Showing papers in "Soviet Journal of Quantum Electronics in 1972"
TL;DR: A review of the principal properties of unstable resonators is given in this article, where applications of these resonators in various laser systems are considered as well as their properties and properties.
Abstract: A review is given of the investigations of the principal properties of unstable resonators. Applications of these resonators in various laser systems are considered
74 citations
TL;DR: In this paper, it was established experimentally that the use of unstable resonators with large equivalent Fresnel numbers made it possible to generate a single transverse mode in a homogeneous active medium.
Abstract: It was established experimentally that the use of unstable resonators with large equivalent Fresnel numbers made it possible to generate a single transverse mode in a homogeneous active medium. The angular divergence of this mode was close to the diffraction limit. A neodymium-glass laser with a divergence of 2 10−5 rad along one coordinate was developed.
27 citations
TL;DR: In this paper, it was shown that slight smoothing of the mirror edges leads to a considerable improvement of the selective properties of a resonator, contrary to the predictions of the theory of unstable resonators with sharp-edged mirrors.
Abstract: The results are given of numerical calculations of oscillation modes in unstable resonators. It is shown that slight smoothing of the mirror edges leads to a considerable improvement of the selective properties of a resonator. It is shown that, contrary to the predictions of the theory of unstable resonators with sharp-edged mirrors, oscillation in the lowest transverse mode described by the geometrical approximation is possible in real resonators with large equivalent Fresnel numbers.
21 citations
TL;DR: In this article, the thresholds of stimulated Brillouin scattering and the velocities of hypersound were determined experimentally for CH4, N2, Xe, and SF6.
Abstract: The thresholds of stimulated Brillouin scattering and the velocities of hypersound were determined experimentally for CH4, N2, Xe, and SF6. The instantaneous powers of a laser beam at the entry to a gas-filled cuvette and of the beam transmitted by the gap were recorded by two photocells. The signals from these photocells were applied to the horizontal and vertical deflection systems of a cathode-ray tube. Oscillograms obtained in this way were used to determine the threshold of stimulated Brillouin scattering. The threshold powers for different gases were compared with the corresponding value for methane at a pressure of 105 atm, for which the gain was calculated theoretically. The velocity of hypersound was deduced from the frequency shift between the spectra of the exciting and scattered radiation. The results of the measurements were used to calculate the linewidths and gains.
21 citations
TL;DR: In this article, the surface damage caused by singlemode radiation of a neodymium-glass laser operating under freeoscillation and giant-pulse (λ = 1.06 and 0.53 μ) conditions was investigated.
Abstract: An investigation was made of the surface damage caused by the single-mode radiation of a neodymium-glass laser operating under free-oscillation (λ = 1.06 μ) and giant-pulse (λ = 1.06 and 0.53 μ) conditions. The damage thresholds were identical at λ = 1.06 and 0.53 μ and were 120 MW/cm2 for LiNbO3 and 240 MW/cm2 for LiTaO3. The surface damage was observed after several flashes. It was established that the damage threshold under free-oscillation conditions increased with decreasing diameter of the light spot, whereas under giant-pulse conditions the threshold was independent of the size of the light spot. The surface damage mechanisms were considered and it was concluded that the Nb5+→Nb4+ reduction process was responsible for the damage to the surface of LiNbO3.
17 citations
TL;DR: In this paper, a theory of the resonant interaction between an ultrashort coherent light pulse and a semiconductor was given, which occurs when the pulse duration is less than the polarization or phase memory relaxation time.
Abstract: A theory is given of the resonant interaction between an ultrashort coherent light pulse and a semiconductor, which occurs when the pulse duration is less than the polarization or phase memory relaxation time. It is shown that, under certain conditions, a stationary 2? pulse can form. Numerical estimates of the velocity of propagation of a stable pulse are obtained for a typical semiconductor.
13 citations
TL;DR: A review of the applications of the Jones matrix method in calculations of the eigenvalues of the polarizations, frequencies, and losses of modes in anisotropic optical resonators is given in this paper.
Abstract: A review is given for the applications of the Jones matrix method in calculations of the eigenvalues of the polarizations, frequencies, and losses of modes in anisotropic optical resonators. Matrices representing anisotropic elements are considered. It is shown that in many cases the most general properties of the eigenpolarizations can be determined without the calculation of the matrix of the resonator in question. The approach is illustrated by calculations of the eigenvalues of the polarizations, frequencies, and losses of modes in linear and ring anisotropic resonators which are of practical importance.
12 citations
TL;DR: In this article, the influence of spiking on the spectral characteristics of injection-laser diodes was investigated and it was found that the emission spectrum obtained in the non-spiking case consisted of one or two longitudinal modes, whereas spikes characterized by a modulation depth of about 50% increased the number of modes to three or four.
Abstract: An investigation was made of the influence of spiking on the spectral characteristics of injection-laser diodes. The investigation was carried out on single and double GaAs diodes operating at 90°K. It was found that the emission spectrum obtained in the non-spiking case consisted of one or two longitudinal modes. Spiking characterized by a modulation depth of about 50% increased the number of modes to three or four. The appearance of spikes with a greater modulation depth gave rise to five to eight axial modes. This behavior of the emission spectrum of semiconductor lasers was attributed to the excitation of axial modes by spikes.
11 citations
TL;DR: In this paper, an experimental investigation was made of the dependence of the stimulated emission threshold of GaAs-AlAs injection lasers on the duration of pumping pulses in the 2-100 nsec range.
Abstract: An experimental investigation was made of the dependence of the stimulated emission threshold of GaAs–AlAs injection lasers on the duration of pumping pulses in the 2–100 nsec range. The effective lifetime of the injected electrons was determined for lasers with one diffused p–n junction (~1 nsec), with one heterojunction (~2.5 nsec), and with two heterojunctions (3–6 nsec).
10 citations
TL;DR: In this article, a waveguide resonator was used to reduce the laser threshold to 0.3 A/cm2 (in the electron energy range 15-20 keV), which was one or two orders of magnitude lower than for a laser with a homogeneous resonator.
Abstract: A method was developed for producing a waveguide resonator structure in an electron-beam- pumped semiconductor laser. When guided waves were excited in such a resonator, the laser threshold was found to be independent of the electron energy and the angular distribution of the output radiation was more complex than for a homogeneous resonator. The use of a waveguide resonator made it possible to reduce the laser threshold to 0.3 A/cm2 (in the electron energy range 15–20 keV), which was one or two orders of magnitude lower than for a laser with a homogeneous resonator.
10 citations
TL;DR: In this article, it was shown that conventional semiconductor lasers can be used for the retrieval of binary data from holograms in which the stored data density is ~104 bits/mm2.
Abstract: It is shown that conventional semiconductor lasers can be used for the retrieval of binary data from holograms in which the stored data density is ~104 bits/mm2.
TL;DR: In this paper, a solution was obtained for the equations describing the passage of a monochromatic radiation pulse of arbitrary shape I0(t) across a two-level absorbing medium with an active particle density N 0 = const.
Abstract: A solution is obtained for the equations describing the passage of a monochromatic radiation pulse of arbitrary shape I0(t) across a two-level absorbing medium with an activeparticle density N0 = const. It is shown that, depending on the ratio of the velocity of the medium v(t) to v0 = 2I0/N0, two modes of propagation of bleaching waves can be observed and the boundary between these modes is v = v0. The treatment is applicable to a radiation source moving at an arbitrary velocity in an absorbing medium.
TL;DR: In this paper, the damage to absorbing materials caused by the radiation generated in a rhodamine 6G laser in the form of structure-free pulses was investigated and some features of the effect on the absorbing materials were analyzed.
Abstract: The first investigations were made of the damage to absorbing materials caused by the radiation generated in a rhodamine 6G laser in the form of structure-free pulses. The laser was pumped by flashlamps and its output was in the form of 55-?sec pulses of 12?J energy. The maximum radiation power density was 3 ? 106 W/cm2. This radiation produced a quasistationary supersonic plasma jet with a relatively large angle of divergence. A static shock wave was formed in this jet. The dome-shaped configuration of this wave was determined by the geometry of the plasma jet. High-speed spectroscopic cinematography established that the spectrum was excited mainly in the static shock wave. The discontinuous structure of the plasma jet was probably due to the explosive (bulk) nature of the evaporation of a solid. The frequency of ejection of plasma bunches from lead was ~1 MHz (this was achieved using laser radiation of ~3 ? 106 W/cm2 power density). The velocity of the plasma jet was determined. The pressure in the interaction zone was estimated. Some features of the effect on the absorbing materials were analyzed.
TL;DR: In this paper, a laser with a telescopic resonator was controlled by injecting a signal from an external source into the axial zone of the resonator and the necessary average power of the external signal was determined for the case when this signal consisted of a random sequence of spikes.
Abstract: Radiation emitted from a laser with a telescopic resonator was controlled by injecting a signal from an external source into the axial zone of the resonator. The necessary average power of the external signal was determined for the case when this signal consisted of a random sequence of "spikes."
TL;DR: In this article, the authors describe a method for the design of energy guides, which is used in laser resonators to reduce the size and improve the parameters and the reliability of laser systems.
Abstract: New laser resonators, called energy guides, are described. These energy guides are small, but the path traveled by the radiation interacting with the active material is long. The use of such guides makes it possible to reduce the size and improve the parameters and the reliability of laser systems. A description is given of a method for the design of energy guides. Examples of design calculations are reported and a guide made of neodymium glass is described. The results of preliminary experiments are reported. It was found that although a neodymium-glass energy guide was small the active path of the radiation could be up to 2.5 m long. The use of this guide reduced the excitation threshold, improved the mode structure, and reduced the divergence of the laser beam.
TL;DR: In this paper, an experimental investigation was made on the dependence of the optical breakdown threshold of various organic liquids on their purity, and it was concluded that the optical strength of laser resonator elements was governed by the presence of absorbing microparticles in the bulk and particularly on the surfaces of these elements.
Abstract: An experimental investigation was made on the dependence of the optical breakdown threshold of various organic liquids on their purity. It was found that the optical strength of a liquid could be increased by two orders of magnitude by the removal of "mechanical" impurities. It was concluded that the optical strength of laser resonator elements was governed by the presence of absorbing microparticles in the bulk and, particularly, on the surfaces of these elements.
TL;DR: In this paper, the authors investigated the influence of the scattering of light in an exploding switch on the angular divergence of the radiation emitted by a single-pulse laser with an unstable resonator.
Abstract: Some problems encountered in the construction of multichannel single-pulse laser systems are considered. Estimates are made and the results are given of an experimental study of the influence of the scattering of light in an exploding switch on the angular divergence of the radiation emitted by a laser with an unstable resonator. An experimental investigation is reported on the performance of a single-channel amplifying system made of neodymium-glass active elements 600 mm long and 45 mm in diameter. A description is given of a multichannel multiple-pulse system with a total output energy of 1000 J and a pulse output power of 15 GW.
TL;DR: In this paper, a spectroscopic investigation was made of the stimulated radiation emitted by excited DF molecules generated by chemical reactions in D2 + F2, D2+ NF3, D 2 + N2F4, and D 2+ FNO2 mixtures at pressures of ~1 torr.
Abstract: A spectroscopic investigation was made of the stimulated radiation emitted by excited DF molecules generated by chemical reactions in D2 + F2, D2 + NF3, D2 + N2F4, and D2 + FNO2 mixtures at pressures of ~1 torr. It was found that the largest number of stimulated emission lines (including those in the 1–0 band) was emitted by the laser utilizing the D2 + NF3 mixture. A study of the time dependences of the intensities of various lines made it possible to explain the features associated with cascade transitions and with the rise of the temperature of the mixture during a reaction.
TL;DR: In this paper, a thin metal film was used in the resonator for the selection of CO2 laser rotational lines of wavelengths 9.6 and 10.6 μ, and a tentative explanation was given of some features of the typical emission spectra obtained when the resonance length is varied by λ/2.
Abstract: A thin metal film was used in the resonator for the selection of CO2 laser rotational lines of wavelengths 9.6 and 10.6 μ. It is shown how this can be carried out in practice. A tentative explanation is given of some features of the typical emission spectra obtained when the resonator length is varied by λ/2.
TL;DR: In this article, an apparatus was developed for measuring the natural resonance frequencies and the amplitudes of vibrations of mechanical structure elements by a contactless method, and the results were given of experimental investigations of elements of semiconductor devices.
Abstract: An apparatus was developed for measuring the natural resonance frequencies and the amplitudes of vibrations of mechanical structure elements by a contactless method. The measurement method is described and the results are given of experimental investigations of elements of semiconductor devices.
TL;DR: In this paper, a theoretical investigation is made of a ring laser subjected to a longitudinal magnetic field in the case when the anisotropy of the resonator is purely circular in nature.
Abstract: A theoretical investigation is made of a ring laser subjected to a longitudinal magnetic field in the case when the anisotropy of the resonator is purely circular in nature. Four-wave emission is considered. Two separate cases are discussed: 1) two pairs of identically polarized circular waves traveling in opposite directions; 2) two orthogonal pairs of circular waves. A nonlinear interaction between the traveling waves and the stability of both cases are considered.
TL;DR: In this paper, a multielement laser of the emitting mirror type was constructed from a GaAs crystal and pumped by electron beam bombardment, achieving an output of 28 kW from a crystal of 1 cm2 area.
Abstract: A multielement laser of the emitting mirror type was constructed from a GaAs crystal and pumped by electron beam bombardment. The output power increased linearly with increasing area of the multielement target. An output of 28 kW from a crystal of 1 cm2 area was achieved. The angular divergence of the beam was 7° and the emission spectrum consisted of several lines corresponding to oscillation modes of the Fabry–Perot resonator.
TL;DR: Holographic diffraction gratings and some systems in which they are employed are described in this paper, where the properties and applications of holographic zone plates, which act as hologram lenses, are considered.
Abstract: Topics associated with the fabrication and applications of holographic optical elements are reviewed. The existing optical elements do not always satisfy the requirements of coherent optics. The properties and applications of holographic zone plates, which act as hologram lenses, are considered. These hologram lenses can be used in holographic multiple imaging systems. Holographic diffraction gratings and some systems in which they are employed are described. Holographic elements used without additional optical parts, i.e., systems demonstrating most clearly the advantages of holographic elements, are discussed. Complex holographic systems performing functions outside the bounds of classical optics are considered.
TL;DR: In this paper, the optimal conditions for the laser action in rhodamine 6G pumped by a pinched discharge were determined as a function of the pressure in the discharge chamber, the reflection coefficients of the mirrors, and the concentration of the rhodamines solution.
Abstract: A study was made of the optimal conditions for the laser action in rhodamine 6G pumped by a pinched discharge. These conditions were determined as a function of the pressure in the discharge chamber, the reflection coefficients of the mirrors, and the concentration of the rhodamine solution. It was found that the laser output energy was a superlinear function of the electrical pumping energy. This was attributed to an increase in the efficiency of the pinched discharge which occurred when the electrical energy was increased. The maximum efficiency of the rhodamine laser was 0.2%, the energy output was 1 J/cm3, and the maximum output power was 10 MW.
TL;DR: In this article, a brief description of the apparatus and method used in laser ranging measurements of the distance from the reflector on board Lunokhod-1 is given and the results of the first experiments are reported.
Abstract: A brief description is given of the apparatus and method used in laser ranging measurements of the distance from the reflector on board Lunokhod-1. The results of the first experiments are reported.
TL;DR: In this paper, the populations of the Ar II laser levels were determined as a function of the current density and the pressure in tubes of 2.8 and 4.8 mm diameter.
Abstract: The populations of the Ar II laser levels were determined as a function of the current density and the pressure in tubes of 2.8 and 4.8 mm diameter. The higher specific output power obtained from the larger diameter tubes was due to the stronger population inversion. The influence of a longitudinal magnetic field on the populations of the Ar II levels was investigated. The dependence of the inversion on the magnetic field was found to be nonmonotonic: There was an optimal magnetic field in which the inversion was strongest. This behavior of the inversion was attributed to the capture of resonance radiation and depopulation of the upper levels as a result of collisions with electrons. The experimentally determined populations of the Ar II levels were compared with the theoretical values.
TL;DR: In this paper, the authors investigated the time characteristics of an electron-beam-pumped GaAs sealed-enclosure laser with a wide-band system of deflecting plates and a grid modulation electrode.
Abstract: The results are given of an investigation of the time characteristics of an electron-beam-pumped GaAs sealed-enclosure laser. Spatial scanning of the electron beam across the GaAs crystal made it possible to vary the power, shape, and repetition frequency of 10−10–10−6 sec laser output pulses. The scanning was achieved by a wide-band system of deflecting plates and a grid modulation electrode.
TL;DR: In this article, the effective nonlinear polarization coefficient d31sinθm+d22 cos θm of proustite was measured for an incident beam propagating in the positive crystallographic quadrant.
Abstract: The effective nonlinear polarization coefficient d31sinθm+d22 cosθmof proustite was measured for an incident beam propagating in the positive crystallographic quadrant. The nonlinear polarization coefficient d11 of tellurium was determined making allowance for the spectral width of the incident beam. This beam was generated by a Q-switched CO2 laser operating in the single-mode regime.
TL;DR: In this paper, a theoretical analysis of the interaction between a charged particle and a plane electromagnetic wave in a medium whose refractive index is n > 1 is given, and it is shown that when the wave field exceeds a certain critical value, a particle located outside the wave cannot penetrate it and a particle inside the wave can escape from it.
Abstract: A theoretical analysis is given of the interaction between a charged particle and a plane electromagnetic wave in a medium whose refractive index is n > 1. It is shown that when the wave field exceeds a certain critical value, a particle located outside the wave cannot penetrate it and a particle inside the wave cannot escape from it. If the initial conditions are such that the wave overtakes the particle, Cerenkov photons are absorbed at the critical point (the inverse Cerenkov effect takes place). Therefore, the energy of the particle increases and the particle detaches itself from the wave. However, if the particle overtakes the wave, the interaction results in a loss of energy by the particle and this energy is transferred to the wave in the form of stimulated Cerenkov radiation.
TL;DR: An improvement in the laser characteristics of CdS single crystals was achieved by the reduction of the sublimation and growth temperatures as discussed by the authors, which had low thresholds (down to 0.2 A/cm2) and high efficiencies (up to 30%).
Abstract: An improvement in the laser characteristics of CdS single crystals was achieved by the reduction of the sublimation andgrowth temperatures. Lasers utilizing these crystals had low thresholds (down to 0.2 A/cm2) and high efficiencies (up to 30%).