title: Measurement of reflection phase using thick-gap Fabry-Perot etalon.
abstract: We report measurement of the reflection phase of a dielectric (glass)/titanium (Ti) surface in the visible wavelength using a thick-gap Fabry-Perot (FP) interferometry technique. Using a two-beam interference model for the reflection peaks and troughs of the FP etalon, we obtain the air-gap spacing of the etalon and, more importantly, the reflection phase of the etalon substrate. We find systematic dependence of the as-measured reflection phase on the air-gap spacing due to the numerical aperture effect of the measuring objective. However, the relative reflection phase of Ti with respect to glass is independent of the air-gap spacing. As a demonstration of our approach in the optical characterization of small metamaterial samples, we also measure the reflection phase of a micron-sized 2D Au sawtooth nanoarray. The experiment is in good agreement with the model simulation.
authors.forename: Tsz Kit
authors.initials: TK
authors.lastname: Yung
authors.forename: Wensheng
authors.initials: W
authors.lastname: Gao
authors.forename: Ho Ming
authors.initials: HM
authors.lastname: Leung
authors.forename: Qiuling
authors.initials: Q
authors.lastname: Zhao
authors.forename: Xia
authors.initials: X
authors.lastname: Wang
authors.forename: Wing Yim
authors.initials: WY
authors.lastname: Tam