Irradiance modulation used to examine sound-radiating cuticular motion in insects

A new, noncontact, optical technique for measurement of movements smaller than a few micrometers has been used to record cuticular motion of insects as they produce sound. The instrument described is highly sensitive to surface movement and offers good spatial resolution, broad dynamic range, tolerance of substantial background motion of the target surface, portability, and simplicity, and as such appears to hold promise for measuring other biologically interesting motions that have proved difficult to measure by other available techniques.