Dynamic alignment system for an FT-NIR Michelson interferometer

We present a description of a system for dynamic alignment of a novel Fourier transform Michelson interferometer which is operating in the near infrared (NIR) band. The technique relies on detection of the phase difference between four photodetectors mounted around the main detector. The system is controlled by a computer in real time. It uses a position observer to record the mirror position and with a feedback loop corrects the tilt of the moving mirror in the interferometer. This relatively simple system is very effective and can be applied to other scanning optical interferometers.