Recount of Program on Acoustic Microscopy at Stanford. Acoustic Microscopy Symposium-Workshop, Indianapolis Center for Advanced Research, Indianapolis, Indiana, February 14-18, 1977

摘要

The work began in the early sixties with an exploration of bulk acoustic waves in high-quality crystals such as Lithium Niobate and piezoelectric semiconductors such as Cadmium Sulphide. The work with Niobate was focused on acousto-optic interactions and a number of devices such as acousto-optic modulators and optical filters and surface wave convolvers have evolved from this initial work. It was the Zinc Oxide thin film transducer that allowed us to enter this domain of technology. We acquired the capacity to fabricate these transducers in a manner that gave us efficient conversion of electromagnetic energy into acoustic energy over a wide band of frequencies. It also permitted us to work at frequencies above 1000 MHz. In liquids the acoustic wavelength of 1.5 microns is in the neighborhood of optical wavelengths. It was natural to think about microscopes based on this form of radiation. Perhaps the resolution would equal or exceed the resolution of the optical instrument.