Rapid time-gated polarimetric Stokes imaging using photoelastic modulators

Abstract

We report a rapid time-gated full Stokes imaging approach without mechanically moving parts, which is well-suited for biomedical applications, using two photoelastic modulators (PEMs). A charge-coupled device (CCD) with microsecond time-gating capability was used to acquire the images. To synchronize the CCD with the PEMs, thus gaining signal-to-noise ratio advantage, a field programmable gate array was employed. After calibration, an evolutionary algorithm was used to select four time points from which the full Stokes vector can be recovered. Using the images taken by the camera at these four times (in ~80 ms), the images of the full Stokes vectors of different incident polarization states were accurately derived.