Mitra, S and Biswas, T and Chattopadhyay, R and Ghosh, J and Bysakh, Sandip and Bhadra, Shyamal Kumar (2016) Safe and simple detection of sparse hydrogen by Pd-Au alloy/air based 1D photonic crystal sensor. Journal of Applied Physics, 120 (17). Article No-173102. ISSN 0021-8979

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Abstract

A simple integrated hydrogen sensor using Pd-Au alloy/air based one dimensional photonic crystal with an air defect layer is theoretically modeled. Structural parameters of the photonic crystal are delicately scaled to generate photonic band gap frequencies in a visible spectral regime. An optimized defect thickness permits a localized defect mode operating at a frequency within the photonic band gap region. Hydrogen absorption causes modification in the band gap characteristics due to variation of refractive index and lattice parameters of the alloy. As a result, the transmission peak appeared due to the resonant defect state gets shifted. This peak shifting is utilized to detect sparse amount of hydrogen present in the surrounding environment. A theoretical framework is built to calculate the refractive index profile of hydrogen loaded alloy using density functional theory and Bruggeman's effective medium approximation. The calculated refractive index variation of Pd3Au alloy film due to hydrogen loading is verified experimentally by measuring the reflectance characteristics. Lattice expansion properties of the alloy are studied through X-ray diffraction analyses. The proposed structure shows about 3 nm red shift of the transmission peak for a rise of 1% atomic hydrogen concentration in the alloy. Published by AIP Publishing.

Item Type:	Article
Subjects:	Electronics
Divisions:	Fiber Optics and Photonics
Depositing User:	Bidhan Chaudhuri
Date Deposited:	27 Jan 2017 08:52
Last Modified:	27 Jan 2017 08:52
URI:	http://cgcri.csircentral.net/id/eprint/3786

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