Sensitive vapor detection with hollow thin film arrays

In this manuscript, we explored the performance of a hollow thin film array (HTFA) for the detection of HCl vapor based on fluorescence quenching. The HTFA structure was fabricated by manually stacking layers of an active thin film and a supporting film, alternately, with a hollow structure in each supporting film. The total penetration depth of vapor molecules in the HTFA sample is 2n times increased, where n is the layer number of the active thin film. We tested the sensing performance of the HTFA sample using fluorescence emission and laser emission in a Fabry-Perot (FP) microcavity. In the fluorescence sensing, the sensing efficiency increases with the vapor concentration, and can be as high as 80% with a vapor concentration of 400 ppm. While in the laser sensing, the efficiency can achieve 100% with an external pump intensity three times of the lasing threshold at a vapor concentration of 85 ppm. The HTFA sample is not only suitable for vapor detection but also suitable for molecule detection in liquid. (c) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

This manuscript explores the performance of a hollow thin film array (HTFA) for detecting HCl vapor based on fluorescence quenching. The HTFA structure is fabricated by stacking active thin film and supporting film layers alternately, with each supporting film having a hollow structure. The results show that the HTFA sample can achieve high sensing efficiency in both fluorescence and laser detection methods.