Tunable nonpolarizing guided-mode resonance filter incorporating electrically driving liquid crystal

A tunable nonpolarizing guided-mode resonance filter (GMRF) incorporating an electrically driving polymer-dispersed liquid crystal (PDLC) cell is designed, fabricated and demonstrated. By studying the dependence of the resonance wavelength on the grating period, the two-dimensional (2D) nonpolarizing GMRF is designed using different grating periods along the x and y axes at oblique incidence. The 2D electrically driving GMRF sample is fabricated through thin-film deposition, electron beam lithography and PDLC injection. Moreover, the resonance spectra of the fabricated sample are measured by a spectrometer and the measured results are consistent with the theory. Thus the nonpolarizing resonance spectra can be tuned by electrically driving the refractive index of PDLC cell in real time.