Characterization of the beam shaper and Fourier transform system in a prototype of the acousto-optical spectrometer for the Mexican Large Millimeter Telescope

Abstract

Two optically matched by each other subsystems related to an advanced prototype of acousto-optical spectrometer for radio-astronomy are analyzed in frames of this work. The main peculiarity of the spectrometer's prototype is exploiting a large-aperture tellurium dioxide cell in the regime of anomalous light scattering by acoustic waves, so that just this circumstance determines the majority of technical requirements to both the subsystems under consideration and their potential performances. This is why the initial section is devoted to describing basic properties inherent in the chosen regime of acousto-optical interaction. Then, within characterizing a multi-prism beam shaper, we restrict ourselves here by the case of linear state of the incident light beam polarization. Broadly speaking, such a restriction does not provide the highest performance data of spectrometer, in particular, the most efficient anomalous light scattering in tellurium dioxide crystal, but similar restriction is exactly in a line with the to-day's level of our progress. The characterization of Fourier transform subsystem is directed, of course, to achieving the resolution corresponding as much as possible to theoretically desirable value, namely, to a pair of the CCD-pixels for each individual resolvable spot. The obtained theoretical and preliminary experimental results are presented and discussed.