Fabry-Perot interferometer를 이용한 N_(2)의 굴절율 측정

Abstract

In this study I measured precisely the index of refraction of nitrogen gas. I made an experiment using a Fabry-perot interferometer. F-P interferometer was assembled with two etalon plate and their holder. Etalon plate was made of synthetic silica (26.4mm diameter, 6.5mm thickness) plate coating with aluminum. The etalon-holder was manufactured to be able to not only shift etalon plate back and forth but also make fine adjustment. The flat iron plate was laid on the bottom of the vacuum chamber so as to attach etalon-holder firmly to the iron plate by the magnetic from shifting according to the pressure change accuring, thereby having the center of the apparatus remained stationary. Light source and wave length used in determining the reflection index of nitrogen by F-P interferometer were Hg-Lamp with Hg = 5461Å. When monochromatic light was projected into F-P interferometer the number of the shifted interfered fringes and their diameter occuring due to the changes in nitrogen pressure were determined by naked eyes. The reflective index of N_(2) were n=1.000292. Imploying theoretical formula adopted by International spectroscopy Council n=1.000297, when Hg 5461Å were used as light source and wave length, respectively this figure was equal to the data abtained in this study employing F-P interferometer. Within a 4/1,000 % of error.;본 연구는 평면특수 유리에 Aluminum Coating을 한 후 그 위에 Silica를 입혀 만든 etalon판을 지지대에 고정시킨 Fabry-Perot etalon 부분과 부수기구로서 압력변화용 진공장치 이용해서 N_(2)의 굴절율을 측정하는데 목적을 두었다. F-P Interferometer의 etalon판은 지름 26.4mm, 두께 6.5mm인 Synthetic Silica 재료에 Aluminum Coating 하였고 etalon판 지지대는 etalon판을 전, 후로 조정하고 그것을 다시 미세조정 할 수 있도록 되어있으며 압력변화때 etalon지지대가 움직여 장치의 center에 변화가 없도록 etalon지지대의 자기화에 의해 지지대와 밀착 고정되도록 평면 철판을 깔았다. N_(2)의 굴절율을 측정할 때 사용한 light Source와 파장은 Hg-Lamp의 λHg=5461 Å으로써 F-P interferometer에 투과시켜 N_(2)의 압력변화에 따른 간섭무늬의 이동수와 diameter를 측정하였다. 측정한 결과 N_(2)의 굴절율은 n=1.000292로 이 값을 국제분광학회의에서 채택한 이론식을 써서 계산한 값인 n=1,000297와 비교해 보면 약 0.0004%의 오차로 나타나 정확함을 알 수 있었다.