反射式相位延迟器的性能研究

Investigation on Properties of Reflection Phase Retarder

多层介质反射镜在非正入射的时候,两个不同的偏振态之间会产生不同的相移。通过优化设计,入射角为45°,在1285～1345nm之间p,s波获得了270°±0.15°的相移和99.5%以上的反射率。对使用的膜系进行了每层光学厚度的误差分析。用离子束溅射技术制备相位延迟膜,在大气中对样品进行不同温度的退火,用分光光度计测试了光谱特性和用椭偏仪测试了相位特性。结果表明,未退火的样品在相应波段获得了267.5°±0.5°的相移和99.6%以上的反射率;根据拟合分析,最外层的误差和折射率与设计值的偏差是发生相移偏小的主要因素;随着退火温度的升高、折射率变小和物理厚度变大,相移将变小。

When incoming light beams enter dielectric reflective mirror with certain incident angle, there is phase shift between the p-polarization and s-polarization. Based on optimizing design, when light is incident at 45 degree, the phase shift of 270°±0.15° is got in the range of 1285-1345 nm, at the same time, the reflectivity of dielectric mirror maintains over 99.5%. The phase retarder was prepared with dual ion beam sputter system and then annealed at different temperatures in atmosphere, the spectrum and the phase of the sample were gained by spectrometer and the Fourier transform infrared spectroscopic ellipsometer, respectively. The results revealed that the as-deposited samples gained phase shift of 267.5°±0.5° and the reflectivity reached over 99.6%. It was found from the fitting analysis that the error of the outermost layer and deviation between refractive index and designed values play principal roles in decrease of phase shift, in addition, with the annealing temperature increasing, the refractive index of film decreases and physical thickness increases so that phase shift drops off.