Self-powered intelligent liquid crystal attenuator for metasurface real-time modulating

Triboelectric Nanogenerator (TENG) is capable of efficiently capturing mechanical energy and transforming it into electrical energy for self-powered systems, making it an ideal power source for Polymer Dispersed Liquid Crystal (PDLC). Herein, a Self-powered Intelligent Liquid Crystal Attenuator (SPILCA) is demonstrated for metasurface real-time modulating. The convergent beam-shaping metasurface consisting of holey meta-atoms with diameters ranging from 100 nm to 300 nm is fabricated by e-beam lithography (EBL). While the unique optical characteristics of the metasurface can be modulated within a certain frequency range, the E7 Liquid Crystal (E7-LC) has a large index of birefringence, and it can be powered by TENG to switch between two optical response states. Therefore, the combination of metasurface and SPILCA can achieve real-time control of metasurface by using the electricity regulatory of LC and the electromagnetic response of the metasurface. In order to build this SPILCA for metasurface modulating, a vertically contact-separated TENG based on Nylon electrospun film as triboelectric material is proposed. The maximum values of the open-circuit voltage, short-circuit current, transferred charge are 165 V, 25 mu A, and 86 nC, respectively. By measuring the optical power and testing the modulation effect of SPILCA on the metasurface, it can be seen that the SPILCA has a good modulation effect on the optical signal, and even can reach 96 % intensity modulation when the laser source wavelength is 450 nm and the current is 0.09 A. This self-powered photoelectric response device does not require additional electrical power supply, and has great potential in future smart optical system design.