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We have modified a transmission acoustic microscope by replacing the input lens with an optical counterpart. The input to this system comes from a mode-locked and Q-switched Nd : YAG laser at 1.06 μm. Acoustic signals arising from thermoelastic coupling are generated in metallic films at frequencies determined by the modulation envelope of the optical beam. The output acoustic lens and transducer responsive to sound waves at 840 MHz detect the acoustic energy which comes from the heated volume (∼2-μm diameter) near the focal region. The sample is mechanically scanned through the focal point in a raster pattern to record the photoacoustic images. We suggest this as a method for collecting new information on microscopic structures.

Surface transverse wave (STW) resonator devices have been designed and fabricated on rotated Y cuts of quartz, with wave propagation perpendicular to the X axis.Packaged devices with center frequencies of 500 and 632 MHz show insertion loss less than 6 d B in a 50 ohm system.Unloaded Q is typically greater than 10,000. Devices at 1726 MHz show packaged insertion loss as low as 10 dB and unloaded Q as high as 5600. Temperature behavior was studied. STW resonators were found to exhibit significantly greater power-handling ability than SAW resonators with comparable design parameters and electrical performance in a comparison study.Device phase noise measurements indicate that STW resonators' noise improves when driven with high incident power.Single sideband device phase noise less than -135 dBc/Hz at 1 H z offset was achieved.

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The role that SAW (surface-acoustic-wave) resonators have come to play in high-performance test instrumentation is reviewed. The contributions made by SAW resonators in a number of Hewlett-Packard (HP) instrument applications are detailed. SAW-controlled oscillators are now the preferred design for precision frequency-control applications in the frequency range 200 MHz-1 GHz. The challenges in device design, fabrication, packaging and testing for these demanding applications are discussed.