract: We have investigated structural, electronic and optical properties of 96 half-Heusler materials, including compounds of I–II–V and I–III–IV types using first-principles calculations based on the density functional theory. The calculated lattice constants and band gaps are used as basis informations to select candidate materials favorable for specific optoelectronic applications. The band gap trend in the selected XYZ materials is found to be similar to the one in the zinc-blende III–V compounds. The assignment of the structures in the optical spectra and band structure transitions are investigated in detail. The predicted values of the dielectric constants for selected half-Heusler systems are close to those of the III–V binary compounds.

  14. Tethered anthracene pair as molecular tweezers for post-production separation of single-walled carbon nanotubes (United States)

    Anderson, Ankoma; Yang, Fengchun; Cao, Li; Li, Huaping; Meziani, Mohammed J.; Sun, Ya-Ping


    As-produced single-walled carbon nanotubes (SWNTs) are metallic and semiconducting mixtures. An anthracene mono-derivative with a long alkyl tail and a molecule with a tethered pair of anthracene species (bis-anthracene) in a ;molecular tweezers;-like configuration were synthesized and evaluated for the separation of SWNTs. While the mono-derivative was incapable of the noncovalent functionalization-solubilization, the bis-anthracene was found to be very effective. The results suggest that molecular tweezers of a tethered pair of planar aromatic species can be coupled with the selection of a suitable solvent or solvent mixture for effective and efficient post-production separation of metallic and semiconducting SWNTs.

  15. Towards nano-optical tweezers with graphene plasmons: Numerical investigation of trapping 10-nm particles with mid-infrared light (United States)

    Zhang, Jianfa; Liu, Wenbin; Zhu, Zhihong; Yuan, Xiaodong; Qin, Shiqiao


    Graphene plasmons are rapidly emerging as a versatile platform for manipulating light at the deep subwavelength scale. Here we show numerically that strong optical near-field forces can be generated under the illumination of mid-IR light when dielectric nanoparticles are located in the vicinity of a nanostructured graphene film. These near-field forces are attributed to the excitation of the graphene’s plasmonic mode. The optical forces can generate an efficient optical trapping potential for a 10-nm-diameter dielectric particle when the light intensity is only about about 4.4 mW/μm2 and provide possibilities for a new type of plasmonic nano-tweezers. Graphene plasmonic tweezers can be potentially exploited for optical manipulation of nanometric biomolecules and particles. Moreover, the optical trapping/tweezing can be combined with biosensing and provide a versatile platform for studing biology and chemistry with mid-IR light.

  16. Application of optical tweezers using DOE and SLM to control of beads with information-DNA for photonic DNA computing (United States)

    Zheng, M. J.; Ogura, Y.; Tanida, J.


    We have proposed photonic DNA computing as a new parallel computing paradigm, in which optical techniques are used to manipulate information-coded DNA. In this paper, we present a parallel transportation of multiple beads bound with hairpin-structure DNA using a dynamic optical tweezers system which combines a spatial light modulator (SLM) with a diffractive optical element (DOE). This system provides and effective method for parallel manipulations of DNA-bound beads at multiple positions. In the experiments, three 2.8-μm-diameter beads bound with hairpin DNA were trapped and transported in 1 μm of step by switching of the SLM patterns. The results demonstrate that the dynamic holographic optical tweezers system with combination of the DOE and the SLM is useful in spatially parallel processing required for photonic DNA computing.

  17. Topical Meeting on Picosecond Electronics and Optoelectronics (United States)


    National Labs, and K.R. Gleason of TriQuint Semiconductor for their help with the GaAs IC’s, and J. Kafka and T. Baer of Spectra- Physics, inc. for their...where a probe beam monitors band edge absorption, an appropriate technique for voltage-biased structures in which the Franz -Keldysh effect is...performance up to a few gigahertz (Table 1). The principle of operation is based on the Franz -Keldysh effect in which the absorption edge of semiconductors

  18. Normal and system lupus erythematosus red blood cell interactions studied by double trap optical tweezers: direct measurements of aggregation forces (United States)

    Khokhlova, Maria D.; Lyubin, Eugeny V.; Zhdanov, Alexander G.; Rykova, Sophia Yu.; Sokolova, Irina A.; Fedyanin, Andrey A.


    Direct measurements of aggregation forces in piconewton range between two red blood cells in pair rouleau are performed under physiological conditions using double trap optical tweezers. Aggregation and disaggregation properties of healthy and pathologic (system lupus erythematosis) blood samples are analyzed. Strong difference in aggregation speed and behavior is revealed using the offered method which is proposed to be a promising tool for SLE monitoring at single cell level.

  19. Research of the fuison methods of the multispectral optoelectronic systems images (United States)

    Vasilev, Aleksandr S.; Korotaev, Valery V.


    This article is devoted to consideration of the issues relating to digital images fusion of the multispectral optoelectronic systems. The images fusion formation methods and methods are studied. Theoretical analysis of the methods was completed in the course of the work, mathematical simulation model of the multispectral optoelectronic systems was developed. Effect of various factors on the result of fusion was demonstrated on the basis of the said model investigation. The paper also considers and suggests the objective assessment methods of the fusion image quality. The paper describes the mostly widely used from the above: the averaging method, the masking technique fusion, the interlacing fusion, fusion of images Fourier spectrum. The quality of the resulting image was assessed on the basis of the calculation of the cross entropy, brightness dispersion and excess of the Fourier spectrum function. Based on the research findings we can state that the images obtained by the mask technique methods, by averaging and the Fourier spectrum fusion methods have the highest information entropy. The best quality feature, in terms of the brightness dispersion and excess of the Fourier spectrum function, was demonstrated by the averaging method. The method allows reducing noise components of an image on the account of smoothing of its local brightness variations smoothing thus the contrast is improved.

  20. Simultaneous topographical, electrical and optical microscopy of optoelectronic devices at the nanoscale. (United States)

    Kumar, Naresh; Zoladek-Lemanczyk, Alina; Guilbert, Anne A Y; Su, Weitao; Tuladhar, Sachetan M; Kirchartz, Thomas; Schroeder, Bob C; McCulloch, Iain; Nelson, Jenny; Roy, Debdulal; Castro, Fernando A


    Novel optoelectronic devices rely on complex nanomaterial systems where the nanoscale morphology and local chemical composition are critical to performance. However, the lack of analytical techniques that can directly probe these structure-property relationships at the nanoscale presents a major obstacle to device development. In this work, we present a novel method for non-destructive, simultaneous mapping of the morphology, chemical composition and photoelectrical properties with performance. For instance, the direct measurement of fullerene phase purity can distinguish between high purity aggregates that lead to poor performance and lower purity aggregates (fullerene intercalated with polymer) that result in strong photocurrent generation and collection. We show that the reliable determination of the structure-property relationship at the nanoscale can remove ambiguity from macroscopic device data and support the identification of the best routes for device optimisation. The multi-parameter measurement approach demonstrated herein is expected to play a significant role in guiding the rational design of nanomaterial-based optoelectronic devices, by opening a new realm of possibilities for advanced investigation via the combination of nanoscale optical spectroscopy with a whole range of scanning probe microscopy modes.

  1. Evaluation of sea bream (Sparus aurata) shelf life using an optoelectronic nose. (United States)

    Zaragozá, Patricia; Fuentes, Ana; Fernández-Segovia, Isabel; Vivancos, José-Luis; Rizo, Arantxa; Ros-Lis, José V; Barat, José M; Martínez-Máñez, Ramón


    A new optoelectronic nose for the shelf-life assessment of fresh sea bream in cold storage has been developed. The chromogenic array used eight sensing materials (based on aluminium oxide and silica gel) containing pH indicators, Lewis acids and an oxidation-reduction indicator. The colour changes of the sensor array were characteristic of sea bream spoilage. Colour modulations were measured on day 0 and for the samples held in cold storage for 2, 4, 7, 9 and 11 days. Determination of moisture content, pH, total volatile basic nitrogen (TVB-N), drip loss, ATP-related compounds and K(1)-value and microbial (mesophilic bacteria and Enterobacteriaceae) analyses were carried out on the same days. The changes in the chromogenic arrays data were processed by statistical analysis (PCA). Moreover, PLS statistical studies allowed the creation of models to correlate the chromogenic data with concentrations of mesophilic and Enterobacteriaceae. The results suggest the feasibility of this system to help develop optoelectronic noses for fish freshness monitoring.

  2. Light Manipulation for Organic Optoelectronics Using Bio-inspired Moth's Eye Nanostructures (United States)

    Zhou, Lei; Ou, Qing-Dong; Chen, Jing-De; Shen, Su; Tang, Jian-Xin; Li, Yan-Qing; Lee, Shuit-Tong


    Organic-based optoelectronic devices, including light-emitting diodes (OLEDs) and solar cells (OSCs) hold great promise as low-cost and large-area electro-optical devices and renewable energy sources. However, further improvement in efficiency remains a daunting challenge due to limited light extraction or absorption in conventional device architectures. Here we report a universal method of optical manipulation of light by integrating a dual-side bio-inspired moth's eye nanostructure with broadband anti-reflective and quasi-omnidirectional properties. Light out-coupling efficiency of OLEDs with stacked triple emission units is over 2 times that of a conventional device, resulting in drastic increase in external quantum efficiency and current efficiency to 119.7% and 366 cd A-1 without introducing spectral distortion and directionality. Similarly, the light in-coupling efficiency of OSCs is increased 20%, yielding an enhanced power conversion efficiency of 9.33%. We anticipate this method would offer a convenient and scalable way for inexpensive and high-efficiency organic optoelectronic designs.

  3. Simulation and Numerical Modeling of the Self-assembly of an Optoelectronic Peptide (United States)

    Mansbach, Rachael; Ferguson, Andrew

    We report molecular dynamics simulations of the self-assembly of synthetic π-conjugated oligopeptides into optoelectronic nanostructures. The electronic properties provide the basis for an array of organic electronic devices, such as light-emitting diodes, field-effect transistors, and solar cells. Control of the structure, stability, and kinetics of self-assembled organic electronics by tuning monomer chemistry and environmental conditions presents a powerful route to the fabrication of biocompatible ``designer materials.'' We have performed coarse-grained simulations of the self-assembly of several hundred peptides over microsecond time scales to probe the morphology and kinetics of aggregation with molecular-level detail. We have subsequently used this simulation data to parameterize a kinetic aggregation model based on Smoluchowski coagulation theory to enable prediction of aggregation dynamics on millisecond time scales. These numerical models are now being integrated into a multi-physics model of peptide aggregation in a microfluidic flow cell developed by our experimental collaborators to model the self-assembly of diverse peptide architectures under tailored flow-fields for the fabrication of biocompatible assemblies with defined morphology and optoelectronic function.

  4. A Flexible and Thin Graphene/Silver Nanowires/Polymer Hybrid Transparent Electrode for Optoelectronic Devices. (United States)

    Dong, Hua; Wu, Zhaoxin; Jiang, Yaqiu; Liu, Weihua; Li, Xin; Jiao, Bo; Abbas, Waseem; Hou, Xun


    A typical thin and fully flexible hybrid electrode was developed by integrating the encapsulation of silver nanowires (AgNWs) network between a monolayer graphene and polymer film as a sandwich structure. Compared with the reported flexible electrodes based on PET or PEN substrate, this unique electrode exhibits the superior optoelectronic characteristics (sheet resistance of 8.06 Ω/□ at 88.3% light transmittance). Meanwhile, the specific up-to-bottom fabrication process could achieve the superflat surface (RMS = 2.58 nm), superthin thickness (∼8 μm thickness), high mechanical robustness, and lightweight. In addition, the strong corrosion resistance and stability for the hybrid electrode were proved. With these advantages, we employ this electrode to fabricate the simple flexible organic light-emitting device (OLED) and perovskite solar cell device (PSC), which exhibit the considerable performance (best PCE of OLED = 2.11 cd/A(2); best PCE of PSC = 10.419%). All the characteristics of the unique hybrid electrode demonstrate its potential as a high-performance transparent electrode candidate for flexible optoelectronics.

  5. Assessment of Density Functional Methods for Exciton Binding Energies and Related Optoelectronic Properties

    CERN Document Server

    Lee, Jui-Che; Lin, Shiang-Tai


    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...

  6. On-Axis Digital Moire Optoelectronic Telemetrology (United States)

    Meilan, Pablo F.; Laquidara, Aníbal P.; Bava, José A.; Garavaglia, Mario


    In previous papers [2,3,4,5] we introduced an operation based on digital moiré pattern processing to measure the distance to an object and its size. The method uses a sequence of digital photographic operations to capture two pictures of the scene with the CCD camera placed at two near and well defined positions along the optical axis of the camera. The distance ΔL between both camera positions is of the order of 1-10% of the distance L from the camera to the selected object in the scene. The teleoperation process algoritm requires to introduce ΔL to determine the distance L. Now we will report a simple and powerful optical system: an optical delay line with an optical path equal to 1.5 m, introduced in the line of sight from the camera to the selected object in the scene. With this optical system it is possible to capture the observed object at distances L and L+ΔL simultaneously in the same picture. The uncertainty in measuring L is of the order of 1%.

  7. Study of liquid transparent encapsulants for the packaging of light emitting diode and other optoelectronic devices (United States)

    Zhou, Yan

    Optically transparent polymeric materials required for the encapsulation of optoelectronic chips are critical to the manufacturability, cost, performance, and reliability of LED and other optoelectronic devices. This work is focused on the development of the transparent epoxy based liquid encapsulants with the objective to enhance the manufacturability, to reduce the cost, and to improve both the performance and the reliability of the packaged optoelectronic devices. First, three transparent encapsulants based on different chemistries were reviewed and their properties compared. These encapsulant systems serve as models of different epoxy chemistries suitable for LED applications. The experimental result gives an overview of the characteristics of each system and guides the further development of the encapsulant for different packaging needs. Then, two new encapsulants were developed and introduced. The first one was a two-component encapsulant based on DGEBA/MHHPA chemistry, but provides lower internal stress, better transmission retention upon thermal aging, and easier processing compared with the current best performer based on the same chemistry. The second one is a novel one-component, low temperature and fast cure encapsulant with a high refractive index of 1.6. This encapsulant provides not only the easy handling, convenient storage, and energy saving, but also higher light output for the packaged LED devices. The third part of this work deals with nanocomposites based on aromatic epoxy and cycloaliphatic epoxy. It was found that these composites provide lower CTE, better toughness, and other advantages while keeping good transparency, therefore are suitable for LED applications. Toughening is another topic studied. Three toughened transparent encapsulants were introduced and compared. The toughening agents selected effectively increased the toughness of the cycloaliphatic epoxy/MHHPA system with minimum negative effect on the transmission of the

  8. 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


    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.

  9. Mild conditions for deuteration of primary and secondary arylamines for the synthesis of deuterated optoelectronic organic molecules. (United States)

    Krause-Heuer, Anwen M; Yepuri, Nageshwar R; Darwish, Tamim A; Holden, Peter J


    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.

  10. Optoelectronic devices based on graded bandgap structures utilising electroplated semiconductors



    The main aim of the work presented in this thesis is to develop low-cost multi-junction graded bandgap solar cells using electroplated semiconductors. The semiconductor materials explored in this research are CdSe, ZnTe, CdS, CdMnTe and CdTe thin films. These layers were characterised for their structural, compositional, morphological, optical, and electrical features using XRD, Raman spectroscopy, EDX, SEM, UV-Vis spectroscopy, PEC cell, C-V, I-V and UPS measurement techniques respectively. ...

  11. Preparation for Ultra High Pure Indium Metal for Optoelectronic Applications

    Directory of Open Access Journals (Sweden)

    Shashwat V. Joshi


    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.

  12. Conjugated polymers and their use in optoelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Marks, Tobin J.; Guo, Xugang; Zhou, Nanjia; Chang, Robert P. H.; Drees, Martin; Facchetti, Antonio


    The present invention relates to certain polymeric compounds and their use as organic semiconductors in organic and hybrid optical, optoelectronic, and/or electronic devices such as photovoltaic cells, light emitting diodes, light emitting transistors, and field effect transistors. The present compounds can provide improved device performance, for example, as measured by power conversion efficiency, fill factor, open circuit voltage, field-effect mobility, on/off current ratios, and/or air stability when used in photovoltaic cells or transistors. The present compounds can have good solubility in common solvents enabling device fabrication via solution processes.

  13. Optoelectronic set for measuring reflectance spectrum of living human skin (United States)

    Gryko, Lukasz; Zajac, Andrzej; Gilewski, Marian; Kulesza, Ewa


    In the paper the authors present the developed optoelectronic set for measuring spectral reflectance of living human skin. The basic elements of the set are: the illuminator consists of the LED illuminator emitting a uniform distribution of spectral irradiance in the exposed field, the semispherical measuring chamber and the spectrometer which measures spectrum of reflected radiation. Measured radiation is from spectral range of tissue optical window (from 600 nm to 1000 nm). Knowledge about the reflectance spectrum of the patient skin allows adjusting spectral and energetic parameters of the radiation used in biostimulation treatment. The developed set also enables the repeatable exposures of patients in the Low Level Laser Therapy procedures.

  14. Acousto-optic collinear filter with optoelectronic feedback (United States)

    Mantsevich, S. N.; Balakshy, V. I.; Kuznetsov, Yu. I.


    A spectral optoelectronic system combining a collinear acousto-optic cell fabricated of calcium molybdate single crystal and a positive electronic feedback is proposed first and examined theoretically and experimentally. The feedback signal is formed at the cell output due to the optical heterodyning effect with the use of an unconventional regime of cell operation. It is shown that the feedback enables controlling spectral characteristics of the acousto-optic cell, resulting in enhancing the spectral resolution and the accuracy of optical wavelength determination. In the experiment, maximal filter passband narrowing was as great as 37 times.

  15. Quantum dot rolled-up microtube optoelectronic integrated circuit. (United States)

    Bhowmick, Sishir; Frost, Thomas; Bhattacharya, Pallab


    A rolled-up microtube optoelectronic integrated circuit operating as a phototransceiver is demonstrated. The microtube is made of a InGaAs/GaAs strained bilayer with InAs self-organized quantum dots inserted in the GaAs layer. The phototransceiver consists of an optically pumped microtube laser and a microtube photoconductive detector connected by an a-Si/SiO2 waveguide. The loss in the waveguide and responsivity of the entire phototransceiver circuit are 7.96 dB/cm and 34 mA/W, respectively.

  16. Wonder of nanotechnology quantum optoelectronic devices and applications

    CERN Document Server

    Razeghi, Manijeh; von Klitzing, Klaus


    When you look closely, Nature is nanotechnology at its finest. From a single cell, a factory all by itself, to complex systems, such as the nervous system or the human eye, each is composed of specialized nanostructures that exist to perform a specific function. This same beauty can be mirrored when we interact with the tiny physical world that is the realm of quantum mechanics.The Wonder of Nanotechnology: Quantum Optoelectronic Devices and Applications, edited by Manijeh Razeghi, Leo Esaki, and Klaus von Klitzing focuses on the application of nanotechnology to modern semiconductor optoelectr

  17. Antenna-enhanced optoelectronic probing of carbon nanotubes. (United States)

    Mauser, Nina; Hartmann, Nicolai; Hofmann, Matthias S; Janik, Julia; Högele, Alexander; Hartschuh, Achim


    We report on the first antenna-enhanced optoelectronic microscopy studies on nanoscale devices. By coupling the emission and excitation to a scanning optical antenna, we are able to locally enhance the electroluminescence and photocurrent along a carbon nanotube device. We show that the emission source of the electroluminescence can be pointlike with a spatial extension below 20 nm. Topographic and antenna-enhanced photocurrent measurements reveal that the emission takes place at the location of highest local electric field indicating that the mechanism behind the emission is the radiative decay of excitons created via impact excitation.

  18. Optoelectronic analysis of multijunction wire array solar cells



    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...

  19. Cooperation and competition in business on example of Internet research of opto-electronic companies (United States)

    Kaliczyńska, Małgorzata


    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.

  20. Study on low-phase-noise optoelectronic oscillator and high-sensitivity phase noise measurement system. (United States)

    Hong, Jun; Liu, An-min; Guo, Jian


    An analytic model for an injection-locked dual-loop optoelectronic oscillator (OEO) is proposed and verified by experiments in this paper. Based on this theoretical model, the effect of injection power on the single-sideband phase noise of the OEO is analyzed, and results suggest that moderate injection is one key factor for a balance between phase noise and spur for OEO. In order to measure superlow phase noise of OEOs, a cross-correlation measurement system based on the fiber delay line is built, in which high linear photodetector and low-phase-noise amplifier are used to improve systematic sensitivity. The cross-correlation measurement system is validated by experiments, and its noise floor for the X band is about -130 dBc/Hz at 1 kHz and -168 dBc/Hz at 10 kHz after a cross correlation of 200 times.