Multilayer porous silicon diffraction gratings operating in the infrared
1 School of Mechanical and Chemical Engineering, University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia, 6009, Australia
2 Department of Electrical Engineering, IIT Madras, Chennai, 600036, India
3 School of Electrical, Electronic and Computer Engineering, University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia, 6009, Australia
Nanoscale Research Letters 2012, 7:645 doi:10.1186/1556-276X-7-645Published: 24 November 2012
Transmission diffraction gratings operating at 1,565 nm based on multilayer porous silicon films are modeled, fabricated, and tested. Features down to 2 μm have been patterned into submicron-thick mesoporous films using standard photolithographic and dry etching techniques. After patterning of the top porous film, a second anodization can be performed, allowing an under-layer of highly uniform porosity and thickness to be achieved. High transmission greater than 40% is measured, and modeling results suggest that a change in diffraction efficiency of 1 dB for a 1% change in normalized refractive index can be achieved. Preliminary measurement of solvent vapor shows a large signal change from the grating sensor in agreement with models.