不同组分铌酸锂晶体的光致吸收研究

Investigation on Light-Induced Absorption of LiNbO_3 Crystals with Different Compositions

研究了生长态纯铌酸锂晶体光致吸收效应.通过对不同组分的纯铌酸锂晶体在绿光激发下光致吸收系数的测定,认为不同组分铌酸锂晶体的光致吸收机制不同.引入氧极化子对实验现象作了解释,认为在锂含量较低的同成分晶体,氧极化子的复合有两条途径,而在锂含量较高的化学计量比晶体的氧极化子复合途径单一.对于近化学计量比晶体,泵浦光强时,吸收机制接近于同成分晶体;泵浦光弱时,吸收机制接近于化学计量比晶体.不同组分铌酸锂晶体由于氧极化子复合途径不同,氧极化子的寿命长短不一,CLN晶体中氧极化子寿命最短.

Transient light-induced absorption（LIA） is researched in nominally pure LiNbO3（as-grow,different compositions） with pulsed illumination.By measuring the LIA coefficient change,it is found that different mechanism of light-induced absorption for the congruent lithium niobate and stoichiometric lithium niobate.In this paper,the results show the possibility that O-hole polarons participates in the light-induced charge transport.The mechanism of light-induced absorption and lifetime of hole polarons are discussed.