Full Stokes imaging polarimetry using dielectric metasurfaces (1803.03384v1)

Abstract: Polarization is a degree of freedom of light carrying important information that is usually absent in intensity and spectral content. Imaging polarimetry is the process of determining the polarization state of light, either partially or fully, over an extended scene. It has found several applications in various fields, from remote sensing to biology. Among different devices for imaging polarimetry, division of focal plane polarization cameras (DoFP-PCs) are more compact, less complicated, and less expensive. In general, DoFP-PCs are based on an array of polarization filters in the focal plane. Here we demonstrate a new principle and design for DoFP-PCs based on dielectric metasurfaces with the ability to control polarization and phase. Instead of polarization filtering, the method is based on splitting and focusing light in three different polarization bases. Therefore, it enables full-Stokes characterization of the state of polarization, and overcomes the 50% theoretical efficiency limit of the polarization-filter-based DoFP-PCs.

• The paper introduces a novel dielectric metasurface that splits and focuses light into distinct polarization channels for complete Stokes parameter measurement.
• The design eliminates lossy polarization filters, achieving transmission efficiencies between 60% and 65%, well above traditional systems' limits.
• Experimental results validate its potential for compact, high-performance polarimetric imaging in applications like remote sensing, biomedical imaging, and materials science.

Full Stokes Imaging Polarimetry Using Dielectric Metasurfaces

The paper "Full Stokes Imaging Polarimetry using Dielectric Metasurfaces" presents an innovative approach to imaging polarimetry through the use of dielectric metasurfaces. This research leverages the ability of dielectric metasurfaces to split and focus light in distinct polarization bases, enabling the full characterization of light's polarization state. Metasurfaces are advantageous over traditional Division of Focal Plane Polarization Cameras (DoFP-PCs) as they surpass the 50% efficiency limit inherent to polarization-filter-based systems.

Imaging polarimetry provides critical information about the shape, texture, and material composition of scenes by detecting polarization states. Existing technologies for polarimetric imaging often rely on complex, expensive apparatuses that are limited by challenges including bulkiness and inefficiency. The advent of dielectric metasurfaces marks a significant shift, as they offer compactness, high efficiency, and integration capability with conventional microfabrication processes.

The authors describe the design of a metasurface that performs the dual function of polarization splitting and focusing at three distinct polarization bases—horizontal/vertical, +/-45-degree linear, and right-/left-handed circular polarization. The metasurface structures, composed of high contrast dielectric materials with nano-scatterers, are capable of independent control of the phase and polarization of the incident light. This property allows for direct integration onto image sensors, creating an imaging setup capable of recording full Stokes parameters with improved efficiency over traditional systems.

The proposed dielectric metasurface achieves improved efficiency by avoiding the use of lossy polarization filters. Instead, it utilizes a mask that facilitates a complete polarization split and focus into six distinct polarization states over an area corresponding to six pixels on an image sensor. The researchers demonstrate that the metasurface DoFP-PC can be used effectively to form polarization images over extended scenes. Their work represents the first successful demonstration of a DoFP-PC system that fully measures polarization states without relying on polarization filtering methods.

Experimental results verify the metasurface mask's ability to accurately measure the state of polarization for various input polarization states. The metasurface devices exhibit a transmission efficiency ranging between 60% and 65% across different pixel sizes, which is notably above the theoretical efficiency attainable by traditional polarimetry devices utilizing polarization filters.

This research has significant implications for the advancement of compact, efficient polarimetric imaging systems. By exploiting metasurfaces' capability to measure full Stokes parameters at high efficiency, this approach paves the way for enhanced imaging capabilities in fields such as remote sensing, biomedical imaging, and materials science. Moreover, by substituting conventional polarization cameras with metasurface-based versions, industries can achieve superior performance without sacrificing compactness or efficiency.

Future work in this domain should aim to refine the metasurface technology further, overcoming current limitations through advanced fabrication techniques and optimization algorithms. Understanding and mitigating the cross-talk between polarization channels will be vital in enhancing the fidelity of polarization measurements. Furthermore, incorporating broadband operation capabilities into metasurface designs could advance their application in varied lighting conditions. As metasurface fabrication techniques evolve, there could be a rise in commercial adoption of these devices for consumer electronic applications, thereby widening their impact across multiple sectors.