Effect of relative nanohole position on colour purity of ultrathin plasmonic subtractive colour filters

Abstract

Plasmonic subtractive color filters through patterning periodic nanostructures on ultrathin Ag films deposited on a glass substrate, exhibiting good durability, simple fabrication, and flexible color tunability, have attracted considerable attention due to their tremendous potential applications. While previous studies have mainly focused on their extraordinary physical mechanisms, color purity, which is another key parameter for high quality imaging applications, has been much less investigated. In this work, we demonstrate that the relative position of nanoholes patterned on ultrathin Ag films can largely affect the color purity of plasmonic subtractive color filters. The calculated results agree reasonably well with the experimental data, revealing that the purity of subtractive colors can be improved by changing the nanohole arrays from square lattice to triangular lattice without reducing transmission at visible frequencies. In addition, underlying mechanisms are clarified by systematically analyzing the dominant valley in transmission spectra.

Nanophotonic Image Sensors

“…Surface plasmonic resonance (SPR) is considered to play an important role in the color filtering, where incident light couples to surface plasmon resonance first and then couples back to light via periodic hole array for wave vector matching . Since the first paper by Ebbesen et al in 1998, considerable efforts have been made to increase transmission, improve color purity, suppress angular sensitivity and improve design and fabrication efficiency . Hole shape, lattice structure, index matching layer and multi‐period array were investigated both numerically and experimentally. ii)The metal‐dielectric‐metal (MIM) grating color filters are based on the coupling between two metallic layers .…”

“…For IS application, transmissive color filters are preferred. So far, most transmissive nanophotonic color filters were fabricated on glass for easy characterization . The simplest way to test the functionality of the nanophotonic color filters for ISs is to place the CFA on glass directly on top of a black and white image sensor pixel array with PMMA as the intermediate layer, proposed and demonstrated by Atwater et al in 2013 .…”

Femtosecond laser fabricated polymeric grating for spectral tuning

“…Recently, some miniaturized microelectromechanical systems (MEMS)-based or optical fiber based tunable gratings have been reported [8][9][10][11]. Wavelength tuning in the visible spectral range, commonly known as color filtering, is particularly important for applications, such as a color filter consisting of an array of annular apertures in a gold film for transmission measurement [12], a multilayered structure incorporating a subwavelength metal-dielectric grating for better reflection resonance and color effects [13], excitation of surface plasmonic effects in nanostructured materials [14][15][16], and plasmonic color filters adopting freestanding resonant membrane waveguides [17]. Most of these reported components are either relatively large in volume for use in free-space optics, costly in the fabrication techniques, or are mostly incompatible with integrated systems, especially for the case of biomedical applications, for example, a lab-on-a-chip platform, where footprint and the compatibility with the fluidic environment are crucial [18].…”

Artificial Structural Color Pixels: A Review

“…Filter-free image sensor pixels [ 50 ] have also been experimentally studied. In addition, the effect of relative nanohole position on color purity [ 51 ] has been investigated. The working principles of artificial structural color devices are using geometrical resonances to manipulate light in visible frequencies and further engineer surface waves at the nanoscale [ 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 ], which is different from traditional optical devices such as fiber Bragg gratings or other constructive interference optical components [ 65 , 66 , 67 , 68 ].…”