An Acoustooptic Spatial-Frequency Filter of Two-Color Radiation Operating in the First Diffraction Order

The characteristics of an acoustooptic (AO) Bragg cell of two-color radiation as a differential spatial-frequency filter, in which the first diffraction order is the working one, have been investigated. It is shown that in a general case, it is impossible to provide two-dimensional image differentiation simultaneously at two wavelengths. A regime has been found that allows one to change from one wavelength to another with preservation of the two-dimensional differentiation operation by adjusting the sound power. This variant has been confirmed experimentally by the formation of a two-dimensional contour using two-color radiation of an Ar laser at wavelengths of 0.488 × 10–4 and 0.514 × 10–4 cm, as well as a TeO2 AO cell that operates at a sound frequency of 51 MHz.