Multi-channel adaptive interferometer based on orthogonal wave mixing in photorefractive crystal

Adaptive interferometry with photorefractive (PR) crystals [1] is well known as robust and effective measuring technique for detection of quite small physical quantities (e.g. ultra-weak vibrations with amplitude of 1 nm and below) in unstable (e.g. industrial) environment. There are a number of practical tasks where not one but several quantities are to be simultaneously measured. If so, a multichannel measurement system is required.