Wide band grating spectrometer
AssigneeInternational Business Machines Corporation
InventorsLawrence Jacobowitz, Einar S. Mathisen, Lawrence D. Thorp
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Abstract
A spectrophotometer includes an illumination section for illuminating a test sample, and a spectrometer portion for receiving light from a test sample and measuring the radiant energy thereof as a function of wavelength. The spectrometer includes an entrance slit and two stationary gratings for dispersing light admitted through the slit into two separate dispersed beams or spectra. The separate beams are focused upon linear arrays of photodiodes providing outputs proportional to the intensity of the light rays at the different wavelengths received thereby. The gratings produce different primary orders of dispersion so that the efficiency of operation thereof is relatively high across a relatively wide band of radiant energy.
Claims7
In a spectrometer for measuring the intensities of radiant energies within a beam of light across different wavelengths thereof, said spectrometer including an elongated rectangular entrance slit for admitting said beam, the combination comprising:
- first and second stationary gratings disposed in the path of said beam admitted by said slit, each of said gratings having lines parallel to said slit, the lines of each grating being different to produce different primary orders of dispersion, said gratings being operative to dispense light in said beam into two separated dispersed beams;
- first and second arrays of photodiodes, said photodiodes being arranged in each array along a line and operative to produce output signals proportional to the intensities of rays of radiant energies illuminated thereby;
- and means for focusing said dispersed beams separately on said arrays so as to image said slit thereon, whereby successive photodiodes in each array produce outputs proportional to the intensities in rays of successive wavelengths.
Dependencies are inferred from the claim text.