Efficient polarization insensitive complex wavefront control using Huygens' metasurfaces based on dielectric resonant meta-atoms (1602.00755v1)

Abstract: Subwavelength-thin metasurfaces have shown great promises for the control of optical wavefronts, thus opening new pathways for the development of efficient flat optics. In particular, Huygens' metasurfaces based on all-dielectric resonant meta-atoms have already shown a huge potential for practical applications with their polarization insensitivity and high transmittance efficiency. Here, we experimentally demonstrate a polarization insensitive holographic Huygens' metasurface based on dielectric resonant meta-atoms capable of complex wavefront control at telecom wavelengths. Our metasurface produces a hologram image in the far-field with 82% transmittance efficiency and 40% imaging efficiency. Such efficient complex wavefront control shows that Huygens' metasurfaces based on resonant dielectric meta-atoms are a big step towards practical applications of metasurfaces in wavefront design related technologies, including computer-generated holograms, ultra-thin optics, security and data storage devices.

• The paper introduces a novel dielectric metasurface design that achieves complex wavefront control with high efficiency.
• Experimental results show 82% transmittance and 40% imaging efficiency using subwavelength-thin Huygens’ metasurfaces.
• The fabrication technique simplifies production with a single lithographic step, reducing alignment errors in holographic devices.

Efficient Polarization Insensitive Complex Wavefront Control Using Huygens' Metasurfaces

In the paper titled "Efficient polarization insensitive complex wavefront control using Huygens' metasurfaces based on dielectric resonant meta-atoms," the authors, led by Katie E. Chong and Yuri S. Kivshar, present significant advancements in the field of optical metasurfaces. This research outlines the experimental realization of metasurfaces capable of complex wavefront control while maintaining high transmittance efficiency and polarization insensitivity.

The paper highlights the utilization of subwavelength-thin Huygens' metasurfaces composed of all-dielectric resonant meta-atoms. These structures are pivotal as they offer polarization insensitivity and remarkable transmittance efficiency. The authors demonstrate the production of a holographic image in the far-field, boasting an 82% transmittance efficiency and a 40% imaging efficiency. Such performance metrics underscore the potential applications of these metasurfaces in a variety of domains including ultra-thin optics, computer-generated holograms, and security and data storage technologies.

The research explores optimizing holographic metasurfaces by leveraging silicon nanodisks as meta-atoms to achieve the desired phase manipulation. The lattice periodicity of these structures was systematically varied to control the optical phase-front, achieving a substantial range of $3\pi/2$, albeit using a single tuning parameter. Noted efficiencies of the hologram reproduction position these metasurfaces as an effective alternative to conventional plasmonic metasurfaces which suffer from intrinsic losses and limited functionality due to designing constraints.

A critical component of this paper is its fabrication technique, which aids in overcoming the challenges associated with traditional multi-step lithography processes inherent in computer-generated holograms. The authors employed electron-beam lithography followed by a photonic process that requires only a single lithographic step, thereby reducing potential alignment errors and enhancing the reliability of the fabricated devices.

The promising attributes of these metasurfaces are accentuated by their disperse-free operation across different wavelengths. The ability to maintain efficient holographic imaging over a wide range of angles and to operate within a 40 nm bandwidth further underlines their potential application in wavelength-selective devices.

While the research focuses predominantly on polarization insensitive metasurfaces, the authors acknowledge the potential for designing polarization sensitive metasurfaces through asymmetric meta-atom structuring, expanding the utility of these devices. Future enhancements could involve the development of metasurfaces with more complex phase profiles and smaller pixel sizes to increase hologram resolution and efficiency.

In summary, this paper provides substantial evidence for the practical application of dielectric Huygens' metasurfaces in complex wavefront control, touting high efficiencies and robust design. The work invites further exploration into dielectric metasurfaces, paving the way for their integration into a new generation of optical devices characterized by compactness, efficiency, and versatility.