Nonlinear wavefront engineering with metasurface decorated quartz crystal

Abstract

In linear optical processes, compact and effective wavefront shaping techniques have been developed with the artificially engineered materials and devices in the past decades. Recently, wavefront shaping of light at newly generated frequencies was also demonstrated using nonlinear photonic crystals and metasurfaces. However, the nonlinear wave-shaping devices with both high nonlinear optical efficiency and high wave shaping efficiency are difficult to realize. To circumvent this constraint, we propose the idea of metasurface decorated optical crystal to take the best aspects of both traditional nonlinear crystals and photonic metasurfaces. In the proof-of-concept experiment, we show that a silicon nitride metasurface decorated quartz crystal can be used for the wavefront shaping of the second harmonic waves generated in quartz. With this crystal-metasurface hybrid platform, the nonlinear vortex beam generation and nonlinear holography were successfully demonstrated. The proposed methodology may have important applications in nonlinear structured light generation, super-resolution imaging, and optical information processing, etc.

Roadmap on nonlinear optics–focus on Chinese research

“…Apart from plasmonic metasurfaces, which consist of meta-atoms whose materials are noble metals, dielectric metasurfaces have also been applied to control the angular momentum of harmonic waves. By decorating traditional nonlinear crystals with dielectric metasurfaces, the on-chip wavefront engineering of the generated harmonic waves can be realized [140]. As shown in figure 22, the metasurface-decorated quartz crystal was first pumped by circularly polarized FWs, the SHWs were generated during the nonlinear process in the crystal.…”

“…Schematic of the crystal-metasurface hybrid platform. The wavefront of the harmonic wave generated in the nonlinear crystal can be artificially engineered by the dielectric metasurface [140]. materials, which have higher NLO susceptibilities or damage thresholds.…”

Nonlinear Optical Wavefront Engineering with Geometric Phase Controlled All‐Dielectric Metadevice

“…By placing the dielectric metasurface after a nonlinear medium, one can also manipulate the polarization and wavefront information of the nonlinear waves. [17][18][19]55] In this work, we integrate the metasurface with the nonlinear crystal to form a metadevice, with which the wavefront engineering of the FW is first realized and then transferred to the SHWs (Figure 1b). The proposed metadevice takes the advantages of the highly efficient dielectric metasurface and the conventional nonlinear crystals.…”