Polarization based interferometric detector

摘要

A sensor and method for determining the optical properties of a sample material is disclosed. The sensor comprises a light source that generates a linearly polarized light beam having a predetermined polarization orientation with respect to the plane of incidence. The linearly polarized light beam is reflected off the sample and is split into second and third light beams where the second and third light beam consist of the combined projections of mutually orthogonal components of the first light beam. A signal processor measures the intensity difference between the second and third light beams to calculate the phase difference induced by the sample material.

主权项

1. A detection device for detecting an optical property of a sample material, comprising:
a prism that comprises or is adjacent to an optical interface comprising a surface configured to come in contact with said sample material; a light source that generates a first light beam for application to said optical interface, wherein said first light beam comprises a first polarization component and a second polarization component, and wherein said optical interface reflects said first light beam into said prism under total internal reflection conditions; at least one optical retarder that provides substantially circular polarization in said first light beam downstream of said optical interface; a polarizing beam splitter downstream of said optical interface, wherein said polarizing beam splitter splits said first light beam into a second light beam and a third light beam after said first light beam is reflected from said optical interface; a detector module downstream of said polarizing beam splitter, wherein said detector module accepts said second light beam and said third light beam; and a processor programmed to calculate a phase shift between the first and second polarization components induced by said sample material, wherein said processor calculates said phase shift based on the difference in intensities between said second light beam and said third light beam.