Harries J E, Chamberlain J
Appl Opt. 1976 Nov 1;15(11):2667-72. doi: 10.1364/AO.15.002667.
This paper describes a new type of filter radiometer-the Selective Interferometer Filter (SIF)-which has extremely high selectivity to the radiation from a given gas. The basic device is a double output Michelson interferometer, with mirrors fixed at zero geometrical path difference. It is shown that if a cell containing a gas is placed in each of the arms, the ensemble can be made to operate as a highly selective filter, passing radiation only very near the center frequencies corresponding to the absorption lines of this gas. This is a result of direct absorption effects and of the variation of refractive index with frequency and consequent modification of the optical path difference of the two arms of the interferometer. The device may, therefore, after calibration be operated as a highly selective ir radiometer; and a feature of importance in atmospheric and space applications is that it requires no internal moving parts to achieve this selectivity. Details of the device are presented, and a thorough examination of the practical realization of it is given.
本文介绍了一种新型的滤光辐射计——选择性干涉滤光器（SIF），它对特定气体的辐射具有极高的选择性。基本装置是一个双输出迈克尔逊干涉仪，其镜子固定在几何光程差为零的位置。结果表明，如果在每个臂中放置一个装有气体的气室，该装置可以作为一个高选择性滤光器工作，只让非常接近该气体吸收线中心频率的辐射通过。这是直接吸收效应以及折射率随频率变化从而导致干涉仪两臂光程差改变的结果。因此，该装置经过校准后可作为高选择性红外辐射计工作；在大气和空间应用中一个重要的特点是，实现这种选择性不需要内部活动部件。文中给出了该装置的详细信息，并对其实际实现进行了全面研究。
