Conditions for the suppression of spatial harmonics at a two-frequency acoustooptic interaction in the Raman-Nath mode

It is demonstrated that the diffraction of a plane light wave by an acoustic wave of fundamental frequency in the Raman-Nath mode with admixture of the second acoustic harmonic may be accompanied by a considerable change in the higher diffraction orders with numbers ±2, ±3, etc. Conditions for the selective suppression of the orders are obtained in the weak and strong interaction modes. Results of a numerical simulation are presented.     

Infrared reflection spectra in contactless nondestructive measurements of the electron density and mobility in indium phosphide

On the basis of numerical calculations and experimental studies we analyze the possibilities of measuring the electrophysical parameters of indium phosphide by means of infrared reflection spectra at wavelengths ranging from 5 to 200 m. We demonstrate that contactless nondestructive measurements of the electron density in the range 10¹⁶–10²⁰ cm^–3 can be made with a relative error not exceeding 15%, and of mobility with a relative error not exceeding 25%. A nomogram method is presented for rapid conversion of data from infrared reflection spectra into the parameters being measured.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 22–27, January, 1988.     

Highly effective acoustooptic diffraction of light by multifrequency sound using a nonaxial deflector

The subject of investigation is multiple-beam Bragg diffraction of light, i.e., the formation of a highly effective multiple-beam field representing a superposition of equidistant monochromatic acoustic waves with determinate phases and amplitudes using a nonaxial TeO₂ deflector. It is shown theoretically and experimentally that the anisotropic character of interaction considerably changes the basic parameters of multiple-beam diffraction (compared with the isotropic case): the net diffraction efficiency grows to 100%, and the frequency band expands noticeably. A modulator splitting the initial laser radiation into five beams of equal intensity with a net efficiency approaching 100% is designed.     

On the possibility of extending the dynamic range in acoustooptic analysis of the spectrum of radio signals

A method is proposed to suppress nonlinear distortions arising in the acoustooptic analysis of the spectrum of radio signals. The method is based on the polynomial nonlinear correction of an electric signal before it comes to a piezoelectric transducer. The necessary form of the correction is determined in a wide range of parameters of the acoustooptic interaction. The results of numerical simulation are presented.     

An Acousto-Optic Polarization-Insensitive Two-Coordinate Deflector

Acoustical Physics - A new scheme of a polarization-independent two-coordinate acousto-optic deflector based on paratellurite crystals has been developed. One specific feature of the optical scheme...     

Theory of Acousto-Optic Filtering of Radiation in the Multifrequency Near-Field Zone of a Plane Piezoelectric Transducer

Acoustical Physics - A theory of acousto-optic filtering is developed based on Bragg diffraction of a plane light wave in the near field of radiation from an acoustic transducer excited by an...     

Determination of the electron beam size at the Kurchatov Synchrotron Radiation Source using an edge screen

The electron beam size of the 2.5-GeV storage ring of the Kurchatov Synchrotron Radiation Source was measured using a fixed edge screen. The obtained vertical beam size of 190 μm and the corresponding calculated value of 198 μm (for 2% betatron coupling) almost coincide within the experimental error.     

Inverse acoustooptic problem: Coherent summing of optical beams into a single optical channel

A highly efficient summing of mutually coherent beams (channels) into a single beam with the same divergence and aperture (an inverse acoustooptic problem) is realized via diffraction in a Bragg cell. The multibeam field to be converged is formed as a result of the diffraction (splitting) of a single laser beam. Theoretical and experimental evidence is obtained for the fact that the repeated diffraction can provide a highly efficient (up to 100%) reconstruction of beam with initial parameters. The experiments are performed with a single-mode laser radiation at 0.63 μm and multimode radiation at 0.96 μm. The virtually attained summing efficiency is on the order of 70%. The factors that act to diminish the experimental efficiency below the predicted value, the ways to raise the efficiency, and possible applications of the results of this study are discussed.