Abstract
In order to measure a thickness distribution of an optical thin film, we have proposed a micro-lens array (MLA) mounted on a prism in the modified Otto's configuration for observing surface plasmon resonance (SPR). The SPR is suitable for measuring a thickness of a thin layer because the SPR is high sensitivity for the thickness of the thin layer. However, the thickness distribution cannot be measured by the modified Otto's configuration because a measurement field is limited in a generated SPR field by using a lens. To overcome the problem, we focused on the MLA for increasing a number of the SPR field. A size of the SPR field depends on a lens size, namely, the spatial resolution is improved by using the lens of micron size. In this paper, we measured the thickness distribution of the Au thin film of 50nm using the MLA of the lens 300μm in diameter. Experimental results showed that it was effective for measuring the thickness distribution by using modified Otto's configuration with the MLA.
