Precision ultrasonic wave measurements with simple equipment

We describe the design and construction of a relatively simple, inexpensive laser interferometer system for accurate measurements of ultrasonic surfac e displacement waveforms in reasonably friendly environments. We show how a nalysis of a single waveform can provide both the calibration constant requ ired for absolute measurements and an estimate of the uncertainty of these measurements. We demonstrate the performance of this interferometer by meas uring ultrasonic waveforms generated by a novel conical-element ultrasonic transducer.