Ordered-mesoporous-silica-thin-film-based chemical gas sensors with integrated optical polarimetric interferometry

Zhi Mei Qi, Itaru Homma, Haoshen Zhou

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)

Abstract

A technology to make integrated optical chemical gas sensors using sol-gel surfactant-templated mesoporous thin films was demonstrated. The sensor was prepared by dip coating of an ordered mesoporous silica thin film onto a tapered thin Ti O2 layer sputtered on top of a tin-diffused glass waveguide. The sensor employs single-beam polarimetric interferometry to detect molecular adsorption in the mesoporous silica film because the adsorption can lead to a change of the phase difference (Δφ) between the fundamental transverse electric (TE0) and magnetic (TM0) modes propagating in the waveguide. The sensor is sensitive to humidity and N H3 gas at room temperature (RT). The sensitivity of Δφ>180° was detected for 40 min exposure of the sensor to 2 ppm of N H3 in dry air. The sensor was recoverable from the H N3 exposure but its recovery was too slow to cause a detectable Δφ per unit time. The slow response and recovery of the sensor were ascribed to slow diffusion of gaseous molecules in the laterally oriented tube-like pores of the silica film.

Original languageEnglish
Article number053503
Pages (from-to)1-3
Number of pages3
JournalApplied Physics Letters
Volume88
Issue number5
DOIs
Publication statusPublished - 2006 Feb 10
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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