Effective Suppression of Stray Light in Rotational Coherent Anti-Stokes Raman Spectroscopy Using an Angle-Tuned Short-Wave-Pass Filter

摘要

Stray light interference is a common problem in spontaneous rotationalnRaman spectroscopy and rotational coherent anti-Stokes Raman spec-ntropscopy (CARS). The reason is that the detected spectrum appears innthe spectral vicinity of the probe beam wavelength, and stray light at thisnwavelength from optics and surfaces is hard to suppress. In this Note,nefficient suppression of stray light is demonstrated for rotational CARSnmeasurements using a commercially available short-wave-pass filter. Bynangle-tuning this filter with a specified cut-off wavelength at 561 nm, thencut-off wavelength could be tuned to a desired spectral position so thatnmore than 80% transmission is achieved as close as 15 cmu00021n(;0.4 nm)nfrom the probe beam wavelength of 532.0 nm, while the intensity at thisnwavelength is suppressed by two orders of magnitude.