Performance of laser beam wavefront sensor

Laser beam wavefront measurement is important for laser beam quality evaluation and beam control. Reported in this paper is a laser beam wavefront sensor consisting of a phase detector and a scanner. With the use of this sensor, the wavefront phase profile across a laser beam has been obtained. The major advantages of this technique are that it is fast, sensitive, and compact. Other features are electric scanning, self-alignment, noise cancellation, and no drift. Wavefront sensor operational principles, features, and experimental results are presented. The sensitivity of the sensor was 5 deg. This sensitivity corresponds to the change of beam quality parameter, the Strehl ratio, by 1%. Hence it is a sensitive beam quality measurement technique.