Apparatus and method for FTIR spectrometer without compensator
US5491551A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 22, 1993 |
| Grant date | Feb 13, 1996 |
| Priority date | — |
| Expiry date | Feb 22, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J3/453
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A Fourier-transform (FT) infrared (IR) spectrometer includes a Michelson interferometer without an IR beam compensator. An input IR beam is directed through a substrate and a beamsplitter attached to the substrate for support, with the input IR beam divided by the beamsplitter into a first beam portion incident upon a fixed retroreflector and a second beam portion incident upon a movable retroreflector. The first and second beam portions are then recombined to provide an uncompensated output IR beam with an interference pattern which is directed onto a sample to provide an uncompensated interferogram. The uncompensated interferogram is converted from a time domain to a frequency domain via a Fourier-transform to provide a complex intermediate spectrum, followed by a calculation of a corrected phase angle in terms of wavenumber arising from the substrate's optical thickness. The complex intermediate spectrum is then rotated by a negative of the corrected phase angle. An inverse Fourier-transform is used to form a corrected real compensated intermediate interferogram. The corrected real compensated intermediate interferogram is then Fourier-transformed into a spectrum using a convent…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.