Single-shot, spatially resolved spectropolarimetry with stress-engineered optics

We describe, and test, a method of obtaining spectrally and spatially sampled Stokes polarimetry measurements based on star test polarimetry enabled by a stress engineered optic (SEO). When the SEO is placed in the pupil plane of an imaging system, the space-variant birefringence of the SEO combined with the intrinsic wavelength dependence of the retardance allows for point spread functions from distinct laser wavelengths to be both spectrally and polarimetrically distinguished in a single frame measurement designed to enable single shot spectropolarimetry of individual laser pulses. In the experiment, the beam is sampled using a lenslet array typical of that used in a Shack-Hartmann sensor with the PSF of each spot relayed to a sensor. Experiments show angular errors as small as 100 mRad on the Poincare sphere, with red and blue measurements outperforming green. Potential applications include polarization sampling of extreme lasers as well as spectropolarimetry of display devices based on liquid crystals.