CO_2激光局域热固定光折变全息的一种新方法

A New M ethod of Local Therm al Fixing by C O_2 Laser

提出用 Ｃ Ｏ２ 激光加热后记录固定的方案对 Ｌｉ Ｎｂ Ｏ３ 晶体中的全息进行实时实地局域热固定。通过加载绝热体， 利用连续激光加热晶体待固定区域局部范围至接近２００℃， 停止加热开始记录， 至该区域温度降至 １００℃时， 将固定一个体全息。文中给出了热传导模型及其数值解。由得到的初步结果参数进行了一系列实验。实验结果显示， 应用这种方案可成功地对光折变全息进行实时实地局域热固定， 并且具有温度更均匀的特点，

A real tim e and in situ recording fixing m ethod after heating w ith C O2 laserbeam s is suggested to therm ally fix a sm all local hologram in a bulk of Fev Li Nb O3 photore fractive crystal. W ith an insulator m antling the crystal, w hen tw o cw C O2 laser beam s heat itto form a 200℃volum e w ith the shape of Gauss beam , C O2 laser beam s are blocked and Ar+laser beam s are used to record a photorefrative hologram , finally fixed a hologram in crystalbefore the tem perature descended to 100℃. A heat transfer m odel and num eric solution aregiven. On the basis of sim ulation, a series of experim ental result are obtained. Both experi m ent and theory analysis show that this schem e can fix a better hologram in realtim e and insitu, the tem perature distribution is uniform .