Metasurface-enabled non-orthogonal four-output polarization splitter for non-redundant full-Stokes imaging.

Area of Science:

• Optics and Photonics
• Metasurface Technology
• Polarization Imaging

Background:

• Imaging polarimetry provides crucial information beyond intensity and spectral data.
• Conventional methods like division-of-focal-plane (DoFP) cameras have efficiency limitations (max 50%) due to polarizer absorption.
• Alternative lossless methods reduce spatial resolution by requiring more sensor pixels.

Purpose of the Study:

• To develop a high-efficiency, high-resolution imaging polarimetry technique.
• To overcome the efficiency and spatial resolution trade-offs of existing polarimetry methods.
• To demonstrate a metasurface-based solution for full Stokes parameter retrieval.

Main Methods:

• Design and fabrication of a single-layer dielectric metasurface using silicon nanoposts.
• Utilizing low-loss four-output polarization splitting without filtering.
• Simultaneous sorting and focusing of light onto four sensor pixels.
• Experimental demonstration in the near-infrared (1500-1600 nm) wavelength range.

Main Results:

• The metasurface achieved over 50% efficiency, exceeding conventional methods.
• Demonstrated complete retrieval of full Stokes parameters.
• Achieved -0.67-dB (85.8%) transmission and -2.28-dB (59.2%) overall efficiency.
• Successfully demonstrated multi-pixel polarimetry with a 3x4 superpixel array.

Conclusions:

• A single-layer dielectric metasurface enables efficient and high-resolution full Stokes polarimetry.
• The developed metasurface overcomes the inherent limitations of existing polarimetry techniques.
• This technology has significant potential for advanced imaging applications requiring detailed polarization information.