Is there any cheap method by which to create tune-able optical band pass filter?
I am working with a chemical process which will fluoresce when excited by a specific wavelength of light. As shown in the image below, the FAM" reaction will fluoresce at ~520nm when excited by a light source of ~490nm. I want to build a cheap device that will go over a well full of samples and shine the various excitation frequencies while monitoring for the emission frequencies. The idea is that this device will then be able to determine which reaction (out of those listed on the left) took place.
It is my understanding using an RGB LED and RGB color detector is not possible because "mixing" RGB LEDs does not actually alter the wavelength of the color - it only appears that way to our eyes. I am exploring thin-film filters like this but was wondering if any other options exist.