Development of a refractive index measurement system for vacuum pressure measurement
Development of a refractive index measurement system for vacuum pressure measurement
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真空压力测量用折射率测量系统的开发
DOI：
10.1007/s40042-020-00012-y
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发表时间：
2021
影响因子：
0.6
通讯作者：
S. Woo
中科院分区：
文献类型：
--
作者：
Han;Jong Hoo Kim;S. Woo
最近进行了许多研究，以取代由于禁止汞而被用作国家标准的汞压力计。特别是，通过使用光子技术的“帕斯卡的新实现”在性能方面与现有的基于水银压力计的初级压力标准相比，显示出一些可比较的结果。在这项研究中，我们描述了一个折射率测量系统的发展，精确的真空压力测量，开发无汞标准。如果要使用激光干涉仪测量介质的折射率，则设计作为压力介质的腔和作为光源的激光器是重要的。我们设计了一种具有两个通道的法布里-珀罗（FP）腔结构，通过比较真空状态下的激光谐振频率（用作参考压力）和任意压力状态下的激光谐振频率来计算任意压力。Zerodur被用作空腔的材料。考虑到用作光源的He-Ne激光器的波长（633 nm）、要实现的压力范围和单模的实现范围，将谐振腔设计为宽度为50 mm且长度为150 mm的矩形平行六面体。我们独立地制造了一个单模（SM）He-Ne激光器，而不是商业上可用的激光器，以自由调制频率，并实现单偏振，而不管量子数。用我们的系统，拍频被测量到一个腔的内部压力。发现1 MHz拍频近似等于1 Pa的压力。
Many studies have recently been conducted to replace the mercury manometer that has been used as a national standard because of the prohibition of mercury. In particular, ‘the new realization of the Pascal’ by using photon technology shows some comparable results in terms of performance compared to the existing primary pressure standard based on the mercury manometer. In this study, we describe the development of a refractive index measuring system for precise vacuum pressure measurements to develop a mercury-free standard. If the refractive index of a medium is to be measured using a laser interferometer, designing a cavity as a pressure medium and a laser as a light source is important. We designed a Fabry–Perot (FP) cavity structure having two channels to calculate an arbitrary pressure by comparing the laser resonance frequency in a vacuum state, which served as a reference pressure, and that in an arbitrary pressure state. Zerodur was used as the material for the cavity. The cavity was designed to be a rectangular parallelepiped with a width of 50 mm and a length of 150 mm considering the wavelength (633 nm) of the He–Ne laser used as a light source, the pressure range to be implemented, and the implementation range of a single mode. We independently fabricated a single-mode (SM) He–Ne laser instead of a commercially available laser to modulate the frequency freely and to achieve a single polarization regardless of the quantum number. With our system, the beat frequency was measured to the internal pressure of a cavity. A 1 MHz beat frequency was found to be approximately equal to a pressure of 1 Pa.