Wide-aperture TeO2 AOTF at low temperatures: Operation and survival

Abstract The effect of temperature on the performance in a wide-angle paratellurite acousto-optic tunable filter (AOTF) is analyzed on the example of two different AOTF configurations. The present study is a by-product of the AOTF characterization for space-borne applications. The two AOTFs serve as dispersion elements in spectrometers for Moon and Mars space missions. The operation of the AO filters was tested in the range of −50° to +40 °C; we have also demonstrated the survival of an AOTF device at −130 °C. The phase matching ultrasound frequency varies with temperature within 2.5 × 10 −5  K −1 and 6.6 × 10 −5  K −1 . We link this temperature shift to elastic characteristics of the TeO 2 , and demonstrate that it is mostly explained by the temperature modification of the slow acoustic wave velocity. We point out the best reference describing experimental results (Silvestrova et al., 1987). A generalization is made for all wide-angle acousto-optic tunable filters based on tellurium dioxide crystal.