Angle measurement using a diffraction of optical frequency comb

The laser autocollimation utilizes the function of a lens to convert the angle change of a plane mirror into the displacement of a reflected laser beam focused spot on a photodetector. However, in this method, it is hard to achieve both a high resolution and a wide range measurement simultaneously. In this paper, a new optical angle sensor utilizing a broadband optical frequency comb generated from a femto-second laser source and a diffraction grating is proposed for solving this tradeoff.