Research on optically controlled active surface filtering technology

摘要

In order to realize the application of active surface filtering technology in an optical window, an optically controlled active surface filtering technology is proposed. Photoelectrically conductive thin-film photovoltaic effect is used to control the dimensional change of the metal frequency-selective surface (FSS), thereby achieving active control of surface filtering. Starting from the theory, the principle of active surface filtering technology is described. CST software is used to simulate the FSS characteristics of two types of metal FSSs, "cross" bandpass type and "Jerusalem" band-stop type, under light irradiation conditions. The results show that the filter center frequency is changed from 23 and 13 GHz to 27.6 and 9.8 GHz, respectively, with the change of the structure size. In this experiment, the cross bandpass type and Jerusalem band-stop type optically controlled active FSS are, respectively, fabricated by coating, etching, and electron beam evaporation techniques. With annealing temperature of 750°C and the annealing time of 300 s, it gets the best optoelectronic performance. The experimental results are that the sensitive wavelength of photoconductive thin film is 0.6 //m and the optimal illumination power is 150 mW/cm2. The sample filter center frequency is changed from 23.8 and 13.5 GHz to 28 and 10.5 GHz, respectively, which is basically consistent with the simulation results. This paper concludes that the use of light control can realize active control of surface filtering.