Polarization holography and its applications to data storage

  • Toyohiko Yatagai Center for Optical Research and Education, Utsunomiya University
Keywords: optical memory, polarization holography, holography


Many techniques on holographic mass storage systems have been developed, in which scalar optical data are stored in holographic materials. We discuss two alternative approaches to holographic memory; the use of vector waves for holographic mass storage systems and complex data formats, multi-level phase coding, are presented to increase memory capacity. A novel optical recording technique called "retardagraphy" for recording a retardance pattern of an optical anisotropic object is mentioned, first. In this technique, a polarization pattern of a single beam modulated by an anisotropic object is illuminated onto a polarization-sensitive medium and the retardance pattern is recorded as an optical anisotropy pattern on the medium. Retardance is generated by relative phase difference between two polarization states. Multiple phase difference coding in off-axis holography is also a promising candidate for mass data storage. Some experimental studies are presented.

About the Speaker

Toyohiko Yatagai received the BE and DE degrees in applied physics from the University of Tokyo, in 1969 and 1980, respectively. From 1970 to 1983 he was with the Institute of Physical and Chemical Research, Japan, where he worked on optical instrumentation, computer-generated holography, and automatic fringe analysis. He moved to the University of Tsukuba as a Professor of Applied Physics in 1983. He is now the Director of the Center for Optical Research and Education at Utsunomiya University. His current research interests include optical computing, optical measurements, holography, and spectral optical coherence tomography for biological applications. He received an Optical Research Award from the Japan Society of Applied Physics in 1978 and the Denis Gabor Award from SPIE in 2017. He is a member of the Optical Society of Japan, a fellow of OSA, SPIE, and the Japan Society of Applied Physics. He was the 2015 President of SPIE. He is the author of ten books and more than three hundred academic papers in applied optics.