Dynamical Electro-Optical Characterization of Policryps Gratings

We have studied the dynamical response at 633 and 1550 nm of a new polymer-liquid crystal composite, realized in a form of a thick grating. This composite is known as Policryps, an acronym that stands for "Polymer Liquid Crystals Polymer Slides", because it shows a sequence of polymeric sheets alternated by layers containing only liquid crystal. Policryps gratings can be electrically switched between diffracting and non-diffracting states with a good diffraction efficiency in the visible region. After optimization of their performances, including response time, in the near infrared region, they can be conveniently proposed as a key component in photonic devices for telecom applications. Our results show very interesting response times ranging from 1 to 3 ms (switching on) and from 0.1 to 0.4 ms (switching off). Furthermore, switching ON times appear to be ruled by two different physical mechanisms with characteristic times differing by one order of magnitude. A deeper insight of these mechanisms might lead to response times, all in the submillisecond range.