Abstract: Sensor interrogation systems based on optical phase changes are configured to quantify analytes. Sensor chips and wells can include light scattering regions, light absorbing regions, or tilted regions to reduce or eliminate unwanted portions of an interrogation optical beam. In some examples, a spatial phase modulation is used to compensate static birefringence or to provide a selected sensor bias point. Phase changes can be detected based on state of polarization using interferometry. Optical resonator structures can be used to enhance phase changes to simplify detection of optical phase changes.