Hybrid modulation schemes for adaptive polarimetry (Conference Presentation)

Channeled polarimeters modulate the Stokes parameters onto harmonic carriers of a particular independent domain such as time, space, wavenumber, or angle of incidence. Because the modulation creates many channels within the frequency sampling space of the detector array, channel bandwidth is crucial for this type of device. Much researches has been conducted to exploit more bandwidth in polarimeters that modulate in space, time, or wavenumber along. Our group and others have provided previous theoretical designs for hybrid-domain modulation strategies in order to extend the distance between channels in the Fourier domain through a bandwidth tradeoff approachin order to provide a wider channel bandwidth than systems utilize only one of the corresponding domains. This paper will present results from a a spatio-temporally modulated Stokes polarimeter. The system trades off the bandwidth between space and time to obtain further channel separations. In this work, we demonstrate the system implementation and the experiment results. The experiment compared the spatio-temporal hybrid domain modulated Stokes polarimeter with the spatial and temporal domain only modulated Stokes polarimeter to verify the prediction from the theoretical work. The experimental results indicated that comparing to the spatial and temporal domain only modulated Stokes polarimeters the hybrid-domain modulated polarimeter provides a better image reconstruction and contrast on signals with moderate bandwidth extension. We also consider adaptive reconstruction methods that allow the reconstruction filters to be tailored to the input data. This strategy will allow the bandwidth of the system to be optimally exploited for any particular task.