Displacement and slope measurements using image plane holography with a BaTiO<inf>3</inf> crystal

Photorefractive crystals have gained importance as a recording medium due to the possibility of real-time operations. Various real-time holographic and interferometric techniques have recently been proposed, exploiting salient features of different photorefractive crystals. In this paper we propose and demonstrate a two-beam illumination method, employing a BaTiO3 crystal, for real-time displacement measurement and a single beam illumination method for real-time slope measurement. © 1997 Elsevier Science Ltd.