Hanany Shaul, Hubmayr Johannes, Johnson Bradley R, Matsumura Tomotake, Oxley Paul, Thibodeau Matthew
School of Physics and Astronomy, University of Minnesota, 116 Church Street, SE, Minneapolis, Minnesota 55455, USA.
Appl Opt. 2005 Aug 1;44(22):4666-70. doi: 10.1364/ao.44.004666.
We have constructed an achromatic half-wave plate (AHWP) suitable for the millimeter wavelength band. The AHWP was made from a stack of three sapphire a-cut birefringent plates with the opticalaxes of the middle plate rotated by 50.5 deg with respect to the aligned axes of the other plates. The measured modulation efficiency of the AHWP at 110 GHz was 96 +/- 1.5%. In contrast, the modulation efficiency of a single sapphire plate of the same thickness was 43 +/- 4%. Both results are in close agreement with theoretical predictions. The modulation efficiency of the AHWP was constant as a function of incidence angles between 0 and 15 deg. We discuss design parameters of an AHWP in the context of astrophysical broadband polarimetry at the millimeter wavelength band.
我们构建了一种适用于毫米波段的消色差半波片（AHWP）。该AHWP由三层蓝宝石a切割双折射板堆叠而成，中间板的光轴相对于其他板的对齐轴旋转了50.5度。在110 GHz下测得的AHWP调制效率为96±1.5%。相比之下，相同厚度的单个蓝宝石板的调制效率为43±4%。这两个结果都与理论预测非常吻合。AHWP的调制效率在0至15度的入射角范围内保持恒定。我们在毫米波段天体物理宽带偏振测量的背景下讨论了AHWP的设计参数。
