Accession Number : ADP008254

Title :   Optimized Read/Write Conditions of PHB Memory,

Corporate Author : HITACHI LTD TOKYO (JAPAN) CENTRAL RESEARCH LAB

Personal Author(s) : Murase, Norio ; Horie, Kazuyuki

Report Date : 22 MAY 1992

Pagination or Media Count : 4

Abstract : PHB memory has been a good candidate for a future ultra-high density memory for these ten years. This PHB memory is considered to realize the recording density of 1000 times higher than conventional optical memories because it can store wavelength-multiplicitically 1000 bits in a 1 -microns diameter recording spot. But not so many researchers are working on PHB memory compared to the number of researchers wrestling with realization of higher recording density of other types of memory such as magnetic or optical ones. One of the reasons is based on the doubt whether high speed readout is possible in such a high density recording in 1 -microns diameter spot. Therefore one of the most important research on PHB memory is the estimation of degree of coexistence between high recording density and high speed readout. With respect to this point, two fundamental estimations have been proposed by Moerner et al. According to their results, even a memory of 10 times higher recording density than conventional optical memories can not be realized in case of 30 nsec/bit readout time for already-known single photon type PHB materials. But the above estimation was done under the conditions of 10 microns for fixed laser spot diameter and 100 MHz for hole width.

Descriptors :   *MOLECULAR SPECTROSCOPY, DENSITY, DIAMETERS, HIGH DENSITY, LASER SPOTS, LASERS, PHOTONS, TIME, VELOCITY, WIDTH, MEMORY DEVICES, OPTICAL STORAGE, FREQUENCY.

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Computer Hardware

Distribution Statement : APPROVED FOR PUBLIC RELEASE