Abstract: An apparatus for determining a polarization-insensitive interferometric signal and a birefringence for a sample and methods for using such an apparatus to characterize the sample are proved herein. Such apparatuses may generally be designed to eliminate birefringence associated with the apparatus itself, collect data from the sample using light in both orthogonal states, and determine the interference birefringence associated with the collected data.

Abstract: An apparatus for determining a polarization-insensitive interferometric signal and a birefringence for a sample and methods for using such an apparatus to characterize the sample are proved herein. Such apparatuses may generally be designed to eliminate birefringence associated with the apparatus itself, collect data from the sample using light in both orthogonal states, and determine the interference birefringence associated with the collected data.

Abstract: A method for determining a characteristic of an analyte in a biological sample comprising: directing broadband light by means of a sensing light path at the biological sample; receiving the broadband light reflected from the biological sample; directing the broadband light by means of the reference light path at a reflecting device; and receiving the broadband light reflected from the reflecting device. The method also includes: interfering the broadband light reflected from the biological sample and the broadband light reflected from the reflecting device; detecting the broadband light resulting from the interfering to provide an interference signal indicative of a first intensity measurement corresponding to a first depth in the biological sample; and varying an effective light path length of at least one of the reference light path and the sensing light path to define a second depth in the biological sample.