Ernest Chuang

Holographic Read-Only-Memory System for High-Speed Replication

A novel high-capacity holographic read-only-memory (ROM) disc system is proposed that stores multiple disc-sized data patterns as multiplexed holograms within a single holographic disc using a conical reference beam for rotational symmetry during recording, with continuous serial readout during playback. Estimates predict user-data capacities of 100 GB or more in a 12 cm disc, with replication speeds of a minute or less, using current holographic media parameters and high-power lasers. A method for fabricating transmissive metallic disc-sized data masks is developed and confirmed experimentally for features down to 0.4 µm, through a variation of the optical disc mastering process. The retrieval of raw holographic eye-patterns at a rotation speed of 1000 rpm without the use of servos is demonstrated for linear densities of 0.67 µm per channel bit with EFMPlus channel coding.

Consumer holographic read-only memory reader with mastering and replication technology

What is believed to be a novel holographic design for read-only memory systems allows a compact low-cost consumer drive within a 10 mm drive height, using a lensless phase conjugate readout and a combination of polytopic and angle multiplexing. A two-step mastering method enables production of high-efficiency holographic masters, and fast replication is possible by using only a series of plane-wave illuminations. Mastering and replication techniques are verified experimentally with an array of 125 holograms with no measured bit errors.

Demonstration of Holographic Read-Only-Memory Mastering, Replication, and Playback with a Compact Reader

Development prototype systems for holographic read-only-memory (ROM) are demonstrated, capable of high density recording at 406.7 nm wavelength with 0.71 numerical aperture optics. A phase-conjugate Fourier transform lens is developed for improved capacity and tolerances and incorporated into a fully functional compact reader about 1 cm in height. The capacity target for the first generation is 4 Gbytes in a 42×35 mm2 media card. Two-step mastering, replication, and playback are demonstrated for digital audio stored in 125 holograms.

Consumer Holographic ROM Reader with Mastering and Replication Technology

A novel holographic ROM design allows a compact low-cost consumer drive with lensless readout in a 10 mm drive height. A two-step mastering method enables high-efficiency holographic masters for fast replication using planewave illuminations