High-performance acousto-optic materials: Hg2Cl2 and PbBr2

New results achieved with recently grown Hg2Cl2 and PbBr2 crystals are described. With an optimized crystal growth technique Hg2Cl2 crystals were grown that show a significantly reduced acoustic attenuation compared to prior crystals, from 13.4 to 8 dB/μs-GHz2. These crystals allow the development of Hg2Cl2 Bragg cells with time-bandwidth product figures in the 5100 to 6900 range, frequency operation as high as that for Te02, and resolution about 25% higher than TeO2 for similar crystal lengths. PbBr2 crystals were also grown that exhibit a large figure of merit (M2 550) with an attenuation coefficient of 12 dB/μs-GHz2. This material may be the choice for infrared devices where large diffraction efficiencies are needed.