Fast rewritable computer generated hologram in photochromic material

A high resolution light modulator which can be controlled in real time is useful as a parallel optical computing device. Also holography has many excellent characteristics such as multi-recorded memory and associative memory. For these purposes several kinds of optical calculating methods with interconnection are proposed. On the other hand, a computer generated hologram (CGH) can display any kind of interconnection table and can vary the table easily by changing the input pattern. The authors consider recording CGH in the photochromic material. The photochromic material for optical memory, which can be recorded fast and repeatedly has been proposed by Lo (1974). First they study the characteristics of photochromic glass and consider the possibility of this material for rewritable optical memory. Next they constitute the optical set up for recording CGH in it. Finally they consider the characteristics of CGH recorded in the photochromic material