Beam-Size-Invariant Spectropolarimeters Using Gap-Plasmon Metasurfaces

Abstract

Metasurfaces enable exceptional control over the light with surface-confined planar components, offering the fascinating possibility of very dense integration and miniaturization in photonics. Here, we design, fabricate and experimentally demonstrate chip-size plasmonic spectropolarimeters for simultaneous polarization state and wavelength determination. Spectropolarimeters, consisting of three gap-plasmon phasegradient metasurfaces that occupy 120° circular sectors each, diffract normally incident light to six predesigned directions, whose azimuthal angles are proportional to the light wavelength, while contrasts in the corresponding diffraction intensities provide a direct measure of the incident polarization state through retrieval of the associated Stokes parameters. The proof-of-concept 96-μm-diameter spectropolarimeter operating in the wavelength range of 750 -950 nm exhibits the expected polarization selectivity and high angular dispersion (0.0133 °/nm). Moreover, we show that, due to the circular-sector design, polarization analysis can be conducted for optical beams of different diameters without prior calibration, demonstrating thereby the beam-size invariant functionality.The proposed spectropolarimeters are compact, cost-effective, robust, and promise highperformance real-time polarization and spectral measurements.

Phase Manipulation of Electromagnetic Waves with Metasurfaces and Its Applications in Nanophotonics

“…[96] By interweaving three types of phase gradient metasurfaces into a metagrating, the state of polarization of the incident light can be determined through simultaneously measuring the six correspondent diffraction intensities that reveal the Stokes parameters of the light. More complex functions, such as spectropolarimeters, [98,99] can also be realized based on metasurface beam deflectors. [97] It was realized by detecting the highly polarizationdependent scattered field of a metasurface in four directions.…”

“…As a result of this division, a reduction of the angular resolution is inevitable. [99] The spectropolarimeters can diffract normally incident light in six predesigned directions whose polar angles are proportional to the wavelengths, and the contrast in the corresponding diffraction intensities provides a direct measure of the incident polarization state through the retrieval of the associated Stokes parameters. Unlike conventional multifoci diffractive lenses, multiple focal points with different focal lengths can be achieved by changing the polarization state of the incident light.…”

“…Optical Mater. [99] Copyright 2017, American Chemical Society. Multifunctional shared-aperture metasurfaces.…”

Theoretical design of eight‐band linear‐to‐circular converter in reflection and transmission modes based on self‐complementary metasurfaces

“…They are nontraditional periodic arrays of synthetic materials that manipulate light in a controlled manner to achieve optical properties that are not found in nature such as negative refractive index, photomagnetic, giant chirality, and so on. However, those conventional metamaterials could only realize one certain type of polarization manipulation. In order to achieve multifunctional polarization conversion, reconfigurable and programmable metamaterials have been proposed .…”

Characteristic Analysis of Compact Spectrometer Based on Off-Axis Meta-Lens

“…As pivotal components in spectroscopy, traditional spectrometers usually employ isolated dispersive elements (mostly gratings or prisms) and focusing lenses, which makes the whole system bulky, complicated and unsuitable for integration [21]. To produce miniature and compact spectrometers, researchers have explored the possibilities of taking the advantages of metasurfaces such as its flexibility to design arbitrary phase response or convenience to be integrated to other optical system to create multifunctional meta-lens-based spectrometers [20,21,[37][38][39]. Spectrometers based on off-axis meta-lenses was first explored by Khorasaninejad et al [20], which unambiguously shows the potential of the technique, i.e., meta-lenses, as an alternative way to build spectrometers.…”