US 6,151,112 AGranted

High-resolution, compact intracavity laser spectrometer

AssigneeInnovative Lasers Corporation

InventorsGeorge H. Atkinson, Yu Yan

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Abstract

In accordance with the present invention, a high-resolution, compact spectrometer is provided for dispersing wavelengths .lambda. of an incoming beam for detection by a detector. The spectrometer comprises: (a) an entrance slit through which the incoming beam passes; (b) a first mirror for collimating the beam from the entrance slit; (c) a first reflectance grating for dispersing the collimated beam to form a beam having a spectral intensity distribution, the first reflectance grating having a number of grooves N.sub.1 ; (d) a second reflectance grating for further dispersing the collimated beam, the second reflectance grating having a number of grooves N.sub.2 ; and (e) a second mirror for focusing the collimated and dispersed beam, wherein the spectrometer has a substantially symmetrical construction. The symmetrical construction of the spectrometer doubles the resolution and dispersion of the gratings. The compact and high-resolution imaging spectrometer is capable of measuring the absorption lines of gases in high sensitivity gas sensors with an intracavity cell.

Claims8

Dependent claims

A spectrometer for dispersing wavelengths .lambda. of an incoming beam for detection by a detector, said spectrometer comprising:

(a) an entrance slit through which said incoming beam passes;
(b) a first mirror for collimating said beam from said entrance slit;
(c) a first reflectance grating for dispersing said collimated beam to form a beam having a spectral intensity distribution, said first reflectance grating having a number of grooves N.sub.1 ;
(d) a second reflectance grating for further dispersing said collimated beam, said second reflectance grating having a number of grooves N.sub.2 ;
(e) a second mirror for focusing said collimated and dispersed beam,
wherein said spectrometer has a substantially symmetrical construction, wherein said symmetrical construction is derived from ##EQU8## where .alpha. is an incident angle and .beta. is a diffraction angle of a said grating, both said gratings fixed in position, and N.sub.1 =N.sub.2 ;
and
(f) an exit plane on which said beam is focused, wherein said exit plane comprises a linear photodiode detector array so as to permit detection of said spectral intensity distribution of said beam at the same time, said linear photodiode detector array comprising a single channel detector.

5 more elements

Dependencies are inferred from the claim text.