根据石英晶体双折射率的色散特性,对石英波片的偏光干涉谱进行了理论分析和数值模拟,提出了一种石英波片延迟量和厚度的偏光干涉标定法。即由偏光干涉谱,可以得出石英波片在200～2000 nm宽光谱范围内的延迟量；通过对长波段的偏光干涉谱极值波长的精确判断,可以准确地计算出该石英波片的厚度。利用Lambda 900 紫外可见近红外分光光度计对一片石英波片的偏光干涉谱进行了测量。在波长精度为0.1 nm的情况下,测量的厚度精度为0.1 μm。误差分析结果表明,通过提高光谱的最小分辨力及选择较长的光谱波段进行测量计算,可以有效地降低误差。

According to the birefringence dispersion character of a quartz crystal, the theoretical analysis and numerical simulation about the polarization interference spectrum are given,and then a systematic way of measuring the phase retardation and thickness of the quartz wave plate, which is based on the principle of polarization interferometry, is put forward. With the polarization interference spectrum, the phase retardation of quartz wave plates can be determined at a wide spectral range from 200～2000 nm. Through accurate judgment of extreme points of the polarization interference spectrum at long-wave band, the physical thickness of the quartz wave plate can also be achieved exactly. Experimentally, the polarization interference spectrum of a quartz wave plate is measured with Lambda 900 UV/VIS/NIR spectrophotometer. Under the conditian of 0.1 nm wavelength resolution, the thickness accuracy is 0.1 μm. The result of error analysis shows that the relative error can be reduced efficiently by use of spectrometers with higher spectral resolution and longer spectral band to measure and calculate.