Challenges for the use of holographic elements in optical storage

Abstract

Significant progress during the last several years has resulted in the successful development of read-only, write-once and erasable optical storage systems. Recently, several optical head desiu s have emerged in the literature that utilize holographic optical elements (HOEs) as replacements for convention. elements. The motivation is to reduce the numberof head components by capitalizing on the multifunctionality of an individual HOE, improve manufacturability, and reduce cost. There is also potential for improved drive performance by reducing the overall size and mass of the head. Following a brief review of ‘conventional’ optical head technology, this paper will describe design modifications utilizing HOEs, their impact on head performance, and the requirements that must be satisfied to permit wider usage. Emphasis will be placed on the issues associated with laser diode wavelength variability, high numerical aperture, high diffraction efficiency, and their use in magneto-optic systems where polarization considerations are important. © 1989 SPIE.