Resonant Nonlinear Synthetic Metasurface with Combined Phase and Amplitude Modulations

Abstract

Nonlinear metasurfaces provide a promising platform for integrated nonlinear photonic devices owing to their unprecedented capability of nonlinear wavefront manipulation. However, the previously reported second-harmonic (SH) metasurfaces are mainly based on the nonlinear Pancharatnam-Berry phase modulation. While this method is quite convenient and robust, it shows limitations of modulation efficiency and the difficulty in extending to multidimensional combined modulations. Here, the resonant nonlinear synthetic metasurface is proposed and experimentally demonstrated for independent phase and amplitude modulations of the SH beam. A high SH modulation efficiency of 75% (with a theoretical limit of 90%) is achieved in the polarization-dependent SH metalens. Moreover, SH holographic imaging with phase and amplitude (at 2 and 4 levels) combined modulation is realized experimentally. Compared with the pure-phase modulation, the signal-to-noise ratios are increased by 2 and 3 times when 2-and 4-level amplitude controls are introduced. This is not only an important step in the improvement and innovation of holographic display technology, but also paves a distinct avenue toward multifunctional, higher efficiency, and ultracompact nonlinear optical devices.

Parametric Nonlinear Optics with Layered Materials and Related Heterostructures

“…[ 253 ] As an alternative to the Berry phase modulation, an advanced wavefront manipulation can be achieved with an independent control the phase and amplitude of the SH beam by a resonant V‐shaped nanohole array. [ 258 ]…”

Recent Advances and Prospects of Optical Metasurfaces

“…Considering the time-consuming nonlinear optical calculation based on finite element simulations, the nonlinear metasurface theory needs to be improved, especially in terms of robust and efficient modulation mechanisms and application conditions. In recent years, Lu et al integrated tungsten disulfide (WS2) on top of metasurfaces, efficiently establishing a series of novel nonlinear modulation principles, including the nonlinear modulations of the geometric phase, , detour phase, resonance phase, and amplitude . In addition, new mechanisms are expected in this area, such as nonlinear imaging (Figure c), giant nonlinear optical activity, , and high-order spin–orbit interaction .…”

“…In recent years, Lu et al integrated tungsten disulfide (WS2) on top of metasurfaces, efficiently establishing a series of novel nonlinear modulation principles, including the nonlinear modulations of the geometric phase, 201,202 detour phase, 203 resonance phase, 204 and amplitude. 204 In addition, new mechanisms are expected in this area, such as nonlinear imaging (Figure 8c), 205 giant nonlinear optical activity, 206,207 and high-order spin−orbit interaction. 208 Recently, a nonlinear Janus metasurface was reported to exhibit different nonlinear patterns for forward and backward excitation (Figure 8d).…”

Emerging Trend in Unconventional Metasurfaces: From Nonlinear, Non-Hermitian to Nonclassical Metasurfaces

“…The nonlinear geometric phase (NGP) metasurfaces have been employed for various applications in the nonlinear optical regime, such as multiplexed nonlinear holography, − optical information encoding and encryption, , control of nonlinear optical spin and orbital angular momentum and nonlinear vortex beam generation, − generation of nondiffraction harmonic signals, nonlinear metalens and imaging systems, , integrated THz generation and manipulation, , full complex amplitude control of harmonic signals, quasi-crystal nonlinear metasurfaces, nonlinear optical diffraction, asymmetric optical transport, and others. − It was shown that the different geometric phases that are involved in the linear and nonlinear optical interactions provide new degrees of freedom for generating wavelength and spin multiplexed information channels . The nonlinear metasurfaces can also be designed to control the local amplitude by arranging multiple nanostructures of identical shapes but different orientations into each unit cell. , It should be noted that besides NGP metasurfaces, there are also other ways to achieve control of the nonlinearity phase in harmonic generations, such as by tailoring the geometry of each individual nanostructure of the metasurface. − …”