Fig. 5From: Nano-structured transmissive spectral filter matrix based on guided-mode resonancesa Back-illuminated microscope images of fabricated spectral filter matrix and two rectangular filters. Filter matrix comprises a hole cell without metal coating and 15 individual GMR filters with the grating period ranging from 360 nm to 640 nm in 20 nm steps. b SEM image of the red rectangular filter having a period of ~ 598 nmBack to article page