Determination of nanometer vibration amplitudes by using a homodyne photorefractive crystal interferometer

We report a low cost and high accuracy interferometric technique for detecting nanometer vibrations by using a photorefractive crystal interferometer based on two-wave mixing within a Bi12SiO20 (BSO) crystal. The results of small displacement detection on the sample (1–2 nm) and comparison between the sensitivity of Michelson and photorefractive adaptive interferometers are presented. Furthermore, the effect of an external electric field applied to the photorefractive crystal on the Signal to Noise Ratio (SNR) and on the vibrometer sensitivity is investigated.