Polarization optics plays a pivotal role in diffractive, refractive, and emerging flat optics, and has been widely employed in contemporary optical industries and daily life. Advanced polarization manipulation leads to robust control of the polarization direction of light. Nevertheless, polarization control has been studied largely independent of the phase or intensity of light. Here, we propose and experimentally validate a Malus-metasurface-assisted paradigm to enable simultaneous and independent control of the intensity and phase properties of light simply by polarization modulation. The orientation degeneracy of the classical Malus's law implies a new degree of freedom and enables us to establish a one-to-many mapping strategy for designing anisotropic plasmonic nanostructures to engineer the Pancharatnam-Berry phase profile, while keeping the continuous intensity modulation unchanged. The proposed Malus metadevice can thus generate a near-field greyscale pattern, and project an independent far-field holographic image using an ultrathin and single-sized metasurface. This concept opens up distinct dimensions for conventional polarization optics, which allows one to merge the functionality of phase manipulation into an amplitude-manipulation-assisted optical component to form a multifunctional nano-optical device without increasing the complexity of the nanostructures. It can empower advanced applications in information multiplexing and encryption, anti-counterfeiting, dual-channel display for virtual/augmented reality, and many other related fields.

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Malus-metasurface-assisted polarization multiplexing

Metasurfaces have recently been used for multichannel image displays with pixel-size lower than a wavelength, which indicates the potential application in ultracompact anticounterfeiting with high-...

Multiplexed Anticounterfeiting Meta-image Displays with Single-Sized Nanostructures.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/adom.202001414

Principles, Functions, and Applications of Optical Meta-Lens

Abstract Like amplitude, phase and frequency, polarization is one of the fundamental properties of light, which can be used to record, process and store information. Optical metasurfaces are ultrathin inhomogeneous media with planar nanostructures that can manipulate the optical properties of light at the subwavelength scale, which have become a current subject of intense research due to the desirable control of light propagation. The unprecedented capability of optical metasurfaces in the manipulation of the light’s polarization at subwavelength resolution has provided an unusual approach for polarization detection and arbitrary manipulation of polarization profiles. A compact metasurface platform has been demonstrated to detect polarization information of a light beam and to arbitrarily engineer a polarization profile that is very difficult or impossible to realize with conventional optical elements. This review will focus on the recent progress on ultrathin metasurface devices for polarization detection and realization of customized polarization profiles. Optical metasurfaces have provided new opportunities for polarization detection and manipulation, which can facilitate real-world deployment of polarization-related devices and systems in various research fields, including sensing, imaging, encryption, optical communications, quantum science, and fundamental physics.

/pdf/recent-advances-in-optical-metasurfaces-for-polarization-ni3sf49t82.pdf

Recent advances in optical metasurfaces for polarization detection and engineered polarization profiles

A Single‐Celled Tri‐Functional Metasurface Enabled with Triple Manipulations of Light

A polarization-dependent metasurface that consists of nanobrick arrays with spatial varying dimensions in two orthogonal directions has shown independent phase control ability, which paves a new way to design a reconfigurable step-zoom lens with two different focal lengths depending on the polarization states of an incident beam. In this paper, we report a highly integrated step-zoom metalens with dual focal lengths based on double-sided metasurfaces sitting on a transparent substrate. By assigning the focal power and balancing the aberrations between the front and rear metasurfaces, a large field-of-view ( ± 20°) step-zoom metalens corrected for monochromatic aberrations was designed, and its high performance (nearly diffraction-limited image quality for both on-axis and off-axis imaging) was verified by full-wave numerical simulations. More interestingly, the image plane of the designed metalens keeps unchanged after the zoom switching, which will bring great convenience for practical applications. With the advantages such as ultra-compactness, flexibility, and simplicity, the proposed metalens indicates the potential in the fields that require highly integrated zoom imaging and beam focusing without optical and mechanical compensations.

Reconfigurable step-zoom metalens without optical and mechanical compensations

Metasurfaces, simultaneously operating in near- and far-fields, can be employed as a promising candidate to implement different functions, thus significantly improving the information density, security, and system integration. Recent works have showcased some approaches for decoupling-at-large between near- and far-field functionalities, but unfortunately, their coupling effects are just reduced and mitigated to some extent rather than eradicated, which in turn leads to the performance limitation of metadevices. Herein, we propose a general platform for the complete rift between near- and far-field functionalities, enabled by strictly decoupled manipulation of optical amplitude and phase, leading to their distinct functions in the near- and far-fields, respectively. This concept is experimentally demonstrated by integrating the functions of a phase-only metalens and an amplitude-only grayscale-imaging nanoprint into a single-cell metasurface. Because of their completely decoupled functions, both meta-elements show high-performance characteristics, i.e., imaging quality close to the diffraction limit and high-definition grayscale-imaging with resolution as high as 63 500 dots per inch (dpi). The validated recipe may empower advanced explorations and applications in highly integrated nano-optoelectronics requiring high performance and less crosstalk.

From Lingering to Rift: Metasurface Decoupling for Near- and Far-Field Functionalization

The unwanted zero-order light accompanied by the birth of diffractive optical elements and caused mainly by fabrication errors and wavelength variations is a key factor that deteriorates the performance of diffraction-related optical devices such as holograms, gratings, beam shapers, beam splitters, optical diffusers, and diffractive microlenses. Here, inspired by the unique characteristic of nano-polarizer-based metasurfaces for both positive and negative amplitude modulation of incident light, we propose a general design paradigm to eliminate zero-order diffraction without burdening the metasurface design and fabrication. The experimentally demonstrated meta-hologram, which projects a holographic image with a wide angle of 70°×70° in the far field, presents a very low zero-order intensity (only 0.7% of the total energy of the reconstructed image). More importantly, the zero-order-free meta-hologram has a large tolerance limit for wavelength variations (under a broadband illumination from 520 to 660 nm), which brings important technical advances. The strategy proposed could significantly relieve the fabrication difficulty of metasurfaces and be viable for various diffractive-optics-related applications including holography, laser beam shaping, optical data storage, vortex beam generation, and so on.

Zero-order-free meta-holograms in a broadband visible range

The invention discloses a dielectric geometric phase metasurface structure material with a low depth-to-width ratio and a structural optimization method thereof. The dielectric geometric phase metasurface structure material comprises a substrate, a reflecting layer on the substrate, a multi-beam interference layer on the reflecting layer and a dielectric nano brick array formed by periodically arranging a plurality of dielectric nano bricks with consistent sizes on the multi-beam interference layer, wherein the dielectric nano brick array is used for receiving perpendicularly incident circularly polarized light and adjusting the phase of the emergent light through adjusting the direction of each dielectric nano brick. The depth-to-width ratio of the dielectric geometric phase metasurface structure material is reduced to half of the depth-to-width ratio of the traditional transmission-type metasurface material, and the depth-to-width ratio is about 1.7, so that the requirements for theprocessing technology are reduced, and the finished product rate and mass production of the device are guaranteed.

Dielectric geometric phase metasurface material with low depth-to-width ratio and structural optimization method thereof

The invention belongs to the technical field of micro-nano optics and discloses an optical information hiding method based on a metasurface array structure. The method comprises the following steps that: the working wavelength is determined; the size parameters of a nano-brick unit structure are optimized; when polarized light in any polarization state under the working wavelength is normally incident to the nano-brick unit structure, the linearly polarized light component reflectivity vibrating in the long axis direction of the nano-brick unit structure is maximum, and the linearly polarizedlight component transmittance vibrating in the short axis direction of the nano-brick unit structure is maximum; the gray scale information of a gray scale image composed of M * N pixels is encoded into the direction angle information of M * N nanometer brick unit structures, and a first direction angle matrix is generated; the direction angles of the n randomly selected nano-brick unit structuresare changed to generate a second direction angle matrix; and M * N nano-brick unit structures which are consistent in size and have direction angles arranged according to a second direction angle matrix are arranged at equal intervals to form a metasurface array structure. According to the invention, the hiding of the optical information can be realized through the metasurface array structure.

Fu Rao

Papers

Reconfigurable step-zoom metalens without optical and mechanical compensations

From Lingering to Rift: Metasurface Decoupling for Near- and Far-Field Functionalization

Zero-order-free meta-holograms in a broadband visible range

Dielectric geometric phase metasurface material with low depth-to-width ratio and structural optimization method thereof

Optical information hiding method based on metasurface array structure