Optically induced Light Modulation in an hybrid nanocomposite system of inorganic CdSe/CdS nanorods and nematic liquid crystals

We studied the thermo-optical properties and nonlinearities of new materials prepared in our labs which consisted in a nanocomposite blend of liquid crystals and semiconductor CdSe/CdS nanorods. We found a thermally induced optical bistability when a laser beam travelled across the cell, as the beam was able to cause a reversible switching in the optical properties of the blend from a scattering state to a transmissive state. The optically induced light modulation by a pump beam (Ar+ laser) was probed by a weak He-Ne beam when the two laser beams were incident on the cell simultaneously. The dependence of the hys- teresis loop on the modulation frequency of the incident beam was also studied, and the variation in the light intensity was successfully exploited as a mean to switch the system from an opaque state to a transmission state, as it had a strong influence on the thermo-optical behaviour of the blend. Our results indicate a thermally- and optically induced light modulation, and demonstrate that the proposed system is promising for applications in thermo-optical switches.