Patent ID: 6522402
Filing Date: 2003-02-18
Classification: G01J,G01N

Abstract:
A tunable absorption spectrometer, comprising:a tunable optical parametric oscillator laser operating to produce a monochromatic beam whose wavelength is tunable in a specified spectral range; a beam splitter positioned in an optical path of said monochromatic beam to divide said monochromatic beam into a reference beam and a sampling beam; a reference photodetector to receive and convert said reference beam into a reference electrical signal indicating an intensity of said sampling beam; a sampling aperture with a dimension less than 10 &mgr;m positioned to limit a spatial extent of said sampling beam; a sample holder adapted to hold a sample relative to said sampling aperture to expose the sample to said sampling beam that transmits through said sampling aperture; a sampling photodetector to receive and convert transmitted light from the sample into a sampling electrical signal; and a control circuit coupled to control the wavelength of said laser and to receive said reference and sampling electrical signals, said control circuit configured to produce absorption data as a function of the wavelength of said monochromatic beam.