Optical double-locked semiconductor lasers

Science.gov (United States)

AlMulla, Mohammad

2018-06-01

Self-sustained period-one (P1) nonlinear dynamics of a semiconductor laser are investigated when both optical injection and modulation are applied for stable microwave frequency generation. Locking the P1 oscillation through modulation on the bias current, injection strength, or detuning frequency stabilizes the P1 oscillation. Through the phase noise variance, the different modulation types are compared. It is demonstrated that locking the P1 oscillation through optical modulation on the output of the master laser outperforms bias-current modulation of the slave laser. Master laser modulation shows wider P1-oscillation locking range and lower phase noise variance. The locking characteristics of the P1 oscillation also depend on the operating conditions of the optical injection system

Squeezing in an injection-locked semiconductor laser

Science.gov (United States)

Inoue, S.; Machida, S.; Yamamoto, Y.; Ohzu, H.

1993-09-01

The intensity-noise properties of an injection-locked semiconductor laser were studied experimentally. The constant-current-driven semiconductor laser producing the amplitude-squeezed state whose intensity noise was reduced below the standard quantum limit (SQL) by 0.72 dB was injection-locked by an external master laser. The measured intensity-noise level of the injection-locked semiconductor laser was 0.91 dB below the SQL. This experimental result indicates that a phase-coherent amplitude-squeezed state or squeezed vacuum state together with a reference local oscillator wave can be generated directly by semiconductor laser systems.

Single frequency semiconductor lasers

CERN Document Server

Fang, Zujie; Chen, Gaoting; Qu, Ronghui

2017-01-01

This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

E-beam-pumped semiconductor lasers

Science.gov (United States)

Rice, Robert R.; Shanley, James F.; Ruggieri, Neil F.

1995-04-01

The collapse of the Soviet Union opened many areas of laser technology to the West. E-beam- pumped semiconductor lasers (EBSL) were pursued for 25 years in several Soviet Institutes. Thin single crystal screens of II-VI alloys (ZnxCd1-xSe, CdSxSe1-x) were incorporated in laser CRTs to produce scanned visible laser beams at average powers greater than 10 W. Resolutions of 2500 lines were demonstrated. MDA-W is conducting a program for ARPA/ESTO to assess EBSL technology for high brightness, high resolution RGB laser projection application. Transfer of II-VI crystal growth and screen processing technology is underway, and initial results will be reported. Various techniques (cathodoluminescence, one- and two-photon laser pumping, etc.) have been used to assess material quality and screen processing damage. High voltage (75 kV) video electronics were procured in the U.S. to operate test EBSL tubes. Laser performance was documented as a function of screen temperature, beam voltage and current. The beam divergence, spectrum, efficiency and other characteristics of the laser output are being measured. An evaluation of the effect of laser operating conditions upon the degradation rate is being carried out by a design-of-experiments method. An initial assessment of the projected image quality will be performed.

Electrically pumped edge-emitting photonic bandgap semiconductor laser

Science.gov (United States)

Lin, Shawn-Yu; Zubrzycki, Walter J.

2004-01-06

A highly efficient, electrically pumped edge-emitting semiconductor laser based on a one- or two-dimensional photonic bandgap (PBG) structure is described. The laser optical cavity is formed using a pair of PBG mirrors operating in the photonic band gap regime. Transverse confinement is achieved by surrounding an active semiconductor layer of high refractive index with lower-index cladding layers. The cladding layers can be electrically insulating in the passive PBG mirror and waveguide regions with a small conducting aperture for efficient channeling of the injection pump current into the active region. The active layer can comprise a quantum well structure. The quantum well structure can be relaxed in the passive regions to provide efficient extraction of laser light from the active region.

Laser Cooling of 2-6 Semiconductors

Science.gov (United States)

2016-08-12

AFRL-AFOSR-JP-TR-2016-0067 Laser Cooling of II-VI Semiconductors Qihua Xiong NANYANG TECHNOLOGICAL UNIVERSITY Final Report 08/12/2016 DISTRIBUTION A...From - To) 15 May 2013 to 14 May 2016 4. TITLE AND SUBTITLE Laser Cooling of II-VI Semiconductors 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA2386-13-1...13. SUPPLEMENTARY NOTES 14. ABSTRACT The breakthrough of laser cooling in semiconductor has stimulated strong interest in further scaling up towards

Semiconductor lasers and herterojunction leds

CERN Document Server

Kressel, Henry

2012-01-01

Semiconductor Lasers and Heterojunction LEDs presents an introduction to the subject of semiconductor lasers and heterojunction LEDs. The book reviews relevant basic solid-state and electromagnetic principles; the relevant concepts in solid state physics; and the p-n junctions and heterojunctions. The text also describes stimulated emission and gain; the relevant concepts in electromagnetic field theory; and the modes in laser structures. The relation between electrical and optical properties of laser diodes; epitaxial technology; binary III-V compounds; and diode fabrication are also consider

Waveguide based external cavity semiconductor lasers

NARCIS (Netherlands)

Oldenbeuving, Ruud; Klein, E.J.; Offerhaus, Herman L.; Lee, Christopher James; Verhaegen, M.; Boller, Klaus J.

2012-01-01

We report on progress of the project waveguide based external cavity semiconductor laser (WECSL) arrays. Here we present the latest results on our efforts to mode lock an array of tunable, external cavity semiconductor lasers.

Semiconductor laser diodes and the design of a D.C. powered laser diode drive unit

OpenAIRE

Cappuccio, Joseph C., Jr.

1988-01-01

Approved for public release; distribution is unlimited This thesis addresses the design, development and operational analysis of a D.C. powered semiconductor laser diode drive unit. A laser diode requires an extremely stable power supply since a picosecond spike of current or power supply switching transient could result in permanent damage. The design offers stability and various features for operational protection of the laser diode. The ability to intensity modulate (analog) and pulse m...

Measurement of the emission spectrum of a semiconductor laser using laser-feedback interferometry.

Science.gov (United States)

Keeley, James; Freeman, Joshua; Bertling, Karl; Lim, Yah L; Mohandas, Reshma A; Taimre, Thomas; Li, Lianhe H; Indjin, Dragan; Rakić, Aleksandar D; Linfield, Edmund H; Davies, A Giles; Dean, Paul

2017-08-03

The effects of optical feedback (OF) in lasers have been observed since the early days of laser development. While OF can result in undesirable and unpredictable operation in laser systems, it can also cause measurable perturbations to the operating parameters, which can be harnessed for metrological purposes. In this work we exploit this 'self-mixing' effect to infer the emission spectrum of a semiconductor laser using a laser-feedback interferometer, in which the terminal voltage of the laser is used to coherently sample the reinjected field. We demonstrate this approach using a terahertz frequency quantum cascade laser operating in both single- and multiple-longitudinal mode regimes, and are able to resolve spectral features not reliably resolved using traditional Fourier transform spectroscopy. We also investigate quantitatively the frequency perturbation of individual laser modes under OF, and find excellent agreement with predictions of the excess phase equation central to the theory of lasers under OF.

Modeling bidirectionally coupled single-mode semiconductor lasers

International Nuclear Information System (INIS)

Mulet, Josep; Masoller, Cristina; Mirasso, Claudio R.

2002-01-01

We develop a dynamical model suitable for the description of two mutually coupled semiconductor lasers in a face-to-face configuration. Our study considers the propagation of the electric field along the compound system as well as the evolution of the carrier densities within each semiconductor laser. Mutual injection, passive optical feedback, and multiple reflections are accounted for in this framework, although under weak to moderate coupling conditions. We systematically describe the effect of the coupling strength on the spectrum of monochromatic solutions and on the respective dynamical behavior. By assuming single-longitudinal-mode operation, weak mutual coupling and slowly varying approximation, the dynamical model can be reduced to rate equations describing the mutual injection from one laser to its counterpart and vice versa. A good agreement between the complete and simplified models is found for small coupling. For larger coupling, higher-order terms lead to a smaller threshold reduction, reflected itself in the spectrum of the monochromatic solutions and in the dynamics of the optical power

Temperature controller of semiconductor laser

Czech Academy of Sciences Publication Activity Database

Matoušek, Vít; Číp, Ondřej

2003-01-01

Roč. 73, č. 3 (2003), s. 10 - 12 ISSN 0928-5008 Institutional research plan: CEZ:AV0Z2065902 Keywords : temperature controller * semiconductor laser * laser diode Subject RIV: BH - Optics, Masers, Lasers

Progress in semiconductor laser diodes: SPIE volume 723

International Nuclear Information System (INIS)

Eichen, E.

1987-01-01

This book contains proceedings arranged under the following session headings: High power diode lasers; single emitters and arrays; Ultrahigh speed modulation of semiconductor diode lasers; Coherence and linewidth stabilized semiconductor lasers; and Growth, fabrication, and evaluation of laser diodes

Theory of semiconductor lasers from basis of quantum electronics to analyses of the mode competition phenomena and noise

CERN Document Server

Yamada, Minoru

2014-01-01

This book provides a unified and complete theory for semiconductor lasers, covering topics ranging from the principles of classical and quantum mechanics to highly advanced levels for readers who need to analyze the complicated operating characteristics generated in the real application of semiconductor lasers.   The author conducts a theoretical analysis especially on the instabilities involved in the operation of semiconductor lasers. A density matrix into the theory for semiconductor lasers is introduced and the formulation of an improved rate equation to help understand the mode competition phenomena which cause the optical external feedback noise is thoroughly described from the basic quantum mechanics. The derivation of the improved rate equation will allow readers to extend the analysis for the different types of semiconductor materials and laser structures they deal with.   This book is intended not only for students and academic researchers but also for engineers who develop lasers for the market, ...

Frequency modulation of semiconductor disk laser pulses

Energy Technology Data Exchange (ETDEWEB)

Zolotovskii, I O; Korobko, D A; Okhotnikov, O G [Ulyanovsk State University, Ulyanovsk (Russian Federation)

2015-07-31

A numerical model is constructed for a semiconductor disk laser mode-locked by a semiconductor saturable absorber mirror (SESAM), and the effect that the phase modulation caused by gain and absorption saturation in the semiconductor has on pulse generation is examined. The results demonstrate that, in a laser cavity with sufficient second-order dispersion, alternating-sign frequency modulation of pulses can be compensated for. We also examine a model for tuning the dispersion in the cavity of a disk laser using a Gires–Tournois interferometer with limited thirdorder dispersion. (control of radiation parameters)

The pursuit of electrically-driven organic semiconductor lasers

NARCIS (Netherlands)

Bisri, Satria Zulkarnaen; Takenobu, Taishi; Iwasa, Yoshihiro

2014-01-01

Organic semiconductors have many favourable and plastic-like optical properties that are promising for the development of low energy consuming laser devices. Although optically-pumped organic semiconductor lasers have been demonstrated since the early days of lasers, electrically-driven organic

Semiconductor Laser Multi-Spectral Sensing and Imaging

Directory of Open Access Journals (Sweden)

Han Q. Le

2010-01-01

Full Text Available Multi-spectral laser imaging is a technique that can offer a combination of the laser capability of accurate spectral sensing with the desirable features of passive multispectral imaging. The technique can be used for detection, discrimination, and identification of objects by their spectral signature. This article describes and reviews the development and evaluation of semiconductor multi-spectral laser imaging systems. Although the method is certainly not specific to any laser technology, the use of semiconductor lasers is significant with respect to practicality and affordability. More relevantly, semiconductor lasers have their own characteristics; they offer excellent wavelength diversity but usually with modest power. Thus, system design and engineering issues are analyzed for approaches and trade-offs that can make the best use of semiconductor laser capabilities in multispectral imaging. A few systems were developed and the technique was tested and evaluated on a variety of natural and man-made objects. It was shown capable of high spectral resolution imaging which, unlike non-imaging point sensing, allows detecting and discriminating objects of interest even without a priori spectroscopic knowledge of the targets. Examples include material and chemical discrimination. It was also shown capable of dealing with the complexity of interpreting diffuse scattered spectral images and produced results that could otherwise be ambiguous with conventional imaging. Examples with glucose and spectral imaging of drug pills were discussed. Lastly, the technique was shown with conventional laser spectroscopy such as wavelength modulation spectroscopy to image a gas (CO. These results suggest the versatility and power of multi-spectral laser imaging, which can be practical with the use of semiconductor lasers.

Semiconductor laser multi-spectral sensing and imaging.

Science.gov (United States)

Le, Han Q; Wang, Yang

2010-01-01

Multi-spectral laser imaging is a technique that can offer a combination of the laser capability of accurate spectral sensing with the desirable features of passive multispectral imaging. The technique can be used for detection, discrimination, and identification of objects by their spectral signature. This article describes and reviews the development and evaluation of semiconductor multi-spectral laser imaging systems. Although the method is certainly not specific to any laser technology, the use of semiconductor lasers is significant with respect to practicality and affordability. More relevantly, semiconductor lasers have their own characteristics; they offer excellent wavelength diversity but usually with modest power. Thus, system design and engineering issues are analyzed for approaches and trade-offs that can make the best use of semiconductor laser capabilities in multispectral imaging. A few systems were developed and the technique was tested and evaluated on a variety of natural and man-made objects. It was shown capable of high spectral resolution imaging which, unlike non-imaging point sensing, allows detecting and discriminating objects of interest even without a priori spectroscopic knowledge of the targets. Examples include material and chemical discrimination. It was also shown capable of dealing with the complexity of interpreting diffuse scattered spectral images and produced results that could otherwise be ambiguous with conventional imaging. Examples with glucose and spectral imaging of drug pills were discussed. Lastly, the technique was shown with conventional laser spectroscopy such as wavelength modulation spectroscopy to image a gas (CO). These results suggest the versatility and power of multi-spectral laser imaging, which can be practical with the use of semiconductor lasers.

Laser vapor phase deposition of semiconductors

Energy Technology Data Exchange (ETDEWEB)

Karlov, N.V.; Luk' ianchuk, B.S.; Sisakian, E.V.; Shafeev, G.A.

1987-06-01

The pyrolytic effect of IR laser radiation is investigated with reference to the initiation and control of the vapor phase deposition of semiconductor films. By selecting the gas mixture composition and laser emission parameters, it is possible to control the deposition and crystal formation processes on the surface of semiconductors, with the main control action achieved due to the nonadiabatic kinetics of reactions in the gas phase and high temperatures in the laser heating zone. This control mechanism is demonstrated experimentally during the laser vapor deposition of germanium and silicon films from tetrachlorides on single-crystal Si and Ge substrates. 5 references.

Semiconductor Laser Diode Pumps for Inertial Fusion Energy Lasers

International Nuclear Information System (INIS)

Deri, R.J.

2011-01-01

Solid-state lasers have been demonstrated as attractive drivers for inertial confinement fusion on the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) and at the Omega Facility at the Laboratory for Laser Energetics (LLE) in Rochester, NY. For power plant applications, these lasers must be pumped by semiconductor diode lasers to achieve the required laser system efficiency, repetition rate, and lifetime. Inertial fusion energy (IFE) power plants will require approximately 40-to-80 GW of peak pump power, and must operate efficiently and with high system availability for decades. These considerations lead to requirements on the efficiency, price, and production capacity of the semiconductor pump sources. This document provides a brief summary of these requirements, and how they can be met by a natural evolution of the current semiconductor laser industry. The detailed technical requirements described in this document flow down from a laser ampl9ifier design described elsewhere. In brief, laser amplifiers comprising multiple Nd:glass gain slabs are face-pumped by two planar diode arrays, each delivering 30 to 40 MW of peak power at 872 nm during a ∼ 200 (micro)s quasi-CW (QCW) pulse with a repetition rate in the range of 10 to 20 Hz. The baseline design of the diode array employs a 2D mosaic of submodules to facilitate manufacturing. As a baseline, they envision that each submodule is an array of vertically stacked, 1 cm wide, edge-emitting diode bars, an industry standard form factor. These stacks are mounted on a common backplane providing cooling and current drive. Stacks are conductively cooled to the backplane, to minimize both diode package cost and the number of fluid interconnects for improved reliability. While the baseline assessment in this document is based on edge-emitting devices, the amplifier design does not preclude future use of surface emitting diodes, which may offer appreciable future cost reductions and

Monolithic integration of microfluidic channels and semiconductor lasers

Science.gov (United States)

Cran-McGreehin, Simon J.; Dholakia, Kishan; Krauss, Thomas F.

2006-08-01

We present a fabrication method for the monolithic integration of microfluidic channels into semiconductor laser material. Lasers are designed to couple directly into the microfluidic channel, allowing submerged particles pass through the output beams of the lasers. The interaction between particles in the channel and the lasers, operated in either forward or reverse bias, allows for particle detection, and the optical forces can be used to trap and move particles. Both interrogation and manipulation are made more amenable for lab-on-a-chip applications through monolithic integration. The devices are very small, they require no external optical components, have perfect intrinsic alignment, and can be created with virtually any planar configuration of lasers in order to perform a variety of tasks. Their operation requires no optical expertise and only low electrical power, thus making them suitable for computer interfacing and automation. Insulating the pn junctions from the fluid is the key challenge, which is overcome by using photo-definable SU8-2000 polymer.

N.G. Basov and early works on semiconductor lasers at P.N. Lebedev Physics Institute

International Nuclear Information System (INIS)

Eliseev, P G

2012-01-01

A survey is presented of works on creation and investigation of semiconductor lasers during 1957 – 1977 at the P.N. Lebedev Physics Institute. Many of these works were initiated by N.G. Basov, starting from pre-laser time, when N.G. Basov and his coworkers formulated principal conditions of creation of lasers on interband transitions in semiconductors. Main directions of further works were diode lasers based on various materials and structures, their characteristics of output power, high-speed operation and reliability. (special issue devoted to the 90th anniversary of n.g. basov)

Key techniques for space-based solar pumped semiconductor lasers

Science.gov (United States)

He, Yang; Xiong, Sheng-jun; Liu, Xiao-long; Han, Wei-hua

2014-12-01

In space, the absence of atmospheric turbulence, absorption, dispersion and aerosol factors on laser transmission. Therefore, space-based laser has important values in satellite communication, satellite attitude controlling, space debris clearing, and long distance energy transmission, etc. On the other hand, solar energy is a kind of clean and renewable resources, the average intensity of solar irradiation on the earth is 1353W/m2, and it is even higher in space. Therefore, the space-based solar pumped lasers has attracted much research in recent years, most research focuses on solar pumped solid state lasers and solar pumped fiber lasers. The two lasing principle is based on stimulated emission of the rare earth ions such as Nd, Yb, Cr. The rare earth ions absorb light only in narrow bands. This leads to inefficient absorption of the broad-band solar spectrum, and increases the system heating load, which make the system solar to laser power conversion efficiency very low. As a solar pumped semiconductor lasers could absorb all photons with energy greater than the bandgap. Thus, solar pumped semiconductor lasers could have considerably higher efficiencies than other solar pumped lasers. Besides, solar pumped semiconductor lasers has smaller volume chip, simpler structure and better heat dissipation, it can be mounted on a small satellite platform, can compose satellite array, which can greatly improve the output power of the system, and have flexible character. This paper summarizes the research progress of space-based solar pumped semiconductor lasers, analyses of the key technologies based on several application areas, including the processing of semiconductor chip, the design of small and efficient solar condenser, and the cooling system of lasers, etc. We conclude that the solar pumped vertical cavity surface-emitting semiconductor lasers will have a wide application prospects in the space.

Design and Characterisation of III-V Semiconductor Nanowire Lasers

Science.gov (United States)

Saxena, Dhruv

The development of small, power-efficient lasers underpins many of the technologies that we utilise today. Semiconductor nanowires are promising for miniaturising lasers to even smaller dimensions. III-V semiconductors, such as Gallium Arsenide (GaAs) and Indium Phosphide (InP), are the most widely used materials for optoelectronic devices and so the development of nanowire lasers based on these materials is expected to have technologically significant outcomes. This PhD dissertation presents a comprehensive study of the design of III-V semiconductor nanowire lasers, with bulk and quantum confined active regions. Based on the design, various III-V semiconductor nanowire lasers are demonstrated, namely, GaAs nanowire lasers, GaAs/AlGaAs multi-quantum well (MQW) nanowire lasers and InP nanowire lasers. These nanowire lasers are shown to operate at room temperature, have low thresholds, and lase from different transverse modes. The structural and optoelectronic quality of nanowire lasers are characterised via electron microscopy and photoluminescence spectroscopic techniques. Lasing is characterised in all these devices by optical pumping. The lasing characteristics are analysed by rate equation modelling and the lasing mode(s) in these devices is characterised by threshold gain modelling, polarisation measurements and Fourier plane imaging. Firstly, GaAs nanowire lasers that operate at room temperature are demonstrated. This is achieved by determining the optimal nanowire diameter to reduce threshold gain and by passivating nanowires to improve their quantum efficiency (QE). High-quality surface passivated GaAs nanowires of suitable diameters are grown. The growth procedure is tailored to improve both QE and structural uniformity of nanowires. Room-temperature lasing is demonstrated from individual nanowires and lasing is characterised to be from TM01 mode by threshold gain modelling. To lower threshold even further, nanowire lasers with GaAs/AlGaAs coaxial multi

Theory of semiconductor laser cooling

Science.gov (United States)

Rupper, Greg

Recently laser cooling of semiconductors has received renewed attention, with the hope that a semiconductor cooler might be able to achieve cryogenic temperatures. In order to study semiconductor laser cooling at cryogenic temperatures, it is crucial that the theory include both the effects of excitons and the electron-hole plasma. In this dissertation, I present a theoretical analysis of laser cooling of bulk GaAs based on a microscopic many-particle theory of absorption and luminescence of a partially ionized electron-hole plasma. This theory has been analyzed from a temperature 10K to 500K. It is shown that at high temperatures (above 300K), cooling can be modeled using older models with a few parameter changes. Below 200K, band filling effects dominate over Auger recombination. Below 30K excitonic effects are essential for laser cooling. In all cases, excitonic effects make cooling easier then predicted by a free carrier model. The initial cooling model is based on the assumption of a homogeneous undoped semiconductor. This model has been systematically modified to include effects that are present in real laser cooling experiments. The following modifications have been performed. (1) Propagation and polariton effects have been included. (2) The effect of p-doping has been included. (n-doping can be modeled in a similar fashion.) (3) In experiments, a passivation layer is required to minimize non-radiative recombination. The passivation results in a npn heterostructure. The effect of the npn heterostructure on cooling has been analyzed. (4) The effect of a Gaussian pump beam was analyzed and (5) Some of the parameters in the cooling model have a large uncertainty. The effect of modifying these parameters has been analyzed. Most of the extensions to the original theory have only had a modest effect on the overall results. However we find that the current passivation technique may not be sufficient to allow cooling. The passivation technique currently used appears

Controlling the emission wavelength in group III-V semiconductor laser diodes

KAUST Repository

Ooi, Boon S.

2016-12-29

Methods are provided for modifying the emission wavelength of a semiconductor quantum well laser diode, e.g. by blue shifting the emission wavelength. The methods can be applied to a variety of semiconductor quantum well laser diodes, e.g. group III-V semiconductor quantum wells. The group III-V semiconductor can include AlSb, AlAs, Aln, AlP, BN, GaSb, GaAs, GaN, GaP, InSb, InAs, InN, and InP, and group III-V ternary semiconductors alloys such as AlxGai.xAs. The methods can results in a blue shifting of about 20 meV to 350 meV, which can be used for example to make group III-V semiconductor quantum well laser diodes with an emission that is orange or yellow. Methods of making semiconductor quantum well laser diodes and semiconductor quantum well laser diodes made therefrom are also provided.

CO2 laser pulse switching by optically excited semiconductors

International Nuclear Information System (INIS)

Silva, V.L. da.

1986-01-01

The construction and the study of a semi-conductor optical switch used for generating short infrared pulses and to analyse the semiconductor characteristics, are presented. The switch response time depends on semiconductor and control laser characteristics. The results obtained using a Ge switch controlled by N 2 , NdYag and Dye lasers are presented. The response time was 50 ns limited by Ge recombination time. The reflectivity increased from 7% to 59% using N 2 laser to control the switch. A simple model for semiconductor optical properties that explain very well the experimental results, is also presented. (author) [pt

The Modulation Response of a Semiconductor Laser Amplifier

DEFF Research Database (Denmark)

Mørk, Jesper; Mecozzi, Antonio; Eisenstein, Gadi

1999-01-01

We present a theoretical analysis of the modulation response of a semiconductor laser amplifier. We find a resonance behavior similar to the well-known relaxation oscillation resonance found in semiconductor lasers, but of a different physical origin. The role of the waveguide (scattering) loss i...

Ring cavity surface emitting semiconductor lasers

International Nuclear Information System (INIS)

Mujagic, E.

2010-01-01

Quantum cascade lasers (QCLs) are electrically driven semiconductor lasers, which have undergone a steady improvement since the first demonstration in 1994. These are now well established as reliable sources of coherent light in the mid-infrared (MIR) and terahertz (THz)range of the electromagnetic spectrum (3-300 μm). The rapid progress of this type of lasers is based on a high degree of freedom in tailoring the emission wavelength within a large variety of semiconductor heterostructure designs and materials. These properties have attracted the attention of various applications such as gas analysis, chemical sensing, spectral imaging and free-space telecommunication. In order to improve the selectivity, sensitivity and efficiency of today's sensor systems, high optical power, continuous wave and room temperature performance, single-mode operation and low divergence optical beams, are highly desirable qualities of a compact laser source in this field of research. Since all of these features cannot be provided by a conventional edge-emitting device at the same time, research has put focus on the development of surface emitting devices. Nowadays, the vertical cavity surface emitting lasers (VCSELs) are the most prominent representative for this type of light emitters. With its capability of producing narrow circular beams, the feasibility of two-dimensional arrays and on-wafer testing, such a coherent light source results in a reduction of the fabrication effort and production costs. Since the radiation in QCLs is strictly polarized normal to the epitaxial layer plane, fabrication of VCSELs based on QC structures is not viable. The subject of this work is the design and realization of 'ring cavity surface emitting lasers' (ring-CSELs). This type of lasers employs a circular ring cavity and a resonant distributed feedback (DFB) surface grating. Ring-CSELs were fabricated on the basis of MIR and THz QC structures, which cover a wavelength range from 4 μm to 93 �

Below-bandgap photoreflection spectroscopy of semiconductor laser structures

International Nuclear Information System (INIS)

Sotnikov, Aleksandr E; Chernikov, Maksim A; Ryabushkin, Oleg A; Trubenko, P; Moshegov, N; Ovchinnikov, A

2004-01-01

A new method of modulated light reflection - below-bandgap photoreflection, is considered. Unlike the conventional photoreflection method, the proposed method uses optical pumping by photons of energy smaller than the bandgap of any layer of a semiconductor structure under study. Such pumping allows one to obtain the modulated reflection spectrum for all layers of the structure without excitation of photoluminescence. This method is especially promising for the study of wide-gap semiconductors. The results of the study of semiconductor structures used in modern high-power multimode semiconductor lasers are presented. (laser applications and other topics in quantum electronics)

Spherical distribution structure of the semiconductor laser diode stack for pumping

International Nuclear Information System (INIS)

Zhao Tianzhuo; Yu Jin; Liu Yang; Zhang Xue; Ma Yunfeng; Fan Zhongwei

2011-01-01

A semiconductor laser diode stack is used for pumping and 8 semiconductor laser diode arrays of the stack are put on a sphere, and the output of every bar is specially off-axis compressed to realize high coupling efficiency. The output beam of this semiconductor laser diode stack is shaped by a hollow duct to the laser active medium. The efficiency of the hollow light pipe, which is used for semiconductor laser diode stack coupling, is analyzed by geometric optics and ray tracing. Geometric optics analysis diagnoses the reasons for coupling loss and guides the design of the structure. Ray tracing analyzes the relation between the structural parameters and the output characteristics of this pumping system, and guides parameter optimization. Simulation and analysis results show that putting the semiconductor laser diode arrays on a spherical surface can increase coupling efficiency, reduce the optimum duct length and improve the output energy field distribution. (semiconductor devices)

Femtosecond all-polarization-maintaining fiber laser operating at 1028 nm

DEFF Research Database (Denmark)

Olsson, R.K.; Andersen, T.V.; Leick, Lasse

2008-01-01

We present an effective solution for an all-polarization-maintaining modelocked femtosecond fiber laser operating at the central wavelength of 1028 nm. The laser is based on an Yb-doped active fiber. Modelocking is enabled by a semiconductor saturable absorber mirror, and the central wavelength i...... is enforced by a fiber Bragg grating. The laser is self-starting and demonstrates excellent stability gainst Q-switching. Pulse energies reach 13 nJ at 34 MHz repetition rate. External compression leads to near transform-limited pulses of 140 fs.......We present an effective solution for an all-polarization-maintaining modelocked femtosecond fiber laser operating at the central wavelength of 1028 nm. The laser is based on an Yb-doped active fiber. Modelocking is enabled by a semiconductor saturable absorber mirror, and the central wavelength...

Semiconductor ring lasers coupled by a single waveguide

Science.gov (United States)

Coomans, W.; Gelens, L.; Van der Sande, G.; Mezosi, G.; Sorel, M.; Danckaert, J.; Verschaffelt, G.

2012-06-01

We experimentally and theoretically study the characteristics of semiconductor ring lasers bidirectionally coupled by a single bus waveguide. This configuration has, e.g., been suggested for use as an optical memory and as an optical neural network motif. The main results are that the coupling can destabilize the state in which both rings lase in the same direction, and it brings to life a state with equal powers at both outputs. These are both undesirable for optical memory operation. Although the coupling between the rings is bidirectional, the destabilization occurs due to behavior similar to an optically injected laser system.

Towards filament free semiconductor lasers

DEFF Research Database (Denmark)

McInerney, John; O'Brien, Peter; Skovgaard, Peter M. W.

2000-01-01

We outline physical models and simulations for suppression of self-focusing and filamentation in large aperture semiconductor lasers. The principal technical objective is to generate multi-watt CW or quasi-CW outputs with nearly diffraction limited beams, suitable for long distance free space...... propagation structures in lasers and amplifiers which suppress lateral reflections....

Stable CW Single Frequency Operation of Fabry-Perot Laser Diodes by Self-Injection Phase Locking

Science.gov (United States)

Duerksen, Gary L.; Krainak, Michael A.

1999-01-01

Previously, single-frequency semiconductor laser operation using fiber Bragg gratings has been achieved by tWo methods: 1) use of the FBG as the output coupler for an anti-reflection-coated semiconductor gain element'; 2) pulsed operation of a gain-switched Fabry-Perot laser diode with FBG-optical and RF-electrical feedback'. Here, we demonstrate CW single frequency operation from a non-AR coated Fabry-Perot laser diode using only FBG optical feedback.

Thermoreflectance spectroscopy—Analysis of thermal processes in semiconductor lasers

Science.gov (United States)

Pierścińska, D.

2018-01-01

This review focuses on theoretical foundations, experimental implementation and an overview of experimental results of the thermoreflectance spectroscopy as a powerful technique for temperature monitoring and analysis of thermal processes in semiconductor lasers. This is an optical, non-contact, high spatial resolution technique providing high temperature resolution and mapping capabilities. Thermoreflectance is a thermometric technique based on measuring of relative change of reflectivity of the surface of laser facet, which provides thermal images useful in hot spot detection and reliability studies. In this paper, principles and experimental implementation of the technique as a thermography tool is discussed. Some exemplary applications of TR to various types of lasers are presented, proving that thermoreflectance technique provides new insight into heat management problems in semiconductor lasers and in particular, that it allows studying thermal degradation processes occurring at laser facets. Additionally, thermal processes and basic mechanisms of degradation of the semiconductor laser are discussed.

Digitally tunable dual wavelength emission from semiconductor ring lasers with filtered optical feedback

International Nuclear Information System (INIS)

Khoder, Mulham; Verschaffelt, Guy; Nguimdo, Romain Modeste; Danckaert, Jan; Leijtens, Xaveer; Bolk, Jeroen

2013-01-01

We report on a novel integrated approach to obtain dual wavelength emission from a semiconductor laser based on on-chip filtered optical feedback. Using this approach, we show experiments and numerical simulations of dual wavelength emission of a semiconductor ring laser. The filtered optical feedback is realized on-chip by employing two arrayed waveguide gratings to split/recombine light into different wavelength channels. Semiconductor optical amplifiers are placed in the feedback loop in order to control the feedback strength of each wavelength channel independently. By tuning the current injected into each of the amplifiers, we can effectively cancel the gain difference between the wavelength channels due to fabrication and material dichroism, thus resulting in stable dual wavelength emission. We also explore the accuracy needed in the operational parameters to maintain this dual wavelength emission. (letter)

Construction of an optical semiconductor amplifier starting from a Fabry-Perot semiconductor laser; Construccion de un amplificador optico de semiconductor a partir de un laser de semiconductor Fabry-Perot

Energy Technology Data Exchange (ETDEWEB)

Garcia, E.; Soto, H.; Marquez, H.; Valles V, N. [Departamento de Electronica y Telecomunicaciones, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada. Km. 107, Carretera Tijuana-Ensenada, 22860 Ensenada, Baja California (Mexico)

2000-07-01

A methodology to convert a semiconductor laser Fabry-Perot (SL-FP) in a semiconductor optical amplifier (SOA) is presented. In order to suppress the cavity resonant an optical thin film coating was deposited on the facets of the SL-FP. The experiment was carried out putting on service a new monitoring technique that consist in the observation of the laser power spectrum during the antireflection coatings deposition. This allows to determine the moment were the facets reflectivity is minimum. The SOA obtained was characterized for different polarization currents. (Author)

The features of modelling semiconductor lasers with a wide contact

Directory of Open Access Journals (Sweden)

Rzhanov Alexey

2017-01-01

Full Text Available The aspects of calculating the dynamics and statics of powerful semiconductor laser diodes radiation are investigated. It takes into account the main physical mechanisms influencing power, spectral composition, far and near field of laser radiation. It outlines a dynamic distributed model of a semiconductor laser with a wide contact and possible algorithms for its implementation.

Singly-resonant sum frequency generation of visible light in a semiconductor disk laser

DEFF Research Database (Denmark)

Andersen, Martin Thalbitzer; Schlosser, P.J.; Hastie, J.E.

2009-01-01

In this paper a generic approach for visible light generation is presented. It is based on sum frequency generation between a semiconductor disk laser and a solid-state laser, where the frequency mixing is achieved within the cavity of the semiconductor disk laser using a singlepass of the solid......-state laser light. This exploits the good beam quality and high intra-cavity power present in the semiconductor disk laser to achieve high conversion efficiency. Combining sum frequency mixing and semiconductor disk lasers in this manner allows in principle for generation of any wavelength within the visible...

Reduced filamentation in high power semiconductor lasers

DEFF Research Database (Denmark)

Skovgaard, Peter M. W.; McInerney, John; O'Brien, Peter

1999-01-01

High brightness semiconductor lasers have applications in fields ranging from material processing to medicine. The main difficulty associated with high brightness is that high optical power densities cause damage to the laser facet and thus require large apertures. This, in turn, results in spatio......-temporal instabilities such as filamentation which degrades spatial coherence and brightness. We first evaluate performance of existing designs with a “top-hat” shaped transverse current density profile. The unstable nature of highly excited semiconductor material results in a run-away process where small modulations...

Semiconductor Laser Tracking Frequency Distance Gauge

Science.gov (United States)

Phillips, James D.; Reasenberg, Robert D.

2009-01-01

Advanced astronomical missions with greatly enhanced resolution and physics missions of unprecedented accuracy will require a spaceworthy laser distance gauge of substantially improved performance. The Tracking Frequency Gauge (TFG) uses a single beam, locking a laser to the measurement interferometer. We have demonstrated this technique with pm (10(exp -12) m) performance. We report on the version we are now developing based on space-qualifiable, fiber-coupled distributed-feedback semiconductor lasers.

Study on guided waves in semiconductor lasers

International Nuclear Information System (INIS)

Pudensi, M.A.A.

1980-01-01

In This work we studied the guided waves in semiconductor lasers. In the first part we carried on the experimental measurements on lasers with stripe nonorthogonal to the mirrors. In the second part we developed a matrix method for the study of propagation and reflection of guided waves in lasers. (author) [pt

Management of gingival hyperpigmentation by semiconductor diode laser

Directory of Open Access Journals (Sweden)

Geeti Gupta

2011-01-01

Full Text Available Gingival hyperpigmentation is caused by excessive deposition of melanin in the basal and suprabasal cell layers of the epithelium. Although melanin pigmentation of the gingiva is completely benign, cosmetic concerns are common, particularly in patients having a very high smile line (gummy smile. Various depigmentation techniques have been employed, such as scalpel surgery, gingivectomy, gingivectomy with free gingival autografting, cryosurgery, electrosurgery, chemical agents such as 90% phenol and 95% alcohol, abrasion with diamond burs, Nd:YAG laser, semiconductor diode laser, and CO 2 laser. The present case report describes simple and effective depigmentation technique using semiconductor diode laser surgery - for gingival depigmentation, which have produced good results with patient satisfaction.

Development of semiconductor laser based Doppler lidars for wind-sensing applications

DEFF Research Database (Denmark)

Rodrigo, Peter John; Hu, Qi; Pedersen, Christian

2015-01-01

We summarize the progress we have made in the development of semiconductor laser (SL) based Doppler lidar systems for remote wind speed and direction measurements. The SL emitter used in our wind-sensing lidar is an integrated diode laser with a tapered (semiconductor) amplifier. The laser source...

All-polymer organic semiconductor laser chips: Parallel fabrication and encapsulation

DEFF Research Database (Denmark)

Vannahme, Christoph; Klinkhammer, Sönke; Christiansen, Mads Brøkner

2010-01-01

Organic semiconductor lasers are of particular interest as tunable visible laser light sources. For bringing those to market encapsulation is needed to ensure practicable lifetimes. Additionally, fabrication technologies suitable for mass production must be used. We introduce all-polymer chips...... comprising encapsulated distributed feedback organic semiconductor lasers. Several chips are fabricated in parallel by thermal nanoimprint of the feedback grating on 4? wafer scale out of poly(methyl methacrylate) (PMMA) and cyclic olefin copolymer (COC). The lasers consisting of the organic semiconductor...... tris(8- hydroxyquinoline) aluminum (Alq3) doped with the laser dye 4-dicyanomethylene-2- methyl-6-(p-dimethylaminostyril)-4H-pyrane (DCM) are hermetically sealed by thermally bonding a polymer lid. The organic thin film is placed in a basin within the substrate and is not in direct contact to the lid...

High brightness semiconductor lasers with reduced filamentation

DEFF Research Database (Denmark)

McInerney, John; O'Brien, Peter.; Skovgaard, Peter M. W.

1999-01-01

High brightness semiconductor lasers have applications in spectroscopy, fiber lasers, manufacturing and materials processing, medicine and free space communication or energy transfer. The main difficulty associated with high brightness is that, because of COD, high power requires a large aperture...

Construction of an optical semiconductor amplifier starting from a Fabry-Perot semiconductor laser

International Nuclear Information System (INIS)

Garcia, E.; Soto, H.; Marquez, H.; Valles V, N.

2000-01-01

A methodology to convert a semiconductor laser Fabry-Perot (SL-FP) in a semiconductor optical amplifier (SOA) is presented. In order to suppress the cavity resonant an optical thin film coating was deposited on the facets of the SL-FP. The experiment was carried out putting on service a new monitoring technique that consist in the observation of the laser power spectrum during the antireflection coatings deposition. This allows to determine the moment were the facets reflectivity is minimum. The SOA obtained was characterized for different polarization currents. (Author)

Ultrafast dynamics and laser action of organic semiconductors

CERN Document Server

Vardeny, Zeev Valy

2009-01-01

Spurred on by extensive research in recent years, organic semiconductors are now used in an array of areas, such as organic light emitting diodes (OLEDs), photovoltaics, and other optoelectronics. In all of these novel applications, the photoexcitations in organic semiconductors play a vital role. Exploring the early stages of photoexcitations that follow photon absorption, Ultrafast Dynamics and Laser Action of Organic Semiconductors presents the latest research investigations on photoexcitation ultrafast dynamics and laser action in pi-conjugated polymer films, solutions, and microcavities.In the first few chapters, the book examines the interplay of charge (polarons) and neutral (excitons) photoexcitations in pi-conjugated polymers, oligomers, and molecular crystals in the time domain of 100 fs-2 ns. Summarizing the state of the art in lasing, the final chapters introduce the phenomenon of laser action in organics and cover the latest optoelectronic applications that use lasing based on a variety of caviti...

Optimal operating conditions for external cavity semiconductor laser optical chaos communication system

International Nuclear Information System (INIS)

Priyadarshi, S; Pierce, I; Hong, Y; Shore, K A

2012-01-01

In optical chaos communications a message is masked in the noise-like broadband output of a chaotic transmitter laser, and message recovery is enabled through the synchronization of the transmitter and the (chaotic) receiver laser. Key issues are to identify the laser operating conditions which provide the highest quality synchronization conditions and those which provide optimized message extraction. In general such operating conditions are not coincident. In this paper numerical simulations are performed with the aim of identifying a regime of operation where the highest quality synchronization and optimizing message extraction efficiency are achieved simultaneously. Use of such an operating regime will facilitate practical deployment of optical chaos communications systems without the need for re-adjustment of laser operating conditions in the field. (paper)

Stable CW Single-Frequency Operation of Fabry-Perot Laser Diodes by Self-Injection Phase Locking

Science.gov (United States)

Duerksen, Gary L.; Krainak, Michael A.

1999-01-01

Previously, single-frequency semiconductor laser operation using fiber Bragg gratings has been achieved by two methods: 1) use of the FBG as the output coupler for an anti-reflection-coated semiconductor gain element'; 2) pulsed operation of a gain-switched Fabry-Perot laser diode with FBG-optical and RF-electrical feedback. Here, we demonstrate CW single frequency operation from a non-AR coated Fabry-Perot laser diode using only FBG optical feedback. We coupled a nominal 935 run-wavelength Fabry-Perot laser diode to an ultra narrow band (18 pm) FBG. When tuned by varying its temperature, the laser wavelength is pulled toward the centerline of the Bragg grating, and the spectrum of the laser output is seen to fall into three discrete stability regimes as measured by the side-mode suppression ratio.

Dynamics of InGaN tandem blue-violet semiconductor lasers

International Nuclear Information System (INIS)

Antohi, I.; Rusu, S.S.; Tronciu, V.Z.

2013-01-01

Full text: Blue-violet semiconductor lasers have received much attention because of their promise for high-density optical storage applications. In particular, blue-violet laser diodes operating at 400 nm are required for BD- systems and for use in medicine, biology, color printers and monitors, etc, In recent years, numerous fabrication methods have been proposed and developed for blue lasers with CW and self-pulsating operations and the lifetime of such lasers has been increased to over 15000 h. Recently, we have reported self-pulsation and excitable behaviour for an InGaN laser with a p-type saturable absorber, and SP in the frequency range from 1.6 to 2.9 GHz has been achieved with such lasers. In this paper, we present an investigation of the dynamics of tandem 400 nm blue-violet lasers with setup presented in Fig.1a. A particular feature of the devices is the connection of the contacts of the SA, to reduce the carrier lifetime in the SA with the intention of producing self-pulsation and excitability. We examine the laser dynamics in terms of bifurcation diagrams. A typical calculation of bifurcation for the periodic solution is shown in Fig. 1b. This figure shows the dependence of the peak of the photon number on the injected.

Controlling the emission wavelength in group III-V semiconductor laser diodes

KAUST Repository

Ooi, Boon S.; Majid, Mohammed Abdul; Afandy, Rami; Aljabr, Ahmad

2016-01-01

Methods are provided for modifying the emission wavelength of a semiconductor quantum well laser diode, e.g. by blue shifting the emission wavelength. The methods can be applied to a variety of semiconductor quantum well laser diodes, e.g. group III

Return-map for semiconductor lasers with optical feedback

DEFF Research Database (Denmark)

Mørk, Jesper; Tromborg, Bjarne; Sabbatier, H.

1999-01-01

It is well known that a semiconductor laser exposed to moderate optical feedback and biased near threshold exhibits the phenomenon of low-frequency intensity fluctuations (LFF). While this behavior can be numerically simulated using the so-called Lang-Kobayshi model, the interpretation of the phe......It is well known that a semiconductor laser exposed to moderate optical feedback and biased near threshold exhibits the phenomenon of low-frequency intensity fluctuations (LFF). While this behavior can be numerically simulated using the so-called Lang-Kobayshi model, the interpretation...

Single-mode very wide tunability in laterally coupled semiconductor lasers with electrically controlled reflectivities

Science.gov (United States)

Griffel, Giora; Chen, Howard Z.; Grave, Ilan; Yariv, Amnon

1991-04-01

The operation of a novel multisection structure comprised of laterally coupled gain-guided semiconductor lasers is demonstrated. It is shown that tunable single longitudinal mode operation can be achieved with a high degree of frequency selectivity. The device has a tuning range of 14.5 nm, the widest observed to date in a monolithic device.

Single filament semiconductor laser

International Nuclear Information System (INIS)

Botez, D.

1980-01-01

A semiconductor laser comprising: a body of semiconductor material including a substrate having a surface and a pair of spaced, substantially parallel dove-tailed shaped grooves in said surface, said body having a pair of end surfaces between which said grooves extend, said end surfaces being reflective to light with at least one of said end surfaces being partially transparent to light a first epitaxial layer over said surface of the substrate and the surfaces of the grooves, said first epitaxial layer having a flat surface portion over the portion of the substrate surface between the grooves, a thin second epitaxial layer over said first epitaxial layer, a third epitaxial layer over said second epitaxial layer, said first and third epitaxial layers being of opposite conductivity types and the second epitaxial layer being the active recombination region of the laser with the light being generated therein in the vicinity of the portion which is over the flat surface portion of the first epitaxial layer, and a pair of contacts on said body with one contact being over said third epitaxial body and the other being on said substrate

Semiconductor processing with excimer lasers

International Nuclear Information System (INIS)

Young, R.T.; Narayan, J.; Christie, W.H.; van der Leeden, G.A.; Rothe, D.E.; Cheng, L.J.

1983-01-01

The advantages of pulsed excimer lasers for semiconductor processing are reviewed. Extensive comparisons of the quality of annealing of ion-implanted Si obtained with XeCl and ruby lasers have been made. The results indicate that irrespective of the large differences in the optical properties of Si at uv and visible wavelengths, the efficiency of usage of the incident energy for annealing is comparable for the two lasers. However, because of the excellent optical beam quality, the XeCl laser can provide superior control of the surface melting and the resulting junction depth. Furthermore, the concentrations of electrically active point defects in the XeCl laser annealed region are 2 to 3 orders of magnitude lower than that obtained from ruby or Nd:YAG lasers. All these results seem to suggest that XeCl lasers should be suitable for fabricating not only solar cells but also the more advanced device structures required for VLSI or VHSIC applications

Semiconductor laser technology for remote sensing experiments

Science.gov (United States)

Katz, Joseph

1988-01-01

Semiconductor injection lasers are required for implementing virtually all spaceborne remote sensing systems. Their main advantages are high reliability and efficiency, and their main roles are envisioned in pumping and injection locking of solid state lasers. In some shorter range applications they may even be utilized directly as the sources.

Integrated semiconductor twin-microdisk laser under mutually optical injection

Energy Technology Data Exchange (ETDEWEB)

Zou, Ling-Xiu; Liu, Bo-Wen; Lv, Xiao-Meng; Yang, Yue-De; Xiao, Jin-Long; Huang, Yong-Zhen, E-mail: yzhuang@semi.ac.cn [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

2015-05-11

We experimentally study the characteristics of an integrated semiconductor twin-microdisk laser under mutually optical injection through a connected optical waveguide. Based on the lasing spectra, four-wave mixing, injection locking, and period-two oscillation states are observed due to the mutually optical injection by adjusting the injected currents applied to the two microdisks. The enhanced 3 dB bandwidth is realized for the microdisk laser at the injection locking state, and photonic microwave is obtained from the electrode of the microdisk laser under the period-two oscillation state. The plentifully dynamical states similar as semiconductor lasers subject to external optical injection are realized due to strong optical interaction between the two microdisks.

Driver circuit for pulse modulation of a semiconductor laser

International Nuclear Information System (INIS)

Ueki, A.

1975-01-01

A pulse modulation driver circuit for a semiconductor laser is disclosed which discriminates among input pulse signals composed of binary codes to detect the occurrence of a pulse having a code of ''I'' following a pulse having a code of ''0''. Detection of this pattern is used to control the driver to increase either or both the width or peak value of the pulse having a code of 1. The effect of this is to eliminate a pattern effect in the light emitted by the semiconductor laser caused by an attenuation of the population inversion in the laser. (U.S.)

Periodic dark pulse emission induced by delayed feedback in a quantum well semiconductor laser

Directory of Open Access Journals (Sweden)

L. Li

2012-12-01

Full Text Available We report the experimental observation of periodic dark pulse emission in a quantum-well semiconductor laser with delayed optical feedback. We found that under appropriate operation conditions the laser can also emit a stable train of dark pulses. The repetition frequency of the dark pulse is determined by the external cavity length. Splitting of the dark pulse was also observed. We speculate that the observed dark pulse is a kind of temporal cavity soliton formed in the laser.

Modes in light wave propagating in semiconductor laser

Science.gov (United States)

Manko, Margarita A.

1994-01-01

The study of semiconductor laser based on an analogy of the Schrodinger equation and an equation describing light wave propagation in nonhomogeneous medium is developed. The active region of semiconductor laser is considered as optical waveguide confining the electromagnetic field in the cross-section (x,y) and allowing waveguide propagation along the laser resonator (z). The mode structure is investigated taking into account the transversal and what is the important part of the suggested consideration longitudinal nonhomogeneity of the optical waveguide. It is shown that the Gaussian modes in the case correspond to spatial squeezing and correlation. Spatially squeezed two-mode structure of nonhomogeneous optical waveguide is given explicitly. Distribution of light among the laser discrete modes is presented. Properties of the spatially squeezed two-mode field are described. The analog of Franck-Condon principle for finding the maxima of the distribution function and the analog of Ramsauer effect for control of spatial distribution of laser emission are discussed.

Heteroclinic dynamics of coupled semiconductor lasers with optoelectronic feedback.

Science.gov (United States)

Shahin, S; Vallini, F; Monifi, F; Rabinovich, M; Fainman, Y

2016-11-15

Generalized Lotka-Volterra (GLV) equations are important equations used in various areas of science to describe competitive dynamics among a population of N interacting nodes in a network topology. In this Letter, we introduce a photonic network consisting of three optoelectronically cross-coupled semiconductor lasers to realize a GLV model. In such a network, the interaction of intensity and carrier inversion rates, as well as phases of laser oscillator nodes, result in various dynamics. We study the influence of asymmetric coupling strength and frequency detuning between semiconductor lasers and show that inhibitory asymmetric coupling is required to achieve consecutive amplitude oscillations of the laser nodes. These studies were motivated primarily by the dynamical models used to model brain cognitive activities and their correspondence with dynamics obtained among coupled laser oscillators.

Mode structure of delay-coupled semiconductor lasers: influence of the pump current

International Nuclear Information System (INIS)

Erzgraeber, Hartmut; Krauskopf, Bernd; Lenstra, Daan

2005-01-01

We consider two identical, mutually delay-coupled semiconductor lasers and show that their compound laser modes (CLMs)-the basic continuous wave solutions-depend rather sensitively on the pump current of the lasers. Specifically, we show with figures and accompanying animations how the underlying CLM structure and the associated locking region, where both lasers operate stably with the same frequency, change as a function of the pump current. Our results provide a natural transition between rather different CLM structures that have been reported in the literature. Moreover, we demonstrate how the locking region as well as the different types of instabilities at its boundary depend on the pump current. This is of fundamental interest for the dynamics of coupled lasers and their possible application

Diagnostic studies of molecular plasmas using mid-infrared semiconductor lasers

NARCIS (Netherlands)

Röpcke, J.; Welzel, S.; Lang, N.; Hempel, F.; Gatilova, L.; Guaitella, O.; Rousseau, A.; Davies, P.B.

2008-01-01

Within the last decade mid-infrared absorption spectroscopy between 3 and 20 µm, known as infrared laser absorption spectroscopy (IRLAS) and based on tuneable semiconductor lasers, namely lead salt diode lasers, often called tuneable diode lasers (TDL), and quantum cascade lasers (QCL) has

A study on the optical parts for a semiconductor laser module

Energy Technology Data Exchange (ETDEWEB)

Oh, Jun-Girl; Lee, Dong-Kil; Kim, Yang-Gyu; Lee, Kwang-Hoon; Park, Young-Sik [Korea Photonics Technology Institute, Gwangju (Korea, Republic of); Jang, Kwang-Ho [Hanvit Optoline, Gwangju (Korea, Republic of); Kang, Seung-Goo [COSET, Gwangju (Korea, Republic of)

2014-11-15

A semiconductor laser module consists of a LD (laser diode) chip that generates a laser beam, two cylindrical lenses to collimate the laser beam, a high-reflection mirror to produce a large output by collecting the laser beam, a collimator lens to guide the laser beam to an optical fiber and a protection filter to block reflected laser light that might damage the LD chip. The cylindrical lenses used in a semiconductor laser module are defined as FACs (fast axis collimators) and SACs (slow axis collimators) and are attached to the system module to control the shape of the laser beam. The FAC lens and the SAC lens are made of a glass material to protect the lenses from thermal deformation. In addition, they have aspheric shapes to improve optical performances. This paper presents a mold core grinding process for an asymmetrical aspheric lens and a GMP (glass molding press), what can be used to make aspheric cylindrical lenses for use as FACs or SACs, and a protection filter made by using IAD (ion-beam-assisted deposition). Finally, we developed the aspheric cylindrical lenses and the protection filter for a 10-W semiconductor laser module.

Review on the dynamics of semiconductor nanowire lasers

Science.gov (United States)

Röder, Robert; Ronning, Carsten

2018-03-01

Semiconductor optoelectronic devices have contributed tremendously to the technological progress in the past 50-60 years. Today, they also play a key role in nanophotonics stimulated by the inherent limitations of electronic integrated circuits and the growing demand for faster communications on chip. In particular, the field of ‘nanowire photonics’ has emerged including the search for coherent light sources with a nano-scaled footprint. The past decade has been dedicated to find suitable semiconductor nanowire (NW) materials for such nanolasers. Nowadays, such NW lasers consistently work at room temperature covering a huge spectral range from the ultraviolet down to the mid-infrared depending on the band gap of the NW material. Furthermore, first approaches towards the modification and optimization of such NW laser devices have been demonstrated. The underlying dynamics of the electronic and photonic NW systems have also been studied very recently, as they need to be understood in order to push the technological relevance of nano-scaled coherent light sources. Therefore, this review will first present novel measurement approaches in order to study the ultrafast temporal and optical mode dynamics of individual NW laser devices. Furthermore, these fundamental new insights are reviewed and deeply discussed towards the efficient control and adjustment of the dynamics in semiconductor NW lasers.

Ultrafast laser-semiconductor interactions

International Nuclear Information System (INIS)

Schile, L.A.

1996-01-01

Studies of the ultrafast (< 100 fs) interactions of infrared, sub-100 fs laser pulses with IR, photosensitive semiconductor materials InGaAs, InSb, and HgCdTe are reported. Both the carrier dynamics and the associated Terahertz radiation from these materials are discussed. The most recent developments of femtosecond (< 100 fs) Optical Parametric Oscillators (OPO) has extended the wavelength range from the visible to 5.2 μm. The photogenerated semiconductor free carrier dynamics are determined in the 77 to 300 degrees K temperature range using the Transmission Correlation Peak (TCP) method. The electron-phonon scattering times are typically 200 - 600 fs. Depending upon the material composition and substrate on which the IR crystalline materials are deposited, the nonlinear TCP absorption gives recombination rates as fast as 10's of picoseconds. For the HgCdTe, there exists a 400 fs electron-phonon scattering process along with a much longer 3600 fs loss process. Studies of the interactions of these ultrashort laser pulses with semiconductors produce Terahertz (Thz) radiative pulses. With undoped InSb, there is a substantial change in the spectral content of this THz radiation between 80 - 260 degrees K while the spectrum of Te-doped InSb remains nearly unchanged, an effect attributed to its mobility being dominated by impurity scattering. At 80 degrees K, the terahertz radiation from undoped InSb is dependent on wavelength, with both a higher frequency spectrum and much larger amplitudes generated at longer wavelengths. No such effect is observed at 260 degrees K. Finally, new results on the dependence of the emitted THz radiation on the InSb crystal's orientation is presented

High-Speed Operation of Interband Cascade Lasers

Science.gov (United States)

Soibel, Alexander; Hill, Cory J.; Keo, Sam A.; Wright, Malcom W.; Farr, William H.; Yang, Rui Q.; Liu, H. C.

2010-01-01

Optical sources operating in the atmospheric window of 3-5 microns are of particular interest for the development of free-space optical communication link. It is more advantageous to operate the free-space optical communication link in 3-5-microns atmospheric transmission window than at the telecom wavelength of 1.5 m due to lower optical scattering, scintillation, and background radiation. However, the realization of optical communications at the longer wavelength has encountered significant difficulties due to lack of adequate optical sources and detectors operating in the desirable wavelength regions. Interband Cascade (IC) lasers are novel semiconductor lasers that have a great potential for the realization of high-power, room-temperature optical sources in the 3-5-microns wavelength region, yet no experimental work, until this one, was done on high-speed direct modulation of IC lasers. Here, highspeed interband cascade laser, operating at wavelength 3.0 m, has been developed and the first direct measurement of the laser modulation bandwidth has been performed using a unique, highspeed quantum well infrared photodetector (QWIP). The developed laser has modulation bandwidth exceeding 3 GHz. This constitutes a significant increase of the IC laser modulation bandwidth over currently existing devices. This result has demonstrated suitability of IC lasers as a mid-IR light source for multi-GHz free-space optical communications links

Bistability and low-frequency fluctuations in semiconductor lasers with optical feedback: a theoretical analysis

DEFF Research Database (Denmark)

Mørk, Jesper; Tromborg, Bjarne; Christiansen, Peter Leth

1988-01-01

Near-threshold operation of a semiconductor laser exposed to moderate optical feedback may lead to low-frequency fluctuations. In the same region, a kink is observed in the light-current characteristic. Here it is demonstrated that these nonlinear phenomena are predicted by a noise driven multimode...

Low-confinement high-power semiconductor lasers

NARCIS (Netherlands)

Buda, M.

1999-01-01

This thesis presents the results of studies related to optimisation of high power semiconductor laser diodes using the low confinement concept. This implies a different approach in designing the transversal layer structure before growth and in processing the wafer after growth, for providing the

Influence of temperature on the spectral characteristics of semiconductor lasers in the visible range

Science.gov (United States)

Adamov, A. A.; Baranov, M. S.; Khramov, V. N.

2018-04-01

The results of studies on the effect of temperature on the output spectral characteristics of continuous semiconductor lasers of the visible range are presented. The paper presents the results of studying the spectral-optical radiation parameters of semiconductor lasers, their coherence lengths, and the dependence of the position of the spectral peak of the wavelength on temperature. This is necessary for the selection of the most optimal laser in order to use it for medical ophthalmologic diagnosis. The experiment was carried out using semiconductor laser modules based on a laser diode. The spectra were recorded by using a two-channel automated spectral complex based on the MDR-23 monochromator. Spectral dependences on the temperature of semiconductor lasers are obtained, in the range from 300 to 370 K. The possibility of determining the internal damage to the stabilization of laser modules without opening the case is shown, but only with the use of their spectral characteristics. The obtained data allow taking into account temperature characteristics and further optimization of parameters of such lasers when used in medical practice, in particular, in ophthalmologic diagnostics.

1-W quasi-cw near-diffraction-limited semiconductor laser pumped optically by a fibre-coupled diode bar

OpenAIRE

Dhanjal, S.; Hoogland, S.; Roberts, J.S.; Hayward, R.A.; Clarkson, W.A.; Tropper, Anne

2000-01-01

We describe a diode-bar-pumped vertical-external-cavity surface-emitting semiconductor laser, which in quasi-cw operation emitted a peak power of >1 W at 1020 nm in a circular, near diffraction-limited beam.

Synchronization scenario of two distant mutually coupled semiconductor lasers

DEFF Research Database (Denmark)

Mulet, Josep; Mirasso, Claudio; Heil, Tilmann

2004-01-01

We present numerical and experimental investigations of the synchronization of the coupling-induced instabilities in two distant mutually coupled semiconductor lasers. In our experiments, two similar Fabry-Perot lasers are coupled via their coherent optical fields. Our theoretical framework is ba...

Operational characteristics of dual gain single cavity Nd:YVO 4 laser

Indian Academy of Sciences (India)

Operational characteristics of a dual gain single cavity Nd:YVO4 laser have been investigated. With semiconductor diode laser pump power of 2 W, 800 mW output was obtained with a slope efficiency of 49%. Further, by changing the relative orientation of the two crystals the polarization characteristics of the output could be ...

All-metal coupling and package of semiconductor laser and amplifier with optical fiber

International Nuclear Information System (INIS)

Xu Fenglan; Li Lina; Zhang Yueqing

1992-01-01

The semiconductor laser and optical amplifier made by Changchun Institute of Physics coupled with optical fiber by use of all-metal coupling are represented. The net gain of semiconductor laser amplifier with optical fiber is 14 ∼18 dB

Theoretical modeling of the dynamics of a semiconductor laser subject to double-reflector optical feedback

Energy Technology Data Exchange (ETDEWEB)

Bakry, A. [King Abdulaziz University, 80203, Department of Physics, Faculty of Science (Saudi Arabia); Abdulrhmann, S. [Jazan University, 114, Department of Physics, Faculty of Sciences (Saudi Arabia); Ahmed, M., E-mail: mostafa.farghal@mu.edu.eg [King Abdulaziz University, 80203, Department of Physics, Faculty of Science (Saudi Arabia)

2016-06-15

We theoretically model the dynamics of semiconductor lasers subject to the double-reflector feedback. The proposed model is a new modification of the time-delay rate equations of semiconductor lasers under the optical feedback to account for this type of the double-reflector feedback. We examine the influence of adding the second reflector to dynamical states induced by the single-reflector feedback: periodic oscillations, period doubling, and chaos. Regimes of both short and long external cavities are considered. The present analyses are done using the bifurcation diagram, temporal trajectory, phase portrait, and fast Fourier transform of the laser intensity. We show that adding the second reflector attracts the periodic and perioddoubling oscillations, and chaos induced by the first reflector to a route-to-continuous-wave operation. During this operation, the periodic-oscillation frequency increases with strengthening the optical feedback. We show that the chaos induced by the double-reflector feedback is more irregular than that induced by the single-reflector feedback. The power spectrum of this chaos state does not reflect information on the geometry of the optical system, which then has potential for use in chaotic (secure) optical data encryption.

MBE System for Antimonide Based Semiconductor Lasers

National Research Council Canada - National Science Library

Lester, Luke

1999-01-01

.... SLR-770 inductively coupled plasma (ICP) processing system. The SLR-770 has been invaluable in the study of plasma etching of AlGaAsSb and GaSb-materials that form the backbone of antimonide-based semiconductor lasers...

High Power Mid-IR Semiconductor Lasers for LADAR

National Research Council Canada - National Science Library

Lester, Luke

2003-01-01

The growing need for antimonide-based, room temperature, 2-5 micrometers, semiconductor lasers for trace gas spectroscopy, ultra-low loss communication, infrared countermeasures, and ladar motivated this work...

Vibration-tolerant narrow-linewidth semiconductor disk laser using novel frequency-stabilisation schemes

Science.gov (United States)

Hunter, Craig R.; Jones, Brynmor E.; Schlosser, Peter; Sørensen, Simon Toft; Strain, Michael J.; McKnight, Loyd J.

2018-02-01

This paper will present developments in narrow-linewidth semiconductor-disk-laser systems using novel frequencystabilisation schemes for reduced sensitivity to mechanical vibrations, a critical requirement for mobile applications. Narrow-linewidth single-frequency lasers are required for a range of applications including metrology and highresolution spectroscopy. Stabilisation of the laser was achieved using a monolithic fibre-optic ring resonator with free spectral range of 181 MHz and finesse of 52 to act as passive reference cavity for the laser. Such a cavity can operate over a broad wavelength range and is immune to a wide band of vibrational frequency noise due to its monolithic implementation. The frequency noise of the locked system has been measured and compared to typical Fabry-Perotlocked lasers using vibration equipment to simulate harsh environments, and analysed here. Locked linewidths of portable, narrow-linewidth laser system for harsh environments that can be flexibly designed for a range of applications.

Delay induced high order locking effects in semiconductor lasers

Science.gov (United States)

Kelleher, B.; Wishon, M. J.; Locquet, A.; Goulding, D.; Tykalewicz, B.; Huyet, G.; Viktorov, E. A.

2017-11-01

Multiple time scales appear in many nonlinear dynamical systems. Semiconductor lasers, in particular, provide a fertile testing ground for multiple time scale dynamics. For solitary semiconductor lasers, the two fundamental time scales are the cavity repetition rate and the relaxation oscillation frequency which is a characteristic of the field-matter interaction in the cavity. Typically, these two time scales are of very different orders, and mutual resonances do not occur. Optical feedback endows the system with a third time scale: the external cavity repetition rate. This is typically much longer than the device cavity repetition rate and suggests the possibility of resonances with the relaxation oscillations. We show that for lasers with highly damped relaxation oscillations, such resonances can be obtained and lead to spontaneous mode-locking. Two different laser types-—a quantum dot based device and a quantum well based device—are analysed experimentally yielding qualitatively identical dynamics. A rate equation model is also employed showing an excellent agreement with the experimental results.

Laser interferometric method for determining the carrier diffusion length in semiconductors

Energy Technology Data Exchange (ETDEWEB)

Manukhov, V. V. [Saint Petersburg State University (Russian Federation); Fedortsov, A. B.; Ivanov, A. S., E-mail: ivaleks58@gmail.com [Saint Petersburg Mining University (Russian Federation)

2015-09-15

A new laser interferometric method for measuring the carrier diffusion length in semiconductors is proposed. The method is based on the interference–absorption interaction of two laser radiations in a semiconductor. Injected radiation generates additional carriers in a semiconductor, which causes a change in the material’s optical constants and modulation of the probing radiation passed through the sample. When changing the distance between carrier generation and probing points, a decrease in the carrier concentration, which depends on the diffusion length, is recorded. The diffusion length is determined by comparing the experimental and theoretical dependences of the probe signal on the divergence of the injector and probe beams. The method is successfully tested on semiconductor samples with different thicknesses and surface states and can be used in scientific research and the electronics industry.

1.9 W yellow, CW, high-brightness light from a high efficiency semiconductor laser-based system

Science.gov (United States)

Hansen, A. K.; Christensen, M.; Noordegraaf, D.; Heist, P.; Papastathopoulos, E.; Loyo-Maldonado, V.; Jensen, O. B.; Stock, M. L.; Skovgaard, P. M. W.

2017-02-01

Semiconductor lasers are ideal sources for efficient electrical-to-optical power conversion and for many applications where their small size and potential for low cost are required to meet market demands. Yellow lasers find use in a variety of bio-related applications, such as photocoagulation, imaging, flow cytometry, and cancer treatment. However, direct generation of yellow light from semiconductors with sufficient beam quality and power has so far eluded researchers. Meanwhile, tapered semiconductor lasers at near-infrared wavelengths have recently become able to provide neardiffraction- limited, single frequency operation with output powers up to 8 W near 1120 nm. We present a 1.9 W single frequency laser system at 562 nm, based on single pass cascaded frequency doubling of such a tapered laser diode. The laser diode is a monolithic device consisting of two sections: a ridge waveguide with a distributed Bragg reflector, and a tapered amplifier. Using single-pass cascaded frequency doubling in two periodically poled lithium niobate crystals, 1.93 W of diffraction-limited light at 562 nm is generated from 5.8 W continuous-wave infrared light. When turned on from cold, the laser system reaches full power in just 60 seconds. An advantage of using a single pass configuration, rather than an external cavity configuration, is increased stability towards external perturbations. For example, stability to fluctuating case temperature over a 30 K temperature span has been demonstrated. The combination of high stability, compactness and watt-level power range means this technology is of great interest for a wide range of biological and biomedical applications.

Optically pumped semiconductor lasers: Conception and characterization of a single mode source for Cesium atoms manipulation

International Nuclear Information System (INIS)

Cocquelin, B.

2009-02-01

Lasers currently used in atomic clocks or inertial sensors are suffering from a lack of power, narrow linewidth or compactness for future spatial missions. Optically pumped semiconductor lasers, which combine the approach of classical solid state lasers and the engineering of semiconductor laser, are considered here as a candidate to a metrological laser source dedicated to the manipulation of Cesium atoms in these instruments. These lasers have demonstrated high power laser emission in a circular single transverse mode, as well as single longitudinal mode emission, favoured by the semiconductor structure and the external cavity design. We study the definition and the characterization of a proper semiconductor structure for the cooling and the detection of Cesium atoms at 852 nm. A compact and robust prototype tunable on the Cesium D2 hyperfine structure is built. The laser frequency is locked to an atomic transition thanks to a saturated absorption setup. The emission spectral properties are investigated, with a particular attention to the laser frequency noise and the laser linewidth. Finally, we describe and model the thermal properties of the semiconductor structure, which enables the simulation of the laser power characteristic. The experimental parameters are optimised to obtain the maximum output power with our structure. Thanks to our analysis, we propose several ways to overcome these limitations, by reducing the structure heating. (authors)

Development of the power control system for semiconductor lasers

International Nuclear Information System (INIS)

Kim, Kwang Suk; Kim, Cheol Jung

1997-12-01

For the first year plan of this program, we developed the power control system for semiconductor lasers. We applied the high-current switching mode techniques to fabricating a power control system. Then, we investigated the direct side pumping techniques with GaA1As diode laser bars to laser crystal without pumping optics. We obtained 0.5W average output power from this DPSSL. (author). 54 refs., 3 tabs., 18 figs

Effect of Suyuping combined with semiconductor laser irradiation on wound healing after anal fistula surgery

Institute of Scientific and Technical Information of China (English)

Min Zhao; Chang-Ye Sang; Zhen-Jun Wang; Yan-Chun Xu

2016-01-01

Objective:To explore the effect of Suyuping combined with semiconductor laser irradiation on the wound healing after anal fistula surgery.Methods:A total of 180 patients with anal fistula who were admitted in our hospital from October, 2013 to May, 2015 for surgery were included in the study and randomized into the treatment group and the control group with 90 cases in each group. The patients in the control group were given the conventional surgical debridement dressing, a time a day. On this basis, the patients in the treatment group were given Suyuping smearing on the wound sinus tract combined with semiconductor laser irradiation, a time a day for 10 min, continuous irradiation until wound healing. The postoperative wound swelling fading, wound surface secretion amount, and the clinical efficacy in the two groups were recorded.Results:The wound surface swelling degree and wound pain degree at each timing point after operation in the treatment group were significantly lower than those in the control group (P<0.05). The wound surface area at each timing point after operation in the treatment group was significantly lower than that in the control group (P<0.05). The wound surface secretion amount 6, 9, and 12 days after operation in the treatment group was significantly lower than that in the control group (P<0.05). The total effective rate in the treatment group was significantly higher than that in the control group (P<0.05). The average healing time in the treatment group was significantly faster than that in the control group (P<0.05). Conclusions: Suyuping combined with semiconductor laser irradiation in the treatment of patients after anal fistula can effectively improve the local blood and lymphatic circulation of wound surface, promote the growth of granulation tissues, and contribute the wound healing.

Effect of Suyuping combined with semiconductor laser irradiation on wound healing after anal fistula surgery

Directory of Open Access Journals (Sweden)

Min Zhao

2016-06-01

Full Text Available Objective: To explore the effect of Suyuping combined with semiconductor laser irradiation on the wound healing after anal fistula surgery. Methods: A total of 180 patients with anal fistula who were admitted in our hospital from October, 2013 to May, 2015 for surgery were included in the study and randomized into the treatment group and the control group with 90 cases in each group. The patients in the control group were given the conventional surgical debridement dressing, a time a day. On this basis, the patients in the treatment group were given Suyuping smearing on the wound sinus tract combined with semiconductor laser irradiation, a time a day for 10 min, continuous irradiation until wound healing. The postoperative wound swelling fading, wound surface secretion amount, and the clinical efficacy in the two groups were recorded. Results: The wound surface swelling degree and wound pain degree at each timing point after operation in the treatment group were significantly lower than those in the control group (P<0.05. The wound surface area at each timing point after operation in the treatment group was significantly lower than that in the control group (P<0.05. The wound surface secretion amount 6, 9, and 12 days after operation in the treatment group was significantly lower than that in the control group (P<0.05. The total effective rate in the treatment group was significantly higher than that in the control group (P<0.05. The average healing time in the treatment group was significantly faster than that in the control group (P<0.05. Conclusions: Suyuping combined with semiconductor laser irradiation in the treatment of patients after anal fistula can effectively improve the local blood and lymphatic circulation of wound surface, promote the growth of granulation tissues, and contribute the wound healing.

Emergence of resonant mode-locking via delayed feedback in quantum dot semiconductor lasers.

Science.gov (United States)

Tykalewicz, B; Goulding, D; Hegarty, S P; Huyet, G; Erneux, T; Kelleher, B; Viktorov, E A

2016-02-22

With conventional semiconductor lasers undergoing external optical feedback, a chaotic output is typically observed even for moderate levels of the feedback strength. In this paper we examine single mode quantum dot lasers under strong optical feedback conditions and show that an entirely new dynamical regime is found consisting of spontaneous mode-locking via a resonance between the relaxation oscillation frequency and the external cavity repetition rate. Experimental observations are supported by detailed numerical simulations of rate equations appropriate for this laser type. The phenomenon constitutes an entirely new mode-locking mechanism in semiconductor lasers.

Quantifying Information Flow between Two Chaotic Semiconductor Lasers Using Symbolic Transfer Entropy

International Nuclear Information System (INIS)

Li Nian-Qiang; Pan Wei; Yan Lian-Shan; Luo Bin; Xu Ming-Feng; Tang Yi-Long

2012-01-01

Symbolic transfer entropy (STE) is employed to quantify the dominant direction of information flow between two chaotic-semiconductor-laser time series. The information flow in unidirectionally and bidirectionally coupled systems was analyzed systematically. Numerical results show that the dependence relationship can be revealed if there exists any coupling between two chaotic semiconductor lasers. More importantly, in both unsynchronized and good synchronization regimes, the STE can be used to quantify the direction of information flow between the lasers, although the former case leads to a better identification. The results thus establish STE as an effective tool for quantifying the direction of information flow between chaotic-laser-based systems

Comparative study of the performance of semiconductor laser based coherent Doppler lidars

DEFF Research Database (Denmark)

Rodrigo, Peter John; Pedersen, Christian

2012-01-01

Coherent Doppler Lidars (CDLs), operating at an eye-safe 1.5-micron wavelength, have found promising applications in the optimization of wind-power production. To meet the wind-energy sector's impending demand for more cost-efficient industrial sensors, we have focused on the development of conti......Coherent Doppler Lidars (CDLs), operating at an eye-safe 1.5-micron wavelength, have found promising applications in the optimization of wind-power production. To meet the wind-energy sector's impending demand for more cost-efficient industrial sensors, we have focused on the development...... of continuous-wave CDL systems using compact, inexpensive semiconductor laser (SL) sources. In this work, we compare the performance of two candidate emitters for an allsemiconductor CDL system: (1) a monolithic master-oscillator-power-amplifier (MOPA) SL and (2) an external-cavity tapered diode laser (ECTDL)....

Laser apparatus for surgery and force therapy based on high-power semiconductor and fibre lasers

International Nuclear Information System (INIS)

Minaev, V P

2005-01-01

High-power semiconductor lasers and diode-pumped lasers are considered whose development qualitatively improved the characteristics of laser apparatus for surgery and force therapy, extended the scope of their applications in clinical practice, and enhanced the efficiency of medical treatment based on the use of these lasers. The characteristics of domestic apparatus are presented and their properties related to the laser emission wavelength used in them are discussed. Examples of modern medical technologies based on these lasers are considered. (invited paper)

On increasing the efficiency of a streamer semiconductor laser

International Nuclear Information System (INIS)

Rusakov, K I; Parashchuk, V V

2007-01-01

The influence of intense electric and optical fields produced by a streamer discharge in wide-gap semiconductors on their spectroscopic properties is studied. The effect is manifested in the reversible change of the luminescence parameters of the active medium. Methods are proposed for increasing the service life and efficiency of a streamer laser in limiting regimes, which are based on the use of semiconductor protective layers of a certain crystallographic orientation and a crystal microrelief with the size of elements of the order of the wavelength of light. Streamer emission was observed and studied in new promising Eu:CaGa 2 S 4 and Eu:Ca 4 Ga 2 S 7 materials. (lasers)

Broadband tunability of gain-flattened quantum-well semiconductor lasers with an external grating

International Nuclear Information System (INIS)

Mittelstein, M.; Mehuys, D.; Yariv, A.; Sarfaty, R.; Ungar, J.E.

1989-01-01

Semiconductor injection lasers are known to be tunable over a range of order kΒ · T. Quantum-well lasers, in particular, are shown to exhibit flattened, broadband gain spectra at a particular pumping condition. The gain requirement for a grating-tuned external cavity configuration is examined and is applied to a semiconductor quantum-well laser with an optimized length of gain region. The coupled-cavity formalism is employed to examine the conditions for continuous tuning. The possible tuning range of double-heterostructure lasers is compared to that of quantum-well lasers. The predicted broadband tunability of quantum-well lasers is confirmed experimentally by grating-tuning of uncoated lasers exceeding 120 nm, with single, longitudinal mode output power exceeding 300 mW

Homogeneous spectral spanning of terahertz semiconductor lasers with radio frequency modulation.

Science.gov (United States)

Wan, W J; Li, H; Zhou, T; Cao, J C

2017-03-08

Homogeneous broadband and electrically pumped semiconductor radiation sources emitting in the terahertz regime are highly desirable for various applications, including spectroscopy, chemical sensing, and gas identification. In the frequency range between 1 and 5 THz, unipolar quantum cascade lasers employing electron inter-subband transitions in multiple-quantum-well structures are the most powerful semiconductor light sources. However, these devices are normally characterized by either a narrow emission spectrum due to the narrow gain bandwidth of the inter-subband optical transitions or an inhomogeneous broad terahertz spectrum from lasers with heterogeneous stacks of active regions. Here, we report the demonstration of homogeneous spectral spanning of long-cavity terahertz semiconductor quantum cascade lasers based on a bound-to-continuum and resonant phonon design under radio frequency modulation. At a single drive current, the terahertz spectrum under radio frequency modulation continuously spans 330 GHz (~8% of the central frequency), which is the record for single plasmon waveguide terahertz lasers with a bound-to-continuum design. The homogeneous broadband terahertz sources can be used for spectroscopic applications, i.e., GaAs etalon transmission measurement and ammonia gas identification.

Copper vapour laser with an efficient semiconductor pump generator having comparable pump pulse and output pulse durations

Energy Technology Data Exchange (ETDEWEB)

Yurkin, A A [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2016-03-31

We report the results of experimental studies of a copper vapour laser with a semiconductor pump generator capable of forming virtually optimal pump pulses with a current rise steepness of about 40 A ns{sup -1} in a KULON LT-1.5CU active element. To maintain the operating temperature of the active element's channel, an additional heating pulsed oscillator is used. High efficiency of the pump generator is demonstrated. (lasers)

Development and characterization of a semi-conductor laser sensor for real time measurement and identification of atmospheric pollutants

International Nuclear Information System (INIS)

Boulos, F.; Zaatar, Y.; Atanas, J.P.; Bechara, J.

2004-01-01

Full text.Tunable diode laser absorption spectroscopy (TDLAS) in the near infrared (NIR) using semiconductor lasers of compounds between elements of group III (Ga, Al and In) and group V (P, As and Sb) is being increasingly used in various environmental and industrial process control applications. This technique exploits the unique properties of these laser materials i.e., high coherence, high monochromaticity, low divergence and high brightness to permit rapid sensitive detection with high selectivity and spectral resolution. A computer-interfaced near infrared semiconductor laser sensor has been developed in our laboratory for spectroscopic applications in air pollution monitoring. The sensor can be operated in two configurations: open path free beam coupled to a multiple pass White cell and fiber optic guided beam coupled to an evanescent wave sensor. This paper will present an overview of the system's modulation, sensing and data acquisition methods and some recent measurement results, together with a description of ongoing research and development for the improvement of the system's performance and sensitivity

A semiconductor laser device

Energy Technology Data Exchange (ETDEWEB)

Takaro, K.; Naoki, T.; Satosi, K.; Yasutosi, K.

1984-03-17

A device is proposed which makes it possible to obtain single vertical mode emission in the absence of noise. Noise suppression is achieved by a method which determines the relationship between the donor densities in the second and third layers of an n type semiconductor laser, and the total output optical emission of layers with respect to the emission from the entire laser. The device consists of a photoresist film with a window applied to a 100 GaAs n type conductivity substrate using a standard method. Chemical etching through this window in the substrate is used to generate a slot approximately 1 micrometer in size. After the photoresist film is removed, the following layers are deposited from the liquid phase onto the substrate in the sequence indicated: a telurium doped protective layer of n type AlxGa(1-x) As; 2) an undoped active p type AlyGa(1-6) As layer and a tellurium doped upper protective n type conductivity GaAs layer.

Semiconductor Mode-Locked Lasers for Optical Communication Systems

DEFF Research Database (Denmark)

Yvind, Kresten

2003-01-01

The thesis deals with the design and fabrication of semiconductor mode-locked lasers for use in optical communication systems. The properties of pulse sources and characterization methods are described as well as requirements for application in communication systems. Especially, the importance of...

Efficiency of soft tissue incision with a novel 445-nm semiconductor laser.

Science.gov (United States)

Braun, Andreas; Kettner, Moritz; Berthold, Michael; Wenzler, Johannes-Simon; Heymann, Paul Günther Baptist; Frankenberger, Roland

2018-01-01

Using a 445-nm semiconductor laser for tissue incision, an effective cut is expected due to the special absorption properties of blue laser light in soft tissues. The aim of the present study was the histological evaluation of tissue samples after incision with a 445-nm diode laser. Forty soft tissue specimens were obtained from pork oral mucosa and mounted on a motorized linear translation stage. The handpiece of a high-frequency surgery device, a 970-nm semiconductor laser, and a 445-nm semiconductor laser were connected to the slide, allowing a constant linear movement (2 mm/s) and the same distance of the working tip to the soft tissue's surface. Four incisions were made each: (I) 970-nm laser with conditioned fiber tip, contact mode at 3-W cw; (II-III): 445-nm laser with non-conditioned fiber tip, contact mode at 2-W cw, and non-contact mode (1 mm) at 2 W; and (IV): high-frequency surgery device with straight working tip, 90° angulation, contact mode at 50 W. Histological analysis was performed after H&E staining of the embedded specimens at 35-fold magnification. The comparison of the incision depths showed a significant difference depending on the laser wavelength and the selected laser parameters. The highest incision depth was achieved with the 445-nm laser contact mode (median depth 0.61 mm, min 0.26, max 1.17, interquartile range 0.58) (p laser, a higher cutting efficiency can be expected when compared with a 970-nm diode laser and high-frequency surgery. Even the 445-nm laser application in non-contact mode shows clinically acceptable incision depths without signs of extensive soft tissue denaturation.

Material Engineering for Monolithic Semiconductor Mode-Locked Lasers

DEFF Research Database (Denmark)

Kulkova, Irina

This thesis is devoted to the materials engineering for semiconductor monolithic passively mode-locked lasers (MLLs) as a compact energy-efficient source of ultrashort optical pulses. Up to the present day, the achievement of low-noise sub-picosecond pulse generation has remained a challenge...

Optically pumped semiconductor lasers for atomic and molecular physics

Science.gov (United States)

Burd, S.; Leibfried, D.; Wilson, A. C.; Wineland, D. J.

2015-03-01

Experiments in atomic, molecular and optical (AMO) physics rely on lasers at many different wavelengths and with varying requirements on spectral linewidth, power and intensity stability. Optically pumped semiconductor lasers (OPSLs), when combined with nonlinear frequency conversion, can potentially replace many of the laser systems currently in use. We are developing a source for laser cooling and spectroscopy of Mg+ ions at 280 nm, based on a frequency quadrupled OPSL with the gain chip fabricated at the ORC at Tampere Univ. of Technology, Finland. This OPSL system could serve as a prototype for many other sources used in atomic and molecular physics.

Laser line scan underwater imaging by complementary metal-oxide-semiconductor camera

Science.gov (United States)

He, Zhiyi; Luo, Meixing; Song, Xiyu; Wang, Dundong; He, Ning

2017-12-01

This work employs the complementary metal-oxide-semiconductor (CMOS) camera to acquire images in a scanning manner for laser line scan (LLS) underwater imaging to alleviate backscatter impact of seawater. Two operating features of the CMOS camera, namely the region of interest (ROI) and rolling shutter, can be utilized to perform image scan without the difficulty of translating the receiver above the target as the traditional LLS imaging systems have. By the dynamically reconfigurable ROI of an industrial CMOS camera, we evenly divided the image into five subareas along the pixel rows and then scanned them by changing the ROI region automatically under the synchronous illumination by the fun beams of the lasers. Another scanning method was explored by the rolling shutter operation of the CMOS camera. The fun beam lasers were turned on/off to illuminate the narrow zones on the target in a good correspondence to the exposure lines during the rolling procedure of the camera's electronic shutter. The frame synchronization between the image scan and the laser beam sweep may be achieved by either the strobe lighting output pulse or the external triggering pulse of the industrial camera. Comparison between the scanning and nonscanning images shows that contrast of the underwater image can be improved by our LLS imaging techniques, with higher stability and feasibility than the mechanically controlled scanning method.

Melting phenomenon and laser annealing in semiconductors

International Nuclear Information System (INIS)

Narayan, J.

1981-03-01

The work on annealing of displacement damage, dissolution of boron precipitates, and the broadening of dopant profiles in semiconductors after treating with ruby and dye laser pulses is reviewed in order to provide convincing evidence for the melting phenomenon and illustrate the mechanism associated with laser annealing. The nature of the solid-liquid interface and the interface instability during rapid solidification is considered in detail. It is shown that solute concentrations after pulsed laser annealing can far exceed retrograde maxima values. However, there is a critical solute concentration above which a planar solid-liquid interface becomes unstable and breaks into a cellular structure. The solute concentrations and cell sizes associated with this instability are calculated using a perturbation theory, and compared with experimental results

Chaotic bursting in semiconductor lasers

Science.gov (United States)

Ruschel, Stefan; Yanchuk, Serhiy

2017-11-01

We investigate the dynamic mechanisms for low frequency fluctuations in semiconductor lasers subjected to delayed optical feedback, using the Lang-Kobayashi model. This system of delay differential equations displays pronounced envelope dynamics, ranging from erratic, so called low frequency fluctuations to regular pulse packages, if the time scales of fast oscillations and envelope dynamics are well separated. We investigate the parameter regions where low frequency fluctuations occur and compute their Lyapunov spectra. Using the geometric singular perturbation theory, we study this intermittent chaotic behavior and characterize these solutions as bursting slow-fast oscillations.

Theory for passive mode-locking in semiconductor laser structures including the effects of self-phase modulation, dispersion and pulse collisions

NARCIS (Netherlands)

Koumans, R.G.M.P.; Roijen, van R.

1996-01-01

We present a theory for passive mode-locking in semiconductor laser structures using a semiconductor laser amplifier and absorber. The mode-locking system is described in terms of the different elements in the semiconductor laser structure. We derive mode-locking conditions and show how other

Plastic lab-on-a-chip for fluorescence excitation with integrated organic semiconductor lasers.

Science.gov (United States)

Vannahme, Christoph; Klinkhammer, Sönke; Lemmer, Uli; Mappes, Timo

2011-04-25

Laser light excitation of fluorescent markers offers highly sensitive and specific analysis for bio-medical or chemical analysis. To profit from these advantages for applications in the field or at the point-of-care, a plastic lab-on-a-chip with integrated organic semiconductor lasers is presented here. First order distributed feedback lasers based on the organic semiconductor tris(8-hydroxyquinoline) aluminum (Alq3) doped with the laser dye 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyril)-4H-pyrane (DCM), deep ultraviolet induced waveguides, and a nanostructured microfluidic channel are integrated into a poly(methyl methacrylate) (PMMA) substrate. A simple and parallel fabrication process is used comprising thermal imprint, DUV exposure, evaporation of the laser material, and sealing by thermal bonding. The excitation of two fluorescent marker model systems including labeled antibodies with light emitted by integrated lasers is demonstrated.

Low-frequency fluctuation in multimode semiconductor laser subject to optical feedback

Institute of Scientific and Technical Information of China (English)

Xu Zhang; Huiying Ye; Zhaoxin Song

2008-01-01

Dynamics of a semiconductor laser subject to moderate optical feedback operating in the low-frequency fluctuation regime is numerically investigated.Multimode Lang-Kobayashi(LK)equations show that the low-frequency intensity dropout including the total intensity and sub-modes intensity is accompanied by sudden dropout simultaneously,which is in good agreement with experimental observation.The power fluctuation is quite annoying in practical applications,therefore it becomes important to study the mechanism of power fluctuation.It is also shown that many factors,such as spontaneous emission noise and feedback parameter,may influence power fluctuation larger than previously expected.

High-Power Hybrid Mode-Locked External Cavity Semiconductor Laser Using Tapered Amplifier with Large Tunability

Directory of Open Access Journals (Sweden)

Andreas Schmitt-Sody

2008-01-01

Full Text Available We report on hybrid mode-locked laser operation of a tapered semiconductor amplifier in an external ring cavity, generating pulses as short as 0.5 ps at 88.1 MHz with an average power of 60 mW. The mode locking is achieved through a combination of a multiple quantum well saturable absorber (>10% modulation depth and an RF current modulation. This designed laser has 20 nm tuning bandwidth in continuous wave and 10 nm tuning bandwidth in mode locking around 786 nm center wavelength at constant temperature.

Diode lasers and arrays

International Nuclear Information System (INIS)

Streifer, W.

1988-01-01

This paper discusses the principles of operation of III-V semiconductor diode lasers, the use of distributed feedback, and high power laser arrays. The semiconductor laser is a robust, miniature, versatile device, which directly converts electricity to light with very high efficiency. Applications to pumping solid-state lasers and to fiber optic and point-to-point communications are reviewed

Advanced excimer laser technologies enable green semiconductor manufacturing

Science.gov (United States)

Fukuda, Hitomi; Yoo, Youngsun; Minegishi, Yuji; Hisanaga, Naoto; Enami, Tatsuo

2014-03-01

"Green" has fast become an important and pervasive topic throughout many industries worldwide. Many companies, especially in the manufacturing industries, have taken steps to integrate green initiatives into their high-level corporate strategies. Governments have also been active in implementing various initiatives designed to increase corporate responsibility and accountability towards environmental issues. In the semiconductor manufacturing industry, there are growing concerns over future environmental impact as enormous fabs expand and new generation of equipments become larger and more powerful. To address these concerns, Gigaphoton has implemented various green initiatives for many years under the EcoPhoton™ program. The objective of this program is to drive innovations in technology and services that enable manufacturers to significantly reduce both the financial and environmental "green cost" of laser operations in high-volume manufacturing environment (HVM) - primarily focusing on electricity, gas and heat management costs. One example of such innovation is Gigaphoton's Injection-Lock system, which reduces electricity and gas utilization costs of the laser by up to 50%. Furthermore, to support the industry's transition from 300mm to the next generation 450mm wafers, technologies are being developed to create lasers that offer double the output power from 60W to 120W, but reducing electricity and gas consumption by another 50%. This means that the efficiency of lasers can be improve by up to 4 times in 450mm wafer production environments. Other future innovations include the introduction of totally Heliumfree Excimer lasers that utilize Nitrogen gas as its replacement for optical module purging. This paper discusses these and other innovations by Gigaphoton to enable green manufacturing.

Nanoimprinted organic semiconductor laser pumped by a light-emitting diode.

Science.gov (United States)

Tsiminis, Georgios; Wang, Yue; Kanibolotsky, Alexander L; Inigo, Anto R; Skabara, Peter J; Samuel, Ifor D W; Turnbull, Graham A

2013-05-28

An organic semiconductor laser, simply fabricated by UV-nanoimprint lithography (UV-NIL), that is pumped with a pulsed InGaN LED is demonstrated. Molecular weight optimization of the polymer gain medium on a nanoimprinted polymer distributed feedback resonator enables the lowest reported UV-NIL laser threshold density of 770 W cm(-2) , establishing the potential for scalable organic laser fabrication compatible with mass-produced LEDs. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimisation of 1.3 μm strained-layer semiconductor lasers

International Nuclear Information System (INIS)

Pacey, C.

1999-03-01

The objectives of the research undertaken have been to investigate the properties of semiconductor lasers operating at around 1.3 μm. The aim of the investigation is to suggest modifications which give rise to improved operating characteristics especially in the high temperature (approaching 85 deg. C) range. The investigation can be divided into 2 sections: a theoretical approach and an experimental section. The theoretical study examined the performance of compressively strained InGaAsP/InP multiple quantum-well lasers emitting at 1.3 μm. in order to investigate the important factors and trends in the threshold current density and differential gain with strain, well width and well number. Structures with a fixed compressive strain of 1% but variable well width, and also with a fixed well width but variable strain from 0% to 1.4% have been considered. It has been found that there is little benefit to having compressive strains greater than 1%. For structures with a fixed 1% compressive strain and unstrained barriers, an optimum structure for lowest threshold current density and a high differential gain has been found to consist of six 35 A quantum-wells. In addition, compensated strain (CS) structures with compressive wells and tensile barriers have been examined. It is shown that the conduction band offset can be significantly increased and the valence band offset reduced in such structures, to give band-offset ratios comparable with aluminium based 1.3 μm devices. The gain calculations performed suggest that there is little degradation in the threshold carrier density or differential gain due to these alterations in the band offsets; and hence a better laser performance is expected due to a reduction in thermal leakage currents due to the improved electron confinement. The experimental study concentrates on looking at certain key design parameters to investigate their effect on the laser performance. These design parameters range from the number of quantum

New semiconductor laser technology for gas sensing applications in the 1650nm range

Science.gov (United States)

Morrison, Gordon B.; Sherman, Jes; Estrella, Steven; Moreira, Renan L.; Leisher, Paul O.; Mashanovitch, Milan L.; Stephen, Mark; Numata, Kenji; Wu, Stewart; Riris, Haris

2017-08-01

Atmospheric methane (CH4) is the second most important anthropogenic greenhouse gas with approximately 25 times the radiative forcing of carbon dioxide (CO2) per molecule. CH4 also contributes to pollution in the lower atmosphere through chemical reactions leading to ozone production. Recent developments of LIDAR measurement technology for CH4 have been previously reported by Goddard Space Flight Center (GSFC). In this paper, we report on a novel, high-performance tunable semiconductor laser technology developed by Freedom Photonics for the 1650nm wavelength range operation, and for LIDAR detection of CH4. Devices described are monolithic, with simple control, and compatible with low-cost fabrication techniques. We present 3 different types of tunable lasers implemented for this application.

Fabrication of metal/semiconductor nanocomposites by selective laser nano-welding.

Science.gov (United States)

Yu, Huiwu; Li, Xiangyou; Hao, Zhongqi; Xiong, Wei; Guo, Lianbo; Lu, Yongfeng; Yi, Rongxing; Li, Jiaming; Yang, Xinyan; Zeng, Xiaoyan

2017-06-01

A green and simple method to prepare metal/semiconductor nanocomposites by selective laser nano-welding metal and semiconductor nanoparticles was presented, in which the sizes, phases, and morphologies of the components can be maintained. Many types of nanocomposites (such as Ag/TiO 2 , Ag/SnO 2 , Ag/ZnO 2 , Pt/TiO 2 , Pt/SnO 2 , and Pt/ZnO) can be prepared by this method and their corresponding performances were enhanced.

Semiconductor laser irradiation improves root canal sealing during routine root canal therapy

Science.gov (United States)

Hu, Xingxue; Wang, Dashan; Cui, Ting; Yao, Ruyong

2017-01-01

Objective To evaluate the effect of semiconductor laser irradiation on root canal sealing after routine root canal therapy (RCT). Methods Sixty freshly extracted single-rooted human teeth were randomly divided into six groups (n = 10). The anatomic crowns were sectioned at the cementoenamel junction and the remaining roots were prepared endodontically with conventional RCT methods. Groups A and B were irradiated with semiconductor laser at 1W for 20 seconds; Groups C and D were ultrasonically rinsed for 60 seconds as positive control groups; Groups E and F without treatment of root canal prior to RCT as negative control groups. Root canal sealing of Groups A, C and E were evaluated by measurements of apical microleakage. The teeth from Groups B, D and F were sectioned, and the micro-structures were examined with scanning electron microscopy (SEM). One way ANOVA and LSD-t test were used for statistical analysis (α = .05). Results The apical sealing of both the laser irradiated group and the ultrasonic irrigated group were significantly different from the control group (pirrigated group (p>0.5). SEM observation showed that most of the dentinal tubules in the laser irradiation group melted, narrowed or closed, while most of the dentinal tubules in the ultrasonic irrigation group were filled with tooth paste. Conclusion The application of semiconductor laser prior to root canal obturation increases the apical sealing of the roots treated. PMID:28957407

High-Speed Semiconductor Vertical-Cavity Surface-Emitting Lasers for Optical Data-Transmission Systems (Review)

Science.gov (United States)

Blokhin, S. A.; Maleev, N. A.; Bobrov, M. A.; Kuzmenkov, A. G.; Sakharov, A. V.; Ustinov, V. M.

2018-01-01

The main problems of providing a high-speed operation semiconductor lasers with a vertical microcavity (so-called "vertical-cavity surface-emitting lasers") under amplitude modulation and ways to solve them have been considered. The influence of the internal properties of the radiating active region and the electrical parasitic elements of the equivalent circuit of lasers are discussed. An overview of approaches that lead to an increase of the cutoff parasitic frequency, an increase of the differential gain of the active region, the possibility of the management of mode emission composition and the lifetime of photons in the optical microcavities, and reduction of the influence of thermal effects have been presented. The achieved level of modulation bandwidth of ˜30 GHz is close to the maximum achievable for the classical scheme of the direct-current modulation, which makes it necessary to use a multilevel modulation format to further increase the information capacity of optical channels constructed on the basis of vertical-cavity surface-emitting lasers.

Passively Q-switched dual-wavelength thulium-doped fiber laser based on a multimode interference filter and a semiconductor saturable absorber

Science.gov (United States)

Wang, M.; Huang, Y. J.; Ruan, S. C.

2018-04-01

In this paper, we have demonstrated a theta cavity passively Q-switched dual-wavelength fiber laser based on a multimode interference filter and a semiconductor saturable absorber. Relying on the properties of the fiber theta cavity, the laser can operate unidirectionally without an optical isolator. A semiconductor saturable absorber played the role of passive Q-switch while a section of single-mode-multimode-single-mode fiber structure served as an multimode interference filter and was used for selecting the lasing wavelengths. By suitably manipulating the polarization controller, stable dual-wavelength Q-switched operation was obtained at ~1946.8 nm and ~1983.8 nm with maximum output power and minimum pulse duration of ~47 mW and ~762.5 ns, respectively. The pulse repetition rate can be tuned from ~20.2 kHz to ~79.7 kHz by increasing the pump power from ~2.12 W to ~5.4 W.

Dynamics of laterally coupled semiconductor lasers: transition to chaos

NARCIS (Netherlands)

Yousefi, M.; Barsella, A.; Lenstra, D.; Lenstra, D.; Morthier, G.; Erneux, T.; Pessa, M.

2004-01-01

A method for the investigation of the dynamics of two semiconductor lasers, grown side-by-side on the same wafer to enhance the lateral optical coupling, is presented. Using steady state analysis, parameter regimes of relevant dynamics are identified. This is completed by a spectral analysis, were

A proposal for Coulomb assisted laser cooling of piezoelectric semiconductors

Energy Technology Data Exchange (ETDEWEB)

Nia, Iman Hassani; Mohseni, Hooman, E-mail: hmohseni@ece.northwestern.edu [Bio-Inspired Sensors and Optoelectronics Laboratory (BISOL), Department of Electrical Engineering, Northwestern University, Evanston, Illinois 60208 (United States)

2014-07-28

Anti-Stokes laser cooling of semiconductors as a compact and vibration-free method is very attractive. While it has achieved significant milestones, increasing its efficiency is highly desirable. The main limitation is the lack of the pristine material quality with high luminescence efficiency. Here, we theoretically demonstrate that the Coulomb interaction among electrons and holes in piezoelectric heterostructures could lead to coherent damping of acoustic phonons; rendering a significantly higher efficiency that leads to the possibility of cooling a broad range of semiconductors.

Field-glass range finder with a semiconductor laser

Science.gov (United States)

Iwanejko, Leszek; Jankiewicz, Zdzislaw; Jarocki, Roman; Marczak, Jan

1995-03-01

This paper presents the project of a laboratory model of a field-glasses range-finger. The optical transmitter of the device contains a commercial pulse semiconductor laser which generates IR wavelength around 905 nm. Some of the technical parameters of this device are: a maximum range of up to 3 km; an accuracy of +/- 5 m, divergence of a laser beam of 1 mrad; a repetition rate of 1 kHz. Dichroic elements of the receiver ensure a capability of an optimization of a field of view, without the worsening of luminance and size of an observation field.

Transistor electronics use of semiconductor components in switching operations

CERN Document Server

Rumpf, Karl-Heinz

2014-01-01

Transistor Electronics: Use of Semiconductor Components in Switching Operations presents the semiconductor components as well as their elementary circuits. This book discusses the scope of application of electronic devices to increase productivity. Organized into eight chapters, this book begins with an overview of the general equation for the representation of integer positive numbers. This text then examines the properties and characteristics of basic electronic components, which relates to an understanding of the operation of semiconductors. Other chapters consider the electronic circuit ar

Laser-based irradiation apparatus and method to measure the functional dose-rate response of semiconductor devices

Science.gov (United States)

Horn, Kevin M [Albuquerque, NM

2008-05-20

A broad-beam laser irradiation apparatus can measure the parametric or functional response of a semiconductor device to exposure to dose-rate equivalent infrared laser light. Comparisons of dose-rate response from before, during, and after accelerated aging of a device, or from periodic sampling of devices from fielded operational systems can determine if aging has affected the device's overall functionality. The dependence of these changes on equivalent dose-rate pulse intensity and/or duration can be measured with the apparatus. The synchronized introduction of external electrical transients into the device under test can be used to simulate the electrical effects of the surrounding circuitry's response to a radiation exposure while exposing the device to dose-rate equivalent infrared laser light.

Chaos-pass filtering in injection-locked semiconductor lasers

International Nuclear Information System (INIS)

Murakami, Atsushi; Shore, K. Alan

2005-01-01

Chaos-pass filtering (CPF) of semiconductor lasers has been studied theoretically. CPF is a phenomenon which occurs in laser chaos synchronization by injection locking and is a fundamental technique for the extraction of messages at the receiver laser in chaotic communications systems. We employ a simple theory based on driven damped oscillators to clarify the physical background of CPF. The receiver laser is optically driven by injection from the transmitter laser. We have numerically investigated the response characteristics of the receiver when it is driven by periodic (message) and chaotic (carrier) signals. It is thereby revealed that the response of the receiver laser in the two cases is quite different. For the periodic drive, the receiver exhibits a response depending on the signal frequency, while the chaotic drive provides a frequency-independent synchronous response to the receiver laser. We verify that the periodic and chaotic drives occur independently in the CPF response, and, consequently, CPF can be clearly understood in the difference of the two drives. Message extraction using CPF is also examined, and the validity of our theoretical explanation for the physical mechanism underlying CPF is thus verified

FY1995 ultra-high performance semiconductor lasers for advanced optical information network; 1995 nendo kodo hikari joho tsushinmo e muketa kyokugen seino handotai laser

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The purpose of this research was to study and develop ultra-high performance semiconductor light source devices that should facilitate construction of advanced optical information networks. The semiconductor devices mentioned above are enhanced and integrated versions of distributed feedback (DFB) lasers based on 'gain coupling', which the group of the research coordinator has been investigating as a pioneer in the world. This research aimed at development of ultra-high performance semiconductor lasers that surpass the first generation conventional DFB lasers in any respect, by strengthening important device characteristics for system applications of the gain-coupled DFB lasers. The achievements of this research are listed below : 1. In-situ characterization of As-P exchange in MOVPE 2. Development of 1.55 {mu}m gain-coupled DFB lasers of absorptive grating type 3. Establishment of measurement technique for gain-coupling coefficients 4. Enlargement of small signal modulation response by the absorptive grating 5. Prediction of lower analog modulation distortion 6. Characterization of reflection-induced noise 7. Proposal and Demonstration of wavelength trimming 8. Proposal and Fabrication of GC DFB laser triode (NEDO)

Deep-red semiconductor monolithic mode-locked lasers

International Nuclear Information System (INIS)

Kong, L.; Bajek, D.; White, S. E.; Forrest, A. F.; Cataluna, M. A.; Wang, H. L.; Pan, J. Q.; Wang, X. L.; Cui, B. F.; Ding, Y.

2014-01-01

A deep-red semiconductor monolithic mode-locked laser is demonstrated. Multi-section laser diodes based on an AlGaAs multi-quantum-well structure were passively mode-locked, enabling the generation of picosecond optical pulses at 752 nm, at pulse repetition rates of 19.37 GHz. An investigation of the dependence of the pulse duration as a function of reverse bias revealed a predominantly exponential decay trend of the pulse duration, varying from 10.5 ps down to 3.5 ps, which can be associated with the concomitant reduction of absorption recovery time with increasing applied field. A 30-MHz-tunability of the pulse repetition rate with bias conditions is also reported. The demonstration of such a compact, efficient and versatile ultrafast laser in this spectral region paves the way for its deployment in a wide range of applications such as biomedical microscopy, pulsed terahertz generation as well as microwave and millimeter-wave generation, with further impact on sensing, imaging and optical communications

Micromachining of semiconductor by femtosecond laser for integrated circuit defect analysis

Energy Technology Data Exchange (ETDEWEB)

Halbwax, M. [Laboratoire LP3 CNRS UMR 6182, Parc Scientifique et Technologique de Luminy, Case 917, 163 Avenue de Luminy, 13009 Marseille (France); Sarnet, T. [Laboratoire LP3 CNRS UMR 6182, Parc Scientifique et Technologique de Luminy, Case 917, 163 Avenue de Luminy, 13009 Marseille (France)], E-mail: sarnet@lp3.univ-mrs.fr; Hermann, J.; Delaporte, Ph.; Sentis, M. [Laboratoire LP3 CNRS UMR 6182, Parc Scientifique et Technologique de Luminy, Case 917, 163 Avenue de Luminy, 13009 Marseille (France); Fares, L.; Haller, G. [STMicroelectronics, 190 Avenue Celestin Coq, ZI, 13106 Rousset Cedex (France)

2007-12-15

The latest International Technology Roadmap for Semiconductors (ITRS) has highlighted the detection and analysis of defects in Integrated Circuits (IC) as a major challenge faced by the semiconductor industry. Advanced tools used today for defect cross sectioning include dual beams (focused ion- and electron-beam technologies) with resolution down to the sub-Angstrom level. However ion milling an IC with a FIB is time consuming because of the need to open wide cavities in front of the cross-sections that need to be analyzed. Therefore the use of a femtosecond laser as a tool for direct material removal is discussed in this paper. Experiments were performed on IC structures to reveal the different layers of fabrication: selective or total ablation can occur depending on the laser energy density, without delamination of the layers. Different laser irradiation conditions like pressure (air, vacuum), polarization, beam shaping, and scanning parameters have been used to produce different types of cavities. The femtosecond laser engraving of silicon-based structures could be useful for cross-sectioning devices but also for other applications like direct-write lithography, photomask repair, maskless implantation or reverse engineering/restructuring.

Micromachining of semiconductor by femtosecond laser for integrated circuit defect analysis

International Nuclear Information System (INIS)

Halbwax, M.; Sarnet, T.; Hermann, J.; Delaporte, Ph.; Sentis, M.; Fares, L.; Haller, G.

2007-01-01

The latest International Technology Roadmap for Semiconductors (ITRS) has highlighted the detection and analysis of defects in Integrated Circuits (IC) as a major challenge faced by the semiconductor industry. Advanced tools used today for defect cross sectioning include dual beams (focused ion- and electron-beam technologies) with resolution down to the sub-Angstrom level. However ion milling an IC with a FIB is time consuming because of the need to open wide cavities in front of the cross-sections that need to be analyzed. Therefore the use of a femtosecond laser as a tool for direct material removal is discussed in this paper. Experiments were performed on IC structures to reveal the different layers of fabrication: selective or total ablation can occur depending on the laser energy density, without delamination of the layers. Different laser irradiation conditions like pressure (air, vacuum), polarization, beam shaping, and scanning parameters have been used to produce different types of cavities. The femtosecond laser engraving of silicon-based structures could be useful for cross-sectioning devices but also for other applications like direct-write lithography, photomask repair, maskless implantation or reverse engineering/restructuring

High-order diffraction gratings for high-power semiconductor lasers

International Nuclear Information System (INIS)

Vasil’eva, V. V.; Vinokurov, D. A.; Zolotarev, V. V.; Leshko, A. Yu.; Petrunov, A. N.; Pikhtin, N. A.; Rastegaeva, M. G.; Sokolova, Z. N.; Shashkin, I. S.; Tarasov, I. S.

2012-01-01

A deep diffraction grating with a large period (∼2 μm) within one of the cladding layers is proposed for the implementation of selective feedback in a semiconductor laser. Frequency dependences of reflectance in the 12th diffraction order for rectangular, triangular, and trapezoidal diffraction gratings are calculated. It is shown that the maximum reflectance of the waveguide mode is attained using a rectangular or trapezoidal grating ∼2 μm deep in the laser structure. Deep trapezoidal diffraction gratings with large periods are fabricated in the Al 0.3 Ga 0.7 As cladding layer of a GaAs/AlGaAs laser structure using photolithography and reactive ion etching.

Conversion from non-orthogonally to orthogonally polarized optical single-sideband modulation using optically injected semiconductor lasers.

Science.gov (United States)

Hung, Yu-Han; Tseng, Chin-Hao; Hwang, Sheng-Kwang

2018-06-01

This Letter investigates an optically injected semiconductor laser for conversion from non-orthogonally to orthogonally polarized optical single-sideband modulation. The underlying mechanism relies solely on nonlinear laser characteristics and, thus, only a typical semiconductor laser is required as the key conversion unit. This conversion can be achieved for a broadly tunable frequency range up to at least 65 GHz. After conversion, the microwave phase quality, including linewidth and phase noise, is mostly preserved, and simultaneous microwave amplification up to 23 dB is feasible.

Multiphoton microscopy in every lab: the promise of ultrafast semiconductor disk lasers

Science.gov (United States)

Emaury, Florian; Voigt, Fabian F.; Bethge, Philipp; Waldburger, Dominik; Link, Sandro M.; Carta, Stefano; van der Bourg, Alexander; Helmchen, Fritjof; Keller, Ursula

2017-07-01

We use an ultrafast diode-pumped semiconductor disk laser (SDL) to demonstrate several applications in multiphoton microscopy. The ultrafast SDL is based on an optically pumped Vertical External Cavity Surface Emitting Laser (VECSEL) passively mode-locked with a semiconductor saturable absorber mirror (SESAM) and generates 170-fs pulses at a center wavelength of 1027 nm with a repetition rate of 1.63 GHz. We demonstrate the suitability of this laser for structural and functional multiphoton in vivo imaging in both Drosophila larvae and mice for a variety of fluorophores (including mKate2, tdTomato, Texas Red, OGB-1, and R-CaMP1.07) and for endogenous second-harmonic generation in muscle cell sarcomeres. We can demonstrate equivalent signal levels compared to a standard 80-MHz Ti:Sapphire laser when we increase the average power by a factor of 4.5 as predicted by theory. In addition, we compare the bleaching properties of both laser systems in fixed Drosophila larvae and find similar bleaching kinetics despite the large difference in pulse repetition rates. Our results highlight the great potential of ultrafast diode-pumped SDLs for creating a cost-efficient and compact alternative light source compared to standard Ti:Sapphire lasers for multiphoton imaging.

A full time-domain approach to spatio-temporal dynamics of semiconductor lasers. II. Spatio-temporal dynamics

Science.gov (United States)

Böhringer, Klaus; Hess, Ortwin

The spatio-temporal dynamics of novel semiconductor lasers is discussed on the basis of a space- and momentum-dependent full time-domain approach. To this means the space-, time-, and momentum-dependent Full-Time Domain Maxwell Semiconductor Bloch equations, derived and discussed in our preceding paper I [K. Böhringer, O. Hess, A full time-domain approach to spatio-temporal dynamics of semiconductor lasers. I. Theoretical formulation], are solved by direct numerical integration. Focussing on the device physics of novel semiconductor lasers that profit, in particular, from recent advances in nanoscience and nanotechnology, we discuss the examples of photonic band edge surface emitting lasers (PBE-SEL) and semiconductor disc lasers (SDLs). It is demonstrated that photonic crystal effects can be obtained for finite crystal structures, and leading to a significant improvement in laser performance such as reduced lasing thresholds. In SDLs, a modern device concept designed to increase the power output of surface-emitters in combination with near-diffraction-limited beam quality, we explore the complex interplay between the intracavity optical fields and the quantum well gain material in SDL structures. Our simulations reveal the dynamical balance between carrier generation due to pumping into high energy states, momentum relaxation of carriers, and stimulated recombination from states near the band edge. Our full time-domain approach is shown to also be an excellent framework for the modelling of the interaction of high-intensity femtosecond and picosecond pulses with semiconductor nanostructures. It is demonstrated that group velocity dispersion, dynamical gain saturation and fast self-phase modulation (SPM) are the main causes for the induced changes and asymmetries in the amplified pulse shape and spectrum of an ultrashort high-intensity pulse. We attest that the time constants of the intraband scattering processes are critical to gain recovery. Moreover, we present

Dual-comb spectroscopy of water vapor with a free-running semiconductor disk laser.

Science.gov (United States)

Link, S M; Maas, D J H C; Waldburger, D; Keller, U

2017-06-16

Dual-comb spectroscopy offers the potential for high accuracy combined with fast data acquisition. Applications are often limited, however, by the complexity of optical comb systems. Here we present dual-comb spectroscopy of water vapor using a substantially simplified single-laser system. Very good spectroscopy measurements with fast sampling rates are achieved with a free-running dual-comb mode-locked semiconductor disk laser. The absolute stability of the optical comb modes is characterized both for free-running operation and with simple microwave stabilization. This approach drastically reduces the complexity for dual-comb spectroscopy. Band-gap engineering to tune the center wavelength from the ultraviolet to the mid-infrared could optimize frequency combs for specific gas targets, further enabling dual-comb spectroscopy for a wider range of industrial applications. Copyright © 2017, American Association for the Advancement of Science.

1.9 W yellow, CW, high-brightness light from a high efficiency semiconductor laser-based system

DEFF Research Database (Denmark)

Hansen, Anders Kragh; Christensen, Mathias; Noordegraaf, Danny

2017-01-01

Semiconductor lasers are ideal sources for efficient electrical-to-optical power conversion and for many applications where their small size and potential for low cost are required to meet market demands. Yellow lasers find use in a variety of bio-related applications, such as photocoagulation......, imaging, flow cytometry, and cancer treatment. However, direct generation of yellow light from semiconductors with sufficient beam quality and power has so far eluded researchers. Meanwhile, tapered semiconductor lasers at near-infrared wavelengths have recently become able to provide neardiffraction...... power in just 60 seconds. An advantage of using a single pass configuration, rather than an external cavity configuration, is increased stability towards external perturbations. For example, stability to fluctuating case temperature over a 30 K temperature span has been demonstrated. The combination...

Laser photo-reflectance characterization of resonant nonlinear electro-refraction in thin semiconductor films

International Nuclear Information System (INIS)

Chism, Will; Cartwright, Jason

2012-01-01

Photo-reflectance (PR) measurements provide a non-contact means for the precise characterization of semiconductor electronic properties. In this paper, we investigate the use of a laser beam as the probe beam in the PR setup. In this case it is seen that the nonlinear refraction is responsible for the amplitude change of the reflected probe field, whereas the phase change is due to nonlinear absorption. The open aperture condition may then be used to eliminate the spatial phase at the detector, thereby isolating the electro-refractive contribution to the PR signal. This greatly simplifies the PR analysis and allows absolute measurements of electro-refraction in thin semiconductor films. We report the application of the laser PR technique to characterize physical strain in thin silicon on silicon-germanium films. - Highlights: ► We describe the theory of laser photoreflectance. ► Laser photoreflectance is used to independently characterize nonlinear refraction. ► We report the characterization of strain in thin strained silicon films.

Bistability and self-oscillations effects in a polariton-laser semiconductor microcavity

International Nuclear Information System (INIS)

Cotta, E A; Matinaga, F M

2007-01-01

We report an experimental observation of polaritonic optical bistability of the laser emission in a planar semiconductor microcavity with a 100 0 A GaAs single quantum well in the strong-coupling regime. The bistability curves show crossings that indicate a competition between a Kerr-like effect induced by the polariton population and thermal effects. Associated with the bistability, laser-like emission occurs at the bare cavity mode

Application of laser spot cutting on spring contact probe for semiconductor package inspection

Science.gov (United States)

Lee, Dongkyoung; Cho, Jungdon; Kim, Chan Ho; Lee, Seung Hwan

2017-12-01

A packaged semiconductor has to be electrically tested to make sure they are free of any manufacturing defects. The test interface, typically employed between a Printed Circuit Board and the semiconductor devices, consists of densely populated Spring Contact Probe (SCP). A standard SCP typically consists of a plunger, a barrel, and an internal spring. Among these components, plungers are manufactured by a stamping process. After stamping, plunger connecting arms need to be cut into pieces. Currently, mechanical cutting has been used. However, it may damage to the body of plungers due to the mechanical force engaged at the cutting point. Therefore, laser spot cutting is considered to solve this problem. The plunger arm is in the shape of a rectangular beam, 50 μm (H) × 90 μm (W). The plunger material used for this research is gold coated beryllium copper. Laser parameters, such as power and elapsed time, have been selected to study laser spot cutting. Laser material interaction characteristics such as a crater size, material removal zone, ablation depth, ablation threshold, and full penetration are observed. Furthermore, a carefully chosen laser parameter (Etotal = 1000mJ) to test feasibility of laser spot cutting are applied. The result show that laser spot cutting can be applied to cut SCP.

Photoacoustic Techniques for Trace Gas Sensing Based on Semiconductor Laser Sources

Directory of Open Access Journals (Sweden)

Vincenzo Spagnolo

2009-12-01

Full Text Available The paper provides an overview on the use of photoacoustic sensors based on semiconductor laser sources for the detection of trace gases. We review the results obtained using standard, differential and quartz enhanced photoacoustic techniques.

Design and construct of a tunable semiconductor laser

Directory of Open Access Journals (Sweden)

J. Sabbaghzadeh

2000-06-01

Full Text Available   In this paper we explain in detail the design of a semiconductor laser coupled with the reflected beams from a grating. Since the beams reflected are diffracted at different angles, only one component of them can be resonated in the cavity. This technique reduces the output frequency of the laser and increases its stability.   Since this system has various applications in the spectroscopy, gas concentrations, air pollution measurements, investigation of atomic and molecular structure, and so on, system is believed to be simple and accurate. This design is made for the first time in Iran and its reliability has been tested by the measurement of the rubidium atom, and the result is given.

The theoretical and numerical models of the novel and fast tunable semiconductor ring laser

Science.gov (United States)

Zhu, Jiangbo; Zhang, Junwen; Chi, Nan; Yu, Siyuan

2011-01-01

Fast wavelength-tunable semiconductor lasers will be the key components in future optical packet switching networks. Especially, they are of great importance in the optical network nodes: transmitters, optical wavelength-routers, etc. In this paper, a new scheme of a next-generation fast tunable ring laser was given. Tunable lasers in this design have better wavelength tunability compared with others, for they are switched faster in wavelength and simpler to control with the injecting light from an external distributed Bragg-reflector(DBR). Then some discussion of the waveguide material system and coupler design of the ring laser were given. And we also derived the multimode rate equations corresponding to this scheme by analyzing some characteristics of the semiconductor ring cavity, directionality, nonlinear mode competition, optical injection locking, etc. We did MatLab simulation based on the new rate equations to research the process of mode competition and wavelength switching in the laser, and achieved the basic functions of a tunable laser. Finally some discussion of the impact of several key parameters was given.

Gigahertz dual-comb modelocked diode-pumped semiconductor and solid-state lasers

Science.gov (United States)

Link, S. M.; Mangold, M.; Golling, M.; Klenner, A.; Keller, U.

2016-03-01

We present a simple approach to generate simultaneously two gigahertz mode-locked pulse trains from a single gain element. A bi-refringent crystal in the laser cavity splits the one cavity beam into two cross-polarized and spatially separated beams. This polarization-duplexing is successfully demonstrated for both a semiconductor disk laser (i.e. MIXSEL) and a diode-pumped solid-state Nd:YAG laser. The beat between the two beams results in a microwave frequency comb, which represents a direct link between the terahertz optical frequencies and the electronically accessible microwave regime. This dual-output technique enables compact and cost-efficient dual-comb lasers for spectroscopy applications.

Modification of semiconductor materials using laser-produced ion streams additionally accelerated in the electric fields

International Nuclear Information System (INIS)

Rosinski, M.; Badziak, B.; Parys, P.; Wolowski, J.; Pisarek, M.

2009-01-01

The laser-produced ion stream may be attractive for direct ultra-low-energy ion implantation in thin layer of semiconductor for modification of electrical and optical properties of semiconductor devices. Application of electrostatic fields for acceleration and formation of laser-generated ion stream enables to control the ion stream parameters in broad energy and current density ranges. It also permits to remove the useless laser-produced ions from the ion stream designed for implantation. For acceleration of ions produced with the use of a low fluence repetitive laser system (Nd:glass: 2 Hz, pulse duration: 3.5 ns, pulse energy:∼0.5 J, power density: 10 10 W/cm 2 ) in IPPLM the special electrostatic system has been prepared. The laser-produced ions passing through the diaphragm (a ring-shaped slit in the HV box) have been accelerated in the system of electrodes. The accelerating voltage up to 40 kV, the distance of the diaphragm from the target, the diaphragm diameter and the gap width were changed for choosing the desired parameters (namely the energy band of the implanted ions) of the ion stream. The characteristics of laser-produced Ge ion streams were determined with the use of precise ion diagnostic methods, namely: electrostatic ion energy analyser and various ion collectors. The laser-produced and post-accelerated Ge ions have been used for implantation into semiconductor materials for nanocrystal fabrication. The characteristics of implanted samples were measured using AES

Study on biological effect on mice and use safety of 830 nm semiconductor laser

International Nuclear Information System (INIS)

Li Keqiu; Li Jian; Miao Xuhong; Liu Shujuan; Li Guang

2006-01-01

Objective: To study biological effect on mice by 830 nm semiconductor laser in different dosage, and determine the optimal irradiating dosage by observing and analyzing the immunoregulation and cytogenetical damage of mice after irradiation. Methods: The spleen and thymus areas of Kunming mice were irradiated in vitro by 830 nm semiconductor laser of 30 mW for 5 min, 10 min and 20 min per day respectively, then the blood samples were collected from orbital vein. Further, the spleen tissue and sternum marrow were collected soon after the mice were killed. Afterwards, IgG, dopamine, serotonin in serum were detected respectively. Besides these, the rate of lymphocyte transformation and the rate of micronuclei in marrow polychromatic erythrocytes were also determined. Results: With the extending of irradiating time, the detected factors changed differently. Statistically, there were differences in IgG concentration and the rate of lymphocyte transformation between 10 min group, 20 min group and control group respectively, but no difference between each experimental group were found. /compare with control group, serotonin concentration in 10 min group increased, and there was statistical difference between these two groups, while there was no difference in dopamine concentration among each group. Besides these, the rate of micronuclei in 20 min group increased. Conclusion: In this study, irradiation by semiconductor laser for appropriate time can improve immuno function of mice, but irradiation in high dosage will result in the damage of genetic material. The optimal time of irradiation by 830 nm semiconductor laser was 10 min. (authors)

Nonlinear gain suppression in semiconductor lasers due to carrier heating

International Nuclear Information System (INIS)

Willatzen, M.; Uskov, A.; Moerk, J.; Olesen, H.; Tromborg, B.; Jauho, A.P.

1991-01-01

We present a simple model for carrier heating in semiconductor lasers, from which the temperature dynamics of the electron and hole distributions can be calculated. Analytical expressions for two new contributions to the nonlinear gain coefficient ε are derived, which reflect carrier heating due to stimulated emission and free carrier absorption. In typical cases, carrier heating and spectral holeburning are found to give comparable contributions to nonlinear gain suppression. The results are in good agreement with recent measurements on InGaAsP laser diodes. (orig.)

Optical trapping with Bessel beams generated from semiconductor lasers

International Nuclear Information System (INIS)

Sokolovskii, G S; Dudelev, V V; Losev, S N; Soboleva, K K; Deryagin, A G; Kuchinskii, V I; Sibbett, W; Rafailov, E U

2014-01-01

In this paper, we study generation of Bessel beams from semiconductor lasers with high beam propagation parameter M 2 and their utilization for optical trapping and manipulation of microscopic particles including living cells. The demonstrated optical tweezing with diodegenerated Bessel beams paves the way to replace their vibronic-generated counterparts for a range of applications towards novel lab-on-a-chip configurations

Optical-cell model based on the lasing competition of mode structures with different Q-factors in high-power semiconductor lasers

Energy Technology Data Exchange (ETDEWEB)

Podoskin, A. A., E-mail: podoskin@mail.ioffe.ru; Shashkin, I. S.; Slipchenko, S. O.; Pikhtin, N. A.; Tarasov, I. S. [Russian Academy of Sciences, Ioffe Institute (Russian Federation)

2015-08-15

A model describing the operation of a completely optical cell, based on the competition of lasing of Fabry-Perot cavity modes and the high-Q closed mode in high-power semiconductor lasers is proposed. Based on rate equations, the conditions of lasing switching between Fabry-Perot modes for ground and excited lasing levels and the closed mode are considered in the case of increasing internal optical loss under conditions of high current pump levels. The optical-cell operation conditions in the mode of a high-power laser radiation switch (reversible mode-structure switching) and in the mode of a memory cell with bistable irreversible lasing switching between mode structures with various Q-factors are considered.

Four distributed feedback laser array integrated with multimode-interference and semiconductor optical amplifier

International Nuclear Information System (INIS)

Ma Li; Zhu Hong-Liang; Liang Song; Zhao Ling-Juan; Chen Ming-Hua

2013-01-01

Monolithic integration of four 1.55-μm-range InGaAsP/InP distributed feedback (DFB) lasers using varied ridge width with a 4 × 1-multimode-interference (MMI) optical combiner and a semiconductor optical amplifier (SOA) is demonstrated. The average output power and the threshold current are 1.8 mW and 35 mA, respectively, when the injection current of the SOA is 100 mA, with a side mode suppression ratio (SMSR) exceeding 40 dB. The four channels have a 1-nm average channel spacing and can operate separately or simultaneously. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Optoelectronic integrated circuits utilising vertical-cavity surface-emitting semiconductor lasers

International Nuclear Information System (INIS)

Zakharov, S D; Fyodorov, V B; Tsvetkov, V V

1999-01-01

Optoelectronic integrated circuits with additional optical inputs/outputs, in which vertical-cavity surface-emitting (VCSE) lasers perform the data transfer functions, are considered. The mutual relationship and the 'affinity' between optical means for data transfer and processing, on the one hand, and the traditional electronic component base, on the other, are demonstrated in the case of implementation of three-dimensional interconnects with a high transmission capacity. Attention is drawn to the problems encountered when semiconductor injection lasers are used in communication lines. It is shown what role can be played by VCSE lasers in solving these problems. A detailed analysis is made of the topics relating to possible structural and technological solutions in the fabrication of single lasers and of their arrays, and also of the problems hindering integrating of lasers into emitter arrays. Considerable attention is given to integrated circuits with optoelectronic smart pixels. Various technological methods for vertical integration of GaAs VCSE lasers with the silicon substrate of a microcircuit (chip) are discussed. (review)

Extracting physical properties of arbitrarily shaped laser-doped micro-scale areas in semiconductors

International Nuclear Information System (INIS)

Heinrich, Martin; Kluska, Sven; Hameiri, Ziv; Hoex, Bram; Aberle, Armin G.

2013-01-01

We present a method that allows the extraction of relevant physical properties such as sheet resistance and dopant profile from arbitrarily shaped laser-doped micro-scale areas formed in semiconductors with a focused pulsed laser beam. The key feature of the method is to use large laser-doped areas with an identical average number of laser pulses per area (laser pulse density) as the arbitrarily shaped areas. The method is verified using sheet resistance measurements on laser-doped silicon samples. Furthermore, the method is extended to doping with continuous-wave lasers by using the average number of passes per area or density of passes

Piezoelectric strained layer semiconductor lasers and integrated modulators

International Nuclear Information System (INIS)

Fleischmann, Thomas

2002-01-01

The properties, benefits and limitations of strained InGaAs/GaAs quantum well lasers and modulators grown on (111)B GaAs have been studied. Particular interest in this material system arose from the predicted increase in critical layer thickness, which would facilitate semiconductor lasers emitting beyond 1 μm. However, the recent discovery of a new type of misfit dislocation indicates that the critical layer thickness in this system is closer to that of (001) orientated structures. Photoluminescence and transmission electron microscopy presented in this study support this predicted reduction of the critical layer thickness and the resulting limitations on the emission wavelength. The absence of 3D growth in this system may however be advantageous when high reproducibility and reliable lasing operation beyond 1 μm are required. The piezoelectric field originating from strained growth on substrate orientations other than (001) was studied and its influence on transition energies and absorptive behaviour were investigated. The piezoelectric constant was found to show significant temperature dependence and, as also indicated in earlier studies, its value is smaller then the linearly interpolated value. When the effects of indium segregation on the transition energies is considered, the reduction is significantly smaller. Good agreement between theory and experiment was obtained using 86% of the value linearly interpolated between the binaries at room temperature and 82% at low temperature. Broad area lasers were fabricated emitting at lasing wavelengths of up to 1.08 μm with threshold current densities as low as 80 A/cm 2 at room temperature under continuous wave operation. Increasing the indium composition and strain within the limit of strain relaxation was demonstrated to improve device performance significantly. Furthermore, ridge waveguide lasers were fabricated exhibiting monomode emission at wavelengths up to 1.07 μm with a threshold current of 19 mA at

Semiconductor optical amplifier-based heterodyning detection for resolving optical terahertz beat-tone signals from passively mode-locked semiconductor lasers

International Nuclear Information System (INIS)

Latkowski, Sylwester; Maldonado-Basilio, Ramon; Carney, Kevin; Parra-Cetina, Josue; Philippe, Severine; Landais, Pascal

2010-01-01

An all-optical heterodyne approach based on a room-temperature controlled semiconductor optical amplifier (SOA) for measuring the frequency and linewidth of the terahertz beat-tone signal from a passively mode-locked laser is proposed. Under the injection of two external cavity lasers, the SOA acts as a local oscillator at their detuning frequency and also as an optical frequency mixer whose inputs are the self-modulated spectrum of the device under test and the two laser beams. Frequency and linewidth of the intermediate frequency signal (and therefore, the beat-tone signal) are resolved by using a photodiode and an electrical spectrum analyzer.

Nanonewton thrust measurement of photon pressure propulsion using semiconductor laser

Science.gov (United States)

Iwami, K.; Akazawa, Taku; Ohtsuka, Tomohiro; Nishida, Hiroyuki; Umeda, Norihiro

2011-09-01

To evaluate the thrust produced by photon pressure emitted from a 100 W class continuous-wave semiconductor laser, a torsion-balance precise thrust stand is designed and tested. Photon emission propulsion using semiconductor light sources attract interests as a possible candidate for deep-space propellant-less propulsion and attitude control system. However, the thrust produced by photon emission as large as several ten nanonewtons requires precise thrust stand. A resonant method is adopted to enhance the sensitivity of the biflier torsional-spring thrust stand. The torsional spring constant and the resonant of the stand is 1.245 × 10-3 Nm/rad and 0.118 Hz, respectively. The experimental results showed good agreement with the theoretical estimation. The thrust efficiency for photon propulsion was also defined. A maximum thrust of 499 nN was produced by the laser with 208 W input power (75 W of optical output) corresponding to a thrust efficiency of 36.7%. The minimum detectable thrust of the stand was estimated to be 2.62 nN under oscillation at a frequency close to resonance.

Memory Effect on Adaptive Decision Making with a Chaotic Semiconductor Laser

Directory of Open Access Journals (Sweden)

Takatomo Mihana

2018-01-01

Full Text Available We investigate the effect of a memory parameter on the performance of adaptive decision making using a tug-of-war method with the chaotic oscillatory dynamics of a semiconductor laser. We experimentally generate chaotic temporal waveforms of the semiconductor laser with optical feedback and apply them for adaptive decision making in solving a multiarmed bandit problem that aims at maximizing the total reward from slot machines whose hit probabilities are dynamically switched. We examine the dependence of making correct decisions on different values of the memory parameter. The degree of adaptivity is found to be enhanced with a smaller memory parameter, whereas the degree of convergence to the correct decision is higher for a larger memory parameter. The relations among the adaptivity, environmental changes, and the difficulties of the problem are also discussed considering the requirement of past decisions. This examination of ultrafast adaptive decision making highlights the importance of memorizing past events and paves the way for future photonic intelligence.

Piezo activated mode tracking system for widely tunable mode-hop-free external cavity mid-IR semiconductor lasers

Science.gov (United States)

Wysocki, Gerard (Inventor); Tittel, Frank K. (Inventor); Curl, Robert F. (Inventor)

2010-01-01

A widely tunable, mode-hop-free semiconductor laser operating in the mid-IR comprises a QCL laser chip having an effective QCL cavity length, a diffraction grating defining a grating angle and an external cavity length with respect to said chip, and means for controlling the QCL cavity length, the external cavity length, and the grating angle. The laser of claim 1 wherein said chip may be tuned over a range of frequencies even in the absence of an anti-reflective coating. The diffraction grating is controllably pivotable and translatable relative to said chip and the effective QCL cavity length can be adjusted by varying the injection current to the chip. The laser can be used for high resolution spectroscopic applications and multi species trace-gas detection. Mode-hopping is avoided by controlling the effective QCL cavity length, the external cavity length, and the grating angle so as to replicate a virtual pivot point.

Mode-Locking in Broad-Area Semiconductor Lasers Enhanced by Picosecond-Pulse Injection

OpenAIRE

Kaiser, J; Fischer, I; Elsasser, W; Gehrig, E; Hess, O

2004-01-01

We present combined experimental and theoretical investigations of the picosecond emission dynamics of broad-area semiconductor lasers (BALs). We enhance the weak longitudinal self-mode-locking that is inherent to BALs by injecting a single optical 50-ps pulse, which triggers the output of a distinct regular train of 13-ps pulses. Modeling based on multimode Maxwell-Bloch equations illustrates how the dynamic interaction of the injected pulse with the internal laser field efficiently couples ...

Frequency locking, quasiperiodicity, subharmonic bifurcations and chaos in high frequency modulated stripe geometry DH semiconductor lasers

International Nuclear Information System (INIS)

Zhao Yiguang

1991-01-01

The method of obtaining self-consistent solutions of the field equation and the rate equations of photon density and carrier concentration has been used to study frequecny locking, quasiperiodicity, subharmonic bifurcations and chaos in high frequency modulated stripe geometry DH semiconductor lasers. The results show that the chaotic behavior arises in self-pulsing stripe geometry semiconductor lasers. The route to chaos is not period-double, but quasiperiodicity to chaos. All of the results agree with the experiments. Some obscure points in previous theory about chaos have been cleared up

Ten years optically pumped semiconductor lasers: review, state-of-the-art, and future developments

Science.gov (United States)

Kannengiesser, Christian; Ostroumov, Vasiliy; Pfeufer, Volker; Seelert, Wolf; Simon, Christoph; von Elm, Rüdiger; Zuck, Andreas

2010-02-01

Optically Pumped Semiconductor Lasers - OPSLs - have been introduced in 2001. Their unique features such as power scalability and wavelength flexibility, their excellent beam parameters, power stability and reliability opened this pioneering technology access to a wide range of applications such as flow cytometry, confocal microscopy, sequencing, medical diagnosis and therapy, semiconductor inspection, graphic arts, forensic, metrology. This talk will introduce the OPSL principles and compare them with ion, diode and standard solid state lasers. It will revue the first 10 years of this exciting technology, its current state and trends. In particular currently accessible wavelengths and power ranges, frequency doubling, ultra-narrow linewidth possibilities will be discussed. A survey of key applications will be given.

Silicon photonics WDM transmitter with single section semiconductor mode-locked laser

Science.gov (United States)

Müller, Juliana; Hauck, Johannes; Shen, Bin; Romero-García, Sebastian; Islamova, Elmira; Azadeh, Saeed Sharif; Joshi, Siddharth; Chimot, Nicolas; Moscoso-Mártir, Alvaro; Merget, Florian; Lelarge, François; Witzens, Jeremy

2015-04-01

We demonstrate a wavelength domain-multiplexed (WDM) optical link relying on a single section semiconductor mode-locked laser (SS-MLL) with quantum dash (Q-Dash) gain material to generate 25 optical carriers spaced by 60.8 GHz, as well as silicon photonics (SiP) resonant ring modulators (RRMs) to modulate individual optical channels. The link requires optical reamplification provided by an erbium-doped fiber amplifier (EDFA) in the system experiments reported here. Open eye diagrams with signal quality factors (Q-factors) above 7 are measured with a commercial receiver (Rx). For higher compactness and cost effectiveness, reamplification of the modulated channels with a semiconductor optical amplifier (SOA) operated in the linear regime is highly desirable. System and device characterization indicate compatibility with the latter. While we expect channel counts to be primarily limited by the saturation output power level of the SOA, we estimate a single SOA to support more than eight channels. Prior to describing the system experiments, component design and detailed characterization results are reported including design and characterization of RRMs, ring-based resonant optical add-drop multiplexers (RR-OADMs) and thermal tuners, S-parameters resulting from the interoperation of RRMs and RR-OADMs, and characterization of Q-Dash SS-MLLs reamplified with a commercial SOA. Particular emphasis is placed on peaking effects in the transfer functions of RRMs and RR-OADMs resulting from transient effects in the optical domain, as well as on the characterization of SS-MLLs in regard to relative intensity noise (RIN), stability of the modes of operation, and excess noise after reamplification.

Numerical investigations on the performance of external-cavity mode-locked semiconductor lasers

DEFF Research Database (Denmark)

Mulet, Josep; Mørk, Jesper

2004-01-01

The performance of an external-cavity mode-locked semiconductor laser is analyzed theoretically and numerically. Passive mode-locking is described using a fully-distributed time-domain model including fast effects, spectral hole burning and carrier heating. We provide optimization rules in order ...

Spectral characteristics of DFB lasers in presence of a semiconductor optical amplifier

DEFF Research Database (Denmark)

Champagne, A.; Camel, J.; Maciejko, R.

2002-01-01

The problem of the linewidth degradation in systems using distributed-feedback lasers together with strained-layer multi-quantum-well semiconductor optical amplifiers (SOAs) is examined. A numerical model combining finite element calculations in the transverse x - y plane and a longitudinal model...

Interband optical pulse injection locking of quantum dot mode-locked semiconductor laser.

Science.gov (United States)

Kim, Jimyung; Delfyett, Peter J

2008-07-21

We experimentally demonstrate optical clock recovery from quantum dot mode-locked semiconductor lasers by interband optical pulse injection locking. The passively mode-locked slave laser oscillating on the ground state or the first excited state transition is locked through the injection of optical pulses generated via the opposite transition bands, i.e. the first excited state or the ground state transition from the hybridly mode-locked master laser, respectively. When an optical pulse train generated via the first excited state from the master laser is injected to the slave laser oscillating via ground state, the slave laser shows an asymmetric locking bandwidth around the nominal repetition rate of the slave laser. In the reverse injection case of, i.e. the ground state (master laser) to the first excited state (slave laser), the slave laser does not lock even though both lasers oscillate at the same cavity frequency. In this case, the slave laser only locks to higher injection rates as compared to its own nominal repetition rate, and also shows a large locking bandwidth of 6.7 MHz.

Identification of amplitude and timing jitter in external-cavity mode-locked semiconductor lasers

DEFF Research Database (Denmark)

Mulet, Josep; Mørk, Jesper; Kroh, Marcel

2004-01-01

We theoretically and experimentally investigate the dynamics of external-cavity mode-locked semiconductor lasers, focusing on stability properties, optimization of pulsewidth and timing jitter. A new numerical approach allows to clearly separate timing and amplitude jitter....

Return-map for low-frequency fluctuations in semiconductor lasers with optical feedback

DEFF Research Database (Denmark)

Mørk, Jesper; Sabbatier, H.; Sørensen, Mads Peter

1999-01-01

We show that the phenomenon of low-frequency fluctuations (LFF) , commonly observed in semiconductor lasers with optical feedback, can be explained by a simple return-map, implying a tremendous simplification in the description of the slow time-scale dynamics of the system. Experimentally observed...

Analog direct-modulation behavior of semiconductor laser transmitters using optical FM demodulation

NARCIS (Netherlands)

Yabre, G.S.

1998-01-01

In this paper, we report a theoretical investigation of the analog modulation performance of a semiconductor laser transmitter which employs the direct optical FM demodulation. This analysis is based on the rate equations in which Langevin noise functions are included. The optical FM response has

Ring-shaped active mode-locked tunable laser using quantum-dot semiconductor optical amplifier

Science.gov (United States)

Zhang, Mingxiao; Wang, Yongjun; Liu, Xinyu

2018-03-01

In this paper, a lot of simulations has been done for ring-shaped active mode-locked lasers with quantum-dot semiconductor optical amplifier (QD-SOA). Based on the simulation model of QD-SOA, we discussed about the influence towards mode-locked waveform frequency and pulse caused by QD-SOA maximum mode peak gain, active layer loss coefficient, bias current, incident light pulse, fiber nonlinear coefficient. In the meantime, we also take the tunable performance of the laser into consideration. Results showed QD-SOA a better performance than original semiconductor optical amplifier (SOA) in recovery time, line width, and nonlinear coefficients, which makes it possible to output a locked-mode impulse that has a higher impulse power, narrower impulse width as well as the phase is more easily controlled. After a lot of simulations, this laser can realize a 20GHz better locked-mode output pulse after 200 loops, where the power is above 17.5mW, impulse width is less than 2.7ps, moreover, the tunable wavelength range is between 1540nm-1580nm.

Instability of stationary lasing and self-starting mode locking in external-cavity semiconductor lasers

International Nuclear Information System (INIS)

Smetanin, Igor V; Vasil'ev, Petr P

2009-01-01

Parameters of external-cavity semiconductor lasers, when the stationary lasing becomes unstable, were analysed within the framework of a theoretical model of self-starting mode locking. In this case, a train of ultrashort pulses can be generated due to intrinsic nonlinearities of the laser medium. A decisive role of the transverse optical field nonuniformity, pump rate, and gain spectral bandwidth in the development of the instability of stationary lasing was demonstrated. (control of laser radiation parameters)

High gain semiconductor optical amplifier — Laser diode at visible wavelength

KAUST Repository

Shen, Chao; Lee, Changmin; Ng, Tien Khee; Nakamura, Shuji; Speck, James S.; DenBaars, Steven P.; Alyamani, Ahmed Y.; El-Desouki, Munir M.; Ooi, Boon S.

2017-01-01

We reported on the first experimental demonstration of a two-section semipolar InGaN-based laser diode with monolithically integrated semiconductor optical amplifier (SOA-LD). The onset of amplification effect was measured at 4V SOA bias (VSOA). The SOA-LD shows a large gain of 5.32 dB at Vsoa = 6 V.

High gain semiconductor optical amplifier — Laser diode at visible wavelength

KAUST Repository

Shen, Chao

2017-02-07

We reported on the first experimental demonstration of a two-section semipolar InGaN-based laser diode with monolithically integrated semiconductor optical amplifier (SOA-LD). The onset of amplification effect was measured at 4V SOA bias (VSOA). The SOA-LD shows a large gain of 5.32 dB at Vsoa = 6 V.

Towards the generation of random bits at terahertz rates based on a chaotic semiconductor laser

International Nuclear Information System (INIS)

Kanter, Ido; Aviad, Yaara; Reidler, Igor; Cohen, Elad; Rosenbluh, Michael

2010-01-01

Random bit generators (RBGs) are important in many aspects of statistical physics and crucial in Monte-Carlo simulations, stochastic modeling and quantum cryptography. The quality of a RBG is measured by the unpredictability of the bit string it produces and the speed at which the truly random bits can be generated. Deterministic algorithms generate pseudo-random numbers at high data rates as they are only limited by electronic hardware speed, but their unpredictability is limited by the very nature of their deterministic origin. It is widely accepted that the core of any true RBG must be an intrinsically non-deterministic physical process, e.g. measuring thermal noise from a resistor. Owing to low signal levels, such systems are highly susceptible to bias, introduced by amplification, and to small nonrandom external perturbations resulting in a limited generation rate, typically less than 100M bit/s. We present a physical random bit generator, based on a chaotic semiconductor laser, having delayed optical feedback, which operates reliably at rates up to 300Gbit/s. The method uses a high derivative of the digitized chaotic laser intensity and generates the random sequence by retaining a number of the least significant bits of the high derivative value. The method is insensitive to laser operational parameters and eliminates the necessity for all external constraints such as incommensurate sampling rates and laser external cavity round trip time. The randomness of long bit strings is verified by standard statistical tests.

Towards the generation of random bits at terahertz rates based on a chaotic semiconductor laser

Science.gov (United States)

Kanter, Ido; Aviad, Yaara; Reidler, Igor; Cohen, Elad; Rosenbluh, Michael

2010-06-01

Random bit generators (RBGs) are important in many aspects of statistical physics and crucial in Monte-Carlo simulations, stochastic modeling and quantum cryptography. The quality of a RBG is measured by the unpredictability of the bit string it produces and the speed at which the truly random bits can be generated. Deterministic algorithms generate pseudo-random numbers at high data rates as they are only limited by electronic hardware speed, but their unpredictability is limited by the very nature of their deterministic origin. It is widely accepted that the core of any true RBG must be an intrinsically non-deterministic physical process, e.g. measuring thermal noise from a resistor. Owing to low signal levels, such systems are highly susceptible to bias, introduced by amplification, and to small nonrandom external perturbations resulting in a limited generation rate, typically less than 100M bit/s. We present a physical random bit generator, based on a chaotic semiconductor laser, having delayed optical feedback, which operates reliably at rates up to 300Gbit/s. The method uses a high derivative of the digitized chaotic laser intensity and generates the random sequence by retaining a number of the least significant bits of the high derivative value. The method is insensitive to laser operational parameters and eliminates the necessity for all external constraints such as incommensurate sampling rates and laser external cavity round trip time. The randomness of long bit strings is verified by standard statistical tests.

Fast physical random bit generation with chaotic semiconductor lasers

Science.gov (United States)

Uchida, Atsushi; Amano, Kazuya; Inoue, Masaki; Hirano, Kunihito; Naito, Sunao; Someya, Hiroyuki; Oowada, Isao; Kurashige, Takayuki; Shiki, Masaru; Yoshimori, Shigeru; Yoshimura, Kazuyuki; Davis, Peter

2008-12-01

Random number generators in digital information systems make use of physical entropy sources such as electronic and photonic noise to add unpredictability to deterministically generated pseudo-random sequences. However, there is a large gap between the generation rates achieved with existing physical sources and the high data rates of many computation and communication systems; this is a fundamental weakness of these systems. Here we show that good quality random bit sequences can be generated at very fast bit rates using physical chaos in semiconductor lasers. Streams of bits that pass standard statistical tests for randomness have been generated at rates of up to 1.7 Gbps by sampling the fluctuating optical output of two chaotic lasers. This rate is an order of magnitude faster than that of previously reported devices for physical random bit generators with verified randomness. This means that the performance of random number generators can be greatly improved by using chaotic laser devices as physical entropy sources.

Laser Doppler perfusion imaging with a complimentary metal oxide semiconductor image sensor

NARCIS (Netherlands)

Serov, Alexander; Steenbergen, Wiendelt; de Mul, F.F.M.

2002-01-01

We utilized a complimentary metal oxide semiconductor video camera for fast f low imaging with the laser Doppler technique. A single sensor is used for both observation of the area of interest and measurements of the interference signal caused by dynamic light scattering from moving particles inside

Experimental control of power dropouts by current modulation in a semiconductor laser with optical feedback

International Nuclear Information System (INIS)

Ticos, Catalin M; Andrei, Ionut R; Pascu, Mihail L; Bulinski, Mircea

2011-01-01

The injection current of an external-cavity semiconductor laser working in a regime of low-frequency fluctuations (LFFs) is modulated at several MHz. The rate of power dropouts in the laser emission is correlated with the amplitude and frequency of the modulating signal. The occurrence of dropouts becomes more regular when the laser is driven at 7 MHz, which is close to the dominant frequency of dropouts in the solitary laser. Driving the laser at 10 MHz also induces dropouts with a periodicity of 0.1 μs, resulting in LFFs with two dominant frequencies.

The ATLAS semi-conductor tracker operation and performance

International Nuclear Information System (INIS)

Robinson, D.

2013-01-01

The Semi-Conductor Tracker (SCT) is a silicon strip detector and one of the key precision tracking devices in the Inner Detector of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The SCT was installed and commissioned within ATLAS in 2007, and has been used to exploit fully the physics potential of the LHC since the first proton–proton collisions at 7 TeV were delivered in 2009. In this paper, its operational status throughout data taking up to the end of 2011 is presented, and its tracking performance is reviewed. -- Highlights: ► The operation and performance of the ATLAS Semi-Conductor Tracker (SCT) is reviewed. ► More than 99% of the SCT strips have remained operational in all data taking periods so far. ► Tracking performance indicators have met or exceeded design specifications. ► Radiation damage effects match closely expectations from delivered fluence.

COHERENT LIDAR SYSTEM BASED ON A SEMICONDUCTOR LASER AND AMPLIFIER

DEFF Research Database (Denmark)

2009-01-01

The present invention relates to a compact, reliable and low-cost coherent LIDAR (Light Detection And Ranging) system for remote wind-speed determination, determination of particle concentration, and/or temperature based on an all semiconductor light source and related methods. The present...... invention provides a coherent LIDAR system comprising a semiconductor laser for emission of a measurement beam of electromagnetic radiation directed towards a measurement volume for illumination of particles in the measurement volume, a reference beam generator for generation of a reference beam, a detector...... for generation of a detector signal by mixing of the reference beam with light emitted from the particles in the measurement volume illuminated by the measurement beam, and a signal processor for generating a velocity signal corresponding to the velocity of the particles based on the detector signal....

2 W high efficiency PbS mid-infrared surface emitting laser

Science.gov (United States)

Ishida, A.; Sugiyama, Y.; Isaji, Y.; Kodama, K.; Takano, Y.; Sakata, H.; Rahim, M.; Khiar, A.; Fill, M.; Felder, F.; Zogg, H.

2011-09-01

High efficiency laser operation with output power exceeding 2 W was obtained for vertical external-cavity PbS based IV-VI compound surface emitting quantum-well structures. The laser showed external quantum efficiency as high as 16%. Generally, mid-infrared III-V or II-VI semiconductor laser operation utilizing interband electron transitions are restricted by Auger recombination and free carrier absorption. Auger recombination is much lower in the IV-VI semiconductors, and the free-carrier absorption is significantly reduced by an optically pumped laser structure including multi-step optical excitation layers.

Carrier-envelope offset frequency stabilization of an ultrafast semiconductor laser

Science.gov (United States)

Jornod, Nayara; Gürel, Kutan; Wittwer, Valentin J.; Brochard, Pierre; Hakobyan, Sargis; Schilt, Stéphane; Waldburger, Dominik; Keller, Ursula; Südmeyer, Thomas

2018-02-01

We present the self-referenced stabilization of the carrier-envelope offset (CEO) frequency of a semiconductor disk laser. The laser is a SESAM-modelocked VECSEL emitting at a wavelength of 1034 nm with a repetition frequency of 1.8 GHz. The 270-fs pulses are amplified to 3 W and compressed to 120 fs for the generation of a coherent octavespanning supercontinuum spectrum. A quasi-common-path f-to-2f interferometer enables the detection of the CEO beat with a signal-to-noise ratio of 30 dB sufficient for its frequency stabilization. The CEO frequency is phase-locked to an external reference with a feedback signal applied to the pump current.

A theoretical analysis for gigabit/second pulse code modulation of semiconductor lasers

DEFF Research Database (Denmark)

Danielsen, Magnus

1976-01-01

Investigation of the rate equations of a semiconductor laser suggests that bit rates of 3-4 Gbit/s can be achieved. Delay, ringing transients, and charge-storage effects can be removed by adjusting the dc-bias current and the peak and width of the current pulse to values prescribed by simple...

High temperature semiconductor diode laser pumps for high energy laser applications

Science.gov (United States)

Campbell, Jenna; Semenic, Tadej; Guinn, Keith; Leisher, Paul O.; Bhunia, Avijit; Mashanovitch, Milan; Renner, Daniel

2018-02-01

Existing thermal management technologies for diode laser pumps place a significant load on the size, weight and power consumption of High Power Solid State and Fiber Laser systems, thus making current laser systems very large, heavy, and inefficient in many important practical applications. To mitigate this thermal management burden, it is desirable for diode pumps to operate efficiently at high heat sink temperatures. In this work, we have developed a scalable cooling architecture, based on jet-impingement technology with industrial coolant, for efficient cooling of diode laser bars. We have demonstrated 60% electrical-to-optical efficiency from a 9xx nm two-bar laser stack operating with propylene-glycolwater coolant, at 50 °C coolant temperature. To our knowledge, this is the highest efficiency achieved from a diode stack using 50 °C industrial fluid coolant. The output power is greater than 100 W per bar. Stacks with additional laser bars are currently in development, as this cooler architecture is scalable to a 1 kW system. This work will enable compact and robust fiber-coupled diode pump modules for high energy laser applications.

Vertical Cavity Surface Emitting Laser for Operation at 1.5 µm with Integral AlGaInAs/InP Bragg mirrors

OpenAIRE

Linnik, M.; Christou, A.

2001-01-01

The design and performance of a low threshold selectively oxidized Vertical Cavity Surface Emitting Laser (VCSEL) fabricated for operation at a wavelength of 1.55 µm is based on III-V quaternary semiconductor alloys and is grown by Molecular Beam Epitaxy technique. The theoretical investigation of the optical properties of the compound semiconductor alloys allows one to select the optimum materials for highly reflective Bragg mirrors. The simulation of the designed VCSEL performance has been ...

Linewidth broadening in a distributed feedback laser integrated with a semiconductor optical amplifier

DEFF Research Database (Denmark)

Champagne, A.; Camel, J.; Maciejko, R.

2002-01-01

The problem of the linewidth degradation in systems using distributed-feedback lasers together with strained-layer multi-quantum-well semiconductor optical amplifiers (SOAs) is examined. A modified expression for the linewidth in the case of antireflection-coated SOA output facets is derived and ...

The astigmatism factor for semiconductor injection lasers

International Nuclear Information System (INIS)

Zhao Yiguang; Guo Changzhi

1988-03-01

The relations between the astigmatism factor and the waveguide structure, working conditions etc. were accurately calculated, using a method for deriving a self-consistent solution of the optical field equation and the carrier diffusion equation. Various theoretical models regarding the spontaneous emission factor were analyzed and compared. The results show that there is a difference between astigmatism factors of semiconductor lasers with different waveguide structures. W. Streifer's results, for a model having an invariable distribution of the complex refractive index, are larger by a factor of 6 to 80 than the accurate calculated value. K. Petermann's theory regarding the spontaneous emission factor is more appropriate than other theories. (author). 19 refs, 6 figs

An electrically injected rolled-up semiconductor tube laser

Energy Technology Data Exchange (ETDEWEB)

Dastjerdi, M. H. T.; Djavid, M.; Mi, Z., E-mail: zetian.mi@mcgill.ca [Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec H3A 0E9 (Canada)

2015-01-12

We have demonstrated electrically injected rolled-up semiconductor tube lasers, which are formed when a coherently strained InGaAs/InGaAsP quantum well heterostructure is selectively released from the underlying InP substrate. The device exhibits strong coherent emission in the wavelength range of ∼1.5 μm. A lasing threshold of ∼1.05 mA is measured for a rolled-up tube with a diameter of ∼5 μm and wall thickness of ∼140 nm at 80 K. The Purcell factor is estimated to be ∼4.3.

A photonic ultra-wideband pulse generator based on relaxation oscillations of a semiconductor laser

DEFF Research Database (Denmark)

Yu, Xianbin; Gibbon, Timothy Braidwood; Pawlik, Michal

2009-01-01

A photonic ultra-wideband (UWB) pulse generator based on relaxation oscillations of a semiconductor laser is proposed and experimentally demonstrated. We numerically simulate the modulation response of a direct modulation laser (DML) and show that due to the relaxation oscillations of the laser......, the generated signals with complex shape in time domain match the Federal Communications Commission (FCC) mask in the frequency domain. Experimental results using a DML agree well with simulation predictions. Furthermore, we also experimentally demonstrate the generation of FCC compliant UWB signals...

The ATLAS SemiConductor Tracker operation and performance

Science.gov (United States)

Pater, J. R.

2012-04-01

The ATLAS SemiConductor Tracker (SCT) is a key precision tracking detector in the ATLAS experiment at CERN's Large Hadron Collider. The SCT is composed of 4088 planar p-in-n silicon micro-strip detectors. The signals from the strips are processed in the front-end ABCD3TA ASICs, which operate in binary readout mode; data are transferred to the off-detector readout electronics via optical fibres. The SCT was completed in 2007. An extensive commissioning phase followed, during which calibration data were collected and analysed to determine the noise performance of the system, and further performance parameters of the detector were determined using cosmic ray data, both with and without magnetic field. After the commissioning phase, the SCT was ready for the first LHC proton-proton collisions in December 2009. From the beginning of data taking, the completed SCT has been in very good shape with more than 99% of its 6.3 million strips operational; the detector is well timed-in and the operational channels are 99.9% efficient in data acquisition. The noise occupancy and hit efficiency are better than the design specifications. The detector geometry is monitored continuously with a laser-based alignment system and is stable to the few-micron level; the alignment accuracy as determined by tracks is near specification and improving as statistics increase. The sensor behaviour in the 2T solenoidal magnetic field has been studied by measuring the Lorentz angle. Radiation damage in the silicon is monitored by periodic measurements of the leakage current; these measurements are in reasonable agreement with predictions.

Operation and performance of the ATLAS semiconductor tracker

CERN Document Server

Aad, Georges; Abdallah, Jalal; Abdel Khalek, Samah; Abdinov, Ovsat; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Abreu, Ricardo; Abulaiti, Yiming; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Adelman, Jahred; Adomeit, Stefanie; Adye, Tim; Agatonovic-Jovin, Tatjana; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Ahlen, Steven; Ahmad, Ashfaq; Ahmadov, Faig; Aielli, Giulio; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Alberghi, Gian Luigi; Albert, Justin; Albrand, Solveig; Alconada Verzini, Maria Josefina; Aleksa, Martin; Aleksandrov, Igor; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Alimonti, Gianluca; Alio, Lion; Alison, John; Allbrooke, Benedict; Allison, Lee John; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alonso, Alejandro; Alonso, Francisco; Alpigiani, Cristiano; Altheimer, Andrew David; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; 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Groth-Jensen, Jacob; Grout, Zara Jane; Grybel, Kai; Guan, Liang; Guescini, Francesco; Guest, Daniel; Gueta, Orel; Guicheney, Christophe; Guido, Elisa; Guillemin, Thibault; Guindon, Stefan; Gul, Umar; Gumpert, Christian; Gunther, Jaroslav; Guo, Jun; Gupta, Shaun; Gutierrez, Phillip; Gutierrez Ortiz, Nicolas Gilberto; Gutschow, Christian; Guttman, Nir; Guyot, Claude; Gwenlan, Claire; Gwilliam, Carl; Haas, Andy; Haber, Carl; Hadavand, Haleh Khani; Haddad, Nacim; Haefner, Petra; Hageboeck, Stephan; Hajduk, Zbigniew; Hakobyan, Hrachya; Haleem, Mahsana; Hall, David; Halladjian, Garabed; Hamacher, Klaus; Hamal, Petr; Hamano, Kenji; Hamer, Matthias; Hamilton, Andrew; Hamilton, Samuel; Hamnett, Phillip George; Han, Liang; Hanagaki, Kazunori; Hanawa, Keita; Hance, Michael; Hanke, Paul; Hansen, Jørgen Beck; Hansen, Jorn Dines; Hansen, Peter Henrik; Hara, Kazuhiko; Hard, Andrew; Harenberg, Torsten; Harkusha, Siarhei; Harper, Devin; Harrington, Robert; Harris, Orin; Harrison, Paul Fraser; Hartjes, Fred; Hasegawa, Satoshi; Hasegawa, Yoji; Hasib, A; Hassani, Samira; Haug, Sigve; Hauschild, Michael; Hauser, Reiner; Havranek, Miroslav; Hawkes, Christopher; Hawkings, Richard John; Hawkins, Anthony David; Hayashi, Takayasu; Hayden, Daniel; Hays, Chris; Hayward, Helen; Haywood, Stephen; Head, Simon; Heck, Tobias; Hedberg, Vincent; Heelan, Louise; Heim, Sarah; Heim, Timon; Heinemann, Beate; Heinrich, Lukas; Heisterkamp, Simon; Hejbal, Jiri; Helary, Louis; Heller, Claudio; Heller, Matthieu; Hellman, Sten; Hellmich, Dennis; Helsens, Clement; Henderson, James; Henderson, Robert; Hengler, Christopher; Henrichs, Anna; Henriques Correia, Ana Maria; Henrot-Versille, Sophie; Hensel, Carsten; Herbert, Geoffrey Henry; Hernández Jiménez, Yesenia; Herrberg-Schubert, Ruth; Herten, Gregor; Hertenberger, Ralf; Hervas, Luis; Hesketh, Gavin Grant; Hessey, Nigel; Hickling, Robert; Higón-Rodriguez, Emilio; Hill, Ewan; Hill, John; Hiller, Karl Heinz; Hillert, Sonja; Hillier, Stephen; Hinchliffe, Ian; Hines, Elizabeth; Hirose, Minoru; Hirschbuehl, Dominic; Hobbs, John; Hod, Noam; Hodgkinson, Mark; Hodgson, Paul; Hoecker, Andreas; Hoeferkamp, Martin; Hoffman, Julia; Hoffmann, Dirk; Hofmann, Julia Isabell; Hohlfeld, Marc; Holmes, Tova Ray; Hong, Tae Min; Hooft van Huysduynen, Loek; Hostachy, Jean-Yves; Hou, Suen; Hoummada, Abdeslam; Howard, Jacob; Howarth, James; Hrabovsky, Miroslav; Hristova, Ivana; Hrivnac, Julius; Hryn'ova, Tetiana; Hsu, Pai-hsien Jennifer; Hsu, Shih-Chieh; Hu, Diedi; Hu, Xueye; Huang, Yanping; Hubacek, Zdenek; Hubaut, Fabrice; Huegging, Fabian; Huffman, Todd Brian; Hughes, Emlyn; Hughes, Gareth; Huhtinen, Mika; Hülsing, Tobias Alexander; Hurwitz, Martina; Huseynov, Nazim; Huston, Joey; Huth, John; Iacobucci, Giuseppe; Iakovidis, Georgios; Ibragimov, Iskander; Iconomidou-Fayard, Lydia; Idarraga, John; Ideal, Emma; Iengo, Paolo; Igonkina, Olga; Iizawa, Tomoya; Ikegami, Yoichi; Ikematsu, Katsumasa; Ikeno, Masahiro; Iliadis, Dimitrios; Ilic, Nikolina; Inamaru, Yuki; Ince, Tayfun; Ioannou, Pavlos; Iodice, Mauro; Iordanidou, Kalliopi; Ippolito, Valerio; Irles Quiles, Adrian; Isaksson, Charlie; Ishino, Masaya; Ishitsuka, Masaki; Ishmukhametov, Renat; Issever, Cigdem; Istin, Serhat; Iturbe Ponce, Julia Mariana; Ivarsson, Jenny; Ivashin, Anton; Iwanski, Wieslaw; Iwasaki, Hiroyuki; Izen, Joseph; Izzo, Vincenzo; Jackson, Brett; Jackson, John; Jackson, Matthew; Jackson, Paul; Jaekel, Martin; Jain, Vivek; Jakobs, Karl; Jakobsen, Sune; Jakoubek, Tomas; Jakubek, Jan; Jamin, David Olivier; Jana, Dilip; Jansen, Eric; Jansen, Hendrik; Janssen, Jens; Janus, Michel; Jarlskog, Göran; Javadov, Namig; Javůrek, Tomáš; Jeanty, Laura; Jeng, Geng-yuan; Jennens, David; Jenni, Peter; Jentzsch, Jennifer; Jeske, Carl; Jézéquel, Stéphane; Ji, Haoshuang; Ji, Weina; Jia, Jiangyong; Jiang, Yi; Jimenez Belenguer, Marcos; Jin, Shan; Jinaru, Adam; Jinnouchi, Osamu; Joergensen, Morten Dam; Johansson, Erik; Johansson, Per; Johns, Kenneth; Jon-And, Kerstin; Jones, Graham; Jones, Roger; Jones, Tim; Jongmanns, Jan; Jorge, Pedro; Joseph, John; Joshi, Kiran Daniel; Jovicevic, Jelena; Ju, Xiangyang; Jung, Christian; Jungst, Ralph Markus; Jussel, Patrick; Juste Rozas, Aurelio; Kaci, Mohammed; Kaczmarska, Anna; Kado, Marumi; Kagan, Harris; Kagan, Michael; Kajomovitz, Enrique; Kama, Sami; Kanaya, Naoko; Kaneda, Michiru; Kaneti, Steven; Kanno, Takayuki; Kantserov, Vadim; Kanzaki, Junichi; Kaplan, Benjamin; Kapliy, Anton; Kar, Deepak; Karakostas, Konstantinos; Karastathis, Nikolaos; Karnevskiy, Mikhail; Karpov, Sergey; Karthik, Krishnaiyengar; Kartvelishvili, Vakhtang; Karyukhin, Andrey; Kashif, Lashkar; Kasieczka, Gregor; Kass, Richard; Kastanas, Alex; Kataoka, Yousuke; Katre, Akshay; Katzy, Judith; Kaushik, Venkatesh; Kawagoe, Kiyotomo; Kawamoto, Tatsuo; Kawamura, Gen; Kazama, Shingo; Kazanin, Vassili; Kazarinov, Makhail; Keeler, Richard; Keener, Paul; Kehoe, Robert; Keil, Markus; Keller, John; Keoshkerian, Houry; Kepka, Oldrich; Kerševan, Borut Paul; Kersten, Susanne; Kessoku, Kohei; Keung, Justin; Khalil-zada, Farkhad; Khandanyan, Hovhannes; Khanov, Alexander; Khodinov, Alexander; Khomich, Andrei; Khoo, Teng Jian; Khoriauli, Gia; Khoroshilov, Andrey; Khovanskiy, Valery; Khramov, Evgeniy; Khubua, Jemal; Kim, Hee Yeun; Kim, Hyeon Jin; Kim, Shinhong; Kimura, Naoki; Kind, Oliver; King, Barry; King, Matthew; King, Robert Steven Beaufoy; King, Samuel Burton; Kirk, Julie; Kiryunin, Andrey; Kishimoto, Tomoe; Kisielewska, Danuta; Kiss, Florian; Kitamura, Takumi; Kittelmann, Thomas; Kiuchi, Kenji; Kladiva, Eduard; Klein, Max; Klein, Uta; Kleinknecht, Konrad; Klimek, Pawel; Klimentov, Alexei; Klingenberg, Reiner; Klinger, Joel Alexander; Klioutchnikova, Tatiana; Klok, Peter; Kluge, Eike-Erik; Kluit, Peter; Kluth, Stefan; Kneringer, Emmerich; Knoops, Edith; Knue, Andrea; Kobayashi, Tomio; Kobel, Michael; Kocian, Martin; Kodys, Peter; Koevesarki, Peter; Koffas, Thomas; Koffeman, Els; Kogan, Lucy Anne; Kohlmann, Simon; Kohout, Zdenek; Kohriki, Takashi; Koi, Tatsumi; Kolanoski, Hermann; Koletsou, Iro; Koll, James; Komar, Aston; Komori, Yuto; Kondo, Takahiko; Kondrashova, Nataliia; Köneke, Karsten; König, Adriaan; König, Sebastian; Kono, Takanori; Konoplich, Rostislav; Konstantinidis, Nikolaos; Kopeliansky, Revital; Koperny, Stefan; Köpke, Lutz; Kopp, Anna Katharina; Korcyl, Krzysztof; Kordas, Kostantinos; Korn, Andreas; Korol, Aleksandr; Korolkov, Ilya; Korolkova, Elena; Korotkov, Vladislav; Kortner, Oliver; Kortner, Sandra; Kostyukhin, Vadim; Kotov, Sergey; Kotov, Vladislav; Kotwal, Ashutosh; Kourkoumelis, Christine; Kouskoura, Vasiliki; Koutsman, Alex; Kowalewski, Robert Victor; Kowalski, Tadeusz; Kozanecki, Witold; Kozhin, Anatoly; Kral, Vlastimil; Kramarenko, Viktor; Kramberger, Gregor; Krasnopevtsev, Dimitriy; Krasny, Mieczyslaw Witold; Krasznahorkay, Attila; Kraus, Jana; Kravchenko, Anton; Kreiss, Sven; Kretz, Moritz; Kretzschmar, Jan; Kreutzfeldt, Kristof; Krieger, Peter; Kroeninger, Kevin; Kroha, Hubert; Kroll, Joe; Kroseberg, Juergen; Krstic, Jelena; Kruchonak, Uladzimir; Krüger, Hans; Kruker, Tobias; Krumnack, Nils; Krumshteyn, Zinovii; Kruse, Amanda; Kruse, Mark; Kruskal, Michael; Kubik, Petr; Kubota, Takashi; Kuday, Sinan; Kuehn, Susanne; Kugel, Andreas; Kuhl, Andrew; Kuhl, Thorsten; Kukhtin, Victor; Kulchitsky, Yuri; Kuleshov, Sergey; Kuna, Marine; Kunkle, Joshua; Kupco, Alexander; Kurashige, Hisaya; Kurochkin, Yurii; Kurumida, Rie; Kus, Vlastimil; Kuwertz, Emma Sian; Kuze, Masahiro; Kvita, Jiri; La Rosa, Alessandro; La Rotonda, Laura; Lacasta, Carlos; Lacava, Francesco; Lacey, James; Lacker, Heiko; Lacour, Didier; Lacuesta, Vicente Ramón; Ladygin, Evgueni; Lafaye, Remi; Laforge, Bertrand; Lagouri, Theodota; Lai, Stanley; Laier, Heiko; Lambourne, Luke; Lammers, Sabine; Lampen, Caleb; Lampl, Walter; Lançon, Eric; Landgraf, Ulrich; Landon, Murrough; Lang, Valerie Susanne; Lange, Clemens; Lankford, Andrew; Lanni, Francesco; Lantzsch, Kerstin; Laplace, Sandrine; Lapoire, Cecile; Laporte, Jean-Francois; Lari, Tommaso; Lassnig, Mario; Laurelli, Paolo; Lavrijsen, Wim; Law, Alexander; Laycock, Paul; Le, Bao Tran; Le Dortz, Olivier; Le Guirriec, Emmanuel; Le Menedeu, Eve; LeCompte, Thomas; Ledroit-Guillon, Fabienne Agnes Marie; Lee, Claire Alexandra; Lee, Hurng-Chun; Lee, Jason; Lee, Shih-Chang; Lee, Lawrence; Lefebvre, Guillaume; Lefebvre, Michel; Legger, Federica; Leggett, Charles; Lehan, Allan; Lehmacher, Marc; Lehmann Miotto, Giovanna; Lei, Xiaowen; Leister, Andrew Gerard; Leite, Marco Aurelio Lisboa; Leitner, Rupert; Lellouch, Daniel; Lemmer, Boris; Leney, Katharine; Lenz, Tatjana; Lenzen, Georg; Lenzi, Bruno; Leone, Robert; Leonhardt, Kathrin; Leontsinis, Stefanos; Leroy, Claude; Lester, Christopher; Lester, Christopher Michael; Levchenko, Mikhail; Levêque, Jessica; Levin, Daniel; Levinson, Lorne; Levy, Mark; Lewis, Adrian; Lewis, George; Leyko, Agnieszka; Leyton, Michael; Li, Bing; Li, Bo; Li, Haifeng; Li, Ho Ling; Li, Liang; Li, Shu; Li, Yichen; Liang, Zhijun; Liao, Hongbo; Liberti, Barbara; Lichard, Peter; Lie, Ki; Liebal, Jessica; Liebig, Wolfgang; Limbach, Christian; Limosani, Antonio; Limper, Maaike; Lin, Simon; Linde, Frank; Lindquist, Brian Edward; Linnemann, James; Lipeles, Elliot; Lipniacka, Anna; Lisovyi, Mykhailo; Liss, Tony; Lissauer, David; Lister, Alison; Litke, Alan; Liu, Bo; Liu, Dong; Liu, Jianbei; Liu, Kun; Liu, Lulu; Liu, Miaoyuan; Liu, Minghui; Liu, Yanwen; Livan, Michele; Livermore, Sarah; Lleres, Annick; Llorente Merino, Javier; Lloyd, Stephen; Lo Sterzo, Francesco; Lobodzinska, Ewelina; Loch, Peter; Lockman, William; Loddenkoetter, Thomas; Loebinger, Fred; Loevschall-Jensen, Ask Emil; Loginov, Andrey; Loh, Chang Wei; Lohse, Thomas; Lohwasser, Kristin; Lokajicek, Milos; Lombardo, Vincenzo Paolo; Long, Brian Alexander; Long, Jonathan; Long, Robin Eamonn; Lopes, Lourenco; Lopez Mateos, David; Lopez Paredes, Brais; Lorenz, Jeanette; Lorenzo Martinez, Narei; Losada, Marta; Loscutoff, Peter; Lou, XinChou; Lounis, Abdenour; Love, Jeremy; Love, Peter; Lowe, Andrew; Lu, Feng; Lubatti, Henry; Luci, Claudio; Lucotte, Arnaud; Luehring, Frederick; Lukas, Wolfgang; Luminari, Lamberto; Lundberg, Olof; Lund-Jensen, Bengt; Lungwitz, Matthias; Lynn, David; Lysak, Roman; Lytken, Else; Ma, Hong; Ma, Lian Liang; Maccarrone, Giovanni; Macchiolo, Anna; Machado Miguens, Joana; Macina, Daniela; Madaffari, Daniele; Madar, Romain; Maddocks, Harvey Jonathan; Mader, Wolfgang; Madsen, Alexander; Maeno, Mayuko; Maeno, Tadashi; Magradze, Erekle; Mahboubi, Kambiz; Mahlstedt, Joern; Mahmoud, Sara; Maiani, Camilla; Maidantchik, Carmen; Maio, Amélia; Majewski, Stephanie; Makida, Yasuhiro; Makovec, Nikola; Mal, Prolay; Malaescu, Bogdan; Malecki, Pawel; Maleev, Victor; Malek, Fairouz; Mallik, Usha; Malon, David; Malone, Caitlin; Maltezos, Stavros; Malyshev, Vladimir; Malyukov, Sergei; Mamuzic, Judita; Mandelli, Beatrice; Mandelli, Luciano; Mandić, Igor; Mandrysch, Rocco; Maneira, José; Manfredini, Alessandro; Manhaes de Andrade Filho, Luciano; Manjarres Ramos, Joany Andreina; Mann, Alexander; Manning, Peter; Manousakis-Katsikakis, Arkadios; Mansoulie, Bruno; Mantifel, Rodger; Mapelli, Livio; March, Luis; Marchand, Jean-Francois; Marchiori, Giovanni; Marcisovsky, Michal; Marino, Christopher; Marques, Carlos; Marroquim, Fernando; Marsden, Stephen Philip; Marshall, Zach; Marti, Lukas Fritz; Marti-Garcia, Salvador; Martin, Brian; Martin, Brian Thomas; Martin, Jean-Pierre; Martin, Tim; Martin, Victoria Jane; Martin dit Latour, Bertrand; Martinez, Homero; Martinez, Mario; Martin-Haugh, Stewart; Martyniuk, Alex; Marx, Marilyn; Marzano, Francesco; Marzin, Antoine; Masetti, Lucia; Mashimo, Tetsuro; Mashinistov, Ruslan; Masik, Jiri; Maslennikov, Alexey; Massa, Ignazio; Massol, Nicolas; Mastrandrea, Paolo; Mastroberardino, Anna; Masubuchi, Tatsuya; Matricon, Pierre; Matsunaga, Hiroyuki; Matsushita, Takashi; Mättig, Peter; Mättig, Stefan; Mattmann, Johannes; Maurer, Julien; Maxfield, Stephen; Maximov, Dmitriy; Mazini, Rachid; Mazzaferro, Luca; Mc Goldrick, Garrin; Mc Kee, Shawn Patrick; McCarn, Allison; McCarthy, Robert; McCarthy, Tom; McCubbin, Norman; McFarlane, Kenneth; Mcfayden, Josh; Mchedlidze, Gvantsa; Mclaughlan, Tom; McMahon, Steve; McPherson, Robert; Meade, Andrew; Mechnich, Joerg; Medinnis, Michael; Meehan, Samuel; Mehlhase, Sascha; Mehta, Andrew; Meier, Karlheinz; Meineck, Christian; Meirose, Bernhard; Melachrinos, Constantinos; Mellado Garcia, Bruce Rafael; Meloni, Federico; Mengarelli, Alberto; Menke, Sven; Meoni, Evelin; Mercurio, Kevin Michael; Mergelmeyer, Sebastian; Meric, Nicolas; Mermod, Philippe; Merola, Leonardo; Meroni, Chiara; Merritt, Frank; Merritt, Hayes; Messina, Andrea; Metcalfe, Jessica; Mete, Alaettin Serhan; Meyer, Carsten; Meyer, Christopher; Meyer, Jean-Pierre; Meyer, Jochen; Middleton, Robin; Migas, Sylwia; Mijović, Liza; Mikenberg, Giora; Mikestikova, Marcela; Mikuž, Marko; Miller, David; Mills, Corrinne; Milov, Alexander; Milstead, David; Milstein, Dmitry; Minaenko, Andrey; Miñano Moya, Mercedes; Minashvili, Irakli; Mincer, Allen; Mindur, Bartosz; Mineev, Mikhail; Ming, Yao; Mir, Lluisa-Maria; Mirabelli, Giovanni; Mitani, Takashi; Mitrevski, Jovan; Mitsou, Vasiliki A; Mitsui, Shingo; Miucci, Antonio; Miyagawa, Paul; Mjörnmark, Jan-Ulf; Moa, Torbjoern; Mochizuki, Kazuya; Moeller, Victoria; Mohapatra, Soumya; Mohr, Wolfgang; Molander, Simon; Moles-Valls, Regina; Mönig, Klaus; Monini, Caterina; Monk, James; Monnier, Emmanuel; Montejo Berlingen, Javier; Monticelli, Fernando; Monzani, Simone; Moore, Roger; Moraes, Arthur; Morange, Nicolas; Morel, Julien; Moreno, Deywis; Moreno Llácer, María; Morettini, Paolo; Morgenstern, Marcus; Morii, Masahiro; Moritz, Sebastian; Morley, Anthony Keith; Mornacchi, Giuseppe; Morris, John; Morvaj, Ljiljana; Moser, Hans-Guenther; Mosidze, Maia; Moss, Josh; Mount, Richard; Mountricha, Eleni; Mouraviev, Sergei; Moyse, Edward; Muanza, Steve; Mudd, Richard; Mueller, Felix; Mueller, James; Mueller, Klemens; Mueller, Thibaut; Mueller, Timo; Muenstermann, Daniel; Munwes, Yonathan; Murillo Quijada, Javier Alberto; Murray, Bill; Musheghyan, Haykuhi; Musto, Elisa; Myagkov, Alexey; Myska, Miroslav; Nackenhorst, Olaf; Nadal, Jordi; Nagai, Koichi; Nagai, Ryo; Nagai, Yoshikazu; Nagano, Kunihiro; Nagarkar, Advait; Nagasaka, Yasushi; Nagel, Martin; Nairz, Armin Michael; Nakahama, Yu; Nakamura, Koji; Nakamura, Tomoaki; Nakano, Itsuo; Namasivayam, Harisankar; Nanava, Gizo; Narayan, Rohin; Nattermann, Till; Naumann, Thomas; Navarro, Gabriela; Nayyar, Ruchika; Neal, Homer; Nechaeva, Polina; Neep, Thomas James; Negri, Andrea; Negri, Guido; Negrini, Matteo; Nektarijevic, Snezana; Nelson, Andrew; Nelson, Timothy Knight; Nemecek, Stanislav; Nemethy, Peter; Nepomuceno, Andre Asevedo; Nessi, Marzio; Neubauer, Mark; Neumann, Manuel; Neves, Ricardo; Nevski, Pavel; Newcomer, Mitchel; Newman, Paul; Nguyen, Duong Hai; Nickerson, Richard; Nicolaidou, Rosy; Nicquevert, Bertrand; Nielsen, Jason; Nikiforou, Nikiforos; Nikiforov, Andriy; Nikolaenko, Vladimir; Nikolic-Audit, Irena; Nikolics, Katalin; Nikolopoulos, Konstantinos; Nilsson, Paul; Ninomiya, Yoichi; Nisati, Aleandro; Nisius, Richard; Nobe, Takuya; Nodulman, Lawrence; Nomachi, Masaharu; Nomidis, Ioannis; Norberg, Scarlet; Nordberg, Markus; Nowak, Sebastian; Nozaki, Mitsuaki; Nozka, Libor; Ntekas, Konstantinos; Nunes Hanninger, Guilherme; Nunnemann, Thomas; Nurse, Emily; Nuti, Francesco; O'Brien, Brendan Joseph; O'grady, Fionnbarr; O'Neil, Dugan; O'Shea, Val; Oakham, Gerald; Oberlack, Horst; Obermann, Theresa; Ocariz, Jose; Ochi, Atsuhiko; Ochoa, Ines; Oda, Susumu; Odaka, Shigeru; Ogren, Harold; Oh, Alexander; Oh, Seog; Ohm, Christian; Ohman, Henrik; Ohshima, Takayoshi; Okamura, Wataru; Okawa, Hideki; Okumura, Yasuyuki; Okuyama, Toyonobu; Olariu, Albert; Olchevski, Alexander; Olivares Pino, Sebastian Andres; Oliveira Damazio, Denis; Oliver Garcia, Elena; Olszewski, Andrzej; Olszowska, Jolanta; Onofre, António; Onyisi, Peter; Oram, Christopher; Oreglia, Mark; Oren, Yona; Orestano, Domizia; Orlando, Nicola; Oropeza Barrera, Cristina; Orr, Robert; Osculati, Bianca; Ospanov, Rustem; Otero y Garzon, Gustavo; Otono, Hidetoshi; Ouchrif, Mohamed; Ouellette, Eric; Ould-Saada, Farid; Ouraou, Ahmimed; Oussoren, Koen Pieter; Ouyang, Qun; Ovcharova, Ana; Owen, Mark; Ozcan, Veysi Erkcan; Ozturk, Nurcan; Pachal, Katherine; Pacheco Pages, Andres; Padilla Aranda, Cristobal; Pagáčová, Martina; Pagan Griso, Simone; Paganis, Efstathios; Pahl, Christoph; Paige, Frank; Pais, Preema; Pajchel, Katarina; Palacino, Gabriel; Palestini, Sandro; Pallin, Dominique; Palma, Alberto; Palmer, Jody; Pan, Yibin; Panagiotopoulou, Evgenia; Panduro Vazquez, William; Pani, Priscilla; Panikashvili, Natalia; Panitkin, Sergey; Pantea, Dan; Paolozzi, Lorenzo; Papadopoulou, Theodora; Papageorgiou, Konstantinos; Paramonov, Alexander; Paredes Hernandez, Daniela; Parker, Michael Andrew; Parodi, Fabrizio; Parsons, John; Parzefall, Ulrich; Pasqualucci, Enrico; Passaggio, Stefano; Passeri, Antonio; Pastore, Fernanda; Pastore, Francesca; Pásztor, Gabriella; Pataraia, Sophio; Patel, Nikhul; Pater, Joleen; Patricelli, Sergio; Pauly, Thilo; Pearce, James; Pedersen, Maiken; Pedraza Lopez, Sebastian; Pedro, Rute; Peleganchuk, Sergey; Pelikan, Daniel; Peng, Haiping; Penning, Bjoern; Penwell, John; Perepelitsa, Dennis; Perez Codina, Estel; Pérez García-Estañ, María Teresa; Perez Reale, Valeria; Perini, Laura; Pernegger, Heinz; Perrino, Roberto; Peschke, Richard; Peshekhonov, Vladimir; Peters, Krisztian; Peters, Yvonne; Petersen, Brian; Petersen, Jorgen; Petersen, Troels; Petit, Elisabeth; Petridis, Andreas; Petridou, Chariclia; Petrolo, Emilio; Petrucci, Fabrizio; Petteni, Michele; Pettersson, Nora Emilia; Pezoa, Raquel; Phillips, Peter William; Piacquadio, Giacinto; Pianori, Elisabetta; Picazio, Attilio; Piccaro, Elisa; Piccinini, Maurizio; Piegaia, Ricardo; Pieron, Jacek Piotr; Pignotti, David; Pilcher, James; Pilkington, Andrew; Pina, João Antonio; Pinamonti, Michele; Pinder, Alex; Pinfold, James; Pingel, Almut; Pinto, Belmiro; Pires, Sylvestre; Pitt, Michael; Pizio, Caterina; Pleier, Marc-Andre; Pleskot, Vojtech; Plotnikova, Elena; Plucinski, Pawel; Poddar, Sahill; Podlyski, Fabrice; Poettgen, Ruth; Poggioli, Luc; Pohl, David-leon; Pohl, Martin; Polesello, Giacomo; Policicchio, Antonio; Polifka, Richard; Polini, Alessandro; Pollard, Christopher Samuel; Polychronakos, Venetios; Pommès, Kathy; Pontecorvo, Ludovico; Pope, Bernard; Popeneciu, Gabriel Alexandru; Popovic, Dragan; Poppleton, Alan; Portell Bueso, Xavier; Pospelov, Guennady; Pospisil, Stanislav; Potamianos, Karolos; Potrap, Igor; Potter, Christina; Potter, Christopher; Poulard, Gilbert; Poveda, Joaquin; Pozdnyakov, Valery; Pralavorio, Pascal; Pranko, Aliaksandr; Prasad, Srivas; Pravahan, Rishiraj; Prell, Soeren; Price, Darren; Price, Joe; Price, Lawrence; Prieur, Damien; Primavera, Margherita; Proissl, Manuel; Prokofiev, Kirill; Prokoshin, Fedor; Protopapadaki, Eftychia-sofia; Protopopescu, Serban; Proudfoot, James; Przybycien, Mariusz; Przysiezniak, Helenka; Ptacek, Elizabeth; Pueschel, Elisa; Puldon, David; Purohit, Milind; Puzo, Patrick; Qian, Jianming; Qin, Gang; Qin, Yang; Quadt, Arnulf; Quarrie, David; Quayle, William; Quilty, Donnchadha; Qureshi, Anum; Radeka, Veljko; Radescu, Voica; Radhakrishnan, Sooraj Krishnan; Radloff, Peter; Rados, Pere; Ragusa, Francesco; Rahal, Ghita; Rajagopalan, Srinivasan; Rammensee, Michael; Randle-Conde, Aidan Sean; Rangel-Smith, Camila; Rao, Kanury; Rauscher, Felix; Rave, Tobias Christian; Ravenscroft, Thomas; Raymond, Michel; Read, Alexander Lincoln; Rebuzzi, Daniela; Redelbach, Andreas; Redlinger, George; Reece, Ryan; Reeves, Kendall; Rehnisch, Laura; Reinsch, Andreas; Reisin, Hernan; Relich, Matthew; Rembser, Christoph; Ren, Zhongliang; Renaud, Adrien; Rescigno, Marco; Resconi, Silvia; Resende, Bernardo; Rezanova, Olga; Reznicek, Pavel; Rezvani, Reyhaneh; Richter, Robert; Ridel, Melissa; Rieck, Patrick; Rijssenbeek, Michael; Rimoldi, Adele; Rinaldi, Lorenzo; Ritsch, Elmar; Riu, Imma; Rizatdinova, Flera; Rizvi, Eram; Robertson, Steven; Robichaud-Veronneau, Andree; Robinson, Dave; Robinson, James; Robson, Aidan; Roda, Chiara; Rodrigues, Luis; Roe, Shaun; Røhne, Ole; Rolli, Simona; Romaniouk, Anatoli; Romano, Marino; Romeo, Gaston; Romero Adam, Elena; Rompotis, Nikolaos; Roos, Lydia; Ros, Eduardo; Rosati, Stefano; Rosbach, Kilian; Rose, Matthew; Rosendahl, Peter Lundgaard; Rosenthal, Oliver; Rossetti, Valerio; Rossi, Elvira; Rossi, Leonardo Paolo; Rosten, Rachel; Rotaru, Marina; Roth, Itamar; Rothberg, Joseph; Rousseau, David; Royon, Christophe; Rozanov, Alexandre; Rozen, Yoram; Ruan, Xifeng; Rubbo, Francesco; Rubinskiy, Igor; Rud, Viacheslav; Rudolph, Christian; Rudolph, Matthew Scott; Rühr, Frederik; Ruiz-Martinez, Aranzazu; Rurikova, Zuzana; Rusakovich, Nikolai; Ruschke, Alexander; Rutherfoord, John; Ruthmann, Nils; Ryabov, Yury; Rybar, Martin; Rybkin, Grigori; Ryder, Nick; Saavedra, Aldo; Sacerdoti, Sabrina; Saddique, Asif; Sadeh, Iftach; Sadrozinski, Hartmut; Sadykov, Renat; Safai Tehrani, Francesco; Sakamoto, Hiroshi; Sakurai, Yuki; Salamanna, Giuseppe; Salamon, Andrea; Saleem, Muhammad; Salek, David; Sales De Bruin, Pedro Henrique; Salihagic, Denis; Salnikov, Andrei; Salt, José; Salvachua Ferrando, Belén; Salvatore, Daniela; Salvatore, Pasquale Fabrizio; Salvucci, Antonio; Salzburger, Andreas; Sampsonidis, Dimitrios; Sanchez, Arturo; Sánchez, Javier; Sanchez Martinez, Victoria; Sandaker, Heidi; Sandbach, Ruth Laura; Sander, Heinz Georg; Sanders, Michiel; Sandhoff, Marisa; Sandoval, Tanya; Sandoval, Carlos; Sandstroem, Rikard; Sankey, Dave; Sansoni, Andrea; Santoni, Claudio; Santonico, Rinaldo; Santos, Helena; Santoyo Castillo, Itzebelt; Sapp, Kevin; Sapronov, Andrey; Saraiva, João; Sarrazin, Bjorn; Sartisohn, Georg; Sasaki, Osamu; Sasaki, Yuichi; Satsounkevitch, Igor; Sauvage, Gilles; Sauvan, Emmanuel; Savard, Pierre; Savu, Dan Octavian; Sawyer, Craig; Sawyer, Lee; Saxon, James; Sbarra, Carla; Sbrizzi, Antonio; Scanlon, Tim; Scannicchio, Diana; Scarcella, Mark; Schaarschmidt, Jana; Schacht, Peter; Schaefer, Douglas; Schaefer, Ralph; Schaepe, Steffen; Schaetzel, Sebastian; Schäfer, Uli; Schaffer, Arthur; Schaile, Dorothee; Schamberger, R. Dean; Scharf, Veit; Schegelsky, Valery; Scheirich, Daniel; Schernau, Michael; Scherzer, Max; Schiavi, Carlo; Schieck, Jochen; Schillo, Christian; Schioppa, Marco; Schlenker, Stefan; Schmidt, Evelyn; Schmieden, Kristof; Schmitt, Christian; Schmitt, Christopher; Schmitt, Sebastian; Schneider, Basil; Schnellbach, Yan Jie; Schnoor, Ulrike; Schoeffel, Laurent; Schoening, Andre; Schoenrock, Bradley Daniel; Schorlemmer, Andre Lukas; Schott, Matthias; Schouten, Doug; Schovancova, Jaroslava; Schram, Malachi; Schramm, Steven; Schreyer, Manuel; Schroeder, Christian; Schuh, Natascha; Schultens, Martin Johannes; Schultz-Coulon, Hans-Christian; Schulz, Holger; Schumacher, Markus; Schumm, Bruce; Schune, Philippe; Schwartzman, Ariel; Schwegler, Philipp; Schwemling, Philippe; Schwienhorst, Reinhard; Schwindling, Jerome; Schwindt, Thomas; Schwoerer, Maud; Sciacca, Gianfranco; Scifo, Estelle; Sciolla, Gabriella; Scott, Bill; Scuri, Fabrizio; Scutti, Federico; Searcy, Jacob; Sedov, George; Sedykh, Evgeny; Seidel, Sally; Seiden, Abraham; Seifert, Frank; Seixas, José; Sekhniaidze, Givi; Sekula, Stephen; Selbach, Karoline Elfriede; Seliverstov, Dmitry; Sellers, Graham; Semprini-Cesari, Nicola; Serfon, Cedric; Serin, Laurent; Serkin, Leonid; Serre, Thomas; Seuster, Rolf; Severini, Horst; Sforza, Federico; Sfyrla, Anna; Shabalina, Elizaveta; Shamim, Mansoora; Shan, Lianyou; Shank, James; Shao, Qi Tao; Shapiro, Marjorie; Shatalov, Pavel; Shaw, Kate; Shaw, Rick; Sherwood, Peter; Shimizu, Shima; Shimmin, Chase Owen; Shimojima, Makoto; Shiyakova, Mariya; Shmeleva, Alevtina; Shochet, Mel; Short, Daniel; Shrestha, Suyog; Shulga, Evgeny; Shupe, Michael; Shushkevich, Stanislav; Sicho, Petr; Sidorov, Dmitri; Sidoti, Antonio; Siegert, Frank; Sijacki, Djordje; Silbert, Ohad; Silva, José; Silver, Yiftah; Silverstein, Daniel; Silverstein, Samuel; Simak, Vladislav; Simard, Olivier; Simic, Ljiljana; Simion, Stefan; Simioni, Eduard; Simmons, Brinick; Simoniello, Rosa; Simonyan, Margar; Sinervo, Pekka; Sinev, Nikolai; Sipica, Valentin; Siragusa, Giovanni; Sircar, Anirvan; Sisakyan, Alexei; Sivoklokov, Serguei; Sjölin, Jörgen; Sjursen, Therese; Skottowe, Hugh Philip; Skovpen, Kirill; Skubic, Patrick; Slater, Mark; Slavicek, Tomas; Sliwa, Krzysztof; Smakhtin, Vladimir; Smart, Ben; Smestad, Lillian; Smirnov, Sergei; Smirnov, Yury; Smirnova, Lidia; Smirnova, Oxana; Smizanska, Maria; Smolek, Karel; Snesarev, Andrei; Snidero, Giacomo; Snow, Joel; Snyder, Scott; Sobie, Randall; Socher, Felix; Sodomka, Jaromir; Soffer, Abner; Soh, Dart-yin; Solans, Carlos; Solar, Michael; Solc, Jaroslav; Soldatov, Evgeny; Soldevila, Urmila; Solfaroli Camillocci, Elena; Solodkov, Alexander; Solovyanov, Oleg; Solovyev, Victor; Sommer, Philip; Song, Hong Ye; Soni, Nitesh; Sood, Alexander; Sopczak, Andre; Sopko, Vit; Sopko, Bruno; Sorin, Veronica; Sosebee, Mark; Soualah, Rachik; Soueid, Paul; Soukharev, Andrey; South, David; Spagnolo, Stefania; Spanò, Francesco; Spearman, William Robert; Spighi, Roberto; Spigo, Giancarlo; Spousta, Martin; Spreitzer, Teresa; Spurlock, Barry; St Denis, Richard Dante; Staerz, Steffen; Stahlman, Jonathan; Stamen, Rainer; Stanecka, Ewa; Stanek, Robert; Stanescu, Cristian; Stanescu-Bellu, Madalina; Stanitzki, Marcel Michael; Stapnes, Steinar; Starchenko, Evgeny; Stark, Jan; Staroba, Pavel; Starovoitov, Pavel; Staszewski, Rafal; Stavina, Pavel; Steele, Genevieve; Steinberg, Peter; Stekl, Ivan; Stelzer, Bernd; Stelzer, Harald Joerg; Stelzer-Chilton, Oliver; Stenzel, Hasko; Stern, Sebastian; Stewart, Graeme; Stillings, Jan Andre; Stockton, Mark; Stoebe, Michael; Stoicea, Gabriel; Stolte, Philipp; Stonjek, Stefan; Stradling, Alden; Straessner, Arno; Stramaglia, Maria Elena; Strandberg, Jonas; Strandberg, Sara; Strandlie, Are; Strauss, Emanuel; Strauss, Michael; Strizenec, Pavol; Ströhmer, Raimund; Strom, David; Stroynowski, Ryszard; Stucci, Stefania Antonia; Stugu, Bjarne; Styles, Nicholas Adam; Su, Dong; Su, Jun; Subramania, Halasya Siva; Subramaniam, Rajivalochan; Succurro, Antonella; Sugaya, Yorihito; Suhr, Chad; Suk, Michal; Sulin, Vladimir; Sultansoy, Saleh; Sumida, Toshi; Sun, Xiaohu; Sundermann, Jan Erik; Suruliz, Kerim; Susinno, Giancarlo; Sutton, Mark; Suzuki, Yu; Svatos, Michal; Swedish, Stephen; Swiatlowski, Maximilian; Sykora, Ivan; Sykora, Tomas; Ta, Duc; Tackmann, Kerstin; Taenzer, Joe; Taffard, Anyes; Tafirout, Reda; Taiblum, Nimrod; Takahashi, Yuta; Takai, Helio; Takashima, Ryuichi; Takeda, Hiroshi; Takeshita, Tohru; Takubo, Yosuke; Talby, Mossadek; Talyshev, Alexey; Tam, Jason; Tamsett, Matthew; Tan, Kong Guan; Tanaka, Junichi; Tanaka, Reisaburo; Tanaka, Satoshi; Tanaka, Shuji; Tanasijczuk, Andres Jorge; Tani, Kazutoshi; Tannoury, Nancy; Tapprogge, Stefan; Tarem, Shlomit; Tarrade, Fabien; Tartarelli, Giuseppe Francesco; Tas, Petr; Tasevsky, Marek; Tashiro, Takuya; Tassi, Enrico; Tavares Delgado, Ademar; Tayalati, Yahya; Taylor, Frank; Taylor, Geoffrey; Taylor, Wendy; Teischinger, Florian Alfred; Teixeira Dias Castanheira, Matilde; Teixeira-Dias, Pedro; Temming, Kim Katrin; Ten Kate, Herman; Teng, Ping-Kun; Terada, Susumu; Terashi, Koji; Terron, Juan; Terzo, Stefano; Testa, Marianna; Teuscher, Richard; Therhaag, Jan; Theveneaux-Pelzer, Timothée; Thoma, Sascha; Thomas, Juergen; Thomas-Wilsker, Joshuha; Thompson, Emily; Thompson, Paul; Thompson, Peter; Thompson, Stan; Thomsen, Lotte Ansgaard; Thomson, Evelyn; Thomson, Mark; Thong, Wai Meng; Thun, Rudolf; Tian, Feng; Tibbetts, Mark James; Tikhomirov, Vladimir; Tikhonov, Yury; Timoshenko, Sergey; Tiouchichine, Elodie; Tipton, Paul; Tisserant, Sylvain; Todorov, Theodore; Todorova-Nova, Sharka; Toggerson, Brokk; Tojo, Junji; Tokár, Stanislav; Tokushuku, Katsuo; Tollefson, Kirsten; Tomlinson, Lee; Tomoto, Makoto; Tompkins, Lauren; Toms, Konstantin; Topilin, Nikolai; Torrence, Eric; Torres, Heberth; Torró Pastor, Emma; Toth, Jozsef; Touchard, Francois; Tovey, Daniel; Tran, Huong Lan; Trefzger, Thomas; Tremblet, Louis; Tricoli, Alessandro; Trigger, Isabel Marian; Trincaz-Duvoid, Sophie; Tripiana, Martin; Triplett, Nathan; Trischuk, William; Trocmé, Benjamin; Troncon, Clara; Trottier-McDonald, Michel; Trovatelli, Monica; True, Patrick; Trzebinski, Maciej; Trzupek, Adam; Tsarouchas, Charilaos; Tseng, Jeffrey; Tsiareshka, Pavel; Tsionou, Dimitra; Tsipolitis, Georgios; Tsirintanis, Nikolaos; Tsiskaridze, Shota; Tsiskaridze, Vakhtang; Tskhadadze, Edisher; Tsukerman, Ilya; Tsulaia, Vakhtang; Tsuno, Soshi; Tsybychev, Dmitri; Tudorache, Alexandra; Tudorache, Valentina; Tuna, Alexander Naip; Tupputi, Salvatore; Turchikhin, Semen; Turecek, Daniel; Turk Cakir, Ilkay; Turra, Ruggero; Tuts, Michael; Tykhonov, Andrii; Tylmad, Maja; Tyndel, Mike; Uchida, Kirika; Ueda, Ikuo; Ueno, Ryuichi; Ughetto, Michael; Ugland, Maren; Uhlenbrock, Mathias; Ukegawa, Fumihiko; Unal, Guillaume; Undrus, Alexander; Unel, Gokhan; Ungaro, Francesca; Unno, Yoshinobu; Urbaniec, Dustin; Urquijo, Phillip; Usai, Giulio; Usanova, Anna; Vacavant, Laurent; Vacek, Vaclav; Vachon, Brigitte; Valencic, Nika; Valentinetti, Sara; Valero, Alberto; Valery, Loic; Valkar, Stefan; Valladolid Gallego, Eva; Vallecorsa, Sofia; Valls Ferrer, Juan Antonio; Van Berg, Richard; Van Der Deijl, Pieter; van der Geer, Rogier; van der Graaf, Harry; Van Der Leeuw, Robin; van der Ster, Daniel; van Eldik, Niels; van Gemmeren, Peter; Van Nieuwkoop, Jacobus; van Vulpen, Ivo; van Woerden, Marius Cornelis; Vanadia, Marco; Vandelli, Wainer; Vanguri, Rami; Vaniachine, Alexandre; Vankov, Peter; Vannucci, Francois; Vardanyan, Gagik; Vari, Riccardo; Varnes, Erich; Varol, Tulin; Varouchas, Dimitris; Vartapetian, Armen; Varvell, Kevin; Vazeille, Francois; Vazquez Schroeder, Tamara; Veatch, Jason; Veloso, Filipe; Veneziano, Stefano; Ventura, Andrea; Ventura, Daniel; Venturi, Manuela; Venturi, Nicola; Venturini, Alessio; Vercesi, Valerio; Verducci, Monica; Verkerke, Wouter; Vermeulen, Jos; Vest, Anja; Vetterli, Michel; Viazlo, Oleksandr; Vichou, Irene; Vickey, Trevor; Vickey Boeriu, Oana Elena; Viehhauser, Georg; Viel, Simon; Vigne, Ralph; Villa, Mauro; Villaplana Perez, Miguel; Vilucchi, Elisabetta; Vincter, Manuella; Vinogradov, Vladimir; Virzi, Joseph; Vivarelli, Iacopo; Vives Vaque, Francesc; Vlachos, Sotirios; Vladoiu, Dan; Vlasak, Michal; Vogel, Adrian; Vokac, Petr; Volpi, Guido; Volpi, Matteo; von der Schmitt, Hans; von Radziewski, Holger; von Toerne, Eckhard; Vorobel, Vit; Vorobev, Konstantin; Vos, Marcel; Voss, Rudiger; Vossebeld, Joost; Vranjes, Nenad; Vranjes Milosavljevic, Marija; Vrba, Vaclav; Vreeswijk, Marcel; Vu Anh, Tuan; Vuillermet, Raphael; Vukotic, Ilija; Vykydal, Zdenek; Wagner, Wolfgang; Wagner, Peter; Wahrmund, Sebastian; Wakabayashi, Jun; Walder, James; Walker, Rodney; Walkowiak, Wolfgang; Wall, Richard; Waller, Peter; Walsh, Brian; Wang, Chao; Wang, Chiho; Wang, Fuquan; Wang, Haichen; Wang, Hulin; Wang, Jike; Wang, Jin; Wang, Kuhan; Wang, Rui; Wang, Song-Ming; Wang, Tan; Wang, Xiaoxiao; Wanotayaroj, Chaowaroj; Warburton, Andreas; Ward, Patricia; Wardrope, David Robert; Warren, Matthew; Warsinsky, Markus; Washbrook, Andrew; Wasicki, Christoph; 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The semiconductor tracker is a silicon microstrip detector forming part of the inner tracking system of the ATLAS experiment at the LHC. The operation and performance of the semiconductor tracker during the first years of LHC running are described. More than 99% of the detector modules were operational during this period, with an average intrinsic hit efficiency of (99.74 +/- 0.04)%. The evolution of the noise occupancy is discussed, and measurements of the Lorentz angle, delta-ray production and energy loss presented. The alignment of the detector is found to be stable at the few-micron level over long periods of time. Radiation damage measurements, which include the evolution of detector leakage currents, are found to be consistent with predictions and are used in the verification of radiation background simulations.

The dynamical complexity of optically injected semiconductor lasers

International Nuclear Information System (INIS)

Wieczorek, S.; Krauskopf, B.; Simpson, T.B.; Lenstra, D.

2005-01-01

This report presents a modern approach to the theoretical and experimental study of complex nonlinear behavior of a semiconductor laser with optical injection-an example of a widely applied and technologically relevant forced nonlinear oscillator. We show that the careful bifurcation analysis of a rate equation model yields (i) a deeper understanding of already studied physical phenomena, and (ii) the discovery of new dynamical effects, such as multipulse excitability. Different instabilities, cascades of bifurcations, multistability, and sudden chaotic transitions, which are often viewed as independent, are in fact logically connected into a consistent web of bifurcations via special points called organizing centers. This theoretical bifurcation analysis has predictive power, which manifests itself in good agreement with experimental measurements over a wide range of parameters and diversity of dynamics. While it is dealing with the specific system of an optically injected laser, our work constitutes the state-of-the-art in the understanding and modeling of a nonlinear physical system in general

Frequency response control of semiconductor laser by using hybrid modulation scheme.

Science.gov (United States)

Mieda, Shigeru; Yokota, Nobuhide; Isshiki, Ryuto; Kobayashi, Wataru; Yasaka, Hiroshi

2016-10-31

A hybrid modulation scheme that simultaneously applies the direct current modulation and intra-cavity loss modulation to a semiconductor laser is proposed. Both numerical calculations using rate equations and experiments using a fabricated laser show that the hybrid modulation scheme can control the frequency response of the laser by changing a modulation ratio and time delay between the two modulations. The modulation ratio and time delay provide the degree of signal mixing of the two modulations and an optimum condition is found when a non-flat frequency response for the intra-cavity loss modulation is compensated by that for the direct current modulation. We experimentally confirm a 8.64-dB improvement of the modulation sensitivity at 20 GHz compared with the pure direct current modulation with a 0.7-dB relaxation oscillation peak.

Controlled Quantum Operations of a Semiconductor Three-Qubit System

Science.gov (United States)

Li, Hai-Ou; Cao, Gang; Yu, Guo-Dong; Xiao, Ming; Guo, Guang-Can; Jiang, Hong-Wen; Guo, Guo-Ping

2018-02-01

In a specially designed semiconductor device consisting of three capacitively coupled double quantum dots, we achieve strong and tunable coupling between a target qubit and two control qubits. We demonstrate how to completely switch on and off the target qubit's coherent rotations by presetting two control qubits' states. A Toffoli gate is, therefore, possible based on these control effects. This research paves a way for realizing full quantum-logic operations in semiconductor multiqubit systems.

Dilute ferromagnetic semiconductors prepared by the combination of ion implantation with pulse laser melting

International Nuclear Information System (INIS)

Zhou, Shengqiang

2015-01-01

Combining semiconducting and ferromagnetic properties, dilute ferromagnetic semiconductors (DFS) have been under intensive investigation for more than two decades. Mn doped III–V compound semiconductors have been regarded as the prototype of DFS from both experimental and theoretic investigations. The magnetic properties of III–V:Mn can be controlled by manipulating free carriers via electrical gating, as for controlling the electrical properties in conventional semiconductors. However, the preparation of DFS presents a big challenge due to the low solubility of Mn in semiconductors. Ion implantation followed by pulsed laser melting (II-PLM) provides an alternative to the widely used low-temperature molecular beam epitaxy (LT-MBE) approach. Both ion implantation and pulsed-laser melting occur far enough from thermodynamic equilibrium conditions. Ion implantation introduces enough dopants and the subsequent laser pulse deposit energy in the near-surface region to drive a rapid liquid-phase epitaxial growth. Here, we review the experimental study on preparation of III–V:Mn using II-PLM. We start with a brief description about the development of DFS and the physics behind II-PLM. Then we show that ferromagnetic GaMnAs and InMnAs films can be prepared by II-PLM and they show the same characteristics of LT-MBE grown samples. Going beyond LT-MBE, II-PLM is successful to bring two new members, GaMnP and InMnP, into the family of III–V:Mn DFS. Both GaMnP and InMnP films show the signature of DFS and an insulating behavior. At the end, we summarize the work done for Ge:Mn and Si:Mn using II-PLM and present suggestions for future investigations. The remarkable advantage of II-PLM approach is its versatility. In general, II-PLM can be utilized to prepare supersaturated alloys with mismatched components. (topical review)

Ultrawideband pulse generation based on overshooting effect in gain-switched semiconductor laser

DEFF Research Database (Denmark)

Torres-Company, V.; Prince, Kamau; Tafur Monroy, Idelfonso

2008-01-01

We demonstrate an alternative procedure to achieve ultrawideband (UWB) radio-frequency (RF) doublet impulses. It is based on the overshooting effect appearing by biasing a semiconductor laser close to the threshold with a large-amplitude signal. Specifically, with an optical bandpass filter...... a reliable, easy, and low-cost alternative for RF UWB impulse generation....

Lasers

CERN Document Server

Milonni, Peter W

1988-01-01

A comprehensive introduction to the operating principles and applications of lasers. Explains basic principles, including the necessary elements of classical and quantum physics. Provides concise discussions of various laser types including gas, solid state, semiconductor, and free electron lasers, as well as of laser resonators, diffraction, optical coherence, and many applications including holography, phase conjugation, wave mixing, and nonlinear optics. Incorporates many intuitive explanations and practical examples. Discussions are self-contained in a consistent notation and in a style that should appeal to physicists, chemists, optical scientists and engineers.

Design and evaluation of modelocked semiconductor lasers for low noise and high stability

DEFF Research Database (Denmark)

Yvind, Kresten; Larsson, David; Christiansen, Lotte Jin

2005-01-01

We present work on design of monolithic mode-locked semiconductor lasers with focus on the gain medium. The use of highly inverted quantum wells in a low-loss waveguide enables both low quantum noise, low-chirped pulses and a large stability region. Broadband noise measurements are performed...

Near infrared laser stimulation of human neural stem cells into neurons on graphene nanomesh semiconductors.

Science.gov (United States)

Akhavan, Omid; Ghaderi, Elham; Shirazian, Soheil A

2015-02-01

Reduced graphene oxide nanomeshes (rGONMs), as p-type semiconductors with band-gap energy of ∼ 1 eV, were developed and applied in near infrared (NIR) laser stimulation of human neural stem cells (hNSCs) into neurons. The biocompatibility of the rGONMs in growth of hNSCs was found similar to that of the graphene oxide (GO) sheets. Proliferation of the hNSCs on the GONMs was assigned to the excess oxygen functional groups formed on edge defects of the GONMs, resulting in superhydrophilicity of the surface. Under NIR laser stimulation, the graphene layers (especially the rGONMs) exhibited significant cell differentiations, including more elongations of the cells and higher differentiation of neurons than glia. The higher hNSC differentiation on the rGONM than the reduced GO (rGO) was assigned to the stimulation effects of the low-energy photoexcited electrons injected from the rGONM semiconductors into the cells, while the high-energy photoelectrons of the rGO (as a zero band-gap semiconductor) could suppress the cell proliferation and/or even cause cell damages. Using conventional heating of the culture media up to ∼ 43 °C (the temperature typically reached under the laser irradiation), no significant differentiation was observed in dark. This further confirmed the role of photoelectrons in the hNSC differentiation. Copyright © 2014 Elsevier B.V. All rights reserved.

Multiclustered chimeras in large semiconductor laser arrays with nonlocal interactions

Science.gov (United States)

Shena, J.; Hizanidis, J.; Hövel, P.; Tsironis, G. P.

2017-09-01

The dynamics of a large array of coupled semiconductor lasers is studied numerically for a nonlocal coupling scheme. Our focus is on chimera states, a self-organized spatiotemporal pattern of coexisting coherence and incoherence. In laser systems, such states have been previously found for global and nearest-neighbor coupling, mainly in small networks. The technological advantage of large arrays has motivated us to study a system of 200 nonlocally coupled lasers with respect to the emerging collective dynamics. Moreover, the nonlocal nature of the coupling allows us to obtain robust chimera states with multiple (in)coherent domains. The crucial parameters are the coupling strength, the coupling phase and the range of the nonlocal interaction. We find that multiclustered chimera states exist in a wide region of the parameter space and we provide quantitative characterization for the obtained spatiotemporal patterns. By proposing two different experimental setups for the realization of the nonlocal coupling scheme, we are confident that our results can be confirmed in the laboratory.

Fiber optical laser spot microscope: A new concept for photoelectrochemical characterization of semiconductor electrodes

OpenAIRE

Carlsson, Per; Holmström, Bertil; Uosaki, Kohei; Kita, Hideaki

1988-01-01

A fiber optical laser spot microscope, which allows the simultaneous measurements of photocurrent and reflected light intensity or the measurement of laser spot photocurrent under the illumination of other light sources, has been developed to study semiconductor/electrolyte interfaces. The capability of this microscope was demonstrated on as-cleaved and Pt-treated p-InSe. The Pt treatment increased the photocurrent and improved the lateral resolution due to the increase of surface reaction ra...

Semiconductor lasers with a continuous tuning range above 100 nm in the nearest IR spectral region

Energy Technology Data Exchange (ETDEWEB)

Kostin, Yu O; Lobintsov, A A; Shramenko, M V [OOO ' Opton' , Moscow (Russian Federation); Ladugin, M A; Marmalyuk, A A [Open Joint-Stock Company M.F. Stel' makh Polyus Research Institute, Moscow (Russian Federation); Chamorovsky, A Yu [Superlum Ltd., Unit B3, Fota Point Enterprise Park, Carrigtwohill, Co Cork (Ireland); Yakubovich, S D [Moscow State Institute of Radio-Engineering, Electronics and Automation (Technical University), Moscow (Russian Federation)

2015-08-31

We have developed two new types of lasers based on quantum-confined semiconductor optical amplifiers with an acousto-optic tunable filter in an external fibre ring cavity. The lasers offer continuous wavelength tuning ranges from 780 to 885 and from 880 to 1010 nm, 20 mW of cw output power, and a tuning rate up to 10{sup 4} nm s{sup -1} at an instantaneous spectral linewidth less than 0.1 nm. (lasers)

On nonequilibrium many-body systems 2: ultra fast relaxation phenomena in semiconductors

International Nuclear Information System (INIS)

Algarte, A.C.S.; Vasconcellos, A.R.; Luzzi, R.

1986-01-01

The application of the nonequilibrium statistical operator (NSO) method to the study of the irreversible thermodynamics and optical responses of semiconductors probed by ultrafast laser spectroscopy is described. (Author) [pt

Preparation of antimony sulfide semiconductor nanoparticles by pulsed laser ablation in liquid

Energy Technology Data Exchange (ETDEWEB)

Sun, Ren-De, E-mail: son003@sekisui.com [Research & Development Institute, High Performance Plastics Company, Sekisui Chemical Co., Ltd. 2-1 Hyakuyama, Shimamoto-Cho, Mishima-Gun, Osaka, 618-0021 (Japan); Tsuji, Takeshi [Interdisciplinary Graduate School of Science and Engineering, Shimane University, 1060 Nishikawatsu-Cho, Matsue, 690-8504 (Japan)

2015-09-01

Highlights: • Pulsed laser ablation in liquid (LAL) was applied to prepare antimony sulfide nanoparticles (Sb{sub 2}S{sub 3} NPs). • Sb{sub 2}S{sub 3} NPs with a stoichiometric composition were successfully prepared by LAL in water without using any surfactants or capping agents. • Thus-prepared Sb{sub 2}S{sub 3} NPs showed low-temperature crystallization and melting at a temperature low as 200 °C. • The NPs-coated Sb{sub 2}S{sub 3} thin film showed comparable semiconductor properties (carrier mobility and carrier density) to the vacuum deposited one. • Byproducts such as CS{sub 2}, CH{sub 4} and CO were detected by GC-MS analysis when LAL was performed in organic solvent. • The LAL-induced decomposition mechanism of Sb{sub 2}S{sub 3} and organic solvents was discussed based on the GC-MS results. - Abstract: In this paper, we report on the synthesis of antimony sulfide (Sb{sub 2}S{sub 3}) semiconductor nanoparticles by pulsed laser ablation in liquid without using any surfactants or capping agents. Different results were obtained in water and organic solvents. In the case of water, Sb{sub 2}S{sub 3} nanoparticles with chemical compositions of stoichiometry were successfully prepared when laser irradiation was performed under the condition with the dissolved oxygen removed by argon gas bubbling. It was shown that thus-obtained Sb{sub 2}S{sub 3} nanoparticles exhibit features of not only low-temperature crystallization but also low-temperature melting at a temperature as low as 200 °C. Nanoparticle-coated Sb{sub 2}S{sub 3} thin films were found to show good visible light absorption and satisfying semiconductor properties (i.e., carrier mobility and density), which are essential for photovoltaic application. On the other hand, in the case of organic solvents (e.g., acetone, ethanol), such unexpected byproducts as CS{sub 2}, CO and CH{sub 4} were detected from the reaction system by GC-MS analysis, which suggests that both Sb{sub 2}S{sub 3} and organic

Semiconductor Nanomaterials-Based Fluorescence Spectroscopic and Matrix-Assisted Laser Desorption/Ionization (MALDI Mass Spectrometric Approaches to Proteome Analysis

Directory of Open Access Journals (Sweden)

Suresh Kumar Kailasa

2013-12-01

Full Text Available Semiconductor quantum dots (QDs or nanoparticles (NPs exhibit very unusual physico-chemcial and optical properties. This review article introduces the applications of semiconductor nanomaterials (NMs in fluorescence spectroscopy and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS for biomolecule analysis. Due to their unique physico-chemical and optical properties, semiconductors NMs have created many new platforms for investigating biomolecular structures and information in modern biology. These semiconductor NMs served as effective fluorescent probes for sensing proteins and cells and acted as affinity or concentrating probes for enriching peptides, proteins and bacteria proteins prior to MALDI-MS analysis.

Packaged semiconductor laser optical phase locked loop for photonic generation, processing and transmission of microwave signals

DEFF Research Database (Denmark)

Langley, L.N.; Elkin, M.D.; Edege, C.

1999-01-01

In this paper, we present the first fully packaged semiconductor laser optical phase-locked loop (OPLL) microwave photonic transmitter. The transmitter is based on semiconductor lasers that are directly phase locked without the use of any other phase noise-reduction mechanisms. In this transmitter......, the lasers have a free-running summed linewidth of 6 MHz and the OPLL has a feedback bandwidth of 70 MHz, A state-of-the-art performance is obtained, with a total phase-error variance of 0.05 rad(2) (1-GHz bandwidth) and a carrier phase-error variance of 7x10(-4) rad(2) in a 15-MHz bandwidth. Carriers...... are generated in the range of 7-14 GHz. The OPLL transmitter has been fully packaged for practical use in field trials. This is the first time this type of transmitter has been fabricated in a packaged state which is a significant advance on the route to practical application....

Quantifying the statistical complexity of low-frequency fluctuations in semiconductor lasers with optical feedback

International Nuclear Information System (INIS)

Tiana-Alsina, J.; Torrent, M. C.; Masoller, C.; Garcia-Ojalvo, J.; Rosso, O. A.

2010-01-01

Low-frequency fluctuations (LFFs) represent a dynamical instability that occurs in semiconductor lasers when they are operated near the lasing threshold and subject to moderate optical feedback. LFFs consist of sudden power dropouts followed by gradual, stepwise recoveries. We analyze experimental time series of intensity dropouts and quantify the complexity of the underlying dynamics employing two tools from information theory, namely, Shannon's entropy and the Martin, Plastino, and Rosso statistical complexity measure. These measures are computed using a method based on ordinal patterns, by which the relative length and ordering of consecutive interdropout intervals (i.e., the time intervals between consecutive intensity dropouts) are analyzed, disregarding the precise timing of the dropouts and the absolute durations of the interdropout intervals. We show that this methodology is suitable for quantifying subtle characteristics of the LFFs, and in particular the transition to fully developed chaos that takes place when the laser's pump current is increased. Our method shows that the statistical complexity of the laser does not increase continuously with the pump current, but levels off before reaching the coherence collapse regime. This behavior coincides with that of the first- and second-order correlations of the interdropout intervals, suggesting that these correlations, and not the chaotic behavior, are what determine the level of complexity of the laser's dynamics. These results hold for two different dynamical regimes, namely, sustained LFFs and coexistence between LFFs and steady-state emission.

Quasi-CW Laser Diode Bar Life Tests

Science.gov (United States)

Stephen, Mark A.; Krainak, Michael A.; Dallas, Joseph L.

1997-01-01

NASA's Goddard Space Flight Center is developing technology for satellite-based, high peak power, LIDAR transmitters requiring 3-5 years of reliable operation. Semi-conductor laser diodes provide high efficiency pumping of solid state lasers with the promise of long-lived, reliable operation. 100-watt quasi- CW laser diode bars have been baselined for the next generation laser altimeters. Multi-billion shot lifetimes are required. The authors have monitored the performance of several diodes for billions of shots and investigated operational modes for improving diode lifetime.

Vortex Laser based on III-V semiconductor metasurface: direct generation of coherent Laguerre-Gauss modes carrying controlled orbital angular momentum.

Science.gov (United States)

Seghilani, Mohamed S; Myara, Mikhael; Sellahi, Mohamed; Legratiet, Luc; Sagnes, Isabelle; Beaudoin, Grégoire; Lalanne, Philippe; Garnache, Arnaud

2016-12-05

The generation of a coherent state, supporting a large photon number, with controlled orbital-angular-momentum L = ħl (of charge l per photon) presents both fundamental and technological challenges: we demonstrate a surface-emitting laser, based on III-V semiconductor technology with an integrated metasurface, generating vortex-like coherent state in the Laguerre-Gauss basis. We use a first order phase perturbation to lift orbital degeneracy of wavefunctions, by introducing a weak anisotropy called here "orbital birefringence", based on a dielectric metasurface. The azimuthal symmetry breakdown and non-linear laser dynamics create "orbital gain dichroism" allowing selecting vortex handedness. This coherent photonic device was characterized and studied, experimentally and theoretically. It exhibits a low divergence (50 dB vortex purity), and single frequency operation in a stable low noise regime (0.1% rms). Such high performance laser opens the path to widespread new photonic applications.

Effective Linewidth of Semiconductor Lasers for Coherent Optical Data Links

DEFF Research Database (Denmark)

Iglesias Olmedo, Miguel; Pang, Xiaodan; Schatz, Richard

2016-01-01

name “Effective Linewidth”. We derive this figure of merit analytically, explore it by numerical simulations and experimentally validate our results by transmitting a 28 Gbaud DP-16QAM over an optical link. Our investigations cover the use of semiconductor lasers both in the transmitter side...... and as a local oscillator at the receiver. The obtained results show that our proposed “effective linewidth” is easy to measure and accounts for frequency noise more accurately, and hence the penalties associated to phase noise in the received signal....

Comprehensive experimental analysis of nonlinear dynamics in an optically-injected semiconductor laser

Directory of Open Access Journals (Sweden)

Kevin Schires

2011-09-01

Full Text Available We present the first comprehensive experimental study, to our knowledge, of the routes between nonlinear dynamics induced in a semiconductor laser under external optical injection based on an analysis of time-averaged measurements of the optical and RF spectra and phasors of real-time series of the laser output. The different means of analysis are compared for several types of routes and the benefits of each are discussed in terms of the identification and mapping of the nonlinear dynamics. Finally, the results are presented in a novel audio/video format that describes the evolution of the dynamics with the injection parameters.

Electroluminescence Analysis by Tilt Polish Technique of InP-Based Semiconductor Lasers

Science.gov (United States)

Ichikawa, Hiroyuki; Sasaki, Kouichi; Hamada, Kotaro; Yamaguchi, Akira

2010-03-01

We developed an effective electroluminescence (EL) analysis method to specify the degraded region of InP-based semiconductor lasers. The EL analysis method is one of the most important methods for failure analysis. However, EL observation was difficult because opaque electrodes surround an active layer. A portion of each electrode had to be left intact for wiring to inject the current. Thus, we developed a partial polish technique for the bottom electrode. Tilt polish equipment with a rotating table was introduced; a flat polished surface and a sufficiently wide remaining portion of the bottom electrode were obtained. As a result, clear EL from the back surface of the laser was observed.

Nanowire Lasers

Directory of Open Access Journals (Sweden)

Couteau C.

2015-05-01

Full Text Available We review principles and trends in the use of semiconductor nanowires as gain media for stimulated emission and lasing. Semiconductor nanowires have recently been widely studied for use in integrated optoelectronic devices, such as light-emitting diodes (LEDs, solar cells, and transistors. Intensive research has also been conducted in the use of nanowires for subwavelength laser systems that take advantage of their quasione- dimensional (1D nature, flexibility in material choice and combination, and intrinsic optoelectronic properties. First, we provide an overview on using quasi-1D nanowire systems to realize subwavelength lasers with efficient, directional, and low-threshold emission. We then describe the state of the art for nanowire lasers in terms of materials, geometry, andwavelength tunability.Next,we present the basics of lasing in semiconductor nanowires, define the key parameters for stimulated emission, and introduce the properties of nanowires. We then review advanced nanowire laser designs from the literature. Finally, we present interesting perspectives for low-threshold nanoscale light sources and optical interconnects. We intend to illustrate the potential of nanolasers inmany applications, such as nanophotonic devices that integrate electronics and photonics for next-generation optoelectronic devices. For instance, these building blocks for nanoscale photonics can be used for data storage and biomedical applications when coupled to on-chip characterization tools. These nanoscale monochromatic laser light sources promise breakthroughs in nanophotonics, as they can operate at room temperature, can potentially be electrically driven, and can yield a better understanding of intrinsic nanomaterial properties and surface-state effects in lowdimensional semiconductor systems.

Rare resource supply crisis and solution technology for semiconductor manufacturing

Science.gov (United States)

Fukuda, Hitomi; Hu, Sophia; Yoo, Youngsun; Takahisa, Kenji; Enami, Tatsuo

2016-03-01

There are growing concerns over future environmental impact and earth resource shortage throughout the world and in many industries. Our semiconductor industry is not excluded. "Green" has become an important topic as production volume become larger and more powerful. Especially, the rare gases are widely used in semiconductor manufacturing because of its inertness and extreme chemical stability. One major component of an Excimer laser system is Neon. It is used as a buffer gas for Argon (Ar) and Krypton (Kr) gases used in deep ultraviolet (DUV) lithography laser systems. Since Neon gas accounting for more than 96% of the laser gas mixture, a fairly large amount of neon gas is consumed to run these DUV lasers. However, due to country's instability both in politics and economics in Ukraine, the main producer of neon gas today, supply reduction has become an issue and is causing increasing concern. This concern is not only based on price increases, but has escalated to the point of supply shortages in 2015. This poses a critical situation for the semiconductor industry, which represents the leading consumer of neon gas in the world. Helium is another noble gas used for Excimer laser operation. It is used as a purge gas for optical component modules to prevent from being damaged by active gases and impurities. Helium has been used in various industries, including for medical equipment, linear motor cars, and semiconductors, and is indispensable for modern life. But consumption of helium in manufacturing has been increased dramatically, and its unstable supply and price rise has been a serious issue today. In this article, recent global supply issue of rare resources, especially Neon gas and Helium gas, and its solution technology to support semiconductor industry will be discussed.

Low-timing-jitter, stretched-pulse passively mode-locked fiber laser with tunable repetition rate and high operation stability

International Nuclear Information System (INIS)

Liu, Yuanshan; Zhang, Jian-Guo; Chen, Guofu; Zhao, Wei; Bai, Jing

2010-01-01

We design a low-timing-jitter, repetition-rate-tunable, stretched-pulse passively mode-locked fiber laser by using a nonlinear amplifying loop mirror (NALM), a semiconductor saturable absorber mirror (SESAM), and a tunable optical delay line in the laser configuration. Low-timing-jitter optical pulses are stably produced when a SESAM and a 0.16 m dispersion compensation fiber are employed in the laser cavity. By inserting a tunable optical delay line between NALM and SESAM, the variable repetition-rate operation of a self-starting, passively mode-locked fiber laser is successfully demonstrated over a range from 49.65 to 50.47 MHz. The experimental results show that the newly designed fiber laser can maintain the mode locking at the pumping power of 160 mW to stably generate periodic optical pulses with width less than 170 fs and timing jitter lower than 75 fs in the 1.55 µm wavelength region, when the fundamental repetition rate of the laser is continuously tuned between 49.65 and 50.47 MHz. Moreover, this fiber laser has a feature of turn-key operation with high repeatability of its fundamental repetition rate in practice

Frequency doubling of an InGaAs multiple quantum wells semiconductor disk laser

Science.gov (United States)

Lidan, Jiang; Renjiang, Zhu; Maohua, Jiang; Dingke, Zhang; Yuting, Cui; Peng, Zhang; Yanrong, Song

2018-01-01

We demonstrate a good beam quality 483 nm blue coherent radiation from a frequency doubled InGaAs multiple quantum wells semiconductor disk laser. The gain chip is consisted of 6 repeats of strain uncompensated InGaAs/GaAs quantum wells and 25 pairs of GaAs/AlAs distributed Bragg reflector. A 4 × 4 × 7 mm3 type I phase-matched BBO nonlinear crystal is used in a V-shaped laser cavity for the second harmonic generation, and 210 mW blue output power is obtained when the absorbed pump power is 3.5 W. The M2 factors of the laser beam in x and y directions are about 1.04 and 1.01, respectively. The output power of the blue laser is limited by the relatively small number of the multiple quantum wells, and higher power can be expected by increasing the number of the multiple quantum wells and improving the heat management of the laser.

Switching waves dynamics in optical bistable cavity-free system at femtosecond laser pulse propagation in semiconductor under light diffraction

Science.gov (United States)

Trofimov, Vyacheslav A.; Egorenkov, Vladimir A.; Loginova, Maria M.

2018-02-01

We consider a propagation of laser pulse in a semiconductor under the conditions of an occurrence of optical bistability, which appears due to a nonlinear absorption of the semiconductor. As a result, the domains of high concentration of free charged particles (electrons and ionized donors) occur if an intensity of the incident optical pulse is greater than certain intensity. As it is well-known, that an optical beam must undergo a diffraction on (or reflection from) the domains boundaries. Usually, the beam diffraction along a coordinate of the optical pulse propagation does not take into account by using the slowly varying envelope approximation for the laser pulse interaction with optical bistable element. Therefore, a reflection of the beam from the domains with abrupt boundary does not take into account under computer simulation of the laser pulse propagation. However, the optical beams, reflected from nonhomogeneities caused by the domains of high concentration of free-charged particles, can essentially influence on a formation of switching waves in a semiconductor. We illustrate this statement by computer simulation results provided on the base of nonlinear Schrödinger equation and a set of PDEs, which describe an evolution of the semiconductor characteristics (concentrations of free-charged particles and potential of an electric field strength), and taking into account the longitudinal and transverse diffraction effects.

Operation of a novel hot-electron vertical-cavity surface-emitting laser

Science.gov (United States)

Balkan, Naci; O'Brien-Davies, Angela; Thoms, A. B.; Potter, Richard J.; Poolton, Nigel; Adams, Michael J.; Masum, J.; Bek, Alpan; Serpenguzel, Ali; Aydinli, Atilla; Roberts, John S.

1998-07-01

The hot Electron Light Emission and Lasing in Semiconductor Heterostructures devices (HELLISH-1) is novel surface emitter consisting of a GaAs quantum well, within the depletion region, on the n side of Ga1-xAlxAs p- n junction. It utilizes hot electron transport parallel to the layers and injection of hot electron hole pairs into the quantum well through a combination of mechanisms including tunnelling, thermionic emission and diffusion of `lucky' carriers. Super Radiant HELLISH-1 is an advanced structure incorporating a lower distributed Bragg reflector (DBR). Combined with the finite reflectivity of the upper semiconductor-air interface reflectivity it defines a quasi- resonant cavity enabling emission output from the top surface with a higher spectral purity. The output power has increased by two orders of magnitude and reduced the full width at half maximum (FWHM) to 20 nm. An upper DBR added to the structure defines HELLISH-VCSEL which is currently the first operational hot electron surface emitting laser and lases at room temperature with a 1.5 nm FWHM. In this work we demonstrate and compare the operation of UB-HELLISH-1 and HELLISH-VCSEL using experimental and theoretical reflectivity spectra over an extensive temperature range.

Advances in semiconductor lasers

CERN Document Server

Coleman, James J; Jagadish, Chennupati

2012-01-01

Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. Originally widely known as the ""Willardson and Beer"" Series, it has succeeded in publishing numerous landmark volumes and chapters. The series publishes timely, highly relevant volumes intended for long-term impact and reflecting the truly interdisciplinary nature of the field. The volumes in Semiconductors and Semimetals have been and will continue to be of great interest to physicists, chemists, materials scientists, and device engineers in academia, scien

Stimulated Brillouin scattering of laser in semiconductor plasma embedded with nano-sized grains

Energy Technology Data Exchange (ETDEWEB)

Sharma, Giriraj, E-mail: grsharma@gmail.com [SRJ Government Girls’ College, Neemuch (M P) (India); Dad, R. C. [Government P G College, Mandsaur (M P) (India); Ghosh, S. [School of Studies in Physics, Vikram University, Ujjain, (M P) (India)

2015-07-31

A high power laser propagating through semiconductor plasma undergoes Stimulated Brillouin scattering (SBS) from the electrostrictively generated acoustic perturbations. We have considered that nano-sized grains (NSGs) ions are embedded in semiconductor plasma by means of ion implantation. The NSGs are bombarded by the surrounding plasma particles and collect electrons. By considering a negative charge on the NSGs, we present an analytically study on the effects of NSGs on threshold field for the onset of SBS and Brillouin gain of generated Brillouin scattered mode. It is found that as the charge on the NSGs builds up, the Brillouin gain is significantly raised and the threshold pump field for the onset of SBS process is lowered.

Single Spatial-Mode Room-Temperature-Operated 3.0 to 3.4 micrometer Diode Lasers

Science.gov (United States)

Frez, Clifford F.; Soibel, Alexander; Belenky, Gregory; Shterengas, Leon; Kipshidze, Gela

2010-01-01

Compact, highly efficient, 3.0 to 3.4 m light emitters are in demand for spectroscopic analysis and identification of chemical substances (including methane and formaldehyde), infrared countermeasures technologies, and development of advanced infrared scene projectors. The need for these light emitters can be currently addressed either by bulky solid-state light emitters with limited power conversion efficiency, or cooled Interband Cascade (IC) semiconductor lasers. Researchers here have developed a breakthrough approach to fabrication of diode mid-IR lasers that have several advantages over IC lasers used for the Mars 2009 mission. This breakthrough is due to a novel design utilizing the strain-engineered quantum-well (QW) active region and quinternary barriers, and due to optimization of device material composition and growth conditions (growth temperatures and rates). However, in their present form, these GaSb-based laser diodes cannot be directly used as a part of sensor systems. The device spectrum is too broad to perform spectroscopic analysis of gas species, and operating currents and voltages are too high. In the current work, the emitters were fabricated as narrow-ridge waveguide index-guided lasers rather than broad stripe-gain guided multimode Fabry-Perot (FP) lasers as was done previously. These narrow-ridge waveguide mid-IR lasers exhibit much lower power consumptions, and can operate in a single spatial mode that is necessary for demonstration of single-mode distributed feedback (DBF) devices for spectroscopic applications. These lasers will enable a new generation of compact, tunable diode laser spectrometers with lower power consumption, reduced complexity, and significantly reduced development costs. These lasers can be used for the detection of HCN, C2H2, methane, and ethane.

Excitonic bistabilities, instabilities and chaos in laser-pumped semiconductor

International Nuclear Information System (INIS)

Nguyen Ba An; Nguyen Trung Dan; Hoang Xuan Nguyen

1992-07-01

The Hurwitz criteria are used for a stability analysis of the steady state excitonic optical bistability curves in a semiconductor pumped by an external laser resonant with the exciton level. Besides the middle branch of the bistability curves which is unstable in the sense of the linear stability theory, we have found other domains of instability in the upper and lower branches of the steady state curves. Numerical results show that a possible route to chaos in the photon-exciton system is period-doubling self-oscillation process. The influence of the presence of free carriers that coexist with the excitons is also discussed. (author). 16 refs, 6 figs

Pump spot size dependent lasing threshold in organic semiconductor DFB lasers fabricated via nanograting transfer.

Science.gov (United States)

Liu, Xin; Klinkhammer, Sönke; Wang, Ziyao; Wienhold, Tobias; Vannahme, Christoph; Jakobs, Peter-Jürgen; Bacher, Andreas; Muslija, Alban; Mappes, Timo; Lemmer, Uli

2013-11-18

Optically excited organic semiconductor distributed feedback (DFB) lasers enable efficient lasing in the visible spectrum. Here, we report on the rapid and parallel fabrication of DFB lasers via transferring a nanograting structure from a flexible mold onto an unstructured film of the organic gain material. This geometrically well-defined structure allows for a systematic investigation of the laser threshold behavior. The laser thresholds for these devices show a strong dependence on the pump spot diameter. This experimental finding is in good qualitative agreement with calculations based on coupled-wave theory. With further investigations on various DFB laser geometries prepared by different routes and based on different organic gain materials, we found that these findings are quite general. This is important for the comparison of threshold values of various devices characterized under different excitation areas.

Pump spot size dependent lasing threshold in organic semiconductor DFB lasers fabricated via nanograting transfer

DEFF Research Database (Denmark)

Liu, Xin; Klinkhammer, Sönke; Wang, Ziyao

2013-01-01

material. This geometrically well-defined structure allows for a systematic investigation of the laser threshold behavior. The laser thresholds for these devices show a strong dependence on the pump spot diameter. This experimental finding is in good qualitative agreement with calculations based on coupled......Optically excited organic semiconductor distributed feedback (DFB) lasers enable efficient lasing in the visible spectrum. Here, we report on the rapid and parallel fabrication of DFB lasers via transferring a nanograting structure from a flexible mold onto an unstructured film of the organic gain......-wave theory. With further investigations on various DFB laser geometries prepared by different routes and based on different organic gain materials, we found that these findings are quite general. This is important for the comparison of threshold values of various devices characterized under different...

QCL seeded, ns-pulse, multi-line, CO2 laser oscillator for laser-produced-plasma extreme-UV source

Science.gov (United States)

Nowak, Krzysztof Michał; Suganuma, Takashi; Kurosawa, Yoshiaki; Ohta, Takeshi; Kawasuji, Yasufumi; Nakarai, Hiroaki; Saitou, Takashi; Fujimoto, Junichi; Mizoguchi, Hakaru; Sumitani, Akira; Endo, Akira

2017-01-01

Successful merger of state-of-the-art, semiconductor quantum-cascade lasers (QCL), with the mature CO2 laser technology, resulted in a delivery of highly-desired qualities of CO2 laser output that were not available previously without much effort. These qualities, such as multi-line operation, excellent spectro-temporal stability and pulse waveform control, became available from a single device of moderate complexity. This paper describes the operation principle and the unique properties of the solid{state seeded CO2 laser, invented for an application in laser-produced-plasma (LPP), extreme-UV (EUV) light source.

Design of pulsed laser diode drive power for ZY3(02) laser altimeter

Science.gov (United States)

Feng, Wen; Li, Mingshan; Meng, Peibei; Yan, Fanjiang; Li, Xu; Wang, Chunhui

2017-11-01

Solid laser pumped by semiconductor laser has the large value in the area of space laser technology, because of the advantages of high efficiency, small volume and long life. As the indispensable component of laser, laser power is also very important. Combined with ZY3(02) laser altimeter project, a high voltage(0-300V), high current(0-80A), long pulse width(0-230us) and high precision temperature semiconductor laser power is developed. IGBT is applied in the driving circuit as the switch to provide a current pulse for LD. The heating or cooling capacity of TEC is controlled by PID compensation circuit quickly adjusts the duty cycle of the UC1637 PWM signal, to realize the high accuracy controlling of LD working temperature. The tests in the external ambient temperature of 5°C, 20°C, 30°C show that the LD current pulse is stable and the stability of LD working temperature up to +/-0.1°C around the set point temperature, which ensure the highly stable operation of DPL.

Field performance of an all-semiconductor laser coherent Doppler lidar

DEFF Research Database (Denmark)

Rodrigo, Peter John; Pedersen, Christian

2012-01-01

We implement and test what, to our knowledge, is the first deployable coherent Doppler lidar (CDL) system based on a compact, inexpensive all-semiconductor laser (SL). To demonstrate the field performance of our SL-CDL remote sensor, we compare a 36 h time series of averaged radial wind speeds...... measured by our instrument at an 80 m distance to those simultaneously obtained from an industry-standard sonic anemometer (SA). An excellent degree of correlation (R2=0.994 and slope=0.996) is achieved from a linear regression analysis of the CDL versus SA wind speed data. The lidar system is capable...

Analysis of timing jitter in external-cavity mode-locked semiconductor lasers

DEFF Research Database (Denmark)

Mulet, Josep; Mørk, Jesper

2006-01-01

We develop a comprehensive theoretical description of passive mode-locking in external-cavity mode-locked semiconductor lasers based on a fully distributed time-domain approach. The model accounts for the dispersion of both gain and refractive index, nonlinear gain saturation from ultrafast...... processes, self-phase modulation, and spontaneous emission noise. Fluctuations of the mode-locked pulses are characterized from the fully distributed model using direct integration of noise-skirts in the phase-noise spectrum and the soliton perturbations introduced by Haus. We implement the model in order...

Freedom from band-gap slavery: from diode lasers to quantum cascade lasers

Science.gov (United States)

Capasso, Federico

2010-02-01

Semiconductor heterostructure lasers, for which Alferov and Kromer received part of the Nobel Prize in Physics in 2000, are the workhorse of technologies such as optical communications, optical recording, supermarket scanners, laser printers and fax machines. They exhibit high performance in the visible and near infrared and rely for their operation on electrons and holes emitting photons across the semiconductor bandgap. This mechanism turns into a curse at longer wavelengths (mid-infrared) because as the bandgap, shrinks laser operation becomes much more sensitive to temperature, material defects and processing. Quantum Cascade Laser (QCL), invented in 1994, rely on a radically different process for light emission. QCLs are unipolar devices in which electrons undergo transitions between quantum well energy levels and are recycled through many stages emitting a cascade of photons. Thus by suitable tailoring of the layers' thickness, using the same heterostructure material, they can lase across the molecular fingerprint region from 3 to 25 microns and beyond into the far-infrared and submillimiter wave spectrum. High power cw room temperature QCLs and QCLs with large continuous single mode tuning range have found many applications (infrared countermeasures, spectroscopy, trace gas analysis and atmospheric chemistry) and are commercially available. )

Stability diagrams for continuous wide-range control of two mutually delay-coupled semiconductor lasers

International Nuclear Information System (INIS)

Junges, Leandro; Gallas, Jason A C

2015-01-01

The dynamics of two mutually delay-coupled semiconductor lasers has been frequently studied experimentally, numerically, and analytically either for weak or strong detuning between the lasers. Here, we present a systematic numerical investigation spanning all detuning ranges. We report high-resolution stability diagrams for wide ranges of the main control parameters of the laser, as described by the Lang–Kobayashi model. In particular, we detail the parameter influence on dynamical performance and map the distribution of chaotic pulsations and self-generated periodic spiking with arbitrary periodicity. Special attention is given to the unfolding of regular pulse packages for both symmetric and non-symmetric configurations with respect to detuning. The influence of the delay –time on the self-organization of periodic and chaotic laser phases as a function of the coupling and detuning is also described in detail. (paper)

Wake fields in semiconductor plasmas

International Nuclear Information System (INIS)

Berezhiani, V.I.; Mahajan, S.M.

1994-05-01

It is shown that an intense short laser pulse propagating through a semiconductor plasma will generated longitudinal Langmuir waves in its wake. The measurable wake field can be used as a diagnostic to study nonlinear optical phenomena. For narrow gap semiconductors (for examples InSb) with Kane-type dispersion relation, the system can simulate, at currently available laser powers, the physics underlying wake-field accelerators. (author). 9 refs, 1 fig

Operating method of amorphous thin film semiconductor element

Energy Technology Data Exchange (ETDEWEB)

Mori, Koshiro; Ono, Masaharu; Hanabusa, Akira; Osawa, Michio; Arita, Takashi

1988-05-31

The existing technologies concerning amorphous thin film semiconductor elements are the technologies concerning the formation of either a thin film transistor or an amorphous Si solar cell on a substrate. In order to drive a thin film transistor for electronic equipment control by the output power of an amorphous Si solar cell, it has been obliged to drive the transistor weth an amorphous solar cell which was formed on a substrate different from that for the transistor. Accordingly, the space for the amorphous solar cell, which was formed on the different substrate, was additionally needed on the substrate for the thin film transistor. In order to solve the above problem, this invention proposes an operating method of an amorphous thin film semiconductor element that after forming an amorphous Si solar cell through lamination on the insulation coating film which covers the thin film transistor formed on the substrate, the thin film transistor is driven by the output power of this solar cell. The invention eliminates the above superfluous space and reduces the size of the amorphous thin film semiconductor element including the electric source. (3 figs)

Pulsed laser deposition of II-VI and III-V semiconductor materials

Energy Technology Data Exchange (ETDEWEB)

Mele, A.; Di Palma, T.M.; Flamini, C.; Giardini Guidoni, A. [Rome, Univ. `La Sapienza` (Italy). Dep. di Chimica

1998-12-01

Pulsed laser irradiation of a solid target involves electronic excitation and heating, followed by expansion from the target of the elliptical gas cloud (plume) which can be eventually condensed on a suitable substrate. Pulsed laser ablation has been found to be a valuable technique to prepare II-VI and III-V thin films of semiconductor materials. Pulsed laser ablation deposition is discussed in the light of the results of an investigation on CdS, CdSe, CdTe and CdSe/CdTe multilayers and AIN, GaN and InN together with Al-Ga-In-N heterostructures. [Italiano] L`irradiazione di un target solido, mediante un fascio laser impulsato, genera una serie di processi che possono essere schematizzati come segue: riscaldamento ed eccitazione elettronica del target, da cui consegue l`espulsione di materiale sotto forma di una nube gassosa di forma ellissoidale (plume), che espande e puo` essere fatta depositare su un opportuno substrato. L`ablazione lasersi e` rivelata una tecnica valida per preparare film sottili di composti di elementi del II-VI e del III-V gruppo della tavola periodica. La deposizione via ablazione laser viene discussa alla luce dei risultati ottenuti nella preparazione di film di CdS, CdSe, CdTe e di film multistrato di CdSe/CdTe, di film di AIN, GaN, InN e di eterostrutture di Al-Ga-In-N.

Optical-feedback semiconductor laser Michelson interferometer for displacement measurements with directional discrimination

International Nuclear Information System (INIS)

Rodrigo, Peter John; Lim, May; Saloma, Caesar

2001-01-01

An optical-feedback semiconductor laser Michelson interferometer (OSMI) is presented for measuring microscopic linear displacements without ambiguity in the direction of motion. The two waves from the interferometer arms, one from the reference mirror and the other from the reflecting moving target, are fed back into the lasing medium (λ=830 nm), causing variations in the laser output power. We model the OSMI into an equivalent Fabry-Perot resonator and derive the dependence of the output power (and the junction voltage) on the path difference between the two interferometer arms. Numerical and experimental results consistently show that the laser output power varies periodically (period, λ/2) with path difference. The output power variation exhibits an asymmetric behavior with the direction of motion, which is used to measure, at subwavelength resolution, the displacement vector (both amplitude and direction) of the moving sample. Two samples are considered in the experiments: (i) a piezoelectric transducer and (ii) an audio speaker

The ATLAS Semiconductor Tracker: operations and performance

CERN Document Server

Pani, P; The ATLAS collaboration

2013-01-01

After more than 3 years of successful operation at 2 the LHC, we report on the operation and performance of the Semi-Conductor Tracker (SCT) functioning in a high luminosity, 4 high radiation environment. The SCT is part of the inner tracking system of the ATLAS 6 experiment at CERN and is constructed of 4088 silicon detector modules for a total of 6.3 million strips. We find 99.3% of the 8 SCT modules are operational, noise occupancy and hit efficiency exceed the design specifications; the alignment is very close to 10 the ideal to allow on-line track reconstruction and invariant mass determination. We will report on the operation and performance 12 of the detector including an overview of the issues encountered. The observables employed to monitor online and offline the 14 quality and the performance of the data acquired by the SCT will be described and discussed.

Degradation of Side-Mode Suppression Ratio in a DFB Laser Integrated With a Semiconductor Optical Amplifier

DEFF Research Database (Denmark)

Champagne, A.; Lestrade, Michel; Camel, Jérôme

2004-01-01

The degradation of the side-mode suppression ratio (SMSR) in a monolithically integrated distributed feedback laser and semiconductor optical amplifier (SOA) cavity is investigated. An expression is derived that gives the degradation of the SMSR in the case of a perfectly antireflection-coated SO...

Tunable and broadband microwave frequency combs based on a semiconductor laser with incoherent optical feedback

International Nuclear Information System (INIS)

Zhao Mao-Rong; Wu Zheng-Mao; Deng Tao; Zhou Zhen-Li; Xia Guang-Qiong

2015-01-01

Based on a semiconductor laser (SL) with incoherent optical feedback, a novel all-optical scheme for generating tunable and broadband microwave frequency combs (MFCs) is proposed and investigated numerically. The results show that, under suitable operation parameters, the SL with incoherent optical feedback can be driven to operate at a regular pulsing state, and the generated MFCs have bandwidths broader than 40 GHz within a 10 dB amplitude variation. For a fixed bias current, the line spacing (or repetition frequency) of the MFCs can be easily tuned by varying the feedback delay time and the feedback strength, and the tuning range of the line spacing increases with the increase in the bias current. The linewidth of the MFCs is sensitive to the variation of the feedback delay time and the feedback strength, and a linewidth of tens of KHz can be achieved through finely adjusting the feedback delay time and the feedback strength. In addition, mappings of amplitude variation, repetition frequency, and linewidth of MFCs in the parameter space of the feedback delay time and the feedback strength are presented. (paper)

Semiconductor quantum-dot lasers and amplifiers

DEFF Research Database (Denmark)

Hvam, Jørn Märcher; Borri, Paola; Ledentsov, N. N.

2002-01-01

-power surface emitting VCSELs. We investigated the ultrafast dynamics of quantum-dot semiconductor optical amplifiers. The dephasing time at room temperature of the ground-state transition in semiconductor quantum dots is around 250 fs in an unbiased amplifier, decreasing to below 50 fs when the amplifier...... is biased to positive net gain. We have further measured gain recovery times in quantum dot amplifiers that are significantly lower than in bulk and quantum-well semiconductor optical amplifiers. This is promising for future demonstration of quantum dot devices with high modulation bandwidth...

Synchronization and bidirectional communication without delay line using strong mutually coupled semiconductor lasers

Science.gov (United States)

Li, Guang-Hui; Wang, An-Bang; Feng, Ye; Wang, Yang

2010-07-01

This paper numerically demonstrates synchronization and bidirectional communication without delay line by using two semiconductor lasers with strong mutual injection in a face-to-face configuration. These results show that both of the two lasers' outputs synchronize with their input chaotic carriers. In addition, simulations demonstrate that this kind of synchronization can be used to realize bidirectional communications without delay line. Further studies indicate that within a small deviation in message amplitudes of two sides (±6%), the message can be extracted with signal-noise-ratio more than 10 dB; and the signal-noise-ratio is extremely sensitive to the message rates mismatch of two sides, which may be used as a key of bidirectional communication.

Synchronization and bidirectional communication without delay line using strong mutually coupled semiconductor lasers

International Nuclear Information System (INIS)

Guang-Hui, Li; An-Bang, Wang; Ye, Feng; Yang, Wang

2010-01-01

This paper numerically demonstrates synchronization and bidirectional communication without delay line by using two semiconductor lasers with strong mutual injection in a face-to-face configuration. These results show that both of the two lasers' outputs synchronize with their input chaotic carriers. In addition, simulations demonstrate that this kind of synchronization can be used to realize bidirectional communications without delay line. Further studies indicate that within a small deviation in message amplitudes of two sides (±6%), the message can be extracted with signal-noise-ratio more than 10 dB; and the signal-noise-ratio is extremely sensitive to the message rates mismatch of two sides, which may be used as a key of bidirectional communication. (general)

Analytical model of ground-state lasing phenomenon in broadband semiconductor quantum dot lasers

Science.gov (United States)

Korenev, Vladimir V.; Savelyev, Artem V.; Zhukov, Alexey E.; Omelchenko, Alexander V.; Maximov, Mikhail V.

2013-05-01

We introduce an analytical approach to the description of broadband lasing spectra of semiconductor quantum dot lasers emitting via ground-state optical transitions of quantum dots. The explicit analytical expressions describing the shape and the width of lasing spectra as well as their temperature and injection current dependences are obtained in the case of low homogeneous broadening. It is shown that in this case these dependences are determined by only two dimensionless parameters, which are the dispersion of the distribution of QDs over the energy normalized to the temperature and loss-to-maximum gain ratio. The possibility of optimization of laser's active region size and structure by using the intentionally introduced disorder is also carefully considered.

Si-Based Germanium Tin Semiconductor Lasers for Optoelectronic Applications

Science.gov (United States)

Al-Kabi, Sattar H. Sweilim

Silicon-based materials and optoelectronic devices are of great interest as they could be monolithically integrated in the current Si complementary metal-oxide-semiconductor (CMOS) processes. The integration of optoelectronic components on the CMOS platform has long been limited due to the unavailability of Si-based laser sources. A Si-based monolithic laser is highly desirable for full integration of Si photonics chip. In this work, Si-based germanium-tin (GeSn) lasers have been demonstrated as direct bandgap group-IV laser sources. This opens a completely new avenue from the traditional III-V integration approach. In this work, the material and optical properties of GeSn alloys were comprehensively studied. The GeSn films were grown on Ge-buffered Si substrates in a reduced pressure chemical vapor deposition system with low-cost SnCl4 and GeH4 precursors. A systematic study was done for thin GeSn films (thickness 400 nm) with Sn composition 5 to 17.5%. The room temperature photoluminescence (PL) spectra were measured that showed a gradual shift of emission peaks towards longer wavelength as Sn composition increases. Strong PL intensity and low defect density indicated high material quality. Moreover, the PL study of n-doped samples showed bandgap narrowing compared to the unintentionally p-doped (boron) thin films with similar Sn compositions. Finally, optically pumped GeSn lasers on Si with broad wavelength coverage from 2 to 3 mum were demonstrated using high-quality GeSn films with Sn compositions up to 17.5%. The achieved maximum Sn composition of 17.5% broke the acknowledged Sn incorporation limit using similar deposition chemistry. The highest lasing temperature was measured at 180 K with an active layer thickness as thin as 270 nm. The unprecedented lasing performance is due to the achievement of high material quality and a robust fabrication process. The results reported in this work show a major advancement towards Si-based electrically pumped mid

TE-TM dynamics in a semiconductor laser subject to polarization-rotated optical feedback

International Nuclear Information System (INIS)

Heil, T.; Uchida, A.; Davis, P.; Aida, T.

2003-01-01

We present a comprehensive experimental characterization of the dynamics of semiconductor lasers subject to polarization-rotated optical feedback. We find oscillatory instabilities appearing for large feedback levels and disappearing at large injection currents, which we classify in contrast to the well-known conventional optical-feedback-induced dynamics. In addition, we compare our experiments to theoretical results of a single-mode model assuming incoherence of the optical feedback, and we identify differences concerning the average power of the laser. Hence, we develop an alternative model accounting for both polarizations, where the emission of the dominant TE mode is injected with delay into the TM mode of the laser. Numerical simulations using this model show good qualitative agreement with our experimental results, correctly reproducing the parameter dependences of the dynamics. Finally, we discuss the application of polarization-rotated-feedback induced instabilities in chaotic carrier communication systems

Photochemistry Aspects of the Laser Pyrolysis Addressing the Preparation of Oxide Semiconductor Photocatalysts

Directory of Open Access Journals (Sweden)

R. Alexandrescu

2008-01-01

Full Text Available The laser pyrolysis is a powerful and a versatile tool for the gas-phase synthesis of nanoparticles. In this paper, some fundamental and applicative characteristics of this technique are outlined and recent results obtained in the preparation of gamma iron oxide (γ-Fe2O3 and titania (TiO2 semiconductor nanostructures are illustrated. Nanosized iron oxide particles (4 to 9 nm diameter values have been directly synthesized by the laser-induced pyrolysis of a mixture containing iron pentacarbonyl/air (as oxidizer/ethylene (as sensitizer. Temperature-dependent Mossbauer spectroscopy shows that mainly maghemite is present in the sample obtained at higher laser power. The use of selected Fe2O3 samples for the preparation of water-dispersed magnetic nanofluids is also discussed. TiO2 nanoparticles comprising a mixture of anatase and rutile phases were synthesized via the laser pyrolysis of TiCl4- (vapors based gas-phase mixtures. High precursor concentration of the oxidizer was found to favor the prevalent anatase phase (about 90% in the titania nanopowders.

Preparation of ZnS semiconductor nanocrystals using pulsed laser ablation in aqueous surfactant solutions

International Nuclear Information System (INIS)

Choi, S-H; Sasaki, T; Shimizu, Y; Yoon, J-W; Nichols, W T; Sung, Y-E; Koshizaki, N

2007-01-01

Cubic ZnS semiconductor nanocrystals with the size of 2 to 5 nm were prepared by pulsed laser ablation in aqueous surfactant solutions of sodium dodecyl sulfate and cetyltrimethylammonium bromide without any further treatments. The obtained suspensions of the nanocrystals have broad photoluminescence emission from 375 to 600 nm. The abundance and emission intensity of the nanocrystals depend on the concentration of the surfactant in solution

Wafer-scale laser pantography: Fabrication of n-metal-oxide-semiconductor transistors and small-scale integrated circuits by direct-write laser-induced pyrolytic reactions

International Nuclear Information System (INIS)

McWilliams, B.M.; Herman, I.P.; Mitlitsky, F.; Hyde, R.A.; Wood, L.L.

1983-01-01

A complete set of processes sufficient for manufacture of n-metal-oxide-semiconductor (n-MOS) transistors by a laser-induced direct-write process has been demonstrated separately, and integrated to yield functional transistors. Gates and interconnects were fabricated of various combinations of n-doped and intrinsic polysilicon, tungsten, and tungsten silicide compounds. Both 0.1-μm and 1-μm-thick gate oxides were micromachined with and without etchant gas, and the exposed p-Si [100] substrate was cleaned and, at times, etched. Diffusion regions were doped by laser-induced pyrolytic decomposition of phosphine followed by laser annealing. Along with the successful manufacture of working n-MOS transistors and a set of elementary digital logic gates, this letter reports the successful use of several laser-induced surface reactions that have not been reported previously

Wavelength switching dynamics of two-colour semiconductor lasers with optical injection and feedback

International Nuclear Information System (INIS)

Osborne, S; Heinricht, P; Brandonisio, N; Amann, A; O’Brien, S

2012-01-01

The wavelength switching dynamics of two-colour semiconductor lasers with optical injection and feedback are presented. These devices incorporate slotted regions etched into the laser ridge waveguide for tailoring the output spectrum. Experimental measurements are presented demonstrating that optical injection in one or both modes of these devices can induce wavelength bistability. Measured switching dynamics with modulated optical injection are shown to be in excellent agreement with numerical simulations based on a simple rate equation model. We also demonstrate experimentally that time-delayed optical feedback can induce wavelength bistability for short external cavity lengths. Numerical simulations indicate that this two-colour optical feedback system can provide fast optical memory functionality based on injected optical pulses without the need for an external holding beam. (paper)

Dynamics of modal power distribution in a multimode semiconductor laser with optical feedback

International Nuclear Information System (INIS)

Buldu, J M; Trull, J; Torrent, M C; GarcIa-Ojalvo, J; Mirasso, Claudio R

2002-01-01

The dynamics of power distribution between longitudinal modes of a multimode semiconductor laser subjected to external optical feedback is experimentally analysed in the low-frequency fluctuation regime. Power dropouts in the total light intensity are invariably accompanied by sudden activations of several longitudinal modes. These activations are seen not to be simultaneous to the dropouts, but to occur after them. The phenomenon is statistically analysed in a systematic way, and the corresponding delay is estimated. (letter to the editor)

Dynamics of modal power distribution in a multimode semiconductor laser with optical feedback

Energy Technology Data Exchange (ETDEWEB)

Buldu, J M [Departament de FIsica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Colom 11, E-08222 Terrassa (Spain); Trull, J [Departament de FIsica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Colom 11, E-08222 Terrassa (Spain); Torrent, M C [Departament de FIsica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Colom 11, E-08222 Terrassa (Spain); GarcIa-Ojalvo, J [Departament de FIsica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Colom 11, E-08222 Terrassa (Spain); Mirasso, Claudio R [Departament de FIsica, Universitat de les Illes Balears, E-07071 Palma de Mallorca (Spain)

2002-02-01

The dynamics of power distribution between longitudinal modes of a multimode semiconductor laser subjected to external optical feedback is experimentally analysed in the low-frequency fluctuation regime. Power dropouts in the total light intensity are invariably accompanied by sudden activations of several longitudinal modes. These activations are seen not to be simultaneous to the dropouts, but to occur after them. The phenomenon is statistically analysed in a systematic way, and the corresponding delay is estimated. (letter to the editor)

Pulsed laser deposition of semiconductor-ITO composite films on electric-field-applied substrates

International Nuclear Information System (INIS)

Narazaki, Aiko; Sato, Tadatake; Kawaguchi, Yoshizo; Niino, Hiroyuki; Yabe, Akira; Sasaki, Takeshi; Koshizaki, Naoto

2002-01-01

The DC electric-field effect on the crystallinity of II-VI semiconductor in composite systems has been investigated for CdS-ITO films fabricated via alternative pulsed laser deposition (PLD) of CdS and indium tin oxide (ITO) on electric-field-applied substrates. The alternative laser ablation was performed under irradiation of ArF excimer laser in mixture gas of helium and oxygen. The application of electric-field facilitated the preferential crystal-growth of CdS in nanometer scale at low pressure, whereas all the films grown without the field were amorphous. There is a large difference in the crystallization between the films grown on field-applied and heated substrates; the latter showed the crystal-growth with random orientations. This difference indicates that the existence of electric-field has an influence on the transformation from amorphous to crystalline phase of CdS. The driving force for the field-induced crystallization is also discussed in the light of the Joule heat

ZnCdMgSe as a Materials Platform for Advanced Photonic Devices: Broadband Quantum Cascade Detectors and Green Semiconductor Disk Lasers

Science.gov (United States)

De Jesus, Joel

The ZnCdMgSe family of II-VI materials has unique and promising characteristics that may be useful in practical applications. For example they can be grown lattice matched to InP substrates with lattice matched bandgaps that span from 2.1 to 3.5 eV, they can be successfully doped n-type, have a large conduction band offset (CBO) with no intervalley scattering present when strained, they have lower average phonon energies, and the InP lattice constant lies in the middle of the ZnSe and CdSe binaries compounds giving room to experiment with tensile and compressive stress. However they have not been studied in detail for use in practical devices. Here we have identified two types of devices that are being currently developed that benefit from the ZnCdMgSe-based material properties. These are the intersubband (ISB) quantum cascade (QC) detectors and optically pumped semiconductor lasers that emit in the visible range. The paucity for semiconductor lasers operating in the green-orange portion of the visible spectrum can be easily overcome with the ZnCdMgSe materials system developed in our research. The non-strain limited, large CBO available allows to expand the operating wavelength of ISB devices providing shorter and longer wavelengths than the currently commercially available devices. This property can also be exploited to develop broadband room temperature operation ISB detectors. The work presented here focused first on using the ZnCdMgSe-based material properties and parameter to understand and predict the interband and intersubband transitions of its heterostructures. We did this by studying an active region of a QC device by contactless electroreflectance, photoluminescence, FTIR transmittance and correlating the measurements to the quantum well structure by transfer matrix modeling. Then we worked on optimizing the ZnCdMgSe material heterostructures quality by studying the effects of growth interruptions on their optical and optoelectronic properties of

Rate equation analysis and non-Hermiticity in coupled semiconductor laser arrays

Science.gov (United States)

Gao, Zihe; Johnson, Matthew T.; Choquette, Kent D.

2018-05-01

Optically coupled semiconductor laser arrays are described by coupled rate equations. The coupled mode equations and carrier densities are included in the analysis, which inherently incorporate the carrier-induced nonlinearities including gain saturation and amplitude-phase coupling. We solve the steady-state coupled rate equations and consider the cavity frequency detuning and the individual laser pump rates as the experimentally controlled variables. We show that the carrier-induced nonlinearities play a critical role in the mode control, and we identify gain contrast induced by cavity frequency detuning as a unique mechanism for mode control. Photon-mediated energy transfer between cavities is also discussed. Parity-time symmetry and exceptional points in this system are studied. Unbroken parity-time symmetry can be achieved by judiciously combining cavity detuning and unequal pump rates, while broken symmetry lies on the boundary of the optical locking region. Exceptional points are identified at the intersection between broken symmetry and unbroken parity-time symmetry.

Ultrafast dynamics of laser-pulse excited semiconductors: non-Markovian quantum kinetic equations with nonequilibrium correlations

Directory of Open Access Journals (Sweden)

V.V.Ignatyuk

2004-01-01

Full Text Available Non-Markovian kinetic equations in the second Born approximation are derived for a two-zone semiconductor excited by a short laser pulse. Both collision dynamics and running nonequilibrium correlations are taken into consideration. The energy balance and relaxation of the system to equilibrium are discussed. Results of numerical solution of the kinetic equations for carriers and phonons are presented.

The 2-6 semiconductor superlattices

Science.gov (United States)

Gunshor, R. L.; Otsuka, N.

1992-12-01

The first operational semiconductor diode lasers were demonstrated in the summer of 1991 independently by two U.S. groups, one at 3M and the other a team effort shared by Purdue and Brown Universities. As a result of the close collaboration between MBE and TEM groups within the grant, the structures for lasing and LED (as well as display device) operation were realized with the lowest defect concentrations ever reported for 2-6 structures grown on GaAs by MBE. The reduction of the dislocation levels resulted from an iterative process where the growth could be modified in response to the TEM analysis. The AFOSR funded interface studies have led to our appreciation of the electrical and microstructural considerations obtaining at 2-6/3-5 heterovalent interfaces. As a result the Purdue/Brown group has had equal success in making laser diodes with substrates of both doping types. The Purdue/Brown collaboration has obtained CW operations at 77 K as well as pulsed operation at room temperature using a Zn(S,Se)-based device configuration emitting in the blue (490 nm at room temperature).

CW and femtosecond operation of a diode-pumped Yb:BaY(2)F(8) laser.

Science.gov (United States)

Galzerano, G; Coluccelli, N; Gatti, D; Di Lieto, A; Tonelli, M; Laporta, P

2010-03-15

We report for the first time on laser action of a diode-pumped Yb:BaY(2)F(8) crystal. Both CW and femtosecond operations have been demonstrated at room-temperature conditions. A maximum output power of 0.56 W, a slope efficiency of 34%, and a tunability range from 1013 to 1067 nm have been obtained in CW regime. Transform-limited pulse trains with a minimum duration of 275 fs, an average power of 40 mW, and a repetition rate of 83 MHz have been achieved in a passive mode-locked regime using a semiconductor saturable absorber mirror.

The ATLAS Semiconductor tracker: operations and performance

CERN Document Server

Pani, P; The ATLAS collaboration

2013-01-01

Tracker After more than 3 years of successful operation at the LHC, we report on the operation and performance of the Semi-Conductor Tracker (SCT) functioning in a high luminosity, high radiation environment. The SCT is part of the ATLAS experiment at CERN and is constructed of 4088 silicon detector modules for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each end of the barrel). The SCT silicon micro-strip sensors are processed in the planar p-in-n technology. The signals are processed in the front-end ABCD3TA ASICs, which use a binary readout architecture. Data is transferred to the off-detector readout electronics via optical fibers. We find 99.3% of the SCT modules are operational, noise occupancy and hit efficiency exceed the design specifications; the alignment is very cl...

THE DETERMINATION OF A CRITICAL VALUE FOR DYNAMIC STABILITY OF SEMICONDUCTOR LASER DIODE WITH EXTERNAL OPTICAL FEEDBACK

Directory of Open Access Journals (Sweden)

Remzi YILDIRIM

1998-01-01

Full Text Available In this study, dynamic stability analysis of semiconductor laser diodes with external optical feedback has been realized. In the analysis the frequency response of the transfer function of laser diode H jw( , the transfer m function of laser diode with external optical feedback TF jw( , and optical feedback transfer function m K jw( obtained from small signal equations has been m accomplished using Nyquist stability analysis in complex domain. The effect of optical feedback on the stability of the system has been introduced and to bring the laser diode to stable condition the working critical boundary range of dampig frequency and reflection power constant (R has been determined. In the study the reflection power has been taken as ( .

Photonic microwave carrier recovery using period-one nonlinear dynamics of semiconductor lasers for OFDM-RoF coherent detection.

Science.gov (United States)

Hung, Yu-Han; Yan, Jhih-Heng; Feng, Kai-Ming; Hwang, Sheng-Kwang

2017-06-15

This study investigates an all-optical scheme based on period-one (P1) nonlinear dynamics of semiconductor lasers, which regenerates the microwave carrier of an orthogonal frequency division multiplexing radio-over-fiber (OFDM-RoF) signal and uses it as a microwave local oscillator for coherent detection. Through the injection locking established between the OFDM-RoF signal and the P1 dynamics, frequency synchronization with highly preserved phase quality is inherently achieved between the recovered microwave carrier and the microwave carrier of the OFDM-RoF signal. A bit-error ratio down to 1.9×10-9 is achieved accordingly using the proposed scheme for coherent detection of a 32-GHz OFDM-RoF signal carrying 4  Gb/s 16-quadrature amplitude modulation data. No electronic microwave generators or electronic phase-locked loops are thus required. The proposed system can be operated up to at least 100 GHz and can be self-adapted to certain changes in the operating microwave frequency.

Observation of modulation speed enhancement, frequency modulation suppression, and phase noise reduction by detuned loading in a coupled-cavity semiconductor laser

OpenAIRE

Vahala, Kerry; Paslaski, Joel; Yariv, Amnon

1985-01-01

Simultaneous direct modulation response enhancement, phase noise (linewidth) reduction, and frequency modulation suppression are produced in a coupled-cavity semiconductor laser by the detuned loading mechanism.

Band Gap Distortion in Semiconductors Strongly Driven by Intense Mid-Infrared Laser Fields

Science.gov (United States)

Kono, J.; Chin, A. H.

2000-03-01

Crystalline solids non-resonantly driven by intense time-periodic electric fields are predicted to exhibit unusual band-gap distortion.(e.g., Y. Yacoby, Phys. Rev. 169, 610 (1968); L.C.M. Miranda, Solid State Commun. 45, 783 (1983); J.Z. Kaminski, Acta Physica Polonica A 83, 495(1993).) Such non-perturbative effects have not been observed to date because of the unavoidable sample damage due to the very high intensity required using conventional lasers ( 1 eV photon energy). Here, we report the first clear evidence of laser-induced bandgap shrinkage in semiconductors under intense mid-infrared (MIR) laser fields. The use of long-wavelength light reduces the required intensity and prohibits strong interband absorption, thereby avoiding the damage problem. The significant sub-bandgap absorption persists only during the existence of the MIR laser pulse, indicating the virtual nature of the effect. We show that this particular example of non-perturbative behavior, known as the dynamical Franz-Keldysh effect, occurs when the effective ponderomotive potential energy is comparable to the photon energy of the applied field. This work was supported by ONR, NSF, JST and NEDO.

Field test of an all-semiconductor laser-based coherent continuous-wave Doppler lidar for wind energy applications

DEFF Research Database (Denmark)

Sjöholm, Mikael; Dellwik, Ebba; Hu, Qi

-produced all-semiconductor laser. The instrument is a coherent continuous-wave lidar with two fixed-focus telescopes for launching laser beams in two different directions. The alternation between the telescopes is achieved by a novel switching technique without any moving parts. Here, we report results from...... signal strength from external atmospheric parameters such as relative humidity and concentrations of atmospheric particles is discussed. This novel lidar instrument design seems to offer a promising low-cost alternative for prevision remote sensing of wind turbine inflow....

Unidirectional ring-laser operation using sum-frequency mixing

DEFF Research Database (Denmark)

Tidemand-Lichtenberg, Peter; Cheng, Haynes Pak Hay; Pedersen, Christian

2010-01-01

A technique enforcing unidirectional operation of ring lasers is proposed and demonstrated. The approach relies on sum-frequency mixing between a single-pass laser and one of the two counterpropagating intracavity fields of the ring laser. Sum-frequency mixing introduces a parametric loss for the...... where lossless second-order nonlinear materials are available. Numerical modeling and experimental demonstration of parametric-induced unidirectional operation of a diode-pumped solid-state 1342 nm cw ring laser are presented.......A technique enforcing unidirectional operation of ring lasers is proposed and demonstrated. The approach relies on sum-frequency mixing between a single-pass laser and one of the two counterpropagating intracavity fields of the ring laser. Sum-frequency mixing introduces a parametric loss...

The dynamics of the laser-induced metal-semiconductor phase transition of samarium sulfide (SmS)

International Nuclear Information System (INIS)

Kaempfer, Tino

2009-01-01

The present thesis is dedicated to the experimental study of the metal-semiconductor phase transition of samarium sulfide (SmS): Temperature- and time-resolved experiments on the characterization of the phase transition of mixed-valence SmS samples (M-SmS) are presented. The measurement of the dynamics of the laser-induced phase transition pursues via time-resolved ultrashort-time microscopy and by X-ray diffraction with sub-picosecond time resolution. The electronic and structural processes, which follow an excitation of M-SmS with infrared femtosecond laser pulses, are physically interpreted on the base of the results obtained in this thesis and model imaginations. [de

Selective injection locking of a multi-mode semiconductor laser to a multi-frequency reference beam

Science.gov (United States)

Pramod, Mysore Srinivas; Yang, Tao; Pandey, Kanhaiya; Giudici, Massimo; Wilkowski, David

2014-07-01

Injection locking is a well known and commonly used method for coherent light amplification. Usually injection locking is obtained on a single-mode laser injected by a single-frequency seeding beam. In this work we show that selective injection locking of a single-frequency may also be achieved on a multi-mode semiconductor laser injected by a multi-frequency seeding beam, if the slave laser provides sufficient frequency filtering. This selective injection locking condition depends critically on the frequency detuning between the free-running slave emission frequency and each injected frequency component. Stable selective injection locking to a set of three seeding components separated by 1.2 GHz is obtained. This system provides an amplification up to 37 dB of each component. This result suggests that, using distinct slave lasers for each frequency line, a set of mutually coherent high-power radiation modes can be tuned in the GHz frequency domain.

Evolution of the Novalux extended cavity surface-emitting semiconductor laser (NECSEL)

Science.gov (United States)

McInerney, John G.

2016-03-01

Novalux Inc was an enterprise founded by Aram Mooradian in 1998 to commercialise a novel electrically pumped vertical extended cavity semiconductor laser platform, initially aiming to produce pump lasers for optical fiber telecommunication networks. Following successful major investment in 2000, the company developed a range of single- and multi-mode 980 nm pump lasers emitting from 100-500 mW with excellent beam quality and efficiency. This rapid development required solution of several significant problems in chip and external cavity design, substrate and DBR mirror optimization, thermal engineering and mode selection. Output coupling to single mode fiber was exceptional. Following the collapse of the long haul telecom market in late 2001, a major reorientation of effort was undertaken, initially to develop compact 60-100 mW hybrid monolithically integrated pumplets for metro/local amplified networks, then to frequency-doubled blue light emitters for biotech, reprographics and general scientific applications. During 2001-3 I worked at Novalux on a career break from University College Cork, first as R&D Director managing a small group tasked with producing new capabilities and product options based on the NECSEL platform, including high power, pulsed and frequency doubled versions, then in 2002 as Director of New Product Realization managing the full engineering team, leading the transition to frequency doubled products.

Strong Exciton-photon Coupling in Semiconductor Microcavities

DEFF Research Database (Denmark)

Jensen, Jacob Riis; Borri, Paola; Hvam, Jørn Märcher

1999-01-01

The basic building block of vertical cavity surface emitting lasers (VCSELs) and high efficiency diodes, is a quantum well embedded in a semiconductor microcavity. The high finesse that may be achieved in such a cavity is utilised to get a low threshold current in the VCSELs and a high directiona......The basic building block of vertical cavity surface emitting lasers (VCSELs) and high efficiency diodes, is a quantum well embedded in a semiconductor microcavity. The high finesse that may be achieved in such a cavity is utilised to get a low threshold current in the VCSELs and a high......-optical switches based on semiconductor microcavities....

Crisis route to chaos in semiconductor lasers subjected to external optical feedback

Science.gov (United States)

Wishon, Michael J.; Locquet, Alexandre; Chang, C. Y.; Choi, D.; Citrin, D. S.

2018-03-01

Semiconductor lasers subjected to optical feedback have been intensively used as archetypical testbeds for high-speed (sub-ns) and high-dimensional nonlinear dynamics. By simultaneously extracting all the dynamical variables, we demonstrate that for larger current, the commonly named "quasiperiodic" route is in fact based on mixed external-cavity solutions that lock the oscillation frequency of the intensity, voltage, and separation in optical frequency through a mechanism involving successive rejections along the unstable manifold of an antimode. We show that chaos emerges from a crisis resulting from the inability to maintain locking as the unstable manifold becomes inaccessible.

Teradiode's high brightness semiconductor lasers

Science.gov (United States)

Huang, Robin K.; Chann, Bien; Burgess, James; Lochman, Bryan; Zhou, Wang; Cruz, Mike; Cook, Rob; Dugmore, Dan; Shattuck, Jeff; Tayebati, Parviz

2016-03-01

TeraDiode is manufacturing multi-kW-class ultra-high brightness fiber-coupled direct diode lasers for industrial applications. A fiber-coupled direct diode laser with a power level of 4,680 W from a 100 μm core diameter, BPP) of 3.5 mm-mrad and is the lowest BPP multi-kW-class direct diode laser yet reported. This laser is suitable for industrial materials processing applications, including sheet metal cutting and welding. This 4-kW fiber-coupled direct diode laser has comparable brightness to that of industrial fiber lasers and CO2 lasers, and is over 10x brighter than state-of-the-art direct diode lasers. We have also demonstrated novel high peak power lasers and high brightness Mid-Infrared Lasers.

Basics of Laser Physics For Students of Science and Engineering

CERN Document Server

Renk, Karl F

2012-01-01

Basics of Laser Physics provides an introductory presentation of the field of all types of lasers. It contains a general description of the laser, a theoretical treatment and a characterization of its operation as it deals with gas, solid state, free-electron and semiconductor lasers and, furthermore, with a few laser related topics. The different subjects are connected to each other by the central principle of the laser, namely, that it is a self-oscillating system. Special emphasis is put on a uniform treatment of gas and solid-state lasers, on the one hand, and semiconductor lasers, on the other hand. The discussions and the treatment of equations are presented in a way that a reader can immediately follow. The book addresses undergraduate and graduate students of science and engineering. Not only should it enable instructors to prepare their lectures, but it can be helpful to students for preparing for an examination.

Multipulse dynamics of a passively mode-locked semiconductor laser with delayed optical feedback

Science.gov (United States)

Jaurigue, Lina; Krauskopf, Bernd; Lüdge, Kathy

2017-11-01

Passively mode-locked semiconductor lasers are compact, inexpensive sources of short light pulses of high repetition rates. In this work, we investigate the dynamics and bifurcations arising in such a device under the influence of time delayed optical feedback. This laser system is modelled by a system of delay differential equations, which includes delay terms associated with the laser cavity and feedback loop. We make use of specialised path continuation software for delay differential equations to analyse the regime of short feedback delays. Specifically, we consider how the dynamics and bifurcations depend on the pump current of the laser, the feedback strength, and the feedback delay time. We show that an important role is played by resonances between the mode-locking frequencies and the feedback delay time. We find feedback-induced harmonic mode locking and show that a mismatch between the fundamental frequency of the laser and that of the feedback cavity can lead to multi-pulse or quasiperiodic dynamics. The quasiperiodic dynamics exhibit a slow modulation, on the time scale of the gain recovery rate, which results from a beating with the frequency introduced in the associated torus bifurcations and leads to gain competition between multiple pulse trains within the laser cavity. Our results also have implications for the case of large feedback delay times, where a complete bifurcation analysis is not practical. Namely, for increasing delay, there is an ever-increasing degree of multistability between mode-locked solutions due to the frequency pulling effect.

Organic semiconductor rubrene thin films deposited by pulsed laser evaporation of solidified solutions

Science.gov (United States)

Majewska, N.; Gazda, M.; Jendrzejewski, R.; Majumdar, S.; Sawczak, M.; Śliwiński, G.

2017-08-01

Organic semiconductor rubrene (C42H28) belongs to most preferred spintronic materials because of the high charge carrier mobility up to 40 cm2(V·s)-1. However, the fabrication of a defect-free, polycrystalline rubrene for spintronic applications represents a difficult task. We report preparation and properties of rubrene thin films deposited by pulsed laser evaporation of solidified solutions. Samples of rubrene dissolved in aromatic solvents toluene, xylene, dichloromethane and 1,1-dichloroethane (0.23-1% wt) were cooled to temperatures in the range of 16.5-163 K and served as targets. The target ablation was provided by a pulsed 1064 nm or 266 nm laser. For films of thickness up to 100 nm deposited on Si, glass and ITO glass substrates, the Raman and AFM data show presence of the mixed crystalline and amorphous rubrene phases. Agglomerates of rubrene crystals are revealed by SEM observation too, and presence of oxide/peroxide (C42H28O2) in the films is concluded from matrix-assisted laser desorption/ionization time-of-flight spectroscopic analysis.

Performance and operation of the semiconductor tracker (SCT)

CERN Document Server

Dervan, P; The ATLAS collaboration

2013-01-01

After more than 3 years of successful operation at the LHC, we report on the operation and performance of the ATLAS Semi-Conductor Tracker (SCT) functioning in a high luminosity, high radiation environment. The SCT is constructed of 4088 silicon detector modules, for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each end of the barrel). The SCT silicon micro-strip sensors are processed in the planar p-in-n technology. The signals are processed in the front-end ABCD3TA ASICs, which use a binary readout architecture. Data is transferred to the off-detector readout electronics via optical fibres. We find 99.3% of the SCT modules are operational and the hit efficiency exceeds the design specifications. We will report on the operation and performance of the detector, including an ove...

Improved performance of high average power semiconductor arrays for applications in diode pumped solid state lasers

International Nuclear Information System (INIS)

Beach, R.; Emanuel, M.; Benett, W.; Freitas, B.; Ciarlo, D.; Carlson, N.; Sutton, S.; Skidmore, J.; Solarz, R.

1994-01-01

The average power performance capability of semiconductor diode laser arrays has improved dramatically over the past several years. These performance improvements, combined with cost reductions pursued by LLNL and others in the fabrication and packaging of diode lasers, have continued to reduce the price per average watt of laser diode radiation. Presently, we are at the point where the manufacturers of commercial high average power solid state laser systems used in material processing applications can now seriously consider the replacement of their flashlamp pumps with laser diode pump sources. Additionally, a low cost technique developed and demonstrated at LLNL for optically conditioning the output radiation of diode laser arrays has enabled a new and scalable average power diode-end-pumping architecture that can be simply implemented in diode pumped solid state laser systems (DPSSL's). This development allows the high average power DPSSL designer to look beyond the Nd ion for the first time. Along with high average power DPSSL's which are appropriate for material processing applications, low and intermediate average power DPSSL's are now realizable at low enough costs to be attractive for use in many medical, electronic, and lithographic applications

The ATLAS semiconductor tracker: operations and performance

CERN Document Server

D'Auria, S; The ATLAS collaboration

2012-01-01

The Semi-Conductor Tracker (SCT) is a silicon strip detector and one of the key precision tracking devices in the Inner Detector of the ATLAS experiment at CERN LHC. The SCT is constructed of 4088 silicon detector modules for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each end of the barrel). The SCT silicon micro-strip sensors are processed in the planar {it p}-in-{it n} technology. The signals are processed in the front-end ASICS ABCD3TA, working in binary readout mode. Data is transferred to the off-detector readout electronics via optical fibres. We find 99.3% of the SCT modules are operational, noise occupancy and hit efficiency exceed the design specifications. In the talk the current results from the successful operation of the SCT Detector at the LHC and its status af...

Study of the spectral width of intermode beats and optical spectrum of an actively mode-locked three-mirror semiconductor laser

International Nuclear Information System (INIS)

Zakharyash, Valerii F; Kashirsky, Aleksandr V; Klementyev, Vasilii M; Kuznetsov, Sergei A; Pivtsov, V S

2005-01-01

Various oscillation regimes of an actively mode-locked semiconductor laser are studied experimentally. Two types of regimes are found in which the minimal spectral width (∼3.5 kHz) of intermode beats is achieved. The width of the optical spectrum of modes is studied as a function of their locking and the feedback coefficients. The maximum width of the spectrum is ∼3.7 THz. (control of laser radiation parameters)

Ultrasensitive detection of cell lysing in an microfabricated semiconductor laser cavity

Energy Technology Data Exchange (ETDEWEB)

Gourley, P.L.; French, T.; McDonald, A.E.; Shields, E.A. [Sandia National Labs., Albuquerque, NM (United States); Gourley, M.F. [Washington Hospital Center, Washington, DC (United States)

1998-01-01

In this paper the authors report investigations of semiconductor laser microcavities for use in detecting changes of human blood cells during lysing. By studying the spectra before and during mixing of blood fluids with de-ionized water, they are able to quantify the cell shape and concentration of hemoglobin in real time during the dynamical process of lysing. The authors find that the spectra can detect subtle changes that are orders of magnitude smaller than can be observed by standard optical microscopy. Such sensitivity in observing cell structural changes has implications for measuring cell fragility, monitoring apoptotic events in real time, development of photosensitizers for photodynamic therapy, and in-vitro cell micromanipulation techniques.

Digital operation and eye diagrams in spin-lasers

International Nuclear Information System (INIS)

Wasner, Evan; Bearden, Sean; Žutić, Igor; Lee, Jeongsu

2015-01-01

Digital operation of lasers with injected spin-polarized carriers provides an improved operation over their conventional counterparts with spin-unpolarized carriers. Such spin-lasers can attain much higher bit rates, crucial for optical communication systems. The overall quality of a digital signal in these two types of lasers is compared using eye diagrams and quantified by improved Q-factors and bit-error-rates in spin-lasers. Surprisingly, an optimal performance of spin-lasers requires finite, not infinite, spin-relaxation times, giving a guidance for the design of future spin-lasers

The ATLAS Semi-Conductor Tracker Operation and Performance

CERN Document Server

Robinson, D; The ATLAS collaboration

2012-01-01

The Semi-Conductor Tracker (SCT), is a silicon strip detector and one of the key precision tracking devices in the Inner Detector of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The SCT was installed and commissioned within ATLAS in 2007, and has been has been used to fully exploit the physics potential of the LHC since the first proton-proton collisions at 7 TeV were delivered in 2009. In this paper, its operational status throughout data taking up to the end of 2011 is presented, and its tracking performance is reviewed.

Improvement in semiconductor laser printing using a sacrificial protecting layer for organic thin-film transistors fabrication

Energy Technology Data Exchange (ETDEWEB)

Rapp, Ludovic, E-mail: rapp@lp3.univ-mrs.fr [Laboratoire LP3 (Lasers, Plasma et Procedes Photoniques) - UMR 6182 CNRS - Universite de la Mediterranee - Campus de Luminy C917, 13288 Marseille Cedex 09 (France); Cibert, Christophe [Laboratoire LP3 (Lasers, Plasma et Procedes Photoniques) - UMR 6182 CNRS - Universite de la Mediterranee - Campus de Luminy C917, 13288 Marseille Cedex 09 (France); Nenon, Sebastien [CINaM (Centre Interdisciplinaire de Nanoscience de Marseille) - UPR 3118 CNRS - Universite Aix Marseille, Case 913, Campus de Luminy, 13288 Marseille Cedex 09 (France); Alloncle, Anne Patricia [Laboratoire LP3 (Lasers, Plasma et Procedes Photoniques) - UMR 6182 CNRS - Universite de la Mediterranee - Campus de Luminy C917, 13288 Marseille Cedex 09 (France); Nagel, Matthias [Empa, Swiss Federal Laboratories for Materials Testing and Reasearch, Laboratory for Functional Polymers, Uberlandstrasse 129, 8600 Duebendorf (Switzerland); Lippert, Thomas [Paul Scherrer Institut, General Energy Research Department, 5232 Villigen PSI (Switzerland); Videlot-Ackermann, Christine; Fages, Frederic [CINaM (Centre Interdisciplinaire de Nanoscience de Marseille) - UPR 3118 CNRS - Universite Aix Marseille, Case 913, Campus de Luminy, 13288 Marseille Cedex 09 (France); Delaporte, Philippe [Laboratoire LP3 (Lasers, Plasma et Procedes Photoniques) - UMR 6182 CNRS - Universite de la Mediterranee - Campus de Luminy C917, 13288 Marseille Cedex 09 (France)

2011-04-01

Laser-induced forward transfer (LIFT) has been used to deposit pixels of an organic semiconductor, distyryl-quaterthiophenes (DS4T). The dynamics of the process have been investigated by shadowgraphic imaging for the nanosecond (ns) and picosecond (ps) regime on a time-scale from the laser iradiation to 1.5 {mu}s. The morphology of the deposit has been studied for different conditions. Intermediate sacrificial layer of gold or triazene polymer has been used to trap the incident radiation. Its role is to protect the layer to be transferred from direct irradiation and to provide a mechanical impulse strong enough to eject the material.

Simulation of the Optimized Structure of a Laterally Coupled Distributed Feedback (LC-DFB Semiconductor Laser Above Threshold

Directory of Open Access Journals (Sweden)

M. Seifouri

2013-10-01

Full Text Available In this paper, the laterally coupled distributed feedback semiconductor laser is studied. In the simulations performed, variations of structural parameters such as the grating amplitude a, the ridge width W, the thickness of the active region d, and other structural properties are considered. It is concluded that for certain values ​​of structural parameters, the laser maintains the highest output power, the lowest distortion Bragg frequency δL and the smallest changes in the wavelength λ. Above threshold, output power more than 40mW and SMSR values greater than 50 dB were achieved.

Performance and operation experience of the Atlas Semiconductor Tracker

CERN Document Server

Liang, Zhijun

2014-01-01

We report on the operation and performance of the ATLAS Semi-Conductor Tracker (SCT), which has been functioning for 3 years in the high luminosity, high radiation environment of the Large Hadron Collider at CERN. Well also report on the few im- provements of the SCT foreseen for the high energy run of the LHC. We find 99.3% of the SCT modules are operational, the noise occupancy and hit efficiency exceed the design specifications; the alignment is very close to the ideal to allow on-line track reconstruc- tion and invariant mass determination. We will report on the operation and performance of the detector including an overview of the issues encountered. We observe a significant increase in leakage currents from bulk damage due to non-ionizing radiation and make comparisons with the predictions.

Semiconductor opto-electronics

CERN Document Server

Moss, TS; Ellis, B

1972-01-01

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

Performance and operation experience of the Atlas Semiconductor Tracker and Pixel Detector at the LHC.

CERN Document Server

Stanecka, E; The ATLAS collaboration

2013-01-01

After more than 3 years of successful operation at the LHC, we report on the operation and performance of the ATLAS Pixel Detector and Semi-Conductor Tracker (SCT) functioning in a high luminosity, high radiation environment.

Frequency-swept laser light source at 1050 nm with higher bandwidth due to multiple semiconductor optical amplifiers in series

DEFF Research Database (Denmark)

Marschall, Sebastian; Thrane, Lars; Andersen, Peter E.

2009-01-01

We report on the development of an all-fiber frequency-swept laser light source in the 1050 nm range based on semiconductor optical amplifiers (SOA) with improved bandwidth due to multiple gain media. It is demonstrated that even two SOAs with nearly equal gain spectra can improve the performance...

Operation and Performance of the ATLAS Semiconductor Tracker

International Nuclear Information System (INIS)

Barlow, Nick

2013-06-01

The ATLAS detector is the largest of the four main particle detectors at the Large Hadron Collider at CERN, Switzerland. A crucial requirement for it to accomplish its physics goals is efficient and precise tracking of charged particles in the region around the point where proton-proton collisions take place. This role is performed by the ATLAS Inner Detector, of which the Semiconductor Tracker (SCT) is a key component. I will briefly describe the design and layout of the SCT, before discussing the commissioning of the detector and its operation over the course of LHC Run 1. (authors)

Operation and Performance of the ATLAS Semiconductor Tracker

CERN Document Server

Barlow, N; The ATLAS collaboration

2013-01-01

The ATLAS detector is the largest of the four main particle detectors at the Large Hadron Collider at CERN, Switzerland. A crucial requirement for it to accomplish its physics goals is efficient and precise tracking of charged particles in the region around the point where proton-proton collisions take place. This role is performed by the ATLAS Inner Detector, of which the Semiconductor Tracker (SCT) is a key component. I will briefly describe the design and layout of the SCT, before discussing the commissioning of the detector and its operation over the course of LHC Run 1.

Continuous anti-Stokes Raman laser operation

International Nuclear Information System (INIS)

Feitisch, A.; Muller, T.; Welling, H.; Wellegehausen, B.

1988-01-01

The anti-Stokes Raman laser (ASRL) process has proved to be a method that works well for frequency upconversion and for the generation of powerful tunable narrowband (pulsed) laser radiation in the UV and VUV spectral range. This conversion process allows large-frequency shifts in single step, high output energies, and high efficiencies. A basic requirement is population inversion on a two-photon transition, where, in general, the upper level of the transition should be metastable. Up to now the ASRL technique has only been demonstrated for the pulsed regime, where the necessary population inversion was generated by photodissociation or inner shell photoionization. These inversion techniques, however, cannot be transferred to cw operation of an ASRL, and, therefore, other inversion techniques have to be developed. Here a novel approach for the creation of the necessary population inversion is proposed, that uses well-known cw gas lasers as the active material for the conversion process. The basic idea is to use either existing two-photon population inversions in a cw laser material or to generate the necessary population inversion by applying a suitable population transfer process to the material. A natural two-photon inversion situation in a laser material is evident whenever a cascade laser can be operated. Cascade laser-based anti-Stokes schemes are possible in a He-Ne laser discharge, and investigations of these schemes are discussed

Laser applications in materials processing

International Nuclear Information System (INIS)

Ready, J.F.

1980-01-01

The seminar focused on laser annealing of semiconductors, laser processing of semiconductor devices and formation of coatings and powders, surface modification with lasers, and specialized laser processing methods. Papers were presented on the theoretical analysis of thermal and mass transport during laser annealing, applications of scanning continuous-wave and pulsed lasers in silicon technology, laser techniques in photovoltaic applications, and the synthesis of ceramic powders from laser-heated gas-phase reactants. Other papers included: reflectance changes of metals during laser irradiation, surface-alloying using high-power continuous lasers, laser growth of silicon ribbon, and commercial laser-shock processes

The Dynamics of Semiconductor Optical Amplifiers – Modeling and Applications

DEFF Research Database (Denmark)

Mørk, Jesper; Nielsen, Mads Lønstrup; Berg, Tommy Winther

2003-01-01

The importance of semiconductor optical amplifiers is discussed. A semiconductor optical amplifier (SOA) is a semiconductor laser with anti-reflection coated facets that amplifies an injected light signal by means of stimulated emission. SOAs have a number of unique properties that open up...

Terahertz-bandwidth coherence measurements of a quantum dash laser in passive and active mode-locking operation.

Science.gov (United States)

Martin, Eamonn; Watts, Regan; Bramerie, Laurent; Shen, Alexandre; Gariah, Harry; Blache, Fabrice; Lelarge, Francois; Barry, Liam

2012-12-01

This research carries out coherence measurements of a 42.7 GHz quantum dash (QDash) semiconductor laser when passively, electrically, and optically mode-locked. Coherence of the spectral lines from the mode-locked laser is determined by examining the radio frequency beat-tone linewidth as the mode spacing is increased up to 1.1 THz. Electric-field measurements of the QDash laser are also presented, from which a comparison between experimental results and accepted theory for coherence in passively mode-locked lasers has been performed.

Janus neodymium glass laser operations manual

International Nuclear Information System (INIS)

Auerbach, J.M.; Holmes, N.C.; Trainor, R.J.

1978-01-01

A manual, prepared to guide personnel in operating and maintaining the Janus glass laser system, is presented. System components are described in detail. Step-by-step procedures are presented for firing the laser and for performing routine maintenance and calibration procedures

Network connectivity enhancement by exploiting all optical multicast in semiconductor ring laser

Science.gov (United States)

Siraj, M.; Memon, M. I.; Shoaib, M.; Alshebeili, S.

2015-03-01

The use of smart phone and tablet applications will provide the troops for executing, controlling and analyzing sophisticated operations with the commanders providing crucial documents directly to troops wherever and whenever needed. Wireless mesh networks (WMNs) is a cutting edge networking technology which is capable of supporting Joint Tactical radio System (JTRS).WMNs are capable of providing the much needed bandwidth for applications like hand held radios and communication for airborne and ground vehicles. Routing management tasks can be efficiently handled through WMNs through a central command control center. As the spectrum space is congested, cognitive radios are a much welcome technology that will provide much needed bandwidth. They can self-configure themselves, can adapt themselves to the user requirement, provide dynamic spectrum access for minimizing interference and also deliver optimal power output. Sometimes in the indoor environment, there are poor signal issues and reduced coverage. In this paper, a solution utilizing (CR WMNs) over optical network is presented by creating nanocells (PCs) inside the indoor environment. The phenomenon of four-wave mixing (FWM) is exploited to generate all-optical multicast using semiconductor ring laser (SRL). As a result same signal is transmitted at different wavelengths. Every PC is assigned a unique wavelength. By using CR technology in conjunction with PC will not only solve network coverage issue but will provide a good bandwidth to the secondary users.

ATLAS SemiConductor Tracker Operation and Performance

CERN Document Server

Tojo, J; The ATLAS collaboration

2011-01-01

The SemiConductor Tracker (SCT), comprising of silicon micro-strip detectors is one of the key precision tracking devices in the ATLAS Inner Detector. ATLAS is one of the experiments at CERN LHC. The completed SCT is in very good shapes with 99.3% of the SCT’s 4088 modules (a total of 6.3 million strips) are operational. The noise occupancy and hit efficiency exceed the design specifications. In the talk the current status of the SCT will be reviewed. We will report on the operation of the detector, its performance and observed problems, with stress on the sensor and electronics performance. In December 2009 the ATLAS experiment at the CERN Large Hadron Collider (LHC) recorded the first proton-proton collisions at a centre-of-mass energy of 900 GeV and this was followed by the unprecedented energy of 7 TeV in March 2010. The Semi- Conductor Tracker (SCT) is the key precision tracking device in ATLAS, made from silicon micro-strip detectors processed in the planar p-in-n technology. The signals from the stri...

Organic semiconductors in a spin

CERN Document Server

Samuel, I

2002-01-01

A little palladium can go a long way in polymer-based light-emitting diodes. Inorganic semiconductors such as silicon and gallium arsenide are essential for countless applications in everyday life, ranging from PCs to CD players. However, while they offer unrivalled computational speed, inorganic semiconductors are also rigid and brittle, which means that they are less suited to applications such as displays and flexible electronics. A completely different class of materials - organic semiconductors - are being developed for these applications. Organic semiconductors have many attractive features: they are easy to make, they can emit visible light, and there is tremendous scope for tailoring their properties to specific applications by changing their chemical structure. Research groups and companies around the world have developed a wide range of organic-semiconductor devices, including transistors, light-emitting diodes (LEDs), solar cells and lasers. (U.K.)

Short pulse generation in a passively mode-locked photonic crystal semiconductor laser

DEFF Research Database (Denmark)

Heuck, Mikkel; Blaaberg, Søren; Mørk, Jesper

2010-01-01

We present a new type of passively mode-locked laser with quantum wells embedded in photonic crystal waveguides operating in the slow light regime, which is capable of emitting sub picosecond pulses with widely controllable properties......We present a new type of passively mode-locked laser with quantum wells embedded in photonic crystal waveguides operating in the slow light regime, which is capable of emitting sub picosecond pulses with widely controllable properties...

Selection of modes in transverse-mode waveguides for semiconductor lasers based on asymmetric heterostructures

International Nuclear Information System (INIS)

Slipchenko, S. O.; Bondarev, A. D.; Vinokurov, D. A.; Nikolaev, D. N.; Fetisova, N. V.; Sokolova, Z. N.; Pikhtin, N. A.; Tarasov, I. S.

2009-01-01

Asymmetric Al 0.3 Ga 0.7 As/GaAs/InGaAs heterostructures with a broadened waveguide produced by the method of MOCVD epitaxy are studied. It is established that the precision shift of the active region to one of the cladding layers ensures the generation of the chosen mode of high order in the transverse broadened waveguide. It is experimentally established that this shift brings about an increase in internal optical losses and a decrease in the internal quantum efficiency of stimulated emission. It is shown experimentally that the shift of the active region to the n-type cladding layer governs the sublinear form of the power-current characteristic for semiconductor lasers; in the case of a shift of the active region towards the p-type cladding layer, the laser diodes demonstrated a linear dependence of optical power on the pump current in the entire range of pump currents.

Low SWaP Semiconductor Laser Transmitter Modules For ASCENDS Mission Applications

Science.gov (United States)

Prasad, Narasimha S.; Rosiewicz, Alex; Coleman, Steven M.

2012-01-01

The National Research Council's (NRC) Decadal Survey (DS) of Earth Science and Applications from Space has identified the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) as an important atmospheric science mission. NASA Langley Research Center, working with its partners, is developing fiber laser architecture based intensity modulated CW laser absorption spectrometer for measuring XCO2 in the 1571 nm spectral band. In support of this measurement, remote sensing of O2 in the 1260 nm spectral band for surface pressure measurements is also being developed. In this paper, we will present recent progress made in the development of advanced transmitter modules for CO2 and O2 sensing. Advanced DFB seed laser modules incorporating low-noise variable laser bias current supply and low-noise variable temperature control circuit have been developed. The 1571 nm modules operate at >80 mW and could be tuned continuously over the wavelength range of 1569-1574nm at a rate of 2 pm/mV. Fine tuning was demonstrated by adjusting the laser drive at a rate of 0.7 pm/mV. Heterodyne linewidth measurements have been performed showing linewidth 200 kHz and frequency jitter 75 MHz. In the case of 1260 nm DFB laser modules, we have shown continuous tuning over a range of 1261.4 - 1262.6 nm by changing chip operating temperature and 1261.0 - 1262.0 nm by changing the laser diode drive level. In addition, we have created a new laser package configuration which has been shown to improve the TEC coefficient of performance by a factor of 5 and improved the overall efficiency of the laser module by a factor of 2.

Gain and Index Dynamics in Semiconductor Lasers

DEFF Research Database (Denmark)

Hvam, Jørn Märcher

Semiconductor optical amplifiers (SOAs) provide ultrafast, i.e. broadband components for optical communication systems. They enter not only as signal generators and amplifiers, but also as nonlinear elements for ultrafast signal processing such as wavelength conversion, switching, and regeneration...... changed character from bulk semiconductor to quantum wells and most recently to quantum dots. By quantum confinement of the carriers, the light-matter interactions can be significantly modified and the optical properties, including dynamics, can be engineered to match the required functionalities...

Electronic structure of semiconductor interfaces

Energy Technology Data Exchange (ETDEWEB)

Herman, F

1983-02-01

The study of semiconductor interfaces is one of the most active and exciting areas of current semiconductor research. Because interfaces play a vital role in modern semiconductor technology (integrated circuits, heterojunction lasers, solar cells, infrared detectors, etc.), there is a strong incentive to understand interface properties at a fundamental level and advance existing technology thereby. At the same time, technological advances such as molecular beam epitaxy have paved the way for the fabrication of semiconductor heterojunctions and superlattices of novel design which exhibit unusual electronic, optical, and magnetic properties and offer unique opportunities for fundamental scientific research. A general perspective on this subject is offered treating such topics as the atomic and electronic structure of semiconductor surfaces and interfaces; oxidation and oxide layers; semiconductor heterojunctions and superlattices; rectifying metal-semiconductor contacts; and interface reactions. Recent progress is emphasized and some future directions are indicated. In addition, the role that large-scale scientific computation has played in furthering our theoretical understanding of semiconductor surfaces and interfaces is discussed. Finally, the nature of theoretical models, and the role they play in describing the physical world is considered.

Electronic structure of semiconductor interfaces

International Nuclear Information System (INIS)

Herman, F.

1983-01-01

The study of semiconductor interfaces is one of the most active and exciting areas of current semiconductor research. Because interfaces play a vital role in modern semiconductor technology (integrated circuits, heterojunction lasers, solar cells, infrared detectors, etc.), there is a strong incentive to understand interface properties at a fundamental level and advance existing technology thereby. At the same time, technological advances such as molecular beam epitaxy have paved the way for the fabrication of semiconductor heterojunctions and superlattices of novel design which exhibit unusual electronic, optical, and magnetic properties and offer unique opportunities for fundamental scientific research. A general perspective on this subject is offered treating such topics as the atomic and electronic structure of semiconductor surfaces and interfaces; oxidation and oxide layers; semiconductor heterojunctions and superlattices; rectifying metal-semiconductor contacts; and interface reactions. Recent progress is emphasized and some future directions are indicated. In addition, the role that large-scale scientific computation has played in furthering our theoretical understanding of semiconductor surfaces and interfaces is discussed. Finally, the nature of theoretical models, and the role they play in describing the physical world is considered. (Author) [pt

Performance and Operation Experience of the ATLAS Semiconductor Tracker

CERN Document Server

Gallop, B J; The ATLAS collaboration

2013-01-01

We report on the operation and performance of the ATLAS Semi-Conductor Tracker (SCT), which has been functioning for 3 years in a high luminosity, high radiation environment. The SCT is constructed of 4088 silicon detector modules, for a total of 6.3 million strips. Each module operates as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel, made of 4 cylinders, and two end-cap systems made of 9 disks. The SCT silicon micro-strip sensors are processed in the planar p-in-n technology. The signals are processed in the front-end ABCD3TA ASICs, which use a binary readout architecture. Data is transferred to the off-detector readout electronics via optical fibres. We find 99.3% of the SCT modules are operational, the noise occupancy and hit efficiency exceed the design specifications; the alignment is very close to the ideal to allow on-line track reconstruction and invariant mass determination. We will report on the operation an...

Performance and Operation Experience of the ATLAS Semiconductor Tracker

CERN Document Server

Gallop, B J

2014-01-01

We report on the operation and performance of the ATLAS Semi-Conductor Tracker (SCT), which has been functioning for 3 years in a high luminosity, high radiation environment. The SCT is constructed of 4088 silicon detector modules, for a total of 6.3 million strips. Each module operates as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel, made of 4 cylinders, and two end-cap systems made of 9 disks. The SCT silicon micro-strip sensors are processed in the planar p-in-n technology. The signals are processed in the front-end ABCD3TA ASICs, which use a binary readout architecture. Data is transferred to the off-detector readout electronics via optical fibres. We find $99.3\\%$ of the SCT modules are operational, the noise occupancy and hit efficiency exceed the design specifications; the alignment is very close to the ideal to allow on-line track reconstruction and invariant mass determination. We will report on the operation...

Precision operation of the Nova laser for fusion experiments

International Nuclear Information System (INIS)

Caird, J.A.; Ehrlich, R.B.; Hermes, G.L.; Landen, O.L.; Laumann, C.W.; Lerche, R.A.; Miller, J.L.; Murray, J.E.; Nielsen, N.D.; Powell, H.T.; Rushford, M.C.; Saunders, R.L.; Thompson, C.E.; VanArsdall, P.J.; Vann, C.S.; Weiland, T.L.

1994-01-01

The operation of a Neodymium glass laser of a special design for fusion experiments is improved by a better pulse synchronization, the gain stabilization, and the laser diagnostics. We used sensor upgrading and antifriction coating of focusing lenses. The pointing accuracy of the Nova laser meets now our goal for precision operation. (AIP) copyright 1994 American Institute of Physics

Pulsed-laser atom-probe field-ion microscopy

International Nuclear Information System (INIS)

Kellogg, G.L.; Tsong, T.T.

1980-01-01

A time-of-flight atom-probe field-ion microscope has been developed which uses nanosecond laser pulses to field evaporate surface species. The ability to operate an atom-probe without using high-voltage pulses is advantageous for several reasons. The spread in energy arising from the desorption of surface species prior to the voltage pulse attaining its maximum amplitude is eliminated, resulting in increased mass resolution. Semiconductor and insulator samples, for which the electrical resistivity is too high to transmit a short-duration voltage pulse, can be examined using pulsed-laser assisted field desorption. Since the electric field at the surface can be significantly smaller, the dissociation of molecular adsorbates by the field can be reduced or eliminated, permitting well-defined studies of surface chemical reactions. In addition to atom-probe operation, pulsed-laser heating of field emitters can be used to study surface diffusion of adatoms and vacancies over a wide range of temperatures. Examples demonstrating each of these advantages are presented, including the first pulsed-laser atom-probe (PLAP) mass spectra for both metals (W, Mo, Rh) and semiconductors (Si). Molecular hydrogen, which desorbs exclusively as atomic hydrogen in the conventional atom probe, is shown to desorb undissociatively in the PLAP. Field-ion microscope observations of the diffusion and dissociation of atomic clusters, the migration of adatoms, and the formation of vacancies resulting from heating with a 7-ns laser pulse are also presented

Controlling the unstable emission of a semiconductor laser subject to conventional optical feedback with a filtered feedback branch.

Science.gov (United States)

Ermakov, I V; Tronciu, V Z; Colet, Pere; Mirasso, Claudio R

2009-05-25

We show the advantages of controlling the unstable dynamics of a semiconductor laser subject to conventional optical feedback by means of a second filtered feedback branch. We give an overview of the analytical solutions of the double cavity feedback and show numerically that the region of stabilization is much larger when using a second branch with filtered feedback than when using a conventional feedback one.

Controlling the unstable emission of a semiconductor laser subject to conventional optical feedback with a filtered feedback branch

OpenAIRE

Ermakov, Ilya; Tronciu, Vasile; Colet, Pere; Mirasso, Claudio R.

2009-01-01

We show the advantages of controlling the unstable dynamics of a semiconductor laser subject to conventional optical feedback by means of a second filtered feedback branch. We give an overview of the analytical solutions of the double cavity feedback and show numerically that the region of stabilization is much larger when using a second branch with filtered feedback than when using a conventional feedback one.

Free electron lasers for 13nm EUV lithography: RF design strategies to minimise investment and operational costs

Science.gov (United States)

Keens, Simon; Rossa, Bernhard; Frei, Marcel

2016-03-01

As the semiconductor industry proceeds to develop ever better sources of extreme ultraviolet (EUV) light for photolithography applications, two distinct technologies have come to prominence: Tin-plasma and free electron laser (FEL) sources. Tin plasma sources have been in development within the industry for many years, and have been widely reported. Meanwhile, FELs represent the most promising alternative to create high power EUV frequencies and, while tin-plasma source development has been ongoing, such lasers have been continuously developed by academic institutions for use in fundamental research programmes in conjunction with universities and national scientific institutions. This paper follows developments in the field of academic FELs, and presents information regarding novel technologies, specifically in the area of RF design strategy, that may be incorporated into future industrial FEL systems for EUV lithography in order to minimize the necessary investment and operational costs. It goes on to try to assess the cost-benefit of an alternate RF design strategy, based upon previous studies.

Continuous-wave lasing in an organic-inorganic lead halide perovskite semiconductor

Science.gov (United States)

Jia, Yufei; Kerner, Ross A.; Grede, Alex J.; Rand, Barry P.; Giebink, Noel C.

2017-12-01

Hybrid organic-inorganic perovskites have emerged as promising gain media for tunable, solution-processed semiconductor lasers. However, continuous-wave operation has not been achieved so far1-3. Here, we demonstrate that optically pumped continuous-wave lasing can be sustained above threshold excitation intensities of 17 kW cm-2 for over an hour in methylammonium lead iodide (MAPbI3) distributed feedback lasers that are maintained below the MAPbI3 tetragonal-to-orthorhombic phase transition temperature of T ≈ 160 K. In contrast with the lasing death phenomenon that occurs for pure tetragonal-phase MAPbI3 at T > 160 K (ref. 4), we find that continuous-wave gain becomes possible at T ≈ 100 K from tetragonal-phase inclusions that are photogenerated by the pump within the normally existing, larger-bandgap orthorhombic host matrix. In this mixed-phase system, the tetragonal inclusions function as carrier recombination sinks that reduce the transparency threshold, in loose analogy to inorganic semiconductor quantum wells, and may serve as a model for engineering improved perovskite gain media.

The danger of semiconductor laser diode radiation to the human eye

International Nuclear Information System (INIS)

Nier, J.

1977-01-01

The UVV 'Laserstrahlen' (laser beam regulation) sets maximum permissible values for radiation exposure that must not be exceeded on the cornea or skin (wavelength range 200 to 1400nm; cornea values: Normal pulsed operation 5 x 10 -7 Ws/cm 2 , continuous operation (>0.1s)5 x 10 -6 W/cm 2 ). Especially laser diodes emitting in the near infrared invite careless handling, of which this paper warns by a detailed illustration of the danger involved and by numerical examples. Data are given on two commercial laser diodes, a continuous operation diode (continuous power 5mW) and a pulse diode (peak pwer 1W, pulse duration 0.2μs), as well as data on aperture angles and geometrical dimensions. Critical cornea and skin distances are distinguished below which the exposure of cornea and skin in the axis of the emission beam is dangerous. For the unfavourable conditions of focussing with a lens (f = 4cm), the following critical cornea distances are obtained: Continuous diode 2.5 km; pulse diode 23.5m. Calculation formulas for special cases are given. (orig.) 891 MG [de

Operator-machine interface at a large laser-fusion facility

International Nuclear Information System (INIS)

Sutton, J.G.; Howell, J.A.

1982-01-01

The operator-machine interface at the Antares Laser Facility provides the operator with a means of controlling the laser system and obtaining operational and performance information. The goal of this interface is to provide an operator with access to the control system in a comfortable way, and to facilitate meeting operational requirements. We describe the philosophy and requirements behind this interface, the hardware used in building it, and the software environment

Ultrafast Degenerate Transient Lens Spectroscopy in Semiconductor Nanosctructures

Directory of Open Access Journals (Sweden)

Leontyev A.V.

2015-01-01

Full Text Available We report the non-resonant excitation and probing of the nonlinear refractive index change in bulk semiconductors and semiconductor quantum dots through degenerate transient lens spectroscopy. The signal oscillates at the center laser field frequency, and the envelope of the former in quantum dots is distinctly different from the one in bulk sample. We discuss the applicability of this technique for polarization state probing in semiconductor media with femtosecond temporal resolution.

Semiconductor Quantum Dash Broadband Emitters: Modeling and Experiments

KAUST Repository

Khan, Mohammed Zahed Mustafa

2013-10-01

Broadband light emitters operation, which covers multiple wavelengths of the electromagnetic spectrum, has been established as an indispensable element to the human kind, continuously advancing the living standard by serving as sources in important multi-disciplinary field applications such as biomedical imaging and sensing, general lighting and internet and mobile phone connectivity. In general, most commercial broadband light sources relies on complex systems for broadband light generation which are bulky, and energy hungry. \\tRecent demonstration of ultra-broadband emission from semiconductor light sources in the form of superluminescent light emitting diodes (SLDs) has paved way in realization of broadband emitters on a completely novel platform, which offered compactness, cost effectiveness, and comparatively energy efficient, and are already serving as a key component in medical imaging systems. The low power-bandwidth product is inherent in SLDs operating in the amplified spontaneous emission regime. A quantum leap in the advancement of broadband emitters, in which high power and large bandwidth (in tens of nm) are in demand. Recently, the birth of a new class of broadband semiconductor laser diode (LDs) producing multiple wavelength light in stimulated emission regime was demonstrated. This very recent manifestation of a high power-bandwidth-product semiconductor broadband LDs relies on interband optical transitions via quantum confined dot/dash nanostructures and exploiting the natural inhomogeneity of the self-assembled growth technology. This concept is highly interesting and extending the broad spectrum of stimulated emission by novel device design forms the central focus of this dissertation. \\tIn this work, a simple rate equation numerical technique for modeling InAs/InP quantum dash laser incorporating the properties of inhomogeneous broadening effect on lasing spectra was developed and discussed, followed by a comprehensive experimental analysis

Materials and Reliability Handbook for Semiconductor Optical and Electron Devices

CERN Document Server

Pearton, Stephen

2013-01-01

Materials and Reliability Handbook for Semiconductor Optical and Electron Devices provides comprehensive coverage of reliability procedures and approaches for electron and photonic devices. These include lasers and high speed electronics used in cell phones, satellites, data transmission systems and displays. Lifetime predictions for compound semiconductor devices are notoriously inaccurate due to the absence of standard protocols. Manufacturers have relied on extrapolation back to room temperature of accelerated testing at elevated temperature. This technique fails for scaled, high current density devices. Device failure is driven by electric field or current mechanisms or low activation energy processes that are masked by other mechanisms at high temperature. The Handbook addresses reliability engineering for III-V devices, including materials and electrical characterization, reliability testing, and electronic characterization. These are used to develop new simulation technologies for device operation and ...

ABC-model analysis of gain-switched pulse characteristics in low-dimensional semiconductor lasers

Science.gov (United States)

Bao, Xumin; Liu, Yuejun; Weng, Guoen; Hu, Xiaobo; Chen, Shaoqiang

2018-01-01

The gain-switching dynamics of low-dimensional semiconductor lasers is simulated numerically by using a two-dimensional rate-equation model. Use is also made of the ABC model, where the carrier recombination rate is described by a function of carrier densities including Shockley - Read - Hall (SRH) recombination coefficient A, spontaneous emission coefficient B and Auger recombination coefficient C. Effects of the ABC parameters on the ultrafast gain-switched pulse characteristics with high-density pulse excitation are analysed. It is found that while the parameter A has almost no obvious effects, the parameters B and C have distinctly different effects: B influences significantly the delay time of the gain-switched pulse, while C affects mainly the pulse intensity.

Semiconductors and semimetals epitaxial microstructures

CERN Document Server

Willardson, Robert K; Beer, Albert C; Gossard, Arthur C

1994-01-01

Newly developed semiconductor microstructures can now guide light and electrons resulting in important consequences for state-of-the-art electronic and photonic devices. This volume introduces a new generation of epitaxial microstructures. Special emphasis has been given to atomic control during growth and the interrelationship between the atomic arrangements and the properties of the structures.Key Features* Atomic-level control of semiconductor microstructures* Molecular beam epitaxy, metal-organic chemical vapor deposition* Quantum wells and quantum wires* Lasers, photon(IR)detectors, heterostructure transistors

A novel image encryption algorithm based on synchronized random bit generated in cascade-coupled chaotic semiconductor ring lasers

Science.gov (United States)

Li, Jiafu; Xiang, Shuiying; Wang, Haoning; Gong, Junkai; Wen, Aijun

2018-03-01

In this paper, a novel image encryption algorithm based on synchronization of physical random bit generated in a cascade-coupled semiconductor ring lasers (CCSRL) system is proposed, and the security analysis is performed. In both transmitter and receiver parts, the CCSRL system is a master-slave configuration consisting of a master semiconductor ring laser (M-SRL) with cross-feedback and a solitary SRL (S-SRL). The proposed image encryption algorithm includes image preprocessing based on conventional chaotic maps, pixel confusion based on control matrix extracted from physical random bit, and pixel diffusion based on random bit stream extracted from physical random bit. Firstly, the preprocessing method is used to eliminate the correlation between adjacent pixels. Secondly, physical random bit with verified randomness is generated based on chaos in the CCSRL system, and is used to simultaneously generate the control matrix and random bit stream. Finally, the control matrix and random bit stream are used for the encryption algorithm in order to change the position and the values of pixels, respectively. Simulation results and security analysis demonstrate that the proposed algorithm is effective and able to resist various typical attacks, and thus is an excellent candidate for secure image communication application.

Use of a reflective semiconductor optical amplifier and dual-ring architecture design to produce a stable multi-wavelength fiber laser

International Nuclear Information System (INIS)

Yeh, Chien-Hung; Chow, Chi-Wai; Lu, Shao-Sheng

2014-01-01

In this work, we propose and demonstrate a multi-wavelength laser source produced by utilizing a C-band reflective semiconductor optical amplifier (RSOA) with a dual-ring fiber cavity. Here, the laser cavity consists of an RSOA, a 1 × 2 optical coupler, a 2 × 2 optical coupler and a polarization controller. As a result, thirteen to eighteen wavelengths around the L band could be generated simultaneously when the bias current of the C-band RSOA was driven at 30–70 mA. In addition, the output stabilities of the power and wavelength are also discussed. (paper)

Use of a reflective semiconductor optical amplifier and dual-ring architecture design to produce a stable multi-wavelength fiber laser

Science.gov (United States)

Yeh, Chien-Hung; Chow, Chi-Wai; Lu, Shao-Sheng

2014-05-01

In this work, we propose and demonstrate a multi-wavelength laser source produced by utilizing a C-band reflective semiconductor optical amplifier (RSOA) with a dual-ring fiber cavity. Here, the laser cavity consists of an RSOA, a 1 × 2 optical coupler, a 2 × 2 optical coupler and a polarization controller. As a result, thirteen to eighteen wavelengths around the L band could be generated simultaneously when the bias current of the C-band RSOA was driven at 30-70 mA. In addition, the output stabilities of the power and wavelength are also discussed.

Narrow-band modulation of semiconductor lasers at millimeter wave frequencies (7100 GHz) by mode locking

International Nuclear Information System (INIS)

Lau, K.Y.

1990-01-01

This paper reports on the possibility of mode locking a semiconductor laser at millimeter wave frequencies approaching and beyond 100 GHz which was investigated theoretically and experimentally. It is found that there are no fundamental theoretical limitations in mode locking at frequencies below 100 GHz. AT these high frequencies, only a few modes are locked and the output usually takes the form of a deep sinusoidal modulation which is synchronized in phase with the externally applied modulation at the intermodal heat frequency. This can be regarded for practical purposes as a highly efficient means of directly modulating an optical carrier over a narrow band at millimeter wave frequencies. Both active and passive mode locking are theoretically possible. Experimentally, predictions on active mode locking have been verified in prior publications up to 40 GHz. For passive mode locking, evidence consistent with passive mode locking was observed in an inhomogeneously pumped GaAIAs laser at a frequency of approximately 70 GHz. A large differential gain-absorption ratio such as that present in an inhomogeneously pumped single quantum well laser is necessary for pushing the passive mode-locking frequency beyond 100 GHz

Nitride semiconductor devices fundamentals and applications

CERN Document Server

Morkoç, Hadis

2013-01-01

This book gives a clear presentation of the necessary basics of semiconductor and device physics and engineering. It introduces readers to fundamental issues that will enable them to follow the latest technological research. It also covers important applications, including LED and lighting, semiconductor lasers, high power switching devices, and detectors. This balanced and up-to-date treatment makes the text an essential educational tool for both advanced students and professionals in the electronics industry.

High-power subnanosecond operation of a bistable optically controlled semiconductor switch (BOSS)

International Nuclear Information System (INIS)

Stoudt, D.C.; Richardson, M.A.; Demske, D.L.; Roush, R.A.; Eure, K.W.

1994-01-01

Recent high-power, subnanosecond-switching results of the Bistable Optically controlled Semiconductor Switch (BOSS) are presented. The process of persistent photoconductivity followed by photo-quenching have been demonstrated at megawatt power levels in copper-compensated, silicon-doped, semi-insulating gallium arsenide. These processes allow a switch to be developed that can be closed by the application of one laser pulse and opened by the application of a second laser pulse with a wavelength equal to twice that of the first laser. Switch closure is primarily achieved by elevating electrons from a deep copper center which has been diffused into the material. The opening phase is a two-step process which relies initially on the absorption of the 2-μm laser causing electrons to be elevated from the valance band back into the copper center, and finally on the recombination of electrons in the conduction band with boles in the valance band. The second step requires a sufficient concentration of recombination centers (RC) in the material for opening to occur in the subnanosecond regime. These RC's are generated in the bulk GaAs material by fast-neutron irradiation (∼ 1 MeV) at a fluence of about 3 x 10 15 cm -2 . High-power switching results which demonstrate that the BOSS switch can be opened in the subnanosecond regime are presented for the first time. Neutron-irradiated BOSS devices have been opened against a rising electric field of about 20 kV/cm (10 kV) in a time less than one nanosecond. Kilovolt electrical pulses have been generated with a FWHM of roughly 250 picoseconds

Laser Raman and resonance Raman spectroscopies of natural semiconductor mineral cinnabar, α-HgS, from various mines

International Nuclear Information System (INIS)

Gotoshia, Sergo V; Gotoshia, Lamara V

2008-01-01

Natural minerals α-HgS from various mines have been studied by laser Raman spectroscopy and resonance Raman spectroscopy. The crystals differ from each other in the content of selenium impurity, included in samples from some mines. Based on the Raman spectra and the factor-group analysis the classification of the first order phonons and then the comparison of the results with the results from other works were carried out. The Raman spectra analysis of minerals from various mines show the selenium impurity gap vibration at 203 cm -1 and 226 cm -1 frequencies, respectively. On the basis of statistical measurements of the Raman spectra one can conclude that impurity frequencies of α-HgS may be generally used for the identification of the mine. Resonance Raman scattering for pure minerals has been studied by a dye laser. Phonon resonance in the indirect semiconductor α-HgS is found to be far more intense than the indirect resonance detected until now in various semiconductors in the proximity of the first indirect band E g , for instance, in GaP. In our opinion, this may be conditioned by cinnabar band structure peculiarities. Low resonance has also been fixed in 'dirty' minerals at the spectral band frequency of 203 cm -1 characterizing gap vibration of isomorphic impurity Se in cinnabar

Performance and operation experience of the Atlas Semiconductor Tracker

CERN Document Server

Liang, Z; The ATLAS collaboration

2013-01-01

We report on the operation and performance of the ATLAS Semi-Conductor Tracker (SCT), which has been functioning for 3 years in the high luminosity, high radiation environment of the Large Hadron Collider at CERN. We’ll also report on the few improvements of the SCT foreseen for the high energy run of the LHC. The SCT is constructed of 4088 silicon detector modules, for a total of 6.3 million strips. Each module operates as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel, made of 4 cylinders, and two end-cap systems made of 9 disks. The SCT silicon micro-strip sensors are processed in the planar p-in-n technology. The signals are processed in the front-end ABCD3TA ASICs, which use a binary readout architecture. Data is transferred to the off-detector readout electronics via optical fibres. We find 99.3% of the SCT modules are operational, the noise occupancy and hit efficiency exceed the design specifications; the alig...

Multi-user bidirectional communication using isochronal synchronisation of array of chaotic directly modulated semiconductor lasers

International Nuclear Information System (INIS)

Krishna, Bindu M.; John, Manu P.; Nandakumaran, V.M.

2010-01-01

Isochronal synchronisation between the elements of an array of three mutually coupled directly modulated semiconductor lasers is utilized for the purpose of simultaneous bidirectional secure communication. Chaotic synchronisation is achieved by adding the coupling signal to the self feedback signal provided to each element of the array. A symmetric coupling is effective in inducing synchronisation between the elements of the array. This coupling scheme provides a direct link between every pair of elements thus making the method suitable for simultaneous bidirectional communication between them. Both analog and digital messages are successfully encrypted and decrypted simultaneously by each element of the array.

Growth and characterization of ZnCdMgSe-based green light emitters and distributed Bragg reflectors towards II-VI based semiconductor disk lasers

International Nuclear Information System (INIS)

De Jesus, Joel; Gayen, Swapan K.; Garcia, Thor A.; Tamargo, Maria C.; Kartazaev, Vladimir; Jones, Brynmor E.; Schlosser, Peter J.; Hastie, Jennifer E.

2015-01-01

We report the structural and optical properties of molecular beam epitaxy grown II-VI semiconductor multiple quantum well (MQW) structures and distributed Bragg reflector (DBR) on InP substrates for application in developing optically-pumped semiconductor disk lasers (SDLs) operating in the green spectral range. One sample was grown directly on an InP substrate with an InGaAs buffer layer, while another had a 5-period ZnCdMgSe-based DBR grown on the InGaAs/InP substrate. X-ray diffraction and scanning electron microscopy measurements revealed sharp superlattice peaks and abrupt layer interfaces, while steady-state photoluminescence measurements demonstrated surface emission between 540-570 nm. Under pulsed excitation both samples exhibited features of amplified spontaneous emission (ASE) or stimulated emission, accompanied by luminescence lifetime shortening. The sample with the DBR showed higher surface luminescence and the onset of ASE at lower pump power. To further explore the design and performance of a ZnCdMgSe-based DBR, a 20-period DBR was grown and a reflectivity of 83% was obtained at ∝560 nm. We estimate that a DBR with ∝40 periods would be needed for optimal performance in a SDL using these materials. These results show the potential of II-VI MQW structures on InP substrates for the development of SDLs operational in the green-yellow wavelength range. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Function analysis of working integrated circuit with scanning laser microscope. Laser kenbikyo ni yoru IC no dosa kansatsu

Energy Technology Data Exchange (ETDEWEB)

Ode, T. (Lasertec Corp., Kanagawa (Japan))

1992-10-20

By scanning a laser light, the reaction of a specimen against the light is detected in some means. The optical effect can be visualized by displaying that on the CRT or the like in synchronism with the scanning. Among these, an image formed and visualized by internal photoelectric effect by light is called OBIC image, and chiefly used for evaluating and analyzing semiconductor devices. Observing this OBIC image by a high speed scanning laser microscope has been spotlighted these days as an effective means for observing the state of p-n junction of an IC in operation. This paper descries the principle, the observing method, the detecting circuit, etc. of the semiconductor observing method using a laser microscope. Further, actual examples of detecting defects of an IC by means of OBIC image are shown. As for the problem, since leak parts are displayed as negative contrast in the OBIC image to affect finding work of leak part, the necessity of improvement is pointed out. 39 refs., 11 figs.

The first picosecond terawatt CO2 laser at the Brookhaven Accelerator Test Facility

International Nuclear Information System (INIS)

Pogorelsky, I.V.; Ben-Zvi, I.; Babzien, M.

1998-02-01

The first terawatt picosecond CO 2 laser will be brought to operation at the Brookhaven Accelerator Test Facility in 1998. System consists of a single-mode TEA oscillator, picosecond semiconductor optical switch, multi-atmosphere. The authors report on design, simulation, and performance tests of the 10 atm final amplifier that allows for direct multi-joule energy extraction in a picosecond laser pulse

Proceedings of the IEEE laser and electro-optics society annual meeting

International Nuclear Information System (INIS)

Hudson, M.J.B.; Raney, H.; Raney, D.; Spalaris, C.N.

1990-01-01

This book is covered under the following headings: Electro-optic systems; Emerging laser technology; Optical sensors and measurements; Optoelectronics; Semiconductor diode lasers; Solid state lasers; UV and short wavelength; Applied optical diagnostics of semiconductor materials and devices symposium and optical sensors and measurements; and Applied optical diagnostics of semiconductor materials and devices symposium

Beat-wave generation of plasmons in semiconductor plasmas

International Nuclear Information System (INIS)

Berezhiani, V.I.; Mahajan, S.M.

1995-08-01

It is shown that in semiconductor plasmas, it is possible to generate large amplitude plasma waves by the beating of two laser beams with frequency difference close to the plasma frequency. For narrow gap semiconductor (for example n-type InSb), the system can simulate the physics underlying beat wave generation in relativistic gaseous plasmas. (author). 7 refs

Analysis of small-signal intensity modulation of semiconductor ...

Indian Academy of Sciences (India)

This paper demonstrates theoretical characterization of intensity modulation of semiconductor lasers (SL's). The study is based on a small-signal model to solve the laser rate equations taking into account suppression of optical gain. Analytical forms of the small-signal modulation response and modulation bandwidth are ...

Time-resolved photoluminescence spectroscopy of semiconductors for optical applications beyond the visible spectral range

Energy Technology Data Exchange (ETDEWEB)

Chernikov, Alexey A.

2011-07-01

the impact of Coulomb-correlations on the carrier-phonon scattering. The experiments presented in chapter 5 deal with the characterization of recently synthesizedmaterial systems: ZnO/(ZnMg)O heterostructures, GaN quantum wires (QWires), as well as (GaAs)Bi quantum wells (QWs). TRPL spectroscopy is applied to gain insight as well as a better understanding of the respective carrier relaxation and recombination processes crucial for the device operation. The aim of the studies is the systematic investigation of carrier dynamics influenced by disorder. The measurements are supported by kinetic Monte- Carlo simulations, providing a quantitative analysis of carrier localization effects. In chapter 6, optimization and characterization studies of semiconductor lasers, based on the well-studied (GaIn)As material system designed for NIR applications, are performed. The device under investigation is the so-called vertical-external-cavity surface emitting laser (VECSEL). The experiments focus on the study of the thermal properties of a high-power VECSEL. The distribution and removal of the excess heat as well as the optimization of the laser for increased performance are addressed applying different heat-spreading and heat-transfer approaches. Based on these investigations, the possibility for power-scaling is evaluated and the underlying restrictions are analyzed. The latter investigations are performed applying spatially-resolved PL spectroscopy. An experimental setup is designed for monitoring the spatial distribution of heat in the semiconductor structure during laser operation.

Advanced materials for the optical delay line of frequency pulse modulator on the basis of semiconductor laser

International Nuclear Information System (INIS)

Abrarov, S.M.

1999-01-01

In the paper some materials which can be sued as an optical delay line of the pulse frequency modulator are considered. The structure and the principle are described as a modulator consisting of a laser diode with two Fabry Perot resonators and an optical wave guide providing a feedback loop. The optical wave guide fulfills the function of delay line and links the two resonators. The pulse sequence of the radiation of the semiconductor laser arises due to failure and recovery of optical generation. The pulse frequency modulation can be carried out by the action of electrical tension field on the electro optic martial of the wave guide. The selection of three electro-optic crystals for making of the optical wave guide of the considered modulator is justified. (author)

Diode-pumped mode-locked femtosecond Tm:CLNGG disordered crystal laser.

Science.gov (United States)

Ma, J; Xie, G Q; Gao, W L; Yuan, P; Qian, L J; Yu, H H; Zhang, H J; Wang, J Y

2012-04-15

A diode-end-pumped passively mode-locked femtosecond Tm-doped calcium lithium niobium gallium garnet (Tm:CLNGG) disordered crystal laser was demonstrated for the first time to our knowledge. With a 790 nm laser diode pumping, stable CW mode-locking operation was obtained by using a semiconductor saturable absorber mirror. The disordered crystal laser generated mode-locked pulses as short as 479 fs, with an average output power of 288 mW, and repetition rate of 99 MHz in 2 μm spectral region. © 2012 Optical Society of America

Performance and operation experience of the ATLAS SemiConductor Tracker

CERN Document Server

Robichaud Veronneau, A; The ATLAS collaboration

2014-01-01

After more than 3 years of successful operation at the LHC, we report on the operation and performance of the SemiConductor Tracker (SCT) functioning in a high luminosity, high radiation environment. The SCT is part of the ATLAS experiment at CERN and is constructed of 4088 silicon detector modules for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each end of the barrel). The SCT silicon micro-strip sensors were produced in the planar p-in-n technology. The signals are processed in the front-end ABCD3TA ASICs, which use a binary readout architecture. Data is transferred to the off-detector readout electronics via optical fibers. We find 99.3% of the SCT modules are operational, noise occupancy and hit efficiency exceed the design specifications; the alignment is very close to th...

Semiconductor Physical Electronics

CERN Document Server

Li, Sheng

2006-01-01

Semiconductor Physical Electronics, Second Edition, provides comprehensive coverage of fundamental semiconductor physics that is essential to an understanding of the physical and operational principles of a wide variety of semiconductor electronic and optoelectronic devices. This text presents a unified and balanced treatment of the physics, characterization, and applications of semiconductor materials and devices for physicists and material scientists who need further exposure to semiconductor and photonic devices, and for device engineers who need additional background on the underlying physical principles. This updated and revised second edition reflects advances in semicondutor technologies over the past decade, including many new semiconductor devices that have emerged and entered into the marketplace. It is suitable for graduate students in electrical engineering, materials science, physics, and chemical engineering, and as a general reference for processing and device engineers working in the semicondi...

Scanning electron microscopy of semiconductor materials

International Nuclear Information System (INIS)

Bresse, J.F.; Dupuy, M.

1978-01-01

The use of scanning electron microscopy in semiconductors opens up a large field of use. The operating modes lending themselves to the study of semiconductors are the induced current, cathodoluminescence and the use of the potential contrast which can also be applied very effectively to the study of the devices (planar in particular). However, a thorough knowledge of the mechanisms of the penetration of electrons, generation and recombination of generated carriers in a semiconductor is necessary in order to attain a better understanding of the operating modes peculiar to semiconductors [fr

Semiconductor laser joint study program with Rome Laboratory

Science.gov (United States)

Schaff, William J.; Okeefe, Sean S.; Eastman, Lester F.

1994-09-01

A program to jointly study vertical-cavity surface emitting lasers (VCSEL) for high speed vertical optical interconnects (VOI) has been conducted under an ES&E between Rome Laboratory and Cornell University. Lasers were designed, grown, and fabricated at Cornell University. A VCSEL measurement laboratory has been designed, built, and utilized at Rome Laboratory. High quality VCSEL material was grown and characterized by fabricating conventional lateral cavity lasers that emitted at the design wavelength of 1.04 microns. The VCSEL's emit at 1.06 microns. Threshold currents of 16 mA at 4.8 volts were obtained for 30 microns diameter devices. Output powers of 5 mW were measured. This is 500 times higher power than from the light emitting diodes employed previously for vertical optical interconnects. A new form of compositional grading using a cosinusoidal function has been developed and is very successful for reducing diode series resistance for high speed interconnection applications. A flip-chip diamond package compatible with high speed operation of 16 VCSEL elements has been designed and characterized. A flip-chip device binding effort at Rome Laboratory was also designed and initiated. This report presents details of the one-year effort, including process recipes and results.

Energy levels and far-infrared optical absorption of impurity doped semiconductor nanorings: Intense laser and electric fields effects

Energy Technology Data Exchange (ETDEWEB)

Barseghyan, M.G., E-mail: mbarsegh@ysu.am

2016-11-10

Highlights: • The electron-impurity interaction on energy levels in nanoring have been investigated. • The electron-impurity interaction on far-infrared absorption have been investigated. • The energy levels are more stable for higher values of electric field. - Abstract: The effects of electron-impurity interaction on energy levels and far-infrared absorption in semiconductor nanoring under the action of intense laser and lateral electric fields have been investigated. Numerical calculations are performed using exact diagonalization technique. It is found that the electron-impurity interaction and external fields change the energy spectrum dramatically, and also have significant influence on the absorption spectrum. Strong dependence on laser field intensity and electric field of lowest energy levels, also supported by the Coulomb interaction with impurity, is clearly revealed.

Organic solid-state lasers

CERN Document Server

Forget, Sébastien

2013-01-01

Organic lasers are broadly tunable coherent sources, potentially compact, convenient and manufactured at low-costs. Appeared in the mid 60’s as solid-state alternatives for liquid dye lasers, they recently gained a new dimension after the demonstration of organic semiconductor lasers in the 90's. More recently, new perspectives appeared at the nanoscale, with organic polariton and surface plasmon lasers. After a brief reminder to laser physics, a first chapter exposes what makes organic solid-state organic lasers specific. The laser architectures used in organic lasers are then reviewed, with a state-of-the-art review of the performances of devices with regard to output power, threshold, lifetime, beam quality etc. A survey of the recent trends in the field is given, highlighting the latest developments with a special focus on the challenges remaining for achieving direct electrical pumping of organic semiconductor lasers. A last chapter covers the applications of organic solid-state lasers.

Chaos-based communications using semiconductor lasers subject to feedback from an integrated double cavity

International Nuclear Information System (INIS)

Tronciu, V Z; Mirasso, Claudio R; Colet, Pere

2008-01-01

We report the results of numerical investigations of the dynamical behaviour of an integrated device composed of a semiconductor laser and a double cavity that provides optical feedback. Due to the influence of the feedback, under the appropriate conditions, the system displays chaotic behaviour appropriate for chaos-based communications. The optimal conditions for chaos generation are identified. It is found that the double cavity feedback requires lower feedback strengths for developing high complexity chaos when compared with a single cavity. The synchronization of two unidirectional coupled (master-slave) systems and the influence of parameters mismatch on the synchronization quality are also studied. Finally, examples of message encoding and decoding are presented and discussed

Microwave Frequency Comb from a Semiconductor in a Scanning Tunneling Microscope.

Science.gov (United States)

Hagmann, Mark J; Yarotski, Dmitry A; Mousa, Marwan S

2017-04-01

Quasi-periodic excitation of the tunneling junction in a scanning tunneling microscope, by a mode-locked ultrafast laser, superimposes a regular sequence of 15 fs pulses on the DC tunneling current. In the frequency domain, this is a frequency comb with harmonics at integer multiples of the laser pulse repetition frequency. With a gold sample the 200th harmonic at 14.85 GHz has a signal-to-noise ratio of 25 dB, and the power at each harmonic varies inversely with the square of the frequency. Now we report the first measurements with a semiconductor where the laser photon energy must be less than the bandgap energy of the semiconductor; the microwave frequency comb must be measured within 200 μm of the tunneling junction; and the microwave power is 25 dB below that with a metal sample and falls off more rapidly at the higher harmonics. Our results suggest that the measured attenuation of the microwave harmonics is sensitive to the semiconductor spreading resistance within 1 nm of the tunneling junction. This approach may enable sub-nanometer carrier profiling of semiconductors without requiring the diamond nanoprobes in scanning spreading resistance microscopy.

Multi-operational tuneable Q-switched mode-locking Er fibre laser

Science.gov (United States)

Qamar, F. Z.

2018-01-01

A wavelength-spacing tuneable, Q-switched mode-locking (QML) erbium-doped fibre laser based on non-linear polarization rotation controlled by four waveplates and a cube polarizer is proposed. A mode-locked pulse train using two quarter-wave plates and a half-wave plate (HWP) is obtained first, and then an extra HWP is inserted into the cavity to produce different operation regimes. The evolutions of temporal and spectral dynamics with different orientation angles of the extra HWP are investigated. A fully modulated stable QML pulse train is observed experimentally. This is, to the author’s best knowledge, the first experimental work reporting QML operation without adding an extra saturable absorber inside the laser cavity. Multi-wavelength pulse laser operation, multi-pulse train continuous-wave mode-locking operation and pulse-splitting operations are also reported at certain HWP angles. The observed operational dynamics are interpreted as a mutual interaction of dispersion, non-linear effect and insertion loss. This work provides a new mechanism for fabricating cheap tuneable multi-wavelength lasers with QML pulses.

fdtd Semiconductor Microlaser Simulator v. 2.0

Energy Technology Data Exchange (ETDEWEB)

2009-01-29

This software simulates the transient optical response of a system of in-plane semiconductor lasers/waveguides of almost arbitrary 2D complexity using the effective index approximation. Gain is calculated by solving a 3D transport equation from an arbitrary contact geometry and epi structure to get an input current density to the active region, followed by a diffusion equation for carriers in that layer. The gain is saturable and frequency dependent so that output powers and frequency spectrum/longitudinal modes are predicted. Solution is by the finite-difference time-domain method on a 2D triangular grid, so that propagation in any direction along the epi plan is allowed, and arbitrary laser/waveguide shapes can be modeled, including rings. Runtime considerations, however, limit the practical solution region to approximately 500 microns**2 so that the applicability of this code is primarily limited to micro-resinators. Modeling of standard-edge-emitting semiconductor lasers is better accomplished using algorithms based on bi-directional beam propagation.

Mode locking in a bismuth fibre laser by using a SESAM

International Nuclear Information System (INIS)

Krylov, A A; Dvoirin, V V; Mashinsky, V M; Kryukov, P G; Okhotnikov, O G; Guina, M

2008-01-01

By using a semiconductor saturable-absorber mirror (SESAM) optimised for operation in the spectral range from 1100 to 1200 nm, passive mode locking is obtained in a cw bismuth-doped fibre laser. Pumping was performed by a cw ytterbium-doped fibre laser at a wavelength of 1075 nm. The operation of the laser is studied by using either a fibre Bragg grating or a loop fibre Sagnac mirror as the output resonator mirror. Stable laser pulses of duration from 50 ps to 3.5 ns, depending on the output mirror type, were generated. The pulse repetition rate was 11 MHz at a wavelength of ∼1160 nm and the maximum spectral width of 2.1 nm. The maximum average output power was 7.8 mW upon pumping by 1140 mW. (control of laser radiation parameters)

Advanced chip designs and novel cooling techniques for brightness scaling of industrial, high power diode laser bars

Science.gov (United States)

Heinemann, S.; McDougall, S. D.; Ryu, G.; Zhao, L.; Liu, X.; Holy, C.; Jiang, C.-L.; Modak, P.; Xiong, Y.; Vethake, T.; Strohmaier, S. G.; Schmidt, B.; Zimer, H.

2018-02-01

The advance of high power semiconductor diode laser technology is driven by the rapidly growing industrial laser market, with such high power solid state laser systems requiring ever more reliable diode sources with higher brightness and efficiency at lower cost. In this paper we report simulation and experimental data demonstrating most recent progress in high brightness semiconductor laser bars for industrial applications. The advancements are in three principle areas: vertical laser chip epitaxy design, lateral laser chip current injection control, and chip cooling technology. With such improvements, we demonstrate disk laser pump laser bars with output power over 250W with 60% efficiency at the operating current. Ion implantation was investigated for improved current confinement. Initial lifetime tests show excellent reliability. For direct diode applications 96% polarization are additional requirements. Double sided cooling deploying hard solder and optimized laser design enable single emitter performance also for high fill factor bars and allow further power scaling to more than 350W with 65% peak efficiency with less than 8 degrees slow axis divergence and high polarization.

Controlling semiconductor nanoparticle size distributions with tailored ultrashort pulses

International Nuclear Information System (INIS)

Hergenroeder, R; Miclea, M; Hommes, V

2006-01-01

The laser generation of size-controlled semiconductor nanoparticle formation under gas phase conditions is investigated. It is shown that the size distribution can be changed if picosecond pulse sequences of tailored ultra short laser pulses (<200 fs) are employed. By delivering the laser energy in small packages, a temporal energy flux control at the target surface is achieved, which results in the control of the thermodynamic pathway the material takes. The concept is tested with silicon and germanium, both materials with a predictable response to double pulse sequences, which allows deduction of the materials' response to complicated pulse sequences. An automatic, adaptive learning algorithm was employed to demonstrate a future strategy that enables the definition of more complex optimization targets such as particle size on materials less predictable than semiconductors

Switchable semiconductor optical fiber laser incorporating AWG and broadband FBG with high SMSR

International Nuclear Information System (INIS)

Ahmad, H; Zulkifli, M Z; Thambiratnam, K; Latiff, A A; Harun, S W

2009-01-01

In this paper we propose and demonstrate a switchable wavelength fiber laser (SWFL) using a semiconductor optical amplifier (SOA) together with an arrayed waveguide grating (AWG). The proposed SOA-based SWFL is capable of generating up to 14 lasing channels from 1530.1 nm to 1534.9 nm at a channel spacing of 0.8 nm (100 GHz) and a bandwidth of 11.8 and 10.2 nm respectively. The EDFA-based SWFL has a higher peak power at –5 dBm, while to SOA-based SWFL has a peak power of only –10 dBm. However, the SOA-based SWFL exhibits a much better SMSR of between 10 to 20 dB as compared to the SMSR of the EDFA-based SWFL due to the inhomogeneous broadening properties of the SOA

CCST [Center for Compound Semiconductor Technology] research briefs

International Nuclear Information System (INIS)

Zipperian, T.E.; Voelker, E.R.

1989-12-01

This paper discusses the following topics: theoretical predictions of valence and conduction band offsets in III-V semiconductors; reflectance modulation of a semiconductor superlattice optical mirror; magnetoquantum oscillations of the phonon-drag thermoelectric power in quantum wells; correlation between photoluminescence line shape and device performance of p-channel strained-layer materials; control of threading dislocations in heteroepitaxial structures; improved growth of CdTe on GaAs by patterning; role of structure threading dislocations in relaxation of highly strained single-quantum-well structures; InAlAs growth optimization using reflection mass spectrometry; nonvolatile charge storage in III-V heterostructures; optically triggered thyristor switches; InAsSb strained-layer superlattice infrared detectors with high detectivities; resonant periodic gain surface-emitting semiconductor lasers; performance advantages of strained-quantum-well lasers in AlGaAs/InGaAs; optical integrated circuit for phased-array radar antenna control; and deposition and novel device fabrication from Tl 2 Ca 2 Ba 2 Cu 3 O y thin films

Key Topics in Producing New Ultraviolet Led and Laser Devices Based on Transparent Semiconductor Zinc Oxide

International Nuclear Information System (INIS)

Tuezemen, S.

2004-01-01

Recently, it has been introduced that ZnO as II-VI semiconductor is promising various technological applications, especially for optoelectronic short wavelength light emitting devices due to its wide and direct band gap profile. The most important advantage of ZnO over the other currently used wide band gap semiconductors such as GaN is that its nearly 3 times higher exciton binding energy (60 meV), which permits efficient excitonic emission at room temperature and above. As-grown ZnO is normally n-type because of the Zn-rich defects such as zinc interstitials (Zn i ) oxygen vacancies (Vo), natively acting as shallow donors and main source of n-type conductivity in as-grown material. Therefore, making p-type ZnO has been more difficult due to unintentional compensation of possible acceptors by these residual donors. In order to develop electro luminescent and laser devices based on the ultraviolet (UV) exciton emission of ZnO, it will be important to fabricate good p-n junctions. Attempts to observe p-type conductivity in ours and our collaborators' laboratories in USA, either by co-doping with N or tuning O pressure have been first successful achievements, resulting in hole concentrations up to 10 1 9 cm - 3 in reactively sputtered thin layers of ZnO. Moreover, in order to produce ZnO based quantum well lasers similar to the previously introduced n-AlGaAs/GaAs/p-AlGaAs structures; we have attempted to grow Zn 1 -xSn x O thin films to enlarge the band gap energy. An increase up to 170 meV has been observed in Zn 1 -xSn x O thin films and this is enough barrier to be able to trap electron-hole pairs in quantum well structures. As a result, two important key issues; p-type conductivity and enhancement of the band gap energy in order to step forward towards the production of electro luminescent UV LEDs and quantum well lasers have been investigated and will be presented in this study

Optics education for machine operators in the semiconductor industry: moving beyond button pushing

Science.gov (United States)

Karakekes, Meg; Currier, Deborah

1995-10-01

In the competitive semiconductor manufacturing industry, employees who operate equipment are able to make greater contributions if they understand how the equipment works. By understanding the 'why' behind the 'what', the equipment operators can better partner with other technical staff to produce quality integrated circuits efficiently and effectively. This additional knowledge also opens equipment operators to job enrichment and enlargement opportunities. Advanced Micro Devices (AMD) is in the process of upgrading the skills of its equipment operators. This paper is an overview of a pilot program that employs optics education to upgrade stepper operators' skills. The paper starts with stepper tasks that require optics knowledge, examines teaching methods, reports both end-of-course and three months post-training knowledge retention, and summarizes how the training has impacted the production floor.

Basics of laser physics for students of science and engineering

CERN Document Server

Renk, Karl F

2017-01-01

This textbook provides an introductory presentation of all types of lasers. It contains a general description of the laser, a theoretical treatment and a characterization of its operation as it deals with gas, solid state, free-electron and semiconductor lasers. This expanded and updated second edition of the book presents a description of the dynamics of free-electron laser oscillation using a model introduced in the first edition that allows a reader to understand basic properties of a free-electron laser and makes the difference to “conventional” lasers. The discussions and the treatment of equations are presented in a way that a reader can immediately follow. The book addresses graduate and undergraduate students in science and engineering, featuring problems with solutions and over 400 illustrations.

Laser warning receiver to identify the wavelength and angle of arrival of incident laser light

Science.gov (United States)

Sinclair; Michael B.; Sweatt, William C.

2010-03-23

A laser warning receiver is disclosed which has up to hundreds of individual optical channels each optically oriented to receive laser light from a different angle of arrival. Each optical channel has an optical wedge to define the angle of arrival, and a lens to focus the laser light onto a multi-wavelength photodetector for that channel. Each multi-wavelength photodetector has a number of semiconductor layers which are located in a multi-dielectric stack that concentrates the laser light into one of the semiconductor layers according to wavelength. An electrical signal from the multi-wavelength photodetector can be processed to determine both the angle of arrival and the wavelength of the laser light.

In situ laser processing in a scanning electron microscope

Energy Technology Data Exchange (ETDEWEB)

Roberts, Nicholas A.; Magel, Gregory A.; Hartfield, Cheryl D.; Moore, Thomas M.; Fowlkes, Jason D.; Rack, Philip D. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States) and Omniprobe, Inc., an Oxford Instruments Company, 10410 Miller Rd., Dallas, Texas 75238 (United States); Omniprobe, Inc., an Oxford Instruments Company, 10410 Miller Rd., Dallas, Texas 75238 (United States); Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States) and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2012-07-15

Laser delivery probes using multimode fiber optic delivery and bulk focusing optics have been constructed and used for performing materials processing experiments within scanning electron microscope/focused ion beam instruments. Controlling the current driving a 915-nm semiconductor diode laser module enables continuous or pulsed operation down to sub-microsecond durations, and with spot sizes on the order of 50 {mu}m diameter, achieving irradiances at a sample surface exceeding 1 MW/cm{sup 2}. Localized laser heating has been used to demonstrate laser chemical vapor deposition of Pt, surface melting of silicon, enhanced purity, and resistivity via laser annealing of Au deposits formed by electron beam induced deposition, and in situ secondary electron imaging of laser induced dewetting of Au metal films on SiO{sub x}.

Study and realisation of a femtosecond dye laser operating at different wavelengths. Ultrashort pulses compression and amplification

International Nuclear Information System (INIS)

Georges, Patrick

1989-01-01

We present the study and the realization of a passively mode-locked dye laser producing pulses shorter than 100 femto-seconds (10 -13 s). In a ring cavity with an amplifier medium (Rhodamine 60) and a saturable absorber (DODCI), a sequence of four prisms controls the group velocity dispersion and allows the generation of very short pulses. Then we have studied the production of femtosecond pulses at other wavelengths directly from the femtosecond dye laser. For the first rime, 60 fs pulses at 685 nm and pulses shorter than 50 fs between 775 nm and 800 nm have been produced by passive mode locking. These near infrared pulses have been used to study the absorption saturation kinetics in semiconductors multiple quantum wells GaAs/GaAlAs. We have observed a singular behavior of the laser operating at 685 nm and analyzed the produced pulses in terms of optical solitons. To perform time resolved spectroscopy with shortest pulses, we have studied a pulse compressor and a multipass amplifier to increase the pulses energy. Pulses of 20 fs and 10 micro-joules (peak power: 0.5 GW) have been obtained at low repetition rate (10 Hz) and pulses of 16 fs and 0.6 micro-joules pulses have been generated at high repetition rate (11 kHz) using a copper vapor laser. These pulses have been used to study the absorption saturation kinetics of an organic dye (the Malachite Green). (author) [fr

Laser materials processing with diode lasers

OpenAIRE

Li, Lin; Lawrence, Jonathan; Spencer, Julian T.

1996-01-01

Laser materials processing is currently dominated by CO2, Nd-YAG and Excimer lasers. Continuous advances in semiconductor laser technology over the last decade have increased the average power output of the devices annualy by two fold, resulting in the commercial availability of the diode lasers today with delivery output powers in excess of 60W in CW mode and 5kW in qasi-CW mode. The advantages of compactness, high reliability, high efficiency and potential low cost, due to the mass producti...

Design strategy for terahertz quantum dot cascade lasers.

Science.gov (United States)

Burnett, Benjamin A; Williams, Benjamin S

2016-10-31

The development of quantum dot cascade lasers has been proposed as a path to obtain terahertz semiconductor lasers that operate at room temperature. The expected benefit is due to the suppression of nonradiative electron-phonon scattering and reduced dephasing that accompanies discretization of the electronic energy spectrum. We present numerical modeling which predicts that simple scaling of conventional quantum well based designs to the quantum dot regime will likely fail due to electrical instability associated with high-field domain formation. A design strategy adapted for terahertz quantum dot cascade lasers is presented which avoids these problems. Counterintuitively, this involves the resonant depopulation of the laser's upper state with the LO-phonon energy. The strategy is tested theoretically using a density matrix model of transport and gain, which predicts sufficient gain for lasing at stable operating points. Finally, the effect of quantum dot size inhomogeneity on the optical lineshape is explored, suggesting that the design concept is robust to a moderate amount of statistical variation.

Layer-by-layer modification of thin-film metal-semiconductor multilayers with ultrashort laser pulses

Science.gov (United States)

Romashevskiy, S. A.; Tsygankov, P. A.; Ashitkov, S. I.; Agranat, M. B.

2018-05-01

The surface modifications in a multilayer thin-film structure (50-nm alternating layers of Si and Al) induced by a single Gaussian-shaped femtosecond laser pulse (350 fs, 1028 nm) in the air are investigated by means of atomic-force microscopy (AFM), scanning electron microscopy (SEM), and optical microscopy (OM). Depending on the laser fluence, various modifications of nanometer-scale metal and semiconductor layers, including localized formation of silicon/aluminum nanofoams and layer-by-layer removal, are found. While the nanofoams with cell sizes in the range of tens to hundreds of nanometers are produced only in the two top layers, layer-by-layer removal is observed for the four top layers under single pulse irradiation. The 50-nm films of the multilayer structure are found to be separated at their interfaces, resulting in a selective removal of several top layers (up to 4) in the form of step-like (concentric) craters. The observed phenomenon is associated with a thermo-mechanical ablation mechanism that results in splitting off at film-film interface, where the adhesion force is less than the bulk strength of the used materials, revealing linear dependence of threshold fluences on the film thickness.

Microscopic analysis of the optoelectronic properties of semiconductor gain media for laser applications; Mikroskopische Analyse optoelektronischer Eigenschaften von Halbleiterverstaerkungsmedien fuer Laseranwendungen

Energy Technology Data Exchange (ETDEWEB)

Bueckers, Christina

2010-12-03

A microscopic many-particle theory is applied to model a wide range of semiconductor laser gain materials. The fundamental understanding of the gain medium and the underlying carrier interaction processes allow for the quantitative prediction of the optoelectronic properties governing the laser performance. Detailed theory-experiment-comparisons are shown for a variety of structures demonstrating the application capabilities of the theoretical approach. The microscopically calculated material properties, in particular absorption, optical gain, luminescence and the intrinsic carrier losses due to radiative and Auger-recombination, constitute the critical input to analyse and design laser structures. On this basis, important system features such as laser wavelength or threshold behaviour become predictable. However, the theory is also used in a diagnostic fashion, e.g. to extract otherwise poorly known structural parameter. Thus, novel concepts for the optimisation of laser designs may be developed with regard to the requirements of specific applications. Moreover, the approach allows for the systematic exploration and assessment of completely novel material systems and their application potential. (orig.)

Semiconductor Optics

CERN Document Server

Klingshirn, Claus F

2012-01-01

This updated and enlarged new edition of Semiconductor Optics provides an introduction to and an overview of semiconductor optics from the IR through the visible to the UV, including linear and nonlinear optical properties, dynamics, magneto and electrooptics, high-excitation effects and laser processes, some applications, experimental techniques and group theory. The mathematics is kept as elementary as possible, sufficient for an intuitive understanding of the experimental results and techniques treated. The subjects covered extend from physics to materials science and optoelectronics. Significantly updated chapters add coverage of current topics such as electron hole plasma, Bose condensation of excitons and meta materials. Over 120 problems, chapter introductions and a detailed index make it the key textbook for graduate students in physics. The mathematics is kept as elementary as possible, sufficient for an intuitive understanding of the experimental results and techniques treated. The subjects covered ...

Resonance ionization mass spectrometry using tunable diode lasers

International Nuclear Information System (INIS)

Shaw, R.W.; Young, J.P.; Smith, D.H.

1990-01-01

Tunable semiconductor diode lasers will find many important applications in atomic spectroscopy. They exhibit the desirable attributes of lasers: narrow bandwidth, tunability, and spatial coherence. At the same time, they possess few of the disadvantages of other tunable lasers. They require no alignment, are simple to operate, and are inexpensive. Practical laser spectroscopic instruments can be envisioned. The authors have applied diode lasers to resonance ionization mass spectrometry (RIMS) of some of the lanthanide elements. Sub-Doppler resolution spectra have been recorded and have been used for atomic hyperfine structure analysis. Isotopically-selective ionization has been accomplished, even in cases where photons from a broadband dye laser are part of the overall ionization process and where the isotopic spectral shift is very small. A convenient RIMS instrument for isotope ratio measurements that employs only diode lasers, along with electric field ionization, should be possible

The Physics of Semiconductors

Science.gov (United States)

Brennan, Kevin F.

1999-02-01

Modern fabrication techniques have made it possible to produce semiconductor devices whose dimensions are so small that quantum mechanical effects dominate their behavior. This book describes the key elements of quantum mechanics, statistical mechanics, and solid-state physics that are necessary in understanding these modern semiconductor devices. The author begins with a review of elementary quantum mechanics, and then describes more advanced topics, such as multiple quantum wells. He then disusses equilibrium and nonequilibrium statistical mechanics. Following this introduction, he provides a thorough treatment of solid-state physics, covering electron motion in periodic potentials, electron-phonon interaction, and recombination processes. The final four chapters deal exclusively with real devices, such as semiconductor lasers, photodiodes, flat panel displays, and MOSFETs. The book contains many homework exercises and is suitable as a textbook for electrical engineering, materials science, or physics students taking courses in solid-state device physics. It will also be a valuable reference for practicing engineers in optoelectronics and related areas.

ON THE ARTIFICIAL SEMICONDUCTOR MATERIALS | Adelabu ...

African Journals Online (AJOL)

For about the last three decades, semiconductor technology began to make its most apparent impact in Solid State Electronics. The field of photonics, which combines laser physics, electro-optics and nonlinear optics has expanded tremendously. Notably, modern light wave communications exemplify photonic systems.

High mobility emissive organic semiconductor

Science.gov (United States)

Liu, Jie; Zhang, Hantang; Dong, Huanli; Meng, Lingqiang; Jiang, Longfeng; Jiang, Lang; Wang, Ying; Yu, Junsheng; Sun, Yanming; Hu, Wenping; Heeger, Alan J.

2015-01-01

The integration of high charge carrier mobility and high luminescence in an organic semiconductor is challenging. However, there is need of such materials for organic light-emitting transistors and organic electrically pumped lasers. Here we show a novel organic semiconductor, 2,6-diphenylanthracene (DPA), which exhibits not only high emission with single crystal absolute florescence quantum yield of 41.2% but also high charge carrier mobility with single crystal mobility of 34 cm2 V−1 s−1. Organic light-emitting diodes (OLEDs) based on DPA give pure blue emission with brightness up to 6,627 cd m−2 and turn-on voltage of 2.8 V. 2,6-Diphenylanthracene OLED arrays are successfully driven by DPA field-effect transistor arrays, demonstrating that DPA is a high mobility emissive organic semiconductor with potential in organic optoelectronics. PMID:26620323

Method of making a self-aligned schottky metal semi-conductor field effect transistor with buried source and drain

International Nuclear Information System (INIS)

Bol, I.

1984-01-01

A semi-conductor structure and particularly a high speed VLSI Self-Aligned Schottky Metal Semi-Conductor Field Effect Transistor with buried source and drain, fabricated by the ion implantation of source and drain areas at a predetermined range of depths followed by very localized laser annealing to electrically reactivate the amorphous buried source and drain areas thereby providing effective vertical separation of the channel from the buried source and drain respectively. Accordingly, spatial separations between the self-aligned gate-to-drain, and gate-to-source can be relatively very closely controlled by varying the doping intensity and duration of the implantation thereby reducing the series resistance and increasing the operating speed

Multichannel, time-resolved picosecond laser ultrasound imaging and spectroscopy with custom complementary metal-oxide-semiconductor detector

International Nuclear Information System (INIS)

Smith, Richard J.; Light, Roger A.; Johnston, Nicholas S.; Pitter, Mark C.; Somekh, Mike G.; Sharples, Steve D.

2010-01-01

This paper presents a multichannel, time-resolved picosecond laser ultrasound system that uses a custom complementary metal-oxide-semiconductor linear array detector. This novel sensor allows parallel phase-sensitive detection of very low contrast modulated signals with performance in each channel comparable to that of a discrete photodiode and a lock-in amplifier. Application of the instrument is demonstrated by parallelizing spatial measurements to produce two-dimensional thickness maps on a layered sample, and spectroscopic parallelization is demonstrated by presenting the measured Brillouin oscillations from a gallium arsenide wafer. This paper demonstrates the significant advantages of our approach to pump probe systems, especially picosecond ultrasonics.

Multichannel, time-resolved picosecond laser ultrasound imaging and spectroscopy with custom complementary metal-oxide-semiconductor detector

Energy Technology Data Exchange (ETDEWEB)

Smith, Richard J.; Light, Roger A.; Johnston, Nicholas S.; Pitter, Mark C.; Somekh, Mike G. [Institute of Biophysics, Imaging and Optical Science, University of Nottingham, Nottinghamshire NG7 2RD (United Kingdom); Sharples, Steve D. [Applied Optics Group, Electrical Systems and Optics Research Division, University of Nottingham, Nottinghamshire NG7 2RD (United Kingdom)

2010-02-15

This paper presents a multichannel, time-resolved picosecond laser ultrasound system that uses a custom complementary metal-oxide-semiconductor linear array detector. This novel sensor allows parallel phase-sensitive detection of very low contrast modulated signals with performance in each channel comparable to that of a discrete photodiode and a lock-in amplifier. Application of the instrument is demonstrated by parallelizing spatial measurements to produce two-dimensional thickness maps on a layered sample, and spectroscopic parallelization is demonstrated by presenting the measured Brillouin oscillations from a gallium arsenide wafer. This paper demonstrates the significant advantages of our approach to pump probe systems, especially picosecond ultrasonics.

Laser-Printed Organic Thin-Film Transistors

KAUST Repository

Diemer, Peter J.

2017-09-20

Solution deposition of organic optoelectronic materials enables fast roll-to-roll manufacturing of photonic and electronic devices on any type of substrate and at low cost. But controlling the film microstructure when it crystallizes from solution can be challenging. This represents a major limitation of this technology, since the microstructure, in turn, governs the charge transport properties of the material. Further, the solvents typically used are hazardous, which precludes their incorporation in large-scale manufacturing processes. Here, the first ever organic thin-film transistor fabricated with an electrophotographic laser printing process using a standard office laser printer is reported. This completely solvent-free additive manufacturing method allows for simultaneous deposition, purification, and patterning of the organic semiconductor layer. Laser-printed transistors using triisopropylsilylethynyl pentacene as the semiconductor layer are realized on flexible substrates and characterized, making this a successful first demonstration of the potential of laser printing of organic semiconductors.

Nonlinear laser dynamics from quantum dots to cryptography

CERN Document Server

Lüdge, Kathy

2012-01-01

A distinctive discussion of the nonlinear dynamical phenomena of semiconductor lasers. The book combines recent results of quantum dot laser modeling with mathematical details and an analytic understanding of nonlinear phenomena in semiconductor lasers and points out possible applications of lasers in cryptography and chaos control. This interdisciplinary approach makes it a unique and powerful source of knowledge for anyone intending to contribute to this field of research.By presenting both experimental and theoretical results, the distinguished authors consider solitary lase

Physics of frequency-modulated comb generation in quantum-well diode lasers

Science.gov (United States)

Dong, Mark; Cundiff, Steven T.; Winful, Herbert G.

2018-05-01

We investigate the physical origin of frequency-modulated combs generated from single-section semiconductor diode lasers based on quantum wells, isolating the essential physics necessary for comb generation. We find that the two effects necessary for comb generation—spatial hole burning (leading to multimode operation) and four-wave mixing (leading to phase locking)—are indeed present in some quantum-well systems. The physics of comb generation in quantum wells is similar to that in quantum dot and quantum cascade lasers. We discuss the nature of the spectral phase and some important material parameters of these diode lasers.

Lasers: principles, applications and energetic measures

International Nuclear Information System (INIS)

Subran, C.; Sagaut, J.; Lapointe, S.

2009-01-01

After having recalled the principles of a laser and the properties of the laser beam, the authors describe the following different types of lasers: solid state lasers, fiber lasers, semiconductor lasers, dye lasers and gas lasers. Then, their applications are given. Very high energy lasers can reproduce the phenomenon of nuclear fusion of hydrogen atoms. (O.M.)

Hydrogen discharges operating at atmospheric pressure in a semiconductor gas discharge system

Energy Technology Data Exchange (ETDEWEB)

Aktas, K; Acar, S; Salamov, B G [Physics Department, Faculty of Arts and Sciences, Gazi University, 06500 Ankara (Turkey)

2011-08-15

Analyses of physical processes which initiate electrical breakdown and spatial stabilization of current and control it with a photosensitive cathode in a semiconductor gas discharge system (SGDS) are carried out in a wide pressure range up to atmospheric pressure p, interelectrode distance d and diameter D of the electrode areas of the semiconductor cathode. The study compares the breakdown and stability curves of the gas discharge in the planar SGDS where the discharge gap is filled with hydrogen and air in two cases. The impact of the ionizing component of the discharge plasma on the control of the stable operation of the planar SGDS is also investigated at atmospheric pressure. The loss of stability is primarily due to modification of the semiconductor-cathode properties on the interaction with low-energy hydrogen ions and the formation of a space charge of positive ions in the discharge gap which changes the discharge from Townsend to glow type. The experimental results show that the discharge current in H{sub 2} is more stable than in air. The breakdown voltages are measured for H{sub 2} and air with parallel-plane electrodes, for pressures between 28 and 760 Torr. The effective secondary electron emission (SEE) coefficient is then determined from the breakdown voltage results and compared with the experimental results. The influence of the SEE coefficient is stated in terms of the differences between the experimental breakdown law.

Army Solid State Laser Program: Design, Operation, and Mission Analysis for a Heat-Capacity Laser

International Nuclear Information System (INIS)

Dane, C B; Flath, L; Rotter, M; Fochs, S; Brase, J; Bretney, K

2001-01-01

Solid-state lasers have held great promise for the generation of high-average-power, high-quality output beams for a number of decades. However, the inherent difficulty of scaling the active solid-state gain media while continuing to provide efficient cooling has limited demonstrated powers to 10X the diffraction limit. Challenges posed by optical distortions and depolarization arising from internal temperature gradients in the gain medium of a continuously cooled system are only increased for laser designs that would attempt to deliver the high average power in the form of high energy pulses (>25J) from a single coherent optical aperture. Although demonstrated phase-locking of multiple laser apertures may hold significant promise for the future scaling of solid-state laser systems,1 the continuing need for additional technical development and innovation coupled with the anticipated complexity of these systems effectively limits this approach for near-term multi-kW laser operation outside of a laboratory setting. We have developed and demonstrated a new operational mode for solid-state laser systems in which the cooling of the gain medium is separated in time from the lasing cycle. In ''heat-capacity'' operation, no cooling takes place during lasing. The gain medium is pumped very uniformly and the waste heat from the excitation process is stored in the solid-state gain medium. By depositing the heat on time scales that are short compared to thermal diffusion across the optical aperture, very high average power operation is possible while maintaining low optical distortions. After a lasing cycle, aggressive cooling can then take place in the absence of lasing, limited only by the fracture limit of the solid-state medium. This mode of operation is ideally suited for applications that require 1-30s engagements at very high average power. If necessary, multiple laser apertures can provide continuous operation. Land Combat mission analysis of a stressing air defense

Studies on Ytterbium-doped Fibre Laser Operating in Different Regimes

International Nuclear Information System (INIS)

Gan, Y; Xiang, W H; Zhang, G Z

2006-01-01

An ytterbium-doped fibre laser with a unidirectional ring cavity containing a polarizer placed between two in-line polarization controllers is presented. Depending on an equivalent saturable absorber, this laser operates in continuous, Q-switched mode-locked or CW mode-locked regimes. The passive method described here allowed us to choose the operating regime of the fibre laser by rotating the two polarization controllers and adjusting the pump power. Results of numerical simulations of pulse propagation in such a mode-locked fibre ring laser are presented, which reveals that the Q-switched mode-locked or CW modelocked regimes can be achieved by aligning the polarizer near the slow or the fast axes of the fibre

A SESAM passively mode-locked fiber laser with a long cavity including a band pass filter

International Nuclear Information System (INIS)

Song, Rui; Chen, Hong-Wei; Chen, Sheng-Ping; Hou, Jing; Lu, Qi-Sheng

2011-01-01

A semiconductor saturable absorber mirror (SESAM) passively mode-locked fiber laser with a long cavity length over 700 m is demonstrated. A band pass filter is inserted into the laser cavity to stabilize the lasing wavelength. Some interesting phenomena are observed and discussed. The central wavelength, repetition rate, average power and single pulse energy of the laser are 1064 nm, 281.5 kHz, 11 mW and 39 nJ, respectively. The laser operates stably without Q-switching instabilities, which greatly reduces the damage opportunities of the SESAM

Single mode operation of a TEA CO2 laser

International Nuclear Information System (INIS)

Wada, Kazuhiro; Tunawaki, Yoshiaki; Yamanaka, Masanobu.

1993-01-01

Single mode operation of a TEA CO 2 laser was performed by using an optical system of Fox-Smith type. Laser beam was taken out from the cavity by using a beam splitter, and was reflected by a mirror back to the cavity. By inserting a Fabry-Perot etalon between the splitter and the mirror, beat of laser pulses can be removed completly. (author)

Vertical cavity surface emitting lasers from all-inorganic perovskite quantum dots

Science.gov (United States)

Sun, Handong; Wang, Yue; Li, Xiaoming; Zeng, Haibo

We report the breakthrough in realizing the challenging while practically desirable vertical cavity surface emitting lasers (VCSELs) based on the CsPbX3 inorganic perovskite nanocrystals (IPNCs). These laser devices feature record low threshold (9 µJ/cm2), unidirectional output (beam divergence of 3.6º) and superb stability. We show that both single-mode and multimode lasing operation are achievable in the device. In contrast to traditional metal chacogenide colloidal quantum dots based lasers where the pump thresholds for the green and blue wavelengths are typically much higher than that of the red, these CsPbX3 IPNC-VCSEL devices are able to lase with comparable thresholds across the whole visible spectral range, which is appealing for achieving single source-pumped full-color lasers. We further reveal that these lasers can operate in quasi-steady state regime, which is very practical and cost-effective. Given the facile solution processibility, our CsPbX3 IPNC-VCSEL devices may hold great potential in developing low-cost yet high-performance lasers, promising in revolutionizing the vacuum-based epitaxial semiconductor lasers.

Reactor operations for nuclear pumping of lasers

Energy Technology Data Exchange (ETDEWEB)

Beck, G; Cooper, G [University of Illinois (United States)

1974-07-01

Experiments involving the measurement of gas parameters that are related to lasing, and lasing of various gas mixtures have comprised a major part of the utilization of the University of Illinois Advanced TRIGA Reactor since the upgrading of the facility was completed in 1969. A thru beam port, which was added during upgrading, has been the facility used for these measurements. The laser cell is placed in the port adjacent to the core. Alignment is then accomplished by using both ends of the port or by a mirror placed at the back side of the apparatus. The reactor has been operated in all modes (pulsing, square wave, and steady state) for the experiments although pulsing is the primary mode that is used. Laser enhancement has been obtained in several cases, but efforts toward direct pumping from the radiation alone have not as yet succeeded. Improved laser operation from direct pumping has been suggested with an emphasis on high-powered systems where the basic input energy is to be derived from a nuclear reactor.

Analysis of small-signal intensity modulation of semiconductor ...

Indian Academy of Sciences (India)

Computer simulation of the model is applied to 1.55-µm ... Semiconductor laser; small-signal modulation; modulation response; gain suppression. ... originates from intraband relaxation processes of charge carriers that extend for times as ...

Quantum theory of the optical and electronic properties of semiconductors

CERN Document Server

Haug, Hartmut

2009-01-01

This invaluable textbook presents the basic elements needed to understand and research into semiconductor physics. It deals with elementary excitations in bulk and low-dimensional semiconductors, including quantum wells, quantum wires and quantum dots. The basic principles underlying optical nonlinearities are developed, including excitonic and many-body plasma effects. Fundamentals of optical bistability, semiconductor lasers, femtosecond excitation, the optical Stark effect, the semiconductor photon echo, magneto-optic effects, as well as bulk and quantum-confined Franz-Keldysh effects, are covered. The material is presented in sufficient detail for graduate students and researchers with a general background in quantum mechanics.This fifth edition includes an additional chapter on 'Quantum Optical Effects' where the theory of quantum optical effects in semiconductors is detailed. Besides deriving the 'semiconductor luminescence equations' and the expression for the stationary luminescence spectrum, the resu...

Rocksalt nitride metal/semiconductor superlattices: A new class of artificially structured materials

Science.gov (United States)

Saha, Bivas; Shakouri, Ali; Sands, Timothy D.

2018-06-01

Artificially structured materials in the form of superlattice heterostructures enable the search for exotic new physics and novel device functionalities, and serve as tools to push the fundamentals of scientific and engineering knowledge. Semiconductor heterostructures are the most celebrated and widely studied artificially structured materials, having led to the development of quantum well lasers, quantum cascade lasers, measurements of the fractional quantum Hall effect, and numerous other scientific concepts and practical device technologies. However, combining metals with semiconductors at the atomic scale to develop metal/semiconductor superlattices and heterostructures has remained a profoundly difficult scientific and engineering challenge. Though the potential applications of metal/semiconductor heterostructures could range from energy conversion to photonic computing to high-temperature electronics, materials challenges primarily had severely limited progress in this pursuit until very recently. In this article, we detail the progress that has taken place over the last decade to overcome the materials engineering challenges to grow high quality epitaxial, nominally single crystalline metal/semiconductor superlattices based on transition metal nitrides (TMN). The epitaxial rocksalt TiN/(Al,Sc)N metamaterials are the first pseudomorphic metal/semiconductor superlattices to the best of our knowledge, and their physical properties promise a new era in superlattice physics and device engineering.

Third harmonic generation of high power far infrared radiation in semiconductors

Energy Technology Data Exchange (ETDEWEB)

Urban, M [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP)

1996-04-01

We investigated the third harmonic generation of high power infrared radiation in doped semiconductors with emphasis on the conversion efficiency. The third harmonic generation effect is based on the nonlinear response of the conduction band electrons in the semiconductor with respect to the electric field of the incident electromagnetic wave. Because this work is directed towards a proposed application in fusion plasma diagnostics, the experimental requirements for the radiation source at the fundamental frequency are roughly given as follows: a wavelength of the radiation at the fundamental frequency in the order of 1 mm and an incident power greater than 1 MW. The most important experiments of this work were performed using the high power far infrared laser of the CRPP. With this laser a new laser line was discovered, which fits exactly the source specifications given above: the wavelength is 676 {mu}m and the maximum power is up to 2 MW. Additional experiments were carried out using a 496 {mu}m laser and a 140 GHz (2.1 mm) gyrotron. The main experimental progress with respect to previous work in this field is, in addition to the use of a very high power laser, the possibility of an absolute calibration of the detectors for the far infrared radiation and the availability of a new type of detector with a very fast response. This detector made it possible to measure the power at the fundamental as well as the third harmonic frequency with full temporal resolution of the fluctuations during the laser pulse. Therefore the power dependence of the third harmonic generation efficiency could be measured directly. The materials investigated were InSb as an example of a narrow gap semiconductor and Si as standard material. The main results are: narrow gap semiconductors indeed have a highly nonlinear electronic response, but the narrow band gap leads at the same time to a low power threshold for internal breakdown, which is due to impact ionization. figs., tabs., refs.

Third harmonic generation of high power far infrared radiation in semiconductors

International Nuclear Information System (INIS)

Urban, M.

1996-04-01

In this work we investigated the third harmonic generation of high power infrared radiation in doped semiconductors with emphasis on the conversion efficiency. The third harmonic generation effect is based on the nonlinear response of the conduction band electrons in the semiconductor with respect to the electric field of the incident electromagnetic wave. Because this work is directed towards a proposed application in fusion plasma diagnostics, the experimental requirements for the radiation source at the fundamental frequency are roughly given as follows: a wavelength of the radiation at the fundamental frequency in the order of 1 mm and an incident power greater than 1 MW. The most important experiments of this work were performed using the high power far infrared laser of the CRPP. With this laser a new laser line was discovered, which fits exactly the source specifications given above: the wavelength is 676 μm and the maximum power is up to 2 MW. Additional experiments were carried out using a 496 μm laser and a 140 GHz (2.1 mm) gyrotron. The main experimental progress with respect to previous work in this field is, in addition to the use of a very high power laser, the possibility of an absolute calibration of the detectors for the far infrared radiation and the availability of a new type of detector with a very fast response. This detector made it possible to measure the power at the fundamental as well as the third harmonic frequency with full temporal resolution of the fluctuations during the laser pulse. Therefore the power dependence of the third harmonic generation efficiency could be measured directly. The materials investigated were InSb as an example of a narrow gap semiconductor and Si as standard material. The main results are: narrow gap semiconductors indeed have a highly nonlinear electronic response, but the narrow band gap leads at the same time to a low power threshold for internal breakdown, which is due to impact ionization. (author) figs

Automation and Integration in Semiconductor Manufacturing

OpenAIRE

Liao, Da-Yin

2010-01-01

Semiconductor automation originates from the prevention and avoidance of frauds in daily fab operations. As semiconductor technology and business continuously advance and grow, manufacturing systems must aggressively evolve to meet the changing technical and business requirements in this industry. Semiconductor manufacturing has been suffering pains from islands of automation. The problems associated with these systems are limited

New Principles In Operating Gastro-Intestinal Tract With CO2 Laser

Science.gov (United States)

Skobelkin, O. K.; Litwin, G. D.; Smoljaninov, M. V.; Brehov, E. I.; Rjabov, V. I.; Kirpitchev, A. G.

1988-06-01

Laser devicea are becoming morn popular in surgery. They are mainly used for controling hemorrages through an endoscope, for radicalevaporating benign and small malignant tumors in esophagus, stomach, colon, and for palliative destruction of inoperable tumors to recanalize the lumen. According, to literature operations on abdominal parenchymal organs with laser are rather seldom. And the operations with laser on hollow organs of digestive tract are being mainly performed in the USSR, and they being rather effective.

Laser-induced removal of a dye C.I. Acid Red 87 using n-type WO{sub 3} semiconductor catalyst

Energy Technology Data Exchange (ETDEWEB)

Qamar, M. [Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, KFUPM Box 741, Dhahran 31261 (Saudi Arabia); Gondal, M.A., E-mail: magondal@kfupm.edu.sa [Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, KFUPM Box 741, Dhahran 31261 (Saudi Arabia); Laser Research Laboratory, Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Hayat, K. [Chemistry Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Yamani, Z.H. [Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, KFUPM Box 741, Dhahran 31261 (Saudi Arabia); Laser Research Laboratory, Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Hooshani, K. [Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, KFUPM Box 741, Dhahran 31261 (Saudi Arabia); Chemistry Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

2009-10-30

Water contamination by organic substances such as dyes is of great concern worldwide due to their utilization in many industrial processes and environmental concerns. To cater the needs for waste water treatment polluted with organic dyes, laser-induced photocatalytic process was investigated for removal of a dye derivative namely Acid Red 87 using n-type WO{sub 3} semiconductor catalyst. The degradation was investigated in aqueous suspensions of tungsten oxide under different experimental conditions using laser instead of conventional UV lamp as an irradiation source. The degradation process was monitored by measuring the change in dye concentration as a function of laser irradiation time by employing UV spectroscopic analysis. The degradation of dye was studied by varying different parameters such as laser energy, reaction pH, substrate concentration, catalyst concentration, and in the presence of electron acceptors such as hydrogen peroxide (H{sub 2}O{sub 2}), and potassium bromate (KBrO{sub 3}). The degradation rates were found to be strongly dependent on all the above-mentioned parameters. Our experimental results revealed that the dye degradation process was very fast (within few minutes) under laser irradiation as compared to conventional setups using broad spectral lamps (hours or days) and this laser-induced photocatalytic degradation method could be an effective means to eliminate the pollutants present in liquid phase. The experience gained through this study could be beneficial for treatment of waste water contaminated with organic dyes and other organic pollutants.

Double Tunneling Injection Quantum Dot Lasers for High Speed Operation

Science.gov (United States)

2017-10-23

Double Tunneling-Injection Quantum Dot Lasers for High -Speed Operation The views, opinions and/or findings contained in this report are those of...SECURITY CLASSIFICATION OF: 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE 13. SUPPLEMENTARY NOTES 12. DISTRIBUTION AVAILIBILITY STATEMENT 6...State University Title: Double Tunneling-Injection Quantum Dot Lasers for High -Speed Operation Report Term: 0-Other Email: asryan@vt.edu Distribution

Coherent Optical Generation of a 6 GHz Microwave Signal with Directly Phase Locked Semiconductor DFB Lasers

DEFF Research Database (Denmark)

Gliese, Ulrik Bo; Nielsen, Torben Nørskov; Bruun, Marlene

1992-01-01

Experimental results of a wideband heterodyne second order optical phase locked loop with 1.5 ¿m semiconductor lasers are presented. The loop has a bandwidth of 180 MHz, a gain of 181 dBHz and a propagation delay of only 400 ps. A beat signal of 8 MHz linewidth is phase locked to become a replica...... of a microwave reference source close to carrier with a noise level of ¿125 dBc/Hz. The total phase variance of the locked carrier is 0.04 rad2 and carriers can be generated in a continuous range from 3 to 18 GHz. The loop reliability is excellent with an average time to cycle slip of 1011 seconds...

Fabrication, operation, and applications of efficient dielectric waveguide lasers

NARCIS (Netherlands)

Pollnau, Markus; van Dalfsen, Koop; Bernhardi, Edward; Geskus, D.; Worhoff, Kerstin; de Ridder, R.M.; García Blanco, Sonia Maria

This paper reviews our recent results on rare-earth-ion-doped integrated lasers. We have concentrated our efforts on crystalline potassium double tungstates and amorphous aluminum oxide. In the former material class we have demonstrated channel waveguide lasers based on Yb3+ doping, operating near 1

Laser diode technology and applications

International Nuclear Information System (INIS)

Figueroa, L.

1989-01-01

This book covers a wide range of semiconductor laser technology, from new laser structures and laser design to applications in communications, remote sensing, and optoelectronics. The authors report on new laser diode physics and applications and present a survey of the state of the art as well as progress in new developments

High power operation of cladding pumped holmium-doped silica fibre lasers.

Science.gov (United States)

Hemming, Alexander; Bennetts, Shayne; Simakov, Nikita; Davidson, Alan; Haub, John; Carter, Adrian

2013-02-25

We report the highest power operation of a resonantly cladding-pumped, holmium-doped silica fibre laser. The cladding pumped all-glass fibre utilises a fluorine doped glass layer to provide low loss cladding guidance of the 1.95 µm pump radiation. The operation of both single mode and large-mode area fibre lasers was demonstrated, with up to 140 W of output power achieved. A slope efficiency of 59% versus launched pump power was demonstrated. The free running emission was measured to be 2.12-2.15 µm demonstrating the potential of this architecture to address the long wavelength operation of silica based fibre lasers with high efficiency.

Semiconductor micro cavities: half light, half matter

International Nuclear Information System (INIS)

Baumberg, Jeremy J.

2003-01-01

Quantum wells sandwiched tightly between two mirrors can be used to make a new type of laser that can amplify light more than any other known material. What do you get if you cross light with matter? It is a question that fascinates today's researchers in quantum optoelectronics, who want to see how far the physical states of the world can be intertwined. Although we have a good understanding of the quantum ingredients of optics and solids - photons and atoms - it turns out that assembling these building blocks in deliberately unfamiliar ways can lead to what is new and often quite unexpected behaviour. Consider 'quantum wells', which form the basis of modern semiconductor lasers. First developed in the 1980s, they lie at the heart of optical-communication and optical-storage technologies such as DVD players and they now have a global market of over 10bn British Pounds. Quantum wells consist of a thin sheet of crystalline semiconductor sandwiched between two sheets of another semiconductor. The outer layers squash the wavefunctions of electrons within the central sheet, increasing the electrons' energy and their interaction with light. Engineers can control the colour of the light emitted by the laser simply by adjusting the energy levels within the central sheet, which acts as a potential well. But this bug-sized playground for electrons has not just had technological ramifications. It has also spawned an enormous variety of new physics, including the quantum Hall effect, which can be used as a fundamental standard for measuring the ratio between the charge on the electron and the Planck constant. Over the last ten years researchers have also become increasingly keen to incorporate quantum wells into what are known as 'semiconductor micro cavities'. Physicists have found that these painstakingly layered materials can be used to create new quantum states that resemble superfluids and can be used in interferometric quantum devices. In the March issue of Physics

Narrow linewidth operation of the RILIS titanium: Sapphire laser at ISOLDE/CERN

CERN Document Server

Rothe, S; Wendt, K D A; Fedosseev, V N; Kron, T; Marsh, B A

2013-01-01

A narrow linewidth operating mode for the Ti:sapphire laser of the CERN ISOLDE Resonance Ionization Laser Ion Source (RILIS) has been developed. This satisfies the laser requirements for the programme of in-source resonance ionization spectroscopy measurements and improves the selectivity for isomer separation using RILIS. A linewidth reduction from typically 10 GHz down to 1 GHz was achieved by the intra-cavity insertion of a second (thick) Fabry-Perot etalon. Reliable operation during a laser scan was achieved through motorized control of the tilt angle of each etalon. A scanning, stabilization and mode cleaning procedure was developed and implemented in LabVIEW. The narrow linewidth operation was confirmed in a high resolution spectroscopy study of francium isotopes by the Collinear Resonance Ionization Spectroscopy experiment. The resulting laser scans demonstrate the suitability of the laser, in terms of linewidth, spectral purity and stability for high resolution in-source spectroscopy and isomer select...

Fiber transmission and generation of ultrawideband pulses by direct current modulation of semi-conductor lasers and chirp-to-intensity conversion

DEFF Research Database (Denmark)

Company Torres, Victor; Prince, Kamau; Tafur Monroy, Idelfonso

2008-01-01

Optical pulses generated by current modulation of semiconductor lasers are strongly frequency chirped. This effect has been considered pernicious for optical communications. We take advantage of this effect for the generation of ultrawideband microwave signals by using an optical filter to achieve...... chirp-to-intensity conversion. We also experimentally achieve propagation through a 20 km nonzero dispersion shifted fiber with no degradation of the signal at the receiver. Our method constitutes a prospective low-cost solution and offers integration capabilities with fiber...

Measurement of laser activated electron tunneling from semiconductor zinc oxide to adsorbed organic molecules by a matrix assisted laser desorption ionization mass spectrometer

International Nuclear Information System (INIS)

Zhong Hongying; Fu Jieying; Wang Xiaoli; Zheng Shi

2012-01-01

Highlights: ► Irradiation of photons with energies more than the band gap generates electron–hole pairs. ► Electron tunneling probability is dependent on the electron mobility. ► Tunneling electrons are captured by charge deficient atoms. ► Unpaired electrons induce cleavages of chemical bonds. - Abstract: Measurement of light induced heterogeneous electron transfer is important for understanding of fundamental processes involved in chemistry, physics and biology, which is still challenging by current techniques. Laser activated electron tunneling (LAET) from semiconductor metal oxides was observed and characterized by a MALDI (matrix assisted laser desorption ionization) mass spectrometer in this work. Nanoparticles of ZnO were placed on a MALDI sample plate. Free fatty acids and derivatives were used as models of organic compounds and directly deposited on the surface of ZnO nanoparticles. Irradiation of UV laser (λ = 355 nm) with energy more than the band gap of ZnO produces ions that can be detected in negative mode. When TiO 2 nanoparticles with similar band gap but much lower electron mobility were used, these ions were not observed unless the voltage on the sample plate was increased. The experimental results indicate that laser induced electron tunneling is dependent on the electron mobility and the strength of the electric field. Capture of low energy electrons by charge-deficient atoms of adsorbed organic molecules causes unpaired electron-directed cleavages of chemical bonds in a nonergodic pathway. In positive detection mode, electron tunneling cannot be observed due to the reverse moving direction of electrons. It should be able to expect that laser desorption ionization mass spectrometry is a new technique capable of probing the dynamics of electron tunneling. LAET offers advantages as a new ionization dissociation method for mass spectrometry.

Laser-beam interactions with materials

International Nuclear Information System (INIS)

Allmen, M.V.

1987-01-01

Lasers are becoming popular tools and research instruments in materials research, metallurgy, semiconductor technology and engineering. This text treats, from a physicist's point of view, the processes that lasers can induce in materials. A broad view of the field and its perspectives is given: physical topics covered range from optics to shock waves, and applications range from semiconductor annealing to fusion-plasma production. Intuitive analytical models are used whenever possible, in order to foster creative thinking and facilitate access to newcomers and nonspecialists

Tunable laser applications

CERN Document Server

Duarte, FJ

2008-01-01

Introduction F. J. Duarte Spectroscopic Applications of Tunable Optical Parametric Oscillators B. J. Orr, R. T. White, and Y. He Solid-State Dye Lasers Costela, I. García-Moreno, and R. Sastre Tunable Lasers Based on Dye-Doped Polymer Gain Media Incorporating Homogeneous Distributions of Functional Nanoparticles F. J. Duarte and R. O. James Broadly Tunable External-Cavity Semiconductor Lasers F. J. Duarte Tunable Fiber Lasers T. M. Shay and F. J. Duarte Fiber Laser Overview and Medical Applications

Radiation effects in semiconductor laser diode arrays

International Nuclear Information System (INIS)

Carson, R.F.

1988-01-01

The effects of radiation events are important for many of the present and future applications that involve optoelectronic components. Laser diodes show a strong resistance to degradation by gamma rays, prompt x-rays and (to a lesser extent), neutrons. This is due to the short carrier lifetime that is associated with stimulated emission and the high current injection conditions that are present in these devices. Radiation-resistant properties should carry over to many of the more recently developed devices such as multi-stripe array and broad area laser diodes. There are, however, additional considerations for radiation tolerance that are introduced by these devices. Arrays and other high power laser diodes have larger active region volumes than lower power single stripe devices. In addition, evanescent field coupling between stripes, the material quality available from newer MOCVD epitaxial growth techniques, and stripe definition methods may all influence the radiation tolerance of the high power laser diode devices. Radiation tests have been conducted on various GaAs-GaAlAs laser diode array and broad area devices. Tests involving total gamma dose have indicated that high power laser diodes and arrays have small degradations in light power output with current input after 4 MRad(Si) of radiation from a Co 60 source. Additional test results involving flash x-rays indicate that high power diode lasers and arrays are tolerant to 10 12 rads(Si)/sec, when observed on microsecond or millisecond time scales. High power diode laser devices were also irradiated with neutrons to a fluence of 10 14 neutrons/cm 2 with some degradation of threshold current level

Modeling Quantum Well Lasers

Directory of Open Access Journals (Sweden)

Dan Alexandru Anghel

2012-01-01

Full Text Available In semiconductor laser modeling, a good mathematical model gives near-reality results. Three methods of modeling solutions from the rate equations are presented and analyzed. A method based on the rate equations modeled in Simulink to describe quantum well lasers was presented. For different signal types like step function, saw tooth and sinus used as input, a good response of the used equations is obtained. Circuit model resulting from one of the rate equations models is presented and simulated in SPICE. Results show a good modeling behavior. Numerical simulation in MathCad gives satisfactory results for the study of the transitory and dynamic operation at small level of the injection current. The obtained numerical results show the specific limits of each model, according to theoretical analysis. Based on these results, software can be built that integrates circuit simulation and other modeling methods for quantum well lasers to have a tool that model and analysis these devices from all points of view.

Laser ablation principles and applications

CERN Document Server

1994-01-01

Laser Ablation provides a broad picture of the current understanding of laser ablation and its many applications, from the views of key contributors to the field. Discussed are in detail the electronic processes in laser ablation of semiconductors and insulators, the post-ionization of laser-desorbed biomolecules, Fourier-transform mass spectroscopy, the interaction of laser radiation with organic polymers, laser ablation and optical surface damage, laser desorption/ablation with laser detection, and laser ablation of superconducting thin films.

Development of Prototype Micro-Lidar using Narrow Linewidth Semiconductor Lasers for Mars Boundary Layer Wind and Dust Opacity Profiles

Science.gov (United States)

Menzies, Robert T.; Cardell, Greg; Chiao, Meng; Esproles, Carlos; Forouhar, Siamak; Hemmati, Hamid; Tratt, David

1999-01-01

We have developed a compact Doppler lidar concept which utilizes recent developments in semiconductor diode laser technology in order to be considered suitable for wind and dust opacity profiling in the Mars lower atmosphere from a surface location. The current understanding of the Mars global climate and meteorology is very limited, with only sparse, near-surface data available from the Viking and Mars Pathfinder landers, supplemented by long-range remote sensing of the Martian atmosphere. The in situ measurements from a lander-based Doppler lidar would provide a unique dataset particularly for the boundary layer. The coupling of the radiative properties of the lower atmosphere with the dynamics involves the radiative absorption and scattering effects of the wind-driven dust. Variability in solar irradiance, on diurnal and seasonal time scales, drives vertical mixing and PBL (planetary boundary layer) thickness. The lidar data will also contribute to an understanding of the impact of wind-driven dust on lander and rover operations and lifetime through an improvement in our understanding of Mars climatology. In this paper we discuss the Mars lidar concept, and the development of a laboratory prototype for performance studies, using, local boundary layer and topographic target measurements.

Biocavity Lasers

Energy Technology Data Exchange (ETDEWEB)

Gourley, P.L.; Gourley, M.F.

2000-10-05

Laser technology has advanced dramatically and is an integral part of today's healthcare delivery system. Lasers are used in the laboratory analysis of human blood samples and serve as surgical tools that kill, burn or cut tissue. Recent semiconductor microtechnology has reduced the size o f a laser to the size of a biological cell or even a virus particle. By integrating these ultra small lasers with biological systems, it is possible to create micro-electrical mechanical systems that may revolutionize health care delivery.

Rapid supersensitive laser-semiconductor monitoring system. Time period covered: Dec. 15, 1993 - Dec. 15, 1994

International Nuclear Information System (INIS)

Pugatch, V.M.

2001-01-01

The creation of the rapid and sensitive system for the determination of the Alpha-radioactivity in the Environmental samples has been determined as the main goal of the Research Contract No. 7200RO/RB. As a result of the first stage of the research accomplished in the year 1993, the prototype of the system based on the combination of the laser photoionization mass spectrometry and many-channel alpha-spectrometer has been built and tested. To improve the sensitivity it was proposed to add one more stage to the laser photoionization mass-spectrometer. To develop the high position sensitivity of the system it was proposed to include into the alpha-radiometer SI strip-detector with submicron position sensitivity. Hardware and software for the laser-semiconductor monitoring system of alpha-radionuclides in the environment have been further developed and tested in frames of the IAEA Research Contract No. 7200/R1/RB. Optimization of the sample evaporation with one more stage of photoionization has been successfully performed in the laser photoionization mass-spectrometer. The automatization of the measurement procedure is under way by means of the IBM PC-386 and specially designed electronic units. The evaluated sensitivity of the new set-up is in the range of 1.0 Bq/kg. A bulk measurement of the alpha-radioactivity concentration in soil samples from the Chernobyl region (100 km) have been performed by means of thick samples method and built under this contract alpha-radiometer with large area SI semiconductor detectors. The lowest detectable level was in the range 100 Bq/kg without any radiochemical separation. Comparison with the data obtained for the same probes by means of the thin sample (with radiochemical separation) has shown higher Pu-concentration values obtained by means of the thick samples. For the first time the Sl-strip-detector with 128 channels has been applied for the alpha-radiometry purposes. Different read-out electronics (including the most

Pump-probe surface photovoltage spectroscopy measurements on semiconductor epitaxial layers

International Nuclear Information System (INIS)

Jana, Dipankar; Porwal, S.; Sharma, T. K.; Oak, S. M.; Kumar, Shailendra

2014-01-01

Pump-probe Surface Photovoltage Spectroscopy (SPS) measurements are performed on semiconductor epitaxial layers. Here, an additional sub-bandgap cw pump laser beam is used in a conventional chopped light geometry SPS setup under the pump-probe configuration. The main role of pump laser beam is to saturate the sub-bandgap localized states whose contribution otherwise swamp the information related to the bandgap of material. It also affects the magnitude of Dember voltage in case of semi-insulating (SI) semiconductor substrates. Pump-probe SPS technique enables an accurate determination of the bandgap of semiconductor epitaxial layers even under the strong influence of localized sub-bandgap states. The pump beam is found to be very effective in suppressing the effect of surface/interface and bulk trap states. The overall magnitude of SPV signal is decided by the dependence of charge separation mechanisms on the intensity of the pump beam. On the contrary, an above bandgap cw pump laser can be used to distinguish the signatures of sub-bandgap states by suppressing the band edge related feature. Usefulness of the pump-probe SPS technique is established by unambiguously determining the bandgap of p-GaAs epitaxial layers grown on SI-GaAs substrates, SI-InP wafers, and p-GaN epilayers grown on Sapphire substrates

A mode-locked external-cavity quantum-dot laser with a variable repetition rate

International Nuclear Information System (INIS)

Wu Jian; Jin Peng; Li Xin-Kun; Wei Heng; Wu Yan-Hua; Wang Fei-Fei; Chen Hong-Mei; Wu Ju; Wang Zhan-Guo

2013-01-01

A mode-locked external-cavity laser emitting at 1.17-μm wavelength using an InAs/GaAs quantum-dot gain medium and a discrete semiconductor saturable absorber mirror is demonstrated. By changing the external-cavity length, repetition rates of 854, 912, and 969 MHz are achieved respectively. The narrowest −3-dB radio-frequency linewidth obtained is 38 kHz, indicating that the laser is under stable mode-locking operation. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Noise and optimum filtering in spectrometers with semiconductor detectors operating at elevated temperature

International Nuclear Information System (INIS)

Dabrowski, W.; Korbel, K.

1983-01-01

The importance of the excess noise in the semiconductor detectors operating at the elevated temperature is discussed. Under the assumption of a conventional CR-RC type filtration the variancy of the noise output is determined. The new term ''second noise-corner time constant'' was proposed. The expression for relative signal-to-noise ratio as the dependence on the noise as well as circuits time constants was derived. It was also presented in a graphical form. 12 refs., 6 figs. (author)

Compound Semiconductor Radiation Detectors

CERN Document Server

Owens, Alan

2012-01-01

Although elemental semiconductors such as silicon and germanium are standard for energy dispersive spectroscopy in the laboratory, their use for an increasing range of applications is becoming marginalized by their physical limitations, namely the need for ancillary cooling, their modest stopping powers, and radiation intolerance. Compound semiconductors, on the other hand, encompass such a wide range of physical and electronic properties that they have become viable competitors in a number of applications. Compound Semiconductor Radiation Detectors is a consolidated source of information on all aspects of the use of compound semiconductors for radiation detection and measurement. Serious Competitors to Germanium and Silicon Radiation Detectors Wide-gap compound semiconductors offer the ability to operate in a range of hostile thermal and radiation environments while still maintaining sub-keV spectral resolution at X-ray wavelengths. Narrow-gap materials offer the potential of exceeding the spectral resolutio...

Nanoimprinted polymer lasers with threshold below 100 W/cm2 using mixed-order distributed feedback resonators.

Science.gov (United States)

Wang, Yue; Tsiminis, Georgios; Kanibolotsky, Alexander L; Skabara, Peter J; Samuel, Ifor D W; Turnbull, Graham A

2013-06-17

Organic semiconductor lasers were fabricated by UV-nanoimprint lithography with thresholds as low as 57 W/cm(2) under 4 ns pulsed operation. The nanoimprinted lasers employed mixed-order distributed feedback resonators, with second-order gratings surrounded by first-order gratings, combined with a light-emitting conjugated polymer. They were pumped by InGaN LEDs to produce green-emitting lasers, with thresholds of 208 W/cm(2) (102 nJ/pulse). These hybrid lasers incorporate a scalable UV-nanoimprint lithography process, compatible with high-performance LEDs, therefore we have demonstrated a coherent, compact, low-cost light source.

Liquid detection with InGaAsP semiconductor lasers having multiple short external cavities.

Science.gov (United States)

Zhu, X; Cassidy, D T

1996-08-20

A liquid detection system consisting of a diode laser with multiple short external cavities (MSXC's) is reported. The MSXC diode laser operates single mode on one of 18 distinct modes that span a range of 72 nm. We selected the modes by setting the length of one of the external cavities using a piezoelectric positioner. One can measure the transmission through cells by modulating the injection current at audio frequencies and using phase-sensitive detection to reject the ambient light and reduce 1/f noise. A method to determine regions of single-mode operation by the rms of the output of the laser is described. The transmission data were processed by multivariate calibration techniques, i.e., partial least squares and principal component regression. Water concentration in acetone was used to demonstrate the performance of the system. A correlation coefficient of R(2) = 0.997 and 0.29% root-mean-square error of prediction are found for water concentration over the range of 2-19%.

Semiconductor lasers in rheumatological treatment

Science.gov (United States)

Pascu, Mihail-Lucian; Suteanu, S.; Ignat, P.; Pruna, Simion; Chitu, A.

1995-03-01

A computer controlled equipment, containing 6 lasers (HeNe and 5 diode lasers--DL) conceived to be used in rheumatological treatment is reported. DL emit at 895 nm and for typical applications, their expanded spots are superposed within the irradiation plane, on the HeNE defocused spot used to define the surface to be irradiated. DL emit 100 nsec pulses between 0.5 KHz and 1.5 KHz repetition rate and 0.5 mW average power (measured at 1 KHz). 150 patients with rheumathologic diseases were treated: lumbar spondylosis (75), gonarthrosis (30), cervical spondylosis (21), coxarthrosis (15), Heberden and Bouchard (9). The treatment consisted of: group I, 50 patients--laser therapy, 10 min/day, 10 days; group II, 50 patients--classical antirheumatic treatment; group III, 50 patients--mixed treatment. Assessment of sympathetic skin activity made using reactometry measurements, shows that latency time was longer before irradiation, 1867 +/- 289) msec then after, (1234 +/- 321) msec. Pain rating indexes decreasing for all three groups of patients were measured. Better results for more superficial diseases were obtained and best results were observed after irradiation with 1 KHz - 1.5 KHz repetition rate IR pulses. Better results were obtained when spot irradiation in a few points combined with zone irradiations was used.

Tracking frequency laser distance gauge

International Nuclear Information System (INIS)

Phillips, J.D.; Reasenberg, R.D.

2005-01-01

Advanced astronomical missions with greatly enhanced resolution and physics missions of unprecedented accuracy will require laser distance gauges of substantially improved performance. We describe a laser gauge, based on Pound-Drever-Hall locking, in which the optical frequency is adjusted to maintain an interferometer's null condition. This technique has been demonstrated with pm performance. Automatic fringe hopping allows it to track arbitrary distance changes. The instrument is intrinsically free of the nm-scale cyclic bias present in traditional (heterodyne) high-precision laser gauges. The output is a radio frequency, readily measured to sufficient accuracy. The laser gauge has operated in a resonant cavity, which improves precision, can suppress the effects of misalignments, and makes possible precise automatic alignment. The measurement of absolute distance requires little or no additional hardware, and has also been demonstrated. The proof-of-concept version, based on a stabilized HeNe laser and operating on a 0.5 m path, has achieved 10 pm precision with 0.1 s integration time, and 0.1 mm absolute distance accuracy. This version has also followed substantial distance changes as fast as 16 mm/s. We show that, if the precision in optical frequency is a fixed fraction of the linewidth, both incremental and absolute distance precision are independent of the distance measured. We discuss systematic error sources, and present plans for a new version of the gauge based on semiconductor lasers and fiber-coupled components

Shockwave generation by a semiconductor bridge operation in water

Energy Technology Data Exchange (ETDEWEB)

Zvulun, E.; Toker, G.; Gurovich, V. Tz.; Krasik, Ya. E. [Physics Department, Technion, Haifa 32000 (Israel)

2014-05-28

A semiconductor bridge (SCB) is a silicon device, used in explosive systems as the electrical initiator element. In recent years, SCB plasma has been extensively studied, both electrically and using fast photography and spectroscopic imaging. However, the value of the pressure buildup at the bridge remains unknown. In this study, we operated SCB devices in water and, using shadow imaging and reference beam interferometry, obtained the velocity of the shock wave propagation and distribution of the density of water. These results, together with a self-similar hydrodynamic model, were used to calculate the pressure generated by the exploding SCB. In addition, the results obtained showed that the energy of the water flow exceeds significantly the energy deposited into the exploded SCB. The latter can be explained by the combustion of the aluminum and silicon atoms released in water, which acts as an oxidizing medium.

Multistate intermittency on the route to chaos of a semiconductor laser subjected to optical feedback from a long external cavity.

Science.gov (United States)

Choi, Daeyoung; Wishon, Michael J; Chang, C Y; Citrin, D S; Locquet, A

2018-01-01

We observe experimentally two regimes of intermittency on the route to chaos of a semiconductor laser subjected to optical feedback from a long external cavity as the feedback level is increased. The first regime encountered corresponds to multistate intermittency involving two or three states composed of several combinations of periodic, quasiperiodic, and subharmonic dynamics. The second regime is observed for larger feedback levels and involves intermittency between period-doubled and chaotic regimes. This latter type of intermittency displays statistical properties similar to those of on-off intermittency.

Photobiostimulation effects on germination and early growth of wheat seeds (Triticum aestivum L) produced by a semiconductor laser with λ=980nm

International Nuclear Information System (INIS)

Michtchenko, A.; Hernandez, M.

2009-01-01

The effect of the exposure of wheat (Triticum aestivum L) seeds to a IR laser radiation with λ=980nm produced by a semiconductor laser on germination and early growth had been studied under laboratory conditions. Seeds were irradiated to one of two laser intensities 15 mWcm - ''2 or 30 mWcm -2 for different periods of time 30, 60 or 120 s. Seeds exposed to a light intensity of 15mWcm -2 and an exposition time of 30 s. showed an increase on the percentage of seeds germinated normally while the percentage of seeds germinated abnormally decreased. At the same time there is a stimulation effect on the growth of the stem and on the growth of the root of 10% on wheat seedlings over control seedlings. Significant differences (ρ < 0.001) were observed between the control and the above treatment. (Author)

Laser action on rare earth doped nitride semiconductor thin layers

International Nuclear Information System (INIS)

Oussif, A.; Diaf, M.

2010-01-01

Complete text of publication follows. The structure, chemical composition, properties, and their relationships in solids lay the foundation of materials science. Recently, great interest in rare-earth (RE)-doped wide-bandgap semiconductors, which combine the electronic properties of semiconductors with the unique luminescence features of RE ions, is from the fundamental standpoint of structure-composition-properties of solids. At first, a significant amount of work has been reported on the study of infrared emissions from Er 3+- doped semiconductors because Er 3+ exhibits luminescence at 1.54 μm, a wavelength used in optical communications. Since Steckl and Birkhahn first reported visible emission associated with Er from GaN:Er films, the RE-doped semiconductors have received considerable interest for possible application in light emitting devices. Molecular-beam epitaxy (MBE) and metalorganic chemical vapour deposition (MOCVD) have been used mainly to grow GaN host films. The RE dopants were typically incorporated into the host films by in situ doping during the growth or by ion implantation after the growth. GaN doped with rare-earth elements (RE) hold significant potential for applications in optical devices, since they show sharp intense luminescence which is only minimally affected by temperature variations. Among the various RE dopants, Eu seems to be the most interesting, since it yields red luminescence 622 nm which has not been realized in commercially available light emitting devices (LEDs) that use InGaN active layers. We have earlier reported single crystalline growth of Eu-doped GaN and nearly temperature independent red luminescence at 622 nm originating from the intra-4f-4f transition of the Eu 3+ ion. The red luminescence was analyzed and determined to be generated through trap-level-mediated energy transfer from the semiconductor host.

Mega-pixel PQR laser chips for interconnect, display ITS, and biocell-tweezers OEIC

Science.gov (United States)

Kwon, O'Dae; Yoon, J. H.; Kim, D. K.; Kim, Y. C.; Lee, S. E.; Kim, S. S.

2008-02-01

We describe a photonic quantum ring (PQR) laser device of three dimensional toroidal whispering gallery cavity. We have succeeded in fabricating the first genuine mega-pixel laser chips via regular semiconductor technology. This has been realized since the present injection laser emitting surface-normal dominant 3D whispering gallery modes (WGMs) can be operated CW with extremely low operating currents (μA-nA per pixel), together with the lasing temperature stabilities well above 140 deg C with minimal redshifts, which solves the well-known integration problems facing the conventional VCSEL. Such properties unusual for quantum well lasers become usual because the active region, involving vertically confining DBR structure in addition to the 2D concave WGM geometry, induces a 'photonic quantum ring (PQR)-like' carrier distribution through a photonic quantum corral effect. A few applications of such mega-pixel PQR chips are explained as follows: (A) Next-generation 3D semiconductor technologies demand a strategy on the inter-chip and intra-chip optical interconnect schemes with a key to the high-density emitter array. (B) Due to mounting traffic problems and fatalities ITS technology today is looking for a revolutionary change in the technology. We will thus outline how 'SLEEP-ITS' can emerge with the PQR's position-sensing capability. (C) We describe a recent PQR 'hole' laser of convex WGM: Mega-pixel PQR 'hole' laser chips are even easier to fabricate than PQR 'mesa' lasers. Genuine Laguerre-Gaussian (LG) beam patterns of PQR holes are very promising for biocell manipulations like sorting mouse myeloid leukemia (M1s) cells. (D) Energy saving and 3D speckle-free POR laser can outdo LEDs in view of red GaAs and blue GaN devices fabricated recently.

Plasmonic Waveguide-Integrated Nanowire Laser

DEFF Research Database (Denmark)

Bermudez-Urena, Esteban; Tutuncuoglu, Gozde; Cuerda, Javier

2017-01-01

Next-generation optoelectronic devices and photonic circuitry will have to incorporate on-chip compatible nanolaser sources. Semiconductor nanowire lasers have emerged as strong candidates for integrated systems with applications ranging from ultrasensitive sensing to data communication technolog......Next-generation optoelectronic devices and photonic circuitry will have to incorporate on-chip compatible nanolaser sources. Semiconductor nanowire lasers have emerged as strong candidates for integrated systems with applications ranging from ultrasensitive sensing to data communication...... technologies. Despite significant advances in their fundamental aspects, the integration within scalable photonic circuitry remains challenging. Here we report on the realization of hybrid photonic devices consisting of nanowire lasers integrated with wafer-scale lithographically designed V-groove plasmonic...

Diode-pumped passively mode-locked sub-picosecond Yb:LuAG ceramic laser

International Nuclear Information System (INIS)

Zhu Jiang-Feng; Liu Kai; Wang Jun-Li; Yang Yu; Wang Hui-Bo; Gao Zi-Ye; Jiang Li; Xie Teng-Fei; Chao-Yu Li; Pan Yu-Bai; Wei Zhi-Yi

2017-01-01

In this paper the laser activities of a diode-pumped Yb:LuAG ceramic which was prepared by the solid-state reactive sintering method were reported. The maximum output power was 1.86 W in the continuous wave (CW) laser operation, corresponding to a slope efficiency of 53.6%. The CW laser could be tuned from 1030 to 1096 nm by inserting a prism in the cavity. With the assist of a semiconductor saturable absorber mirror (SESAM), passive mode-locking was realized, delivering sub-picosecond pulses with 933 fs duration and an average power of 532 mW at a repetition rate of 90.35 MHz. (paper)

Generalized bipolariton model. propagation of a ultrashort laser pulse through a thin semiconductor film in the conditions of two-photon generation of biexcitons

International Nuclear Information System (INIS)

Igor Beloussov

2013-01-01

A generalized bipolariton model is proposed. Bipolaritons is formed from virtual excitons of four kinds. There exists both attractive and repulsive interaction between these excitons, though only excitons of a specific type can interact with light. A substantial difference between conventional and our models is shown for the case of nonlinear transmission/reflection of ultrashort laser pulses by a thin semiconductor film under two-photon generation of biexcitons. (author)