You can test this out by taking a photoresistor and an ultraviolet LED and butting them up together, then passing a simple analog signal (like a mono audio cabl

You can test this out by taking a photoresistor and an ultraviolet LED and butting them up together, then passing a simple analog signal (like a mono audio cable) through them. Pull them apart slowly while playing the music. Later you can try the same with a laser.