A new method for measuring the gas-kinetic pressure in pulsed plasma flows is developed in which an acoustic line in the form of a thin rod built in the optical scheme of a laser interferometer is used as a detector. The time evolution of the gas-kinetic pressure in particle flows emerging from a micropinch discharge (a low-inductance vacuum spark) was studied. Due to the wide dynamic range of the method (∼10 5 ), it can be applied in various plasma devices with a wide range of parameters.

Представлены результаты разработки методики измерения газокинетического давления корпускулярных потоков импульсной плазмы, в которой в качестве датчика используется звукопровод в виде тонкого стержня, встроенный в оптическую схему лазерного интерферометра. Проведены исследования временной динамики газокинетического давления корпускулярных потоков из области микропинчевого разряда типа низкоиндуктивная вакуумная искра. Большой динамический диапазон измерений 105 позволяет использовать данную методику на различных плазменных установках с широким диапазоном параметров.

The influence of intracavity second harmonic generation on the mode competition in a double-mode diode-pumped Nd:YAG laser is studied theoretically and experimentally. Various configurations of the optical cavity with II-type phase-matching frequency-doubling crystals are considered. The conditions of steady-state lasing and of lasing with a small level of amplitude pulsation in the output laser beam are determined.

The performance of a linear three-mirror coupled-cavity Nd:YAG laser is studied both theoretically and experimentally for various ratios of the compartment lengths and various geometries of the compartments.

The mode competition in a double-mode diode-pumped Nd:YAG laser is studied theoretically and experimentally. In particular, the influence of various laser parameters on the steady-state double-mode regime for parallel and orthogonal polarization of the modes is studied. It is shown that the establishment of steady-state double-mode lasing is accompanied by relaxation oscillations more complicated than for single-mode lasing. It is found that the scanning rate of the cavity modes influences the character of the relaxation oscillations.

The operating of a two-frequency Nd3+:YAG laser with a phase-anisotropic cavity upon intracavity SHG (ICSHG) is considered theoretically and experimentally. It is shown that for an appropriate choice of the cavity configuration, an intensity-stabilised two-frequency lasing mode may be obtained at the first (1.064 μm) and second (0.532 μm) harmonics, with the mode interval changing continuously over a broad range.

We present the results of experimental and theoretical studies of amplitude and frequency characteristics of a double-mode He-Ne laser with linear- and orthogonal-polarized modes with the optical length of the cavity modulated with a frequency Omega approximately equal to the intermode-beat frequency. We investigate the regime of synchronous modulation (mode locking) of two orthogonal-polarized modes, when the difference of mode frequencies is completely determined by the modulation frequency. The main specific features arising in the behavior of the mode-locking area and the mode-locking band in response to variations in the operation parameters of the laser and the modulation frequency of the optical cavity length are examined. The behavior of the intensities of separate modes and the intermode-beat frequency on the boundaries of the mode-locking area is analyzed for different directions of cavity-mode scanning.

Results of experimental and theoretical studies of the shape of power resonances of a single-mode CO2/SF6 laser with a linear three-mirror cavity for cases when the amplifying and the absorbing media are located in various sections are reported.

Intensity behavior of a single-mode diode-pumped Nd:YAG laser with frequency scanning is studied experimentally and theoretically. The specific features in the behavior of the frequency of relaxation oscillations and the oscillation area in response to variations in the magnitude and direction of the scanning rate and working parameters of the laser are determined.

Theoretical background and experimental testing of sub-Doppler polarization spectroscopy are described. The considered spectroscopic approach is based on stable stationary single-frequency lasing in the regime of locking of two orthogonal-polarized competing modes. The polarization of laser radiation is subject to a resonant rotation around the central frequency of the analytical line of an intracavity absorber. Resonances of polarization of a He-Ne/CH4 laser with a homogeneous width of the F-2((2)) line in the spectrum of methane are demonstrated. The experimental sensitivity of the polarization photoresponse to absorption was on the order of 100 rad/cm(-1). The methods of improving this sensitivity and the possibilities of extending this method of spectroscopy to other lasers and objects of studies are discussed.

Intensity and intermode beating frequency fluctuations of a two-mode He-Ne laser with a phase-anisotropic cavity and orthogonally polarized modes in a regime of synchronization have been studied both experimentally and theoretically. It is shown that synchronization yields a considerable reduction of the spectral density of fluctuations in the intermode beating frequency.

A review is given of the state-of-the-art and of likely developments in laser frequency standards based on two-mode gas (He — Ne) and solid-state (Li : RbCl) lasers, in which the reference points are ultranarrow saturated-dispersion resonances of lines in ν3 vibrational — rotational methane bands (λ = 3.2 — 3.4 μm). The methane standard, now traditionally attracting the attention of investigators, can provide a frequency reproducibility of ∼ 1015 in compact transportable systems. Recent progress in laser techniques (optically pumped solid-state lasers, efficient nonlinear crystals) can make this standard the basis for simplified optical-frequency synthesis systems accessible to many laboratories.

For the first time a continuous wave RF pumped atomic xenon laser was operated in a two mode regime. Simultaneous generation on two orthogonally polarized longitudinal modes was observed in the range from 0.5 to 145 MHz close to the maximum possible range. An anisotropic element was used to control the inter-mode frequency difference and mode coupling.

The influence of mode locking on the spectrum of natural fluctuations of intensity and the frequency of intermode beating in a He-Ne laser is studied experimentally and theoretically. A substantial decrease in the spectral density of fluctuations of the intermode beating frequency in the frequency range omega less than or equal to Gamma is revealed. The value Gamma is close to the range of detunings of the modulation frequency from the frequency of intermode beating where the regime of mode locking can be implemented.

A linear two-frequency cw Nd3+:YAG laser with laser-diode pumping at the wavelength λ = 1.06 μm is described. Stable lasing in two linear axial modes with mutually orthogonal polarizations is implemented within the range of intermode separations from 5 MHz up to approximately 9 GHz. The maximum frequency range of double-mode lasing achieved is about 9 GHz.

An investigation was made of the amplitude characteristics of a double-mode He—Ne/CH4 laser with linearly and orthogonally polarised modes, when the cavity was frequency-modulated at a frequency close to the intermode spacing. Under these conditions the intensities of the individual modes had resonance structures near the centre of an absorption line. These structures were narrow: their widths were less than the homogeneous width of an absorption line.