Fabrication of the Fabry-Perot cavity with acrylate AB glue film via dual pressure assistance for humidity sensing

A method for fabricating a thin film Fabry-Perot (F-P) cavity via dual pressure-assisted acrylate AB glue was studied. The method pressurizes both the acrylate AB glue to generate bubbles and the subsequent inflated film to make it thinner and more sensitive. The F-P cavity was fabricated by attaching the ultrathin film to a glass tube end face and a single-mode fiber in the glass tube to form a two-beam interference model. On the basis of two cycles and several repeated experiments for the humidity gradient, the linear and stable characteristics, and the humidity sensitivity of the F-P cavity with a thin film was demonstrated. The humidity sensitivity was 80.68 pm/% RH and 82.17 pm/% RH under two rising humidity experiments. Acting as the humidity sensing material for the first time, the acrylate AB glue film of the F-P cavity shows good stability and repeatability. In addition, the dual pressure-assisted method introduces a way to produce fiber-optic sensors with ultrathin film. (c) 2022 Society of Photo-Optical Instrumentation Engineers (SPIE)