Dual-differential laser Doppler angular vibrometer using a ring laser.

A laser Doppler angular vibrometer using a He-Ne dual-frequency ring laser (DF-RL) is demonstrated. By detecting the interference signal of two beams which are diffracted by the surface of two gratings, the displacement of angular vibration can be measured. To our knowledge, this is the first time that a DF-RL has been utilized as the source of a Doppler angular vibrometer. It shows in theory and experiment that this dualdifferential laser Doppler angular vibrometer possesses a high precision and can suppress the error in horizontal vibration at the same time, which can be applied to high-frequency microangular vibration measurement. [ABSTRACT FROM AUTHOR]