Angle selectivity of liquid crystal superstructure and applications in bio-detection

In this paper, a temperature-controlled angle selection device based on a photonic bandgap is proposed, consisting of MLC-6608 liquid crystal (MLC) and common electrolytes stacked in layers. This device has an angular transmission stability for electromagnetic waves over a wide frequency band (600–660 THz). A high transmissivity (T>0.85) area, also called an angle window, is formed at 25° and 75°, and an area of zero transmissivity is formed beyond the angle window. The MLC is temperature-responsive, and the range of angle selection can be expanded or narrowed by temperature adjustment. When the MLC is replaced by the biological sample, it shows good sensing performance. It can be used to detect in vitro dermis, in vivo stratum corneum, and in vivo epidermis and it is of great significance in medicine, with a sensing sensitivity of 90.91°/refractive index unit.