Explanation

Some electro-optic crystal belonging to ferroelectric body are as follows: BaTiO3 crystal: perovskite structure, melting point 1618 ° C. It is ferroelectricity at temperatures below 120 ° C. The electro-optic coefficient r13=802X10-12 m/V, r42=1640X10-12 m/V. It has high photorefractive sensitivity within the visible light wavelength range, ranging from 7X10-6 cm ^ 2/J. Although the diffraction efficiency is high, the response time is slow. For medium power lasers (1W/cm2), the response time is in the order of 0.5 seconds. The crystal can only grow at a temperature lower than 146 ° C to ensure that the single crystal has ferroelectricity. The top seed method is usually used to obtain large BaTiO3 crystal blanks. Fe: KNbO3 crystal: It has excellent photorefractive properties, and the response time is less than 10 ms. Its sensitive wavelength is visible light wavelength. Sr0.5Ba0.5Nb2O6 (SBN) crystal: it belongs to tungsten bronze ore type structure, and is the solid solution crystal of SBN system, where x=0.5, 0.6 and 0.75, and x=0.6 is the only component with uniform melting in the solid solution system. Bulk crystal can be easily prepared by the pull-up method. Its electro-optic coefficient r33=420X10-12 m/V, response time is about 1000 milliseconds, and photorefractive sensitivity is 3.2X10-8 cm ^ 2/J. LiNbO3 crystal: It has a ilmenite like structure and belongs to the trigonal crystal system. It is one of the earliest materials with photorefractive effect. Its electro-optic coefficient is 31X10-12 m/V, and the response time is in the order of seconds. It is suitable for applications such as optical amplifiers, phase conjugators, and memories.

Classification