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A vertical-cavity surface-emitting laser (VCSEL) based on (110) InGaAs/GaAs multiple quantum wells (MQWs) was fabricated and characterized. Circularly polarized lasing by optical pumping was demonstrated. A high degree of circular polarization, 0.94, was observed at 77 K, reflecting the long electron spin relaxation time in the (110) MQWs.
A pneumatic optical medium (POM) sensitive to pressure and temperature due to gaseous voids inside is studied theoretically. The properties of glass, quartz and mica made POM in infrared and visual regions are analyzed. The Kerr type nonlinearity is predicted. Multiscale regimes of pressure and temperature indication are discussed.
The phenomenon of collective recombination (superfluorescence or superradiance) of electrons and holes in semiconductor laser structures of various dimensions is reviewed. At the current level of technology, this phenomenon can be realized most easily in quantum-well and quantum-dot heterostructures. Under CW pumping, it could lead to the generation of powerful coherent radiation pulses which are...
Tapered semiconductor optical amplifier (SOA) based on SQW improved nanostructure (gain maximum at 840 nm) was used as output power amplifier in MOPA-system with SLD as master oscillator. CW output power of up to 0.5 W ex standard multimode fiber (MMF) was obtained.
Device structures in high refractive index materials, notably semiconductors such as silicon, will form the basis for high-density integrated photonics. Nanometre-scale structuring - in conjunction with photonic crystal, photonic wire and plasmonic/metamaterial principles - will be required in order to realise the full potential for a variety of applications.
Spiraling of laser beams in nonlinear media is one of the manifestations of optical orbital angular momentum (OAM). We explore unusual dynamics of spiraling spatial solitons, including stabilization of azimuthons and quasi-periodic transformations of nonlocal solitons, as well as contribution of OAM towards suppression of catastrophic self-focusing, or collapse, in Kerr media.
Of a high interest now are the light fields with spatially inhomogeneous polarization state. These fields give new possibilities for many aspects of optical science and engineering. We consider a new effective method for the synthesis of light fields with predetermined polarization structure by means of specific diffractive optical element (DOE).
We discuss tunability and nonlinear properties of metamaterials operating at microwave and optical frequencies. We also study the fundamental nonlinear effects in metal-dielectric waveguides supporting surface plasmon polaritons, and discuss nanofocusing of a plasmon beam and soliton formation in a tapered waveguide in the presence of losses.
We study the lasing eigenvalue problem for a generic open dielectric resonator with gain material. The gain is introduced within the active region via the “active” imaginary part of the refractive index. Each eigenvalue is constituted of two positive numbers, namely, the lasing wavenumber and the threshold value of material gain. This approach yields clear insight into the lasing thresholds of individual...
The water cooled deformable mirror of the bimorph type is intended for beam correction in the CW solid state laser with output power of 10 kW level. An operation of the adaptive system using Shack-Hartmann wavefront sensor and deformable mirror is based on the phase conjugating algorithm. The first results will be presented in this report.
Lasing properties of dyed random media under different excited region size and the medium thickness were investigated. Random lasing threshold, spectrum wavelength and intensity are appreciably dependent both on the excited region size and the medium thickness. It proves both lengthwise and crosswise spatial confinement of random lasing.
We consider the lasing modes in a thin kite-shaped active microcavity as solutions to the 2-D linear eigenproblem for the Maxwell equations with exact boundary and radiation conditions. This problem is reduced to the set of Muller's integral equations with smooth and integrable kernels discretized using the adequate quadrature formulas. The eigenvalues are found numerically as the roots of the corresponding...
Accuracy of differential-phase measurements depends on actual shape of laser beams formed by focusing optics. In present work two factors affecting beam profile are considered: aperture limiting and asymmetrical intensity irregularities. Ripples in measured signal are found to be caused by beam sidelobes. Asymmetry of beams leads to direction-dependent measurements.
The results of experimental study of spectral, power and field characteristics of spiral resonators with whispering gallery-like modes (WGM) in the millimeter wave band by means of the computerized measuring stand are presented. Design of tunable filters and systems with directional radiation on the base of such resonators is discussed.
Investigation of compact slab guide resonators with variable geometry, guide material and surface quality by automated scanning interferometer with high precision positioning system has been performed. Obtained optimization criteria are used to improve parameters of compact (including dimensions up to less then some cm) slab guide and multi pass laser resonators. On the other hand very high sensitivity...
We study the dynamical properties of the RZ-DPSK encoded sequences of bits, focusing on the instabilities in the train leading to the bit stream corruption. The problem is studied within the framework of the complex Toda chain model for optical solitons. We show how the bit composition of the pattern affects the initial stage of the train dynamics and explain the general mechanisms of the appearance...
With an emphasis on experimental observations, we review the state of the art in the area of optical spatial solitons in unbiased nematic liquid crystals, outlining their basic and applied features and discussing recent results, including soliton interaction with curved surfaces and observation of dynamical instability of two counterpropagating solitons.
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