Ellipsometric microscopy

We modified an optical microscope to enable quantitative ellipsometric studies with I nm height and 0.9 mu m lateral resolution. A beam of polarised light impinging on the object under a shallow angle of incidence is generated by focusing a pinhole into an off-axis point in the back focal plane of a high-power microscope objective. The entire image of the object is focused which greatly reduces stray light. In addition, this enables a drastic reduction of the measuring time. For thicknesses of organic films exceeding 20 nm both the film thickness and its refractive index may be determined simultaneously.