A new method to measure ultralow stray light in a double monochromator is proposed. This method can not only omit the linear checking of photoelectric testing system in large-order scale and the transmittance calibration of the neutral density filter, and improve the measured accuracy, but can also realize the measurement of ultralow stray light of any order. Roughly speaking, the testing limit of stray light is limited only by the power of the incident laser. A measured limit of the order of 10-14 and a ratio of relative light intensity are obtained, and the relative measured error can be reduced below 5%.
"Measurement of the ultralow stray light in a double monochromator," Optical Engineering 35(10), (1 October 1996). http://dx.doi.org/10.1117/1.600986