MIT Museum

Direct amplification of ultrasonic waves in a piezoelectric semiconductor was reported last fall by A.R. Hutson, '54, standing at right, and his Bell Telephone Laboratories colleagues D.L. White (left) and J.H. McFee (seated). They amplified an ultrasonic wave traveling through a cadmium sulfide crystal by applying a direct-current electric field in the direction of wave propagation.

Credit: The Technology Review