Polarization‐sensitive scanned fiber confocal microscope

TLDR: In this article, a Se´narmont polarization rotator is used to measure the intensity and polarization orientation of linearly polarized light reflected from a birefringent sample.

Abstract: We describe a polarization-sensitive fiber optic based confocal microscope. Polarization maintaining single mode fibers are used to illuminate a specimen with linearly polarized light. The orientation of the incident linearly polarized light is continuously variable using a Se´narmont polarization rotator. A polarization-sensitive light detector enables the microscope to record the intensity and polarization orientation of the reflected light. The microscope can thus function as a conventional confocal microscope as well as detect rotations of the polarization orientation of the incident light by a birefringent specimen. Lateral scanning of the microscope focal volume is achieved by moving the fiber tip in a reciprocal layout. Confocal operation of the system is demonstrated both theoretically and experimentally. The theoretical and measured responses of the microscope to a dielectric mirror, glass slide, quarter wave plate, linear polarizer, and calcite crystal are considered. Images of a birefringent specimen are presented.