Techniques to eliminate error induced due to acousto-optic modulator vibration in heterodyne interferometry

Noise reduction and improved resolution are some serious challenges for precision measurement in the era of nanotechnology. Although several factors that lead to the loss of accuracy in precision measurement system were realized and some were eventually eliminated, some critical factors that were overlooked remain. One such factor, which has become an inherent part of the system, is that caused by the vibration of the acousto optic modulator (AOM) in heterodyne interferometry. We highlight the effect of error induced by the vibration of the AOM and, different methods of eliminating this error by the modification of the optical layout discussed. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(99)01612-8].