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It was demonstrated experimentally that a metal?insulator?semiconductor?insulator?metal (MISIM) structure based on a high-resistivity semiconductor can be used as a memory with optical write and read operations. The power of the light pulses required for the write and read operations was estimated. The storage time at room temperature did not exceed 10?3 sec, but at 77?K it was in excess of 8 h. Repeated readout of the information was confirmed experimentally. The duration of the read light pulses should not exceed ~10?8 sec. The information could be erased by switching off the static bias or by applying a field of the polarity opposite to that bias. The write?read?erase cycle time was ~10?7 sec.

An analysis is made of the possibility of construction of arithmetic units based on the passage of light signals through electric-field-controlled optical transparencies. Such arithmetic units can perform any Boolean algebraic operations. Methods for performing the basic arithmetic operations (addition, subtraction, multiplication, and division) are described. A brief discussion is given of the block diagram of an optoelectronic arithmetic unit with a speed of several tens of millions of algorithmic operations per second.

An analysis is made of the properties of a metal–insulator–semiconductor–insulator–metal structure which can be used in memory devices with optical write and read stages. It is shown that optically recorded information can be stored in the form of free-charge layers which screen the external field for several days. The capture of free carriers by surface centers makes it possible to dispense the division of a memory into separate cells. The information can be erased by the application of a voltage pulse. The time of drift of free carriers (~10–9 sec) into the surface layers governs the response in the write stage. The resolution is determined by the edge effect of the electric field in microcapacitors formed in such a structure and by the diffusion of carriers: The resolution may amount to 300 lines/mm. The information is read out using the Franz–Keldysh effect or the electrooptic effect. The main disadvantage of the first method is the change in the information during the readout process, which reduces considerably the information storage time. The electrooptic readout method requires higher electric fields, and consequently, materials of high electric strength. It is shown that ZnS can be used (its electric strength permits the use of fields of ~105 V/cm). Other suitable materials include ZnTe and CdTe, which have the highest known electrooptic coefficients.

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.

An investigation was made of the possibility of using the photoelectric effect in a Schottky barrier at a metal–semiconductor interface for detection of waveguide radiation. The dependences of the photocurrent and photo-emf on the power at the entry to such a photodetector were determined for GaAsxP1–x–GaP waveguide structures with barriers formed at gold and silver contacts, and the quantum efficiency was calculated.

An investigation was made of the photoluminescence spectra (T=77°K) of CdS crystals as a function of the equilibrium carrier density n=1013–1018cm−3. The effective optical gain and the threshold current density were determined at T=85°K when the same crystals were excited by an electron beam. The highest gain, amounting to 70–100 cm−1 (corresponding to j=1 A/cm2), and the lowest threshold current density were recorded for undoped crystals (n=1013–1014cm−3), whose photoluminescence spectra included the line due to free A excitons and the luminescence resulting from the recombination of these excitons accompanied by the emission of one or two longitudinal optical phonons. The results indicated that CdS crystals with n>5×1016cm−3 were unsuitable as the active material for electron-beam-excited lasers.

Electromagnetic oscillations of 180 kHz frequency tunable in a range of 30 kHz were generated in a metal–barrier–metal–barrier–metal (MBMBM) structure characterized by a negative differential resistance. Such structures are potential tunable sources of electromagnetic radiation ranging from the radio to the optical frequencies.

An investigation was made of mode matching in multilayer waveguide structures using inclined volume phase grating structures and methods of recording these were compared. An analysis was made of the feasibility of using these structures to match waveguides having different refractive indices on a single substrate. A study was made of the influence of the interface between the waveguides on their matching efficiency. A matching efficiency of ~80% was achieved.

Laser radiation was generated in zinc sulfide crystals by streamer excitation using both transverse and longitudinal systems for coupling out the radiation. The output power was 170 W (T = 77 K) in the first case and 1 kW (300 K) in the second. A study was made of the crystallographic orientation of the streamer tracks in zinc sulfide single crystals containing between 2% and 10% of the hexagonal phase.

An investigation was made of the matching between various types of semiconductor sources and thin-film planar and stripe waveguides by the tunneling of the optical energy via a prism coupling device and via a system comprising an optical fiber and a planar waveguide. The maximum coupling efficiency was found to be ~ 60%.

A theoretical investigation is reported of the influence of the electron-phonon interaction on the long-wavelength edge of the gain band of semiconductors. A numerical study is made of the specific case of a CdS crystal. It is shown that this interaction allows us to explain some of the experimentally observed effects.

An analysis is made of some aspects of defect formation in laser semiconductor crystals under conditions of capture of nonequilibrium carriers by the resonance level of a deep center. Calculations are made of the resonance level width GAMMA/sub n/ with respect to electron autoionization for the cases of acceptor and donor centers. A numerical investigation is made by computer of the dependence of GAMMA/sub n/ on the captured electron energy and on various center parameters. A comparison is made with the experiment for the case of a donor center. Analyses are also made of some aspects of the defect formation kinetics. Functions describing the increase in the stimulated emission threshold and the laser service life are determined and a comparison is made with some experimental results.

Single-crystal ingots of ZnSe1–xTex, (0 ≤ x ≤ 0.03), Zn1–xCdxSe (0 ≤ x ≤ 0.15), and ZnxCd1–xS (0 ≤ x ≤ 0.35) with diameters up to 50 mm and height up to 20 mm were prepared from the vapor phase. Investigations were made of the cathodoluminescence emitted by these crystals and of the characteristics of the lasers made from them and subjected to longitudinal pumping with an electron beam. In contrast to the two other systems, single crystals of ZnSe1–xTex were unsuitable for semiconductor lasers emitting in the dark blue range because deep levels appeared in the band gap at low Te concentrations.

A calculation is made of the spectral characteristics and kinetics of emission of radiation by a streamer semiconductor laser. The influence of the resonator parameters and of the cooling time of the electron-hole subsystem on the laser spectra is considered. It is shown that lasing results in a nonmonotonic change in the effective temperature of the electron–hole subsystem at the leading edge of the output radiation pulse and slows down the cooling of carriers.

Laser screens for cathode-ray tubes were made of single-crystal ingots of cadmium sulfide, cadmium sulfide-selenide solid solutions, and zinc selenide emitting in the 0.45–0.64 μ range. The homogeneity and stability of the radiation emitted from these screens were studied. The service life of laser screens was found to be governed mainly by the stability of the reflection coatings.

A report is given of the first ever investigations of an injection laser having an unstable resonator. It was found that in such a laser the transverse field distribution is stabilized and only one longitudinal mode is excited.

It is shown theoretically that self-induced transparency may occur during propagation of a laser radiation pulse in the case of two-photon interaction with small-radius excitons. An experimental method for the observation of this effect is suggested.

An investigation was made of the characteristics of switching and photosensitivity of a reusable optoelectronic storage medium based on planar metal–insulator–semiconductor–insulator–metal structures. Estimates indicate that data can be stored in such a medium with a density in excess of 107 bit/cm2 and the energy needed to record one bit is about 2×10−13 J.

An experimental study was made of the process of quenching and buildup of relaxation and self-modulation oscillations of the output radiation of an injection laser by external illumination under strong optical coupling conditions. The influence of external illumination (provided by a second laser) was manifested even in the superradiance regime. Periodic increase and reduction in the depth of relaxation oscillations was observed when the pump current through the laser providing external illumination was increased. This was due to the shift of the spectrum of the external illumination because of heating of the laser providing it. Measurements indicated that the range in which the buildup changed to quenching corresponded to a shift of the external illumination by half the mode spacing of the laser providing it.

An analysis is made of the influence of the phase modulation and Stark shift of levels on the coherence of light pulses propagating in media with a two-photon resonant interaction. An analytic solution is obtained for the case of two pulses, each carrying the same number of photons. The case of arbitrary numbers of photons in light pulses is also discussed.

A self-consistent system of equations is obtained for the field and medium (semiconductor) in the propagation of high-power light pulses under interband absorption conditions. Allowance is made for the relaxation processes. It is shown that a sufficiently strong pulse field may "suppress" the polarization relaxation processes, increase the coherence time, and thus facilitate the appearance of the self-induced transparency in semiconductors.

An analysis is made of the characteristics of optical fiber communication lines for computer technology. The main characteristics are reported of the working protype of an eight-channel line between computer units.

Lasing was observed as a result of electric-discharge (streamer) excitation of Fe-doped InP crystals. The orientation of the discharge channels in InP and the rate of growth of the discharge (~ 109 cm/sec) were determined. The output power per track was 200 W at 300 K. The short duration of the process (10?12 sec) of intense excitation of nonequilibrium carriers (1031cm?3 ? sec?1) and their rapid deexcitation as a result of lasing (2 ? 10?11sec) made it possible to achieve lasing in materials characterized by strong nonradiative processes corresponding to nonequilibrium carrier lifetimes (10?10?3?10?11sec). Electric-discharge (streamer) InP lasers can be used as sources of nanosecond and picosecond pulses of near infrared radiation.

Calculations are reported of the parameters of a rectangular-core fiber waveguide needed to achieve an efficient matching to an injection laser which is in direct optical contact with the waveguide. Simple expressions are obtained for the relationships between the permittivity discontinuity at the core-cladding interface and the optimal thickness of the core on the one hand, and the laser parameters on the other. The requirements which the passband of the waveguide must satisfy impose restrictions on the laser-waveguide coupling coefficient. If the permissible distortion of a laser pulse is 30 nsec/km, about 65% of the injection laser radiation can be coupled into the waveguide.

A study was made of light emitted as a result of decay of surface plasma oscillations in metal–oxide–metal structures. An absolute increase in the intensity of this light and its control were achieved by using a medium external to the metal film. This medium was a liquid crystal forming a domain structure in a static electric field. The arrangement provided a convenient means for investigating the processes of radiative decay of surface plasmons.

An investigation was made of the depth of a layer in cadmium sulfide single crystals disturbed by mechanical polishing of the surface with various diamond abrasives and by chemomechanical polishing. The depth of the disturbed layer was found by the periodic etching method and was deduced from the rate of etching and from the intensity of the photoluminescence emitted in the 0.47–0.8 μ spectral range at T=77°K. The least depth of the disturbed layer (3.5–5 μ) and the best luminescence properties were obtained as a result of chemomechanical polishing.

A study was made of the efficiency of coupling of radiation emitted by heterolasers (including lasers made of new multicomponent compounds and emitting at 1.08 μ) into a multimode fiber by direct contact or by matching with a microlens at the fiber end. A coupling efficiency up to 0.9 was obtained using a strip heterolaser and an SiO2 fiber (light losses ~25 dB/Km). An increase in the pump current lowered the coupling efficiency. Experiments on a single-mode heterolaser with an external selective resonator showed that one of the reasons for the nonmonotonic dependence of the coupling efficiency on the pump current was the mode deformation as a result of self-focusing effects.

A theoretical analysis is made of the interaction of radiation with a semiconductor crystal under the Gunn oscillation conditions. It is shown that the reflection coefficient of a domain may differ considerably from the reflection coefficient of a crystal as a whole. A method for amplitude modulation utilizing this effect is suggested. The plasma and magnetoplasma reflections are analyzed.

An investigation was made of the amplification of light signals in metal–SiO2(TiO2)–Si–SiO2(TiO2)–metal structures. A gain of about 32 was achieved. When the source of light (an electroluminescent diode) was operated as a laser, the ratio of the output power of the structure (which produced a photocurrent) to the power consumed in the diode exceeded unity and sometimes amounted to four. It is concluded that metal–insulator–semiconductor–insulator–metal structures can be used as high-sensitivity and fast-response radiation detectors.

A theoretical analysis is made of the dependences of the Fermi level and absorption coefficient on the field in optical transitions occurring in doped semiconductors. The distribution of the intensity of the optical field in a semiconductor crystal is obtained under saturation conditions.

Streamer semiconductor lasers can be used for optical pumping of certain laser materials, such as dyes and semiconductors, and also in studies of photoluminescence of various substances with a high temporal and spatial resolution. A report is given of the use of radiation from a CdS streamer laser for optical pumping of a CdS0.5Se0.5 laser

Communication channel crosstalk was investigated in a Y-shaped frequency-division data channel multiplexer of a fiber-optic communication line.

An analytic expression is obtained for the threshold of a semiconductor laser in the form of a five-layer structure with separate electron and optical confinement. An analysis is made of the dependence of the lasing threshold on the thickness of the active and waveguide layers, and also on the permittivities of these layers.

A study was made of the polarization characteristics of the radiation emitted by double-heterostructure AlGaAs injection lasers and of the influence of these characteristics on the efficiency of scattering of laser radiation by volume acoustic waves in a crystal of paratellurite. The efficiency of the acoustooptic interaction increased linearly on increase in the degree of linear polarization of the incident radiation. When the plane of polarization of this radiation was rotated relative to the scattering plane by 90° from the optimal position, the efficiency of this interaction was more than halved. The central frequency of an ultrasonic cell for the interaction with radiation of wavelength λ = 0.9 μ was 50 MHz and the efficiency of the interaction was ~50%.

It is shown that a widely used method for measuring the gain in semiconductors, based on the dependence of the radiation intensity on the length of the active region, is incorrect since it neglects the escape of radiation through the surface of the excited region into the passive part of the crystal.

The frequency shift (chirp) of a picosecond pulse emitted by an actively mode-locked cw injection laser with an external dispersive resonator was observed and measured. The chirp was ?? = 0.5?1012sec?1(?? = 0.2nm at the 880 nm wavelength) for a 30 psec pulse and the frequency decreased during a pulse (down chirp). The measurements were made using dynamic spectrograms obtained using an image-converter streak camera operated in the linear horizontal scanning mode. Frequency sweeping within the pulse is attributed to the influence of changes in the injected carrier density on the refractive index of the active region and on the optical length of the laser resonator.

An investigation was made of the coherence of the radiation emitted by a compact cw semiconductor laser with a holographic selector, operating at room temperature. The coherence length was 20 mm for an output power of 10 mW. Holograms with a diffraction efficiency of 5.5% were recorded. The contrast in the reconstructed image was at least 10:1 and the data storage density was 104 mm2.

A numerical method was used to calculate the optical amplification spectra of an electron–hole plasma in CdS making an allowance for the screened Coulomb interaction between electrons and holes. It was found that the interaction can increase significantly the calculated value of the optical gain.

An experimental investigation was made of holographic recording of binary data and readout by a multichannel photodetector array. Both recording and readout with performed with semiconductor injection lasers. Data were recorded in I-88OG infrachromatic holographic photographic plates in the form of a line of holograms.

An experimental study was made of photosensitive metal-insulator-semiconductor structures in contact with a nematic liquid crystal. Utilization of the orientational electrooptic effect in the liquid crystal ensured a high energy sensitivity of a structure with gallium arsenide as the semiconductor. Modulation of the phase of light by π or attainment of the highest optical contrast (of the order of 100:1) was achieved when the minimum intensity of the exciting helium-neon laser radiation (λ=633 nm) was 5×10–7 W/cm2 and the switching energy was 10–8–10–9J/cm2. Spatial resolution was at least 10–12 lines/mm. A structure of this kind could be used for coupling in and conversion of optical data, including visualization of infrared radiation.

Stimulated emission from single-crystal ZnSe and ZnTe films grown on sapphire was observed when they were excited longitudinally by an electron beam.

An increase in the efficiency of light emission (by over an order of magnitude) was achieved for plasma oscillations in a thin silver film of a gold–aluminum oxide–silver (Au–Al2O3–Ag) structure by altering the permittivity of a nematic liquid crystal adjoining the silver film.

The aim of the investigation was to build a laser cathode-ray tube operating with a television-type screen operating at room temperature. A study was made of the thermal conditions on the laser screen, the optimal rate of scanning with the electron beam was determined, and the parameters of cadmium sulfide laser screens were optimized. The results made it possible to achieve stimulated emission from cadmium sulfide laser screens by television-type scanning with an electron beam when the screens were cooled with running water. The output power obtained from such screens was 0.5 W and the conversion efficiency was 3% at λ = 525 nm. The image was projected from the laser screen onto an external screen which was a few square meters in area.

An experimental study was made of the amplification of surface plasma oscillations due to a negative differential resistance of an Au–Al2O3–In2O3–Al2O3–In2O3–Al2O3–Ag structure resulting from resonance tunneling of electrons in a periodic potential field of a complex insulator barrier in this metal–barrier–metal structure.

A theoretical study is made of the influence of diffusion and surface recombination on the spatial distribution of nonequilibrium carriers with depth and on the optical gain of an electron-beam-excited semiconductor laser. The dependences of the threshold current on the diffusion length, surface recombination velocity, and thickness of the dead layer are found for the longitudinal and transverse electron-beam pumping configurations.

A calculation is reported of the gain curve for a luminescence band associated with the process of inelastic collisions between two excitons, one of which is transferred to a higher excited state, and the other transformed into a light quantum. It is shown that in the case of II–VI compounds the luminescence band differs considerably in width and location from the usual P and M bands associated with the ionizing collisions between two excitons.

The power and time characteristics of a semiconductor streamer laser with longitudinal coupling out of radiation were determined in the picosecond range. Methods for determination of the laser parameters are described and the service life of the semiconductor component of a streamer laser is estimated.

Aperture synthesis was performed by phase diffraction gratings in a coherent optical system. A proportional reduction in the useful object field enhanced the spatial resolution by two orders of magnitude compared with the classical diffraction limit. The required precision of alignment of the whole system, including diffraction gratings, was not greater than that needed for conventional optical systems and was governed by the object lenses employed.

Stimulated emission was obtained from cadmium sulfide and sulfide-selenide crystals excited transversely by a sharply focused scanning electron beam at a frequency up to 16 kHz. The output power reached 1.2 W. A television image on a 1 m2 screen was obtained.