Abstract

We present a new interferometer based on the technique of phase-shift keying of holographic gratings. The presented interferometer employs a combination of transmission geometry and reBection geometry for the recording and readout process of a holographic Bragg grating. We record two adjacent gratings with the same grating period but a relative phase-shift. Using a tunable IR laser for the readout process, we can measure the spectral transfer function of both combined gratings. The shape of the measured transfer function is extremely sensitive to the phase-shift between the two gratings. We will demonstrate an application of this measurement method by the determination of refractive index variations due to pressure changes of gases. The achieved resolution in respect to measuring phase shifts is about 40n. We will present experimental investigations on krypton gas.

© 2005 Optical Society of America