Implementation of a narrowband guided-mode resonance optical filter using the multiple-mold replica method in the nanoimprinting process

In this paper, we propose a simple method to reduce the grating modulation depth of guided-mode resonance (GMR) filter devices by using a multiple-mold replica method in the nanoimprinting process in order to achieve narrowband optical filters. This method is based on the shrinking effect of the polydimethylsiloxane (PDMS) mold during solidification. The shrinking effect in the groove depth (vertical) direction can be modulated by selecting different UV curing glues. On the other hand, the shrinking effect in the pitch (lateral) direction is prevented by the groove shape and not related to the UV glues. Therefore, the groove pitch can be kept constant during harness shrinkage. We show that different UV curing glues used in the nanoimprinting process have different effects on the replica PDMS mold. In our experiments, two kinds of UV glues were used and PDMS molds with five different grating depths were obtained. Finally, five transmitted GMR band-reject filters with different full width at half-maximum values were fabricated. These five GMR filters made by the nanoimprinting solgel SiO2 process have five different grating depths: 75, 56, 36, 27, and 18 nm. (C) 2016 Optical Society of America