Infrared two-dimensional acoustooptic deflector using a tellurium crystal

The first single element 2-D acoustooptic (2DAO) laser beam deflector using a tellurium crystal was designed and fabricated for laser wavelength applications from 5 to 20 microm. The giant values of the figure of merit M associated with these two AO interactions equal to 285,000 x 10(-15) s(3)/kg, are between 2 and 3 orders of magnitude higher than germanium, the next best AO material for 10.6 microm. This latter value indicates that acoustic power densities inside the crystal of the order of 0.1 W/mm(2) are sufficient to diffract 100% of the incident light. The experimental data confirm the predicted 13 degrees /25 MHz deflection slope. The theoretical amplitude and frequency modulation characteristics of the 2DAO deflector are also evaluated.