Abstract

The Young interference experiment is the fundamental setup to combine two beams and a reconstruction of phase modulated light. Homodyne phase demodulator is based on signal decoding in back Fourier focal plane using bicell-photodetector (B-PD)[1,2]. In the paper we present a novel experimental approach to the signals demodulation by using the optical interferometer operates in homodyne mode [1,2]. Real time analysis of Young interference fringes is proposed to obtain an extremely high resolution of phase changes. A phase modulation effect in a signal arm of interferometer is observed as a shift of the interference fringes. A simple arithmetic combination of signals from B-PD placed in a fringe pattern plane is only one necessary numerical manipulation to obtain exactly a phase difference Δφ [1,2]. Concept of signals demodulation in the Fourier focal plane can be only used for exactly defined geometrical B-PD and Young interferometer geometry and physical parameters (polarization, wavelength). We demonstrate the individual demodulator characteristics which depend on all geometrical and physical parameters[1,2]. In the paper we explain how to optimize the setup geometry to obtain an extremely high resolution of measurement in (–π, π) range of detected phase.

© 2013 IEEE