Racism in Modern Russia

In October 2013, one of the largest anti-migrant riots took place in Moscow. Clashes and arrests continued late into the night. Some in the crowd, which grew to several thousand people, could be heard chanting “Russia for the Russians” with their animus directed towards dark-skinned labor migrants from the southern border. The slogan “Russia for the Russians” is not a recent invention. It first gained notoriety in the very last years of the tsarist regime, appealing primarily to individuals drawn to the radical right. Analyzing a wide range of printed and visual sources, Racism in Modern Russia marks the first serious attempt to understand the history of racism over a span of 150 years. A brilliant examination of the complexities of racism, Eugene M. Avrutin’s panoramic book asks powerful questions about inequality and privilege, denigration and belonging, power and policy, and the complex historical links between race, whiteness, and geography. The ebook editions of this book are available open access under a CC BY-NC-ND 4.0 license on www.bloomsburycollections.com

Racism in Modern Russia

In October 2013, one of the largest anti-migrant riots took place in Moscow. Clashes and arrests continued late into the night. Some in the crowd, which grew to several thousand people, could be heard chanting “Russia for the Russians” with their animus directed towards dark-skinned labor migrants from the southern border. The slogan “Russia for the Russians” is not a recent invention. It first gained notoriety in the very last years of the tsarist regime, appealing primarily to individuals drawn to the radical right. Analyzing a wide range of printed and visual sources, Racism in Modern Russia marks the first serious attempt to understand the history of racism over a span of 150 years. A brilliant examination of the complexities of racism, Eugene M. Avrutin’s panoramic book asks powerful questions about inequality and privilege, denigration and belonging, power and policy, and the complex historical links between race, whiteness, and geography. The ebook editions of this book are available open access under a CC BY-NC-ND 4.0 license on www.bloomsburycollections.com

Delay-differential-equation modeling of mode-locked vertical-external-cavity surface-emitting lasers in different cavity configurations

A simple, versatile model for the dynamics of electrically and optically pumped vertical-external-cavity surface-emitting lasers mode locked by semiconductor saturable absorber mirror is presented. The difference between the laser operation in the linear and folded cavity, as well as the potential for colliding pulse operation, are studied

Dynamics of of single- and multicontact external cavity semiconductor lasers under intracavity frequency sweeping: effects of material and laser parameters.

We present numerical analysis of the dynamic behaviour of a single- and multicontact Fabry-Perot semiconductor laser frequency-swept by means of an ultrafast intracavity filter. The interrelated roles of the tuning speed, the filter bandwidth, the cavity length, and the self phase modulation in laser dynamics are analysed. Regular and irregular mode hopping, as well as fundamental and second harmonic sliding frequency mode locking and chaotic laser operation are identified as important dynamic regimes. The relation between the tuning dynamics asymmetry and the self-phase modulation in the laser is studied. The operation of a multicontact laser with an intracavity saturable absorber in a combined sliding-frequency and passive mode locking regime is shown; the dynamic asymmetry in the laser behaviour is shown to be reduced but not eliminated by the presence of the absorber

Photoelectric Properties of InAs/GaAs Quantum Dot Photoconductive Antenna Wafers

In this paper, the study of the photoconductivity in self-assembled InAs/GaAs quantum dot photoconductive antenna in the wavelength region between 1140 nm and 1250 nm at temperatures ranging from 13 to 400 K is reported. These antennas are aimed to work in conjunction with quantum dot semiconductor lasers to effectively generate pulsed and continuous wave terahertz radiation. For the efficient operation, laser wavelengths providing the highest photocurrent should be determined. To study the interband photoconductivity of quantum dot photoconductive antennas, at room and cryogenic temperatures, we employed a broadly-tunable InAs/GaAs quantum dot based laser providing a coherent pump with power exceeding 20 mW over a 100 nm tunability range. The quantum dot antenna structure revealed sharp temperature-dependent photoconductivity peaks in the vicinity of wavelengths, corresponding to the ground and excited states of InAs/GaAs quantum dots. The ground state photoconductivity peak vanishes with a temperature drop, whereas the excited state peak persists. We associate this effect with different mechanisms of photoexcited carriers extraction from quantum dots

Photoconductivity of an InAs/GaAs self-assembled quantum dot photoconductive THz antenna

A broadband terahertz (THz) source is desirable for applications such as imaging, spectroscopy and security. Towards this, an InAs/GaAs quantum dot (QD) based photoconductive antenna (PCA) is a promising and compact solution for THz generation. Coherent THz radiation in the pulsed and the CW regime has been generated with a QD PCA under a resonant and off-resonant pumps [1, 2]. While photoconductivity of QD materials in mid- and far-IR at lower temperatures has been studied for cryogenic sensors and attributed to interlevel transitions, near-IE interband photoconductivity needs further investigation [3, 4]. In this work, we report on the photoconductive properties of an InAs/GaAs QD PCA pumped by a broadly-tunable InAs/GaAs QD external-cavity diode laser

High-energy sub-nanosecond optical pulse generation with a semiconductor laser diode for pulsed TOF laser ranging utilizing the single photon detection approach

Bulk and quantum well laser diodes with a large equivalent spot size of da/Γa ≈ 3 µm and stripe width/cavity length of 30 µm/3 mm were realized and tested. They achieved a pulse energy and pulse length of the order of ~1 nJ and ~100 ps, respectively, with a peak pulse current of 6–8 A and a current pulse width of 1 ns. The 2D characteristics of the optical output power versus wavelength and time were also analyzed with a monochromator/streak camera set-up. The far-field characteristics were studied with respect to the time-homogeneity and energy distribution. The feasibility of a laser diode with a large equivalent spot size in single photon detection based laser ranging was demonstrated to a non-cooperative target at a distance of a few tens of meters

Strong Doping of the n-Optical Confinement Layer for Increasing Output Power of High- Power Pulsed Laser Diodes in the Eye Safe Wavelength Range

Abstract—An analytical model for internal optical losses at high power in a 1.5 μm laser diode with strong n-doping in the n-side of the optical confinement layer is created. The model includes intervalence band absorption by holes supplied by both current flow and two-photon absorption, as well as the direct two-photon absorption effect. The resulting losses are compared with those in an identical structure with a weakly doped waveguide, and shown to be substantially lower, resulting in a significant improvement in the output power and efficiency in the structure with a strongly doped waveguid

Edge emitting mode-locked quantum dot lasers

Edge-emitting mode-locked quantum-dot (QD) lasers are compact, highly efficient sources for the generation of picosecond and femtosecond pulses and/or broad frequency combs. They provide direct electrical control and footprints down to few millimeters. Their broad gain bandwidths (up to 50 nm for ground to ground state transitions as discussed below, with potential for increase to more than >200 nm by overlapping ground and excited state band transitions) allow for wavelength-tuning and generation of pico- and femtosecond laser pulses over a broad wavelength range. In the last two decades, mode-locked QD laser have become promising tools for low-power applications in ultrafast photonics. In this article, we review the development and the state-of-the-art of edge-emitting mode-locked QD lasers. We start with a brief introduction on QD active media and their uses in lasers, amplifiers, and saturable absorbers. We further discuss the basic principles of mode-locking in QD lasers, including theory of nonlinear phenomena in QD waveguides, ultrafast carrier dynamics, and mode-locking methods. Different types of mode-locked QD laser systems, such as monolithic one- and two-section devices, external-cavity setups, two-wavelength operation, and master-oscillator power-amplifier systems, are discussed and compared. After presenting the recent trends and results in the field of mode-locked QD lasers, we briefly discuss the application areas

High Power 1.5um Pulsed Laser Diode with Asymmetric Waveguide and Active Layer Near p-cladding

We report first experimental results on a high-power pulsed semiconductor laser operating in the eye-safe spectral range (wavelength around 1.5 lm) with an asymmetric waveguide structure. The laser has a bulk active layer positioned very close to the p-cladding in order to eliminate current-induced nonuniform carrier accumulation in the p-side of the waveguide and the associated carrier losses. Moderate doping of the n-side of the waveguide is used to strongly suppress nonuniform carrier accumulation within this part of the waveguide. Highly p-doped InP p-cladding facilitates low series resistance. An as-cleaved sample with a stripe width of 90 lm exhibits an output power of about 18 W at a pumping current amplitude of 80 A. Theoretical calculations, validated by comparison to experiment, suggest that the performance of lasers of this type can be improved further by optimization of the waveguide thickness and doping as well as improvement of injection efficiency.publishedVersionPeer reviewe