由于温度会对云母晶体的最大双折射率产生影响, 影响云母波片的使用精确度。利用偏光干涉法测定了云母晶体的最大双折射率温度系数。利用岛津UV-3101PC分光光度计, 在其样品室中加入温控装置, 测出80 μm,300 μm和813.5 μm三个不同厚度的云母波片在不同温度下的偏光干涉谱, 发现干涉谱发生漂移。通过对偏光干涉谱极值点所对应波长的精确判断, 准确计算出相应温度下波片的最大双折射率。求出云母晶体在紫外波段和可见光波谱段的最大双折射率温度系数表达式。实验是在波长精度为0.05 nm时进行的, 测量的双折射率精度可达到10-5。

The variation of temperature has an effect on maximal birefringent index of mica crystal, which accordingly influences the use precision of mica wave-plate. In order to reduce this negative effect and improve the precision of mica wave-plate under different temperature conditions, the thermal maximal birefringent index coefficients of mica crystal is measured by using the method of polarization interference spectrum. Firstly, with Daojing UV-3101PC spectrophotometer, the polarization interference spectrums of mica wave-plates with thickness of 80 μm, 300 μm and 813.5 μm are measured and the spectral drift is discovered at different temperatures. Then through accurate judgment of extreme points of the polarization interference spectrums, the maximal birefringent index of the mica wave-plate is calculated exactly. At last, expressions of the thermal maximal birefringent index coefficients for mica crystal are deduced at visible and ultraviolet bands. The experiment is performed under the condition of 0.05 nm wavelength resolution and the measurement accuracy of birefringent index can reach 10-5.