冰洲石晶体紫外波段偏光吸收系数的测试研究

Measurement of absorption coefficients for the ultraviolet polarized light in the iceland crystal

为了研究冰洲石晶体在紫外波段的偏光吸收特性,制作了长、宽不相等的测试样品。利用双光路分光光度计,在测试与参考光路同时加入偏振方向相互平行的起偏棱镜,分别测量同一晶体不同长度的偏振透射光谱。通过消除光在晶体表面反射损失的影响,得到两只测试样品在紫外波段对o光、e光的吸收系数。在紫外波段同一冰洲石晶体中e光吸收系数小于o光,且波长越短差别越大;不同冰洲石晶体个体在紫外波段的吸收系数存在较大差异。结果表明,先对冰洲石晶体进行紫外偏振光谱测试,选出吸收系数小的晶体,是制作高性能紫外偏光棱镜的关键。

To study the absorption coefficients for the ultraviolet polarized light in the iceland crystal, two crystal samples in different length and width were manufactured. Using the dual beam path spectrometer and inserting polarizers whose polarization directions are parallel separately into the sample and the reference paths, the transmission spectra of the light passing through the crystal in different lengths were measured. Canceling out the losses on the crystal surfaces, the absorption coefficients of the o light and the e light in the ultraviolet region in both the crystal samples were achieved. The absorption coefficients of e light in the ultraviolet region are usually smaller than o light in the same crystal and as the wavelength gets shorter, their difference becomes larger. The absorption coefficient in the ultraviolet region varies greatly in the different crystals. The results show that it is important for making high performance ultraviolet polarizers to get the ultraviolet polarization spectra of the raw materials and to pick out the crystals with low absorption coefficients.