| Abstract: | We present two displacement sensing techniques which rely on amplitude variations of Bessel frequency components contained in the photodetected output of a phase modulated two-beam interferometer. Experimental results demonstrate demodulated output signals that correspond to the absolute optical path difference between the two arms of an interferometer. Optical displacements over a 50 mm range have been recorded with a resolution of 25 microns. Both approaches are suitable for passive remote sensing applications. |
