According to one aspect of the invention, there is provided an ellipsometry system for measuring any one or more of molecular binding, adsorption and desorption on a substrate, the system comprising: a) a cuvette comprising i) a body within which a cavity is formed and an opening on the body, wherein the cavity extends into the opening through which the substrate is immersed; ii) a window formed on each of two oppositely located walls of the body, wherein the windows are aligned to allow light to enter through one of the two windows to reflect off the portion of the substrate immersed in the cavity and exit through the other of the two windows; iii) a channel arrangement enclosed within the body of the cuvette and comprising two non-contiguous portions, wherein one of the two non-contiguous portions guides fluid into the cavity and the other non-contiguous portion guides fluid out of the cavity; b) a polarized light source disposed to provide the light that enters into one of the two windows on the body of the cuvette; and c) a detection stage disposed to receive the light that exits through the other of the two windows on the body of the cuvette, wherein the detection stage is configured to measure polarization rotation of the received light, the polarization rotation caused by any one or more of molecular binding, adsorption and desorption occurring on the substrate surface. The detection stage preferably contains a polarization modulator, which is configured to measure polarization rotation of the received light.