Acoustic Switching Ratios of Piezoelectric and Electrostrictive Oats
The conventional piezoelectric Opto-Acoustic Transducer (PEOAT) has been studied theoretically and experimentally. The results indicate that due to the characteristics of the present photoconductive layer the Acoustic Switching Ratio (ACSWR) in the megahertz range of frequencies is in general inadequate for beam focusing or beam shaping applications. The physical properties of the present photoconductive layer must be successfully altered to bring about an improvement in the acoustic switching ratio.
We have recently started work on an alternative approach towards improving the ACSWR. This approach involves the use of an electrostrictive layer in the place of the piezoelectric layer in previous OATs. Electrostrictive layers have been prepared from some commercially available powders with very high dielectric constants. With these layers electrostrictive OATs (ESOATs) have been built. Preliminary experimental measurements indicate improved ACSWR and demonstrate the potential usefulness of this new class of OATs.
KeywordsHigh Dielectric Constant Piezoelectric Layer High Frequency Field Acoustic Output Switching Ratio
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