Nonlinear bicolor holography using plasmonic metasurfaces

TL;DR

This paper presents a novel nonlinear metasurface hologram capable of generating two different harmonic colors simultaneously, enabling advanced applications in holographic displays, encryption, and data storage.

Contribution

It introduces a single-layer plasmonic metasurface with dissimilar nanostructures for dual harmonic generation and two-color holography, which was not demonstrated before.

Findings

Successful generation of second and third harmonic signals

Reconstruction of two-color hologram at visible wavelengths

Amplitude control of harmonic signals via nanostructure resonance

Abstract

Nonlinear metasurface holography shows the great potential of metasurfaces to control the phase, amplitude, and polarization of light while simultaneously converting the frequency of the light. The possibility of tailoring the scattering properties of a coherent beam, as well as the scattering properties of nonlinear signals originating from the meta-atoms facilitates a huge degree of freedom in beam shaping application. Recently, several approaches showed that virtual objects or any kind of optical information can be generated at a wavelength different from the laser input beam. Here, we demonstrate a single-layer nonlinear geometric-phase metasurface made of plasmonic nanostructures for a simultaneous second and third harmonic generation. Different from previous works, we demonstrate a two-color hologram with dissimilar types of nanostructures that generate the color information by different nonlinear optical processes. The amplitude ratio of both harmonic signals can be adapted depending on the nanostructures' resonance as well as the power and the wavelength of the incident laser beam. The two-color holographic image is reconstructed in the Fourier space at visible wavelengths with equal amplitudes using a single near-infrared wavelength. Nonlinear holography using multiple nonlinear processes simultaneously provides an alternative path to holographic color display applications, enhanced optical encryption schemes, and multiplexed optical data-storage.