PIN Hole Detector With Output Unit

This sheet/film is made from polyvinyl Alcohol (PVA) that is stretched and embedded with iodine. The said film absorbs light vibrating in one direction w h i l e t ra n s m i tt i n g l i g ht v i b rat i n g perpendicular to that direction - effectively polarising the light. This detector is used to record the contrast variation at the fringe pattern.