Wavelength modulation derivative spectrometer
US4752129A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 18, 1986 |
| Grant date | Jun 21, 1988 |
| Priority date | — |
| Expiry date | Mar 18, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J3/433
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Light to be measured is input to a diffraction grating after is has been oscillated by a wavelength modulation device with a constant frequency F. The light is incident to the diffraction grating at an angle of incidence, .theta., and is oscillated with a frequency F with a center angle of incidence, .theta..sub.0, as a center. An output spectrum of said diffraction grating is received by a photoelectric converter. An electric signal from the photoelectric converter is oscillated with a frequency F over a wavelength range of .lambda..sub.0 .+-..DELTA..lambda. where .lambda..sub.0 is a center wavelength measured at the center angle of incidence .theta..sub.0. The oscillated spectrum signal is synchronously detected, by a synchronous detector, with a frequency 2F through a high-pass filter, obtaining a variation spectrum at the measured center wavelength .lambda..sub.0. The output electric signal of the photoelectric converter passes through a DC amplifier to a sampling circuit where it is sampled with the frequency F or 2F. In this way it is possible to obtain a full intensity of a spectrum at the center wavelength .lambda..sub.0. The driving of a wavelength scanning mechanism cause…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.