I'm working on an experiment to measure the quenching of an oxygen-sensitive dye. The excitation light is blue and the light fluoresced is red. When I collect data, there is always a peak for blue and red, which makes it impossible to measure really the quenching in low dye concentrations because the blue overlaps the small red emission. I'm thinking of using a polarizing film, but dont know the best setup. Below is the current setup: [film w/ dye] — |glass wall| — spectrometer & blue light source Can you guys tell me how to minimize the pickup of blue light without affecting red light pickup?