Phased array slow shear TeO2 Bragg cells: design and performance

The phased array transducer, when combined with the anisotropic Bragg interaction, provides a unique combination of features not available with the usual acoustical or optical rotation schemes used in the design of slow shear TeO₂ Bragg cells. A general theory for a phased array Bragg interaction in a birefringent medium is applied to the design of a 60 MHz bandwidth, 50 μs time-aperture slow shear TeO₂ Bragg cell. A 90 MHz center frequency device designed for 810 nm illumination with a 12-element Gaussian apodized phased array transducer with 154 μm element spacing oriented 1° from [110] was fabricated. The device exhibited the design center frequency and bandwidth with over 30%/W peak diffraction efficiency with a fully illuminated aperture. The device exhibits Hecht limited two-tone third order intermodulation products over at least half of the time-aperture