In many applications, the measurement accuracy of spectroradiometers, particularly instruments with a single dispersive element, is limited by the presence of stray radiation within the instrument. A simple, practical method has been developed to correct a spectroradiometer s response for measurement errors arising from stray-light. By characterizing the instrument s response to a set of monochromatic lasers that cover the instrument s spectral range, a stray-light signal distribution matrix is obtained which quantifies the magnitude of the stray-light signal within the instrument. Using these data, the instrument s response can be corrected with a simple matrix multiplication. The method has been implemented and validated using a commercial CCD-array spectrograph. Residual stray-light after the correction was applied were reduced by one to two orders of magnitude, to a level less that one part in 10-5, equivalent to less than one count of the 15-bit-resolution instrument. This method is fast enough to be implemented into an instrument s software to perform real time stray-light corrections with minimal impact on acquisition speed. Using instruments that have been corrected for stray light, significant reductions of overall measurement uncertainties are expected in many applications where spectrometers are commonly used, including colorimetry, radiometry, photometry, and biotechnology.
Citation: Applied Optics
Pub Type: Journals
CCD array, colorimeter, photodiode array (PDA), spectrograph, spectrometer, spectrophotometer, spectroradiometer, stray light