CO_2激光加热局域热固定LiNbO_3光折变全息的温度影响

Temperature Dependence of the Photorefractive Hologram Locally Thermo-fixed by CO_2 Laser Heating LiNbO_3

利用 CO2 激光加热铌酸锂 ( L i Nb O3)光折变晶体可局域固定体全息 ,但形成的温度场空间上是不均匀的。在对固定显影后空间电荷场幅度 Esc 与固定温度 Tf 的关系进行理论分析的基础上 ,通过定义局域性系数和平均空间电荷场幅度两个判据 ,来评价不同的激光加热温度场的固定效果。这种方法也适用于对其他各类边界条件的 CO2 激光加热温度场局域热固定进行分析。

CO 2 laser has been suggested to heat the LiNbO 3 for locally thermal fixing photorefractive hologram. Here a heating model is theoretically analysed and the stable temperature fields for demonstration aim are obtained. Based on the analysis of the relation between the fixed space charge field amplitude E sc and the fixing temperature T f, two parameters, the localization coefficient Ψ and the average space charge field amplitude E ave sc , are defined to evaluate the fixed local photorefractive hologram by CO 2 laser heating the LiNbO 3. The same analysis can also be used when boundary conditions and laser beam profile are changed.