Patent ID: 6151112
Filing Date: 2000-11-21
Classification: G01J

Abstract:
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.