3D mapping of the output laser beam from a PDLC sample

Self-transparency due to thermal non-linearities is presented as a basic switching effect in a thick polymer dispersed liquid crystal sample. For the first time a detailed 3D mapping of the output laser beam as a function of the x-y coordinates is presented: changes of the transmitted beam profile are recorded vs. both incident power and time. It is discussed how light intensity and temperature can be used as control parameters for the non-linear part of the refractive index. The experimental results confirm the existence of a threshold value of the incident light intensity at which the device switches from the scattering state to the transmissive state.