Patent ID: 6683686
Filing Date: 2004-01-27
Classification: G01J

Abstract:
An apparatus for determining the wavelength of a sample source of light, said apparatus having:a reference light source of known wavelength; a collimator for collimating light from said sample source and from said reference source; a dispersing means for receiving and spatially dispersing collimated light from said collimator according to wavelength; focusing means for focusing dispersed light from said dispersing means; and a photodetector located in the focal plane of said focusing means and having an aperture for spatially selectively admitting light from said focusing means, and operable to provide a temporally calibratable output signal indicative of the wavelength of said selectively admitted light; wherein said apparatus is operable to provide relative rotation of said dispersing means of uniform speed and thereby scan said focused spatially dispersed beam across said aperture, and said photodetector output includes a resolvable reference feature corresponding to light from said reference source and a resolvable sample feature corresponding to light from said sample source, and said apparatus includes a timer for determining a time difference between detection of said reference feature and detection of said sample feature whereby a wavelength difference between said light from said reference source and said sample source can be determined from said time difference and said speed, and said wavelength of said sample source can be determined from said wavelength difference and said known wavelength of reference source.