Time-delay Fizeau phase-conjugate interferometer

Abstract

A time-delay Fizeau phase-conjugate interferometer is constructed by using a BaTiO(3) crystal in a degenerate four-wave-mixing configuration. The slow response time of BaTiO(3) is used to build a phase-conjugate mirror that functions as a holographic memory. An optical wave and its time-delayed version are stored inside the crystal sequentially while their phase-conjugate waves are generated simultaneously. Superposition of the two phase-conjugate waves produces an interferogram as a result of the relative phase change of the input waves. The simplicity and real-time operation of this technique lead to several advantages over the conventional holographic interferometry. The use of photorefractive crystal eliminates the darkroom process and reposition procedure. A higher accuracy can be achieved because the interfering waves are phase-conjugate waves. The principle of this technique is presented and the experimental results and its applications are discussed.