Fabricationand current optical performance of a largediamond-machined ZnSe immersion grating
Fabricationand current optical performance of a largediamond-machined ZnSe immersion grating
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大型金刚石加工 ZnSe 浸没光栅的制造和当前光学性能
DOI：
10.1117/12.856631
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
and Yuki Sarugaku
中科院分区：
文献类型：
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作者：
Yuji Ikeda;Naoto Kobayashi;Paul J. Kuzmenko;Steve L. Little;Chikako Yasui;Sohei Kondo;Hiroyuki Mito;Kenshi Nakanishi;and Yuki Sarugaku
ZnSe 浸没光栅为从 NIR（近红外）到 MIR（中红外）的宽红外波长区域提供高分辨率光谱的可能性，因为 ZnSe 在这些波长区域具有高折射率 (n ~ 2.45) 和低内消光。我们正在开发用于地面近红外高分辨率光谱仪和空间中红外高分辨率光谱仪的 ZnSe 浸没光栅。我们已经在劳伦斯利弗莫尔国家实验室使用纳米精密飞切技术在 ZnSe 平面基板上制作了小节距（~ 30 μm）的精细凹槽，1 即使是短 NIR 应用也能满足我们的要求。2我们的下一步是利用该技术制造大型棱镜形 ZnSe 浸没光栅。三棱镜的入射面为50mm×23mm，顶角为70°。到目前为止，我们已经尝试了三轮研发削减。我们检查了第二次切割的浸没式光栅样品的光学性能，该样品显示出最佳的性能。虽然通过显微观察在火焰边缘看到了很多碎裂，但我们发现凹槽形状非常好，表面不规则度为0.74λ（pv），随机节距误差为5.2 nm（rms），非常符合我们的要求。在棱镜和浸没配置下获取的氦氖激光光谱中，在衍射级的中间观察到强烈的重影。这些序间重影可能源自奇数和偶数凹槽之间由于切割过程而导致的节距和/或形状的差异。此外，我们还研究了适合衍射表面的反射涂层。因此，我们得出结论，经过超级处理的铝或铜是 WINERED 波长范围内最好的材料。最后，我们讨论了可能的改进点以及对今年夏天下一次试验的展望。
ZnSe immersion gratings provide the possibility of high resolution spectroscopy in the wide infrared wavelength region from the NIR (Near Infrared) to the MIR (Mid Infrared), because ZnSe has a high refractive index (n ~ 2.45) and a low internal extinction in these wavelength regions. We are developing ZnSe immersion grating for a ground-based NIR high-resolution spectrograph and a space MIR high-resolution spectrograph. We already have produced fine grooves on the ZnSe flat substrate with a small pitch (~ 30 μm) using nano precision flycutting technique at the Lawrence Livermore National Laboratory,1 which satisfies our requirements even for the short NIR application.2Our next step is to fabricate a large prism-shaped ZnSe immersion grating with this technology. The triangle prism has the entrance surface 50mm × 23mm and the apex angle of 70 deg. Untile now, we tried three R&D cutting runs. We examined the optical performances of the immersion grating sample from the second cutting run, which showed the best performances. Although a lot of chipping are seen at the edge of the blaze by the microscopic observation, we found that the groove shape is quite good with the surface irregularity of 0.74λ (pv) and the random pitch error of 5.2 nm (rms), which closely meet with our requirements. In the HeNe laser spectra taken under both grism and immersion configurations, strong ghosts were observed at the intermedium of the diffracted orders. These interorder ghosts may originate from the differences of the pitch and/or shape between odd and even grooves due to the cutting procedures. In addition, we also investigated a suitable reflectivecoating for the diffraction surface. As a result, we concluded that aluminum or cupper by suppering process is the best materials in the wavelength region of WINERED. Finally, we discuss the pssible improvement points and prospect for the next trial in this summer.