MEASUREMENT OF THE ULTRALOW STRAY LIGHT IN A DOUBLE MONOCHROMATOR

A new method to measure ultralow stray light in a double monochromator is proposed. This method can not only omit the linear checking of pho toelectric testing system in large-order scale and the transmittance c alibration of the neutral density filter, and improve the measured acc uracy, but can also realize the measurement of ultralow stray light of any order. Roughly speaking, the testing limit of stray light is limi ted only by the power of the incident laser. A measured limit of the o rder of 10(-14) and a ratio of relative light intensity are obtained, and the relative measured error can be reduced below 5%. (C) 1996 Soci ety of Photo-Optical Instrumentation Engineers.