3-D surface profile measurement by 2-D heterodyne low-coherence interferometer

A Novel setup for two-dimensional (2-D) parallel measurements of low-coherence heterodyne signal by using a tandem mterferometer and a 2-D sensor has been developed. Generally speaking, it is difficult to obtain heterodyne signals whose frequencies are much higher than the frame rate of the conventional 2-D sensor. A mode-locked femtosecond laser (MLFL) is used as a light source. 1