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US 6,150,661 AGranted
Gas spectroscopy
AssigneeBruce W. McCaul
InventorsBruce W. McCaul, David E. Doggett
Life of this patent
Estimating the term…
Abstract
An absorption spectroscopy device for determining the concentration of a gas (such as oxygen) in a sample cell includes a neutral density absorber or a quarter wave plate. Laser radiation from a laser diode passes through the neutral density absorber or the quarter wave plate, then passes through the sample cell, and then is incident upon a detector. In some embodiments, the laser diode is driven with a drive current having a stepped periodic waveform.
Claims12
An absorption spectroscopy device, comprising:
- a laser diode emitting laser radiation;
- a quarter wave plate;
- a sample cell containing a volume of material to be analyzed;
- and
- a detector for measuring an absorption spectrum of said material to be analyzed, said laser radiation emitted from said laser diode passing through said quarter wave plate before passing through said sample cell and being incident on said detector.
2 more elements
An absorption spectroscopy device, comprising:
- a neutral density absorber;
- a sample cell;
- a detector;
- and
- a source of laser radiation emitting laser radiation, at least some of said laser radiation passing through said neutral density absorber and then through said sample cell before being incident on said detector.
2 more elements
A method, comprising the steps of:
- providing a neutral density absorber in a path of laser radiation between a source of laser radiation and a sample cell of an absorption spectroscopy device;
- and
- detecting laser radiation which passes through said neutral density absorber and then through said sample cell.
Dependencies are inferred from the claim text.