Nankai University

Baiquan Tang

Jingjun Xu

Qian Sun

Guangyin Zhang

Hui Huang

Yongfa Kong

Shaolin Chen

Xinzheng Zhang

Qiang Wu

Xiaojun Chen

Ziheng Huang

Haijun Qiao

Guangao Li

Zuojin Sha

This invention relates to the field of materials of the photorefractive crystal. The composition of these crystals is Li Nb O : Fe , M , where M can be magnesium, indium, or zinc; when using q to denote the ion valence of M (q&equals;2 when M is Mg or Zn, and q&equals;3 when M is In), the values of x, y, m, and n are in the range of 0.05&lE;x&lE;0.13, 0.00&lE;y&lE;0.01, 5.0&times;10 &lE;m&lE;7.5&times;10 , and 0.02&lE;qn&lE;0.13. This invention greatly improves the photorefractive properties of LiNbO crystals: makes it have a high diffraction efficiency (more than 68%), a fast response speed for photorefraction (an order of magnitude faster than iron doped LiNbO ), and a high resistance to optical scattering (the light intensity threshold to photorefractive fan scattering near two orders of magnitude larger than LiNbO : Fe). This invention is an excellent three-dimensional optical storage material and has a vast potential market.

Doubly doped lithium niobate crystals

The invention relates to the information storage. It consists of a computer, a precise rotary table, a writing laser source, a readout laser source, a spatial filter, a spatial light modulator, lens, mirrors, photorefractive crystals (such as doubly doped lithium niobate), and a phase-mismatch adjustor; Due to used a green light (532 nm) as the writing light, and a red light (670 nm) as the readout light, the signal-to-noise ratio is improved greatly and the problem of fixing the stored information is solved. The transmission configuration is used to realize the high-density digital storage in which the irregular lens is designed to work as a phase-mismatch adjustor and read out the whole stored image with no distortion and loss. The dynamically differential encoding and decoding technique is used to suppress the bit-error-rate to lower than 10 .

Only-readable three-dimensional optical storage device

Growing community of inventors

Tianjin, China

Baiquan Tang