Here are the possible solutions for prefix with light or sound clue
Answer
Clue
Relevancy
ultra
Clue
Prefix with light or sound
glorybeam
Clue
"The light" of "I saw the light!"?
laser
Clue
Light in a light show
Light-show light
Light show light
Light in a light show, perhaps
Definition
a source of high-intensity optical, infrared, or ultraviolet radiation produced as a result of stimulated emission maintained within a solid, liquid, or gaseous medium