Fast-response & Polarization-independent Optical Shutter Using Nano-PDLC Inside a Fabry-Perot Cavity

In this paper, we present experimental results obtained for a device incorporating a nano-PDLC inside a Fabry-Perot cavity. Our aim is to produce a fast-response and polarization-independent light shutter with potential applications in e.g. telecommunication systems since nano-PDLC is known for its fast response time. In our chosen example of nano-PDLC with 70 wt% polymer and 30 wt% liquid crystal (E7), we obtained a light shutter with contrast ratio = similar to 7.5 under an applied voltage of similar to 50 V. Response time is similar to 2 to 3ms and transmission is similar to 20%. All these device performances, such as operation voltage, transmission and response time can be improved in future by improving the cavity performance and using a faster liquid crystal material. Moreover, comparison in performance is also made for devices with different concentrations of polymer and liquid crystals. Discussion on the residual scattering effect of the nano-PDLC inside the Fabry-Perot cavity is also included. It is interesting to observe that the undesirable effect of the residual scattering of nano-PDLC at low voltages may actually help improve the contrast ratio and/or lower the operation voltage of the device.