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Proceedings Paper

Global characterization of an advanced prototype of a multi-channel acousto-optical spectrometer for the Mexican large millimeter telescope
Author(s): Alexandre S. Shcherbakov; Daniel Sanchez Lucero; Abraham Luna Castellanos
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Paper Abstract

Both ground-based and satellite applications have demonstrated that acousto-optical spectrometers of radio-signals represent really reliable signal-processing technique for sub-millimeter and millimeter radio-astronomy due to these devices exhibit rather well efficiency as well as present sufficiently high frequency resolution in reasonably large frequency bandwidth. The key component of spectrometer is the acousto-optical cell, which dictates the basic parameters of signal processing. Its operation is based on the ability of cell to produce a large amount of independent from one another dynamic acoustic diffractive gratings, so that each of them reproduces the amplitude and frequency of only one spectral component from the incoming radio-signal. A multi-pixel CCD linear array detects and digitizes the obtained responses in the Fourier plane of a large-aperture integrating lens. The main peculiarity of this prototype lies in exploiting a large-aperture tellurium dioxide crystalline acousto-optical cell, which is oriented under a small angle to the [001]- and [110]-axes, in the regime of anomalous light scattering by extremely slow acoustic waves providing the improved frequency resolution. This circumstance determines the majority of technical requirements to the framing sub-systems and performances of prototype as a whole. Due to an extremely high anisotropy of this crystal, the efficiency of light scattering depends essentially on the incident light polarization, so that high-efficient operation needs the eigen-state polarization, which is determined by the incidence angle, light wavelength, and accuracy of the cell's crystallographic orientation. The first trial experiments have shown frequency resolution of about 45 KHz within about 1500 parallel frequency channels in real time scale.

Paper Details

Date Published: 23 February 2011
PDF: 12 pages
Proc. SPIE 7934, Optical Components and Materials VIII, 793417 (23 February 2011);
Show Author Affiliations
Alexandre S. Shcherbakov, National Institute for Astrophysics, Optics, and Electronics (Mexico)
Daniel Sanchez Lucero, National Institute for Astrophysics, Optics, and Electronics (Mexico)
Abraham Luna Castellanos, National Institute for Astrophysics, Optics, and Electronics (Mexico)

Published in SPIE Proceedings Vol. 7934:
Optical Components and Materials VIII
Michel J. F. Digonnet; Shibin Jiang; John W. Glesener; J. Christopher Dries, Editor(s)

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