METHOD FOR OPTICAL MEASUREMENT OF VELOCITY OF SURFACE ACOUSTIC WAVES

摘要

A method for optical measurement of velocity of surface acoustic waves includes excitation of a surface acoustic wave on the surface of the sample, direction of probing acoustic beam to the surface, this after reflection from the surface is directed through a slot with controlled width to a photo-receiver. On the surface of the photo-receiver interference pattern is built. With change of width of the slot minimum of signal from photo-receiver is achieved. By the value of the wavelength and its frequency velocity is determined. Interference pattern is formed as periodical lines. The reference beam is modulated by phase. Value of slot width is determined by value at which minimum of depth of modulation of the signal from photo-receiver is observed.