Enhanced transparency in strongly scattering media

The well-known optical theorem describes that extinction energy lost from a light beam is equal to scattering in all directions, and possible absorption [1] . Recently, our group has generalized the theorem to multiple incident beams [2] , with which we discovered it is possible to either enhanced transparency or enhanced extinction in a scattering system with multiple beams, controlling the relative phase and angle between them. This effect is called mutual transparency or extinction. Here, we present an experimental study of this effect. We use a strongly scattering sample made from a strip of silicon (see figure 1.b ). A liquid crystal phase retarder is used to control the phase difference between two incident beams and using an unbalanced March-Zehnder interferometer, we can control the relative angle with a movable mirror.