Premium
Color Generation and Refractive Index Sensing Using Diffraction from 2D Silicon Nanowire Arrays
Author(s) -
Walia Jaspreet,
Dhindsa Navneet,
Khorasaninejad Mohammadreza,
Saini Simarjeet Singh
Publication year - 2014
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201300601
Subject(s) - materials science , refractive index , optics , silicon , diffraction , structural coloration , optoelectronics , rgb color model , diffraction grating , nanowire , grating , trichromacy , color vision , photonic crystal , physics , computer science , operating system
Tunable structural color generation from vertical silicon nanowires arranged in different square lattices is demonstrated. The generated colors are adjustable using well‐defined Bragg diffraction theory, and only depend on the lattice spacing and angles of incidence. Vivid colors spanning from bright red to blue are easily achieved. In keeping with this, a single square lattice of silicon nanowires is also able to produce different colors spanning the entire visible range. It is also shown that the 2D gratings also have a third grating direction when rotated 45 degrees. These simple and elegant solutions to color generation from silicon are used to demonstrate a cost‐effective refractive index sensor. The sensor works by measuring color changes resulting from changes in the refractive index of the medium surrounding the nanowires using a trichromatic RGB decomposition. Moreover, the sensor produces linear responses in the trichromatic decomposition values versus the surrounding medium index. An index resolution of 10 −4 is achieved by performing basic image processing on the collected images, without the need for a laser or a spectrometer. Spectral analysis enables an increase in the index resolution of the sensor to a value of 10 −6 , with a sensitivity of 400 nm/RIU.