Infrared interferometric spectrometers
Abstract
The theoretical and practical bases of infrared interferometric (Fourier transform) spectroscopy are examined. The operating principles of the Michelson interferometer are discussed, and consideration is given to the mathematic process of obtaining a spectrum from an interferogram, including asymmetric interferograms, Gaussian functions, sampling, the use of filters, one-sided interferograms, and the interferogram as an auto-correlation function. The optical aspects of the Michelson interferometer are discussed, and the design of the interferometer is examined in detail. Methods employing digital computers for the calculation of spectra are considered, including the fast Fourier transformation, and commercial instruments are presented. Means for the measurement of refractive indices by the interferometric spectrometer are indicated, and possible modifications of the basic Michelson optical system are examined, including the change of the incidence angle to the beamsplitter, the Mach Zehnder interferometer, and the spherical mirror interferometry, together with other interfererometers and associated instruments, including the lamellar grating interferometer, the Fabry-Perot interferometer and the Hadamard-transform spectrometer.
- Publication:
-
NASA STI/Recon Technical Report A
- Pub Date:
- November 1980
- Bibcode:
- 1980STIA...8123378M
- Keywords:
-
- Fourier Transformation;
- Infrared Interferometers;
- Infrared Spectrometers;
- Beam Splitters;
- Computer Techniques;
- Digital Computers;
- Fabry-Perot Interferometers;
- Incidence;
- Mach-Zehnder Interferometers;
- Michelson Interferometers;
- Mirrors;
- Normal Density Functions;
- Optical Filters;
- Polarized Radiation;
- Refractivity;
- Instrumentation and Photography