Akinori Watanabe

TeO2 anisotropic Bragg light deflector without midband degeneracy

An advanced acousto‐optic light deflector has been designed using the acoustic shear wave traveling slightly off the [110] axis in TeO2. The midband mode degeneracy reported by Warner et al., which decreases the diffracted light intensity, has been shifted off from the active frequency region. A linearly polarized wave can be used as the incident light instead of the elliptically polarized wave used in the conventional deflector designed by Warner et al. The deflector yields a larger number of resolvable spots due to the broadened bandwidth. Experimentally, with 6328‐A light, a 3‐dB bandwidth of 50 MHz was observed with a diffraction efficiency of 80% and an electric power of 350 mW. The new deflector has a capacity of 500 resolvable spots with a random access time of 10 μsec.

Tellurite Glass: A New Acousto‐Optic Material

A new glass, composed of TeO2, was found to be well suited to acousto‐optical devices. It exhibits a high figure of merit: Me(p2n6/ρv3) = 23.9×10−18 sec3/g and has very good optical qualities with regard to visible light.A new glass, composed of TeO2, was found to be well suited to acousto‐optical devices. It exhibits a high figure of merit: Me(p2n6/ρv3) = 23.9×10−18 sec3/g and has very good optical qualities with regard to visible light.

A NEW CRYSTAL Pb5(GeO4)(VO4)2 FOR ACOUSTO‐OPTIC DEVICE APPLICATIONS

A new melt‐grown crystal of apatite type Pb5(GeO4)(VO4)2 has been found to be well suited for acousto‐optic device applications. Acousto‐optic figure of merit is 50.6 × 10−18 sec3/g and acoustic absorption is about 1.2 dB/cm at 200 MHz.

Liquid Materials and Their Figures of Merit as Acoustooptical Deflector

Three figures of merit defined by Dixon for acoustooptical deflectors are reconsidered using combinations which include scattering efficiency, sound frequency bandwidth, number of resolvable spots and sound attenuation constant. A fourth figure of merit is proposed which is applicable to materials with non-negligible acoustic losses. Liquid materials were evaluated according to the proposed criteria and some were selected as good for use as acoustooptical deflectors. Experiments showed that the scattering efficiency and the fourth figure of merit of n-propyl iodide were 7.7 and 2.5 times those of water.

Broad bandwidth TeO 2 acoustooptic devices bonded with tin metal

A paratellurite acoustooptic device with broad bandwidth characteristic has been developed by using a tin adhesion layer instead of indium for a X-cut LiNb03 transducer bonding. Acoustic impedances of tin and indium evaporated layers for shear sound wave were estimated to be about 9.1 X l05 and 5.5 X l05 g/cm2 s from coincidences between experimental results and simulations, respectively. A typical device with a near quarter wavelength thickness of a tin layer yielded about 100% 3 dB bandwidth at the midband frequency with the minimum insertion loss of 0.1 dB.