Development of an Optical Pressure-sensitive Membrane based on Plasmon Resonance on a Gold Island Film

Abstract

In this paper, an optical pressure-sensitive membrane based on plasmon resonance absorption has been designed, fabricated, and demonstrated. The membrane utilizes plasmon resonance on a gold island film embedded in a polydimethylsiloxane (PDMS) layers, and the shift of the resonant wavelength was used as an indicator of pressure-induced strain of the membrane. The membrane with total thickness of 100 µm were prepared with spin-coating of PDMS and vacuum evaporation of gold island film with the nominal thickness of 10 nm. Pressure sensitivity of the fabricated membrane was demonstrated from the measurement of absorbance spectra and the maximum sensitivity of 0.35 nm/kPa was achieved by applying pressure up to 35 kPa. Plasmon resonance mode attributing to the pressure sensitivity has been analyzed through comparison between electromagnetic simulation and membrane stretching test. From the stretching test, red shifts of the resonant wavelength were obtained for both parallel and perpendicular polarizations to the tensile direction with the sensitivities of 0.372 and 0.134 nm/%, respectively. From the electromagnetic simulation, these red shifts can be attributed to both gap-mode and deformation-mode resonances of the gold island film.