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

Abstract

Optical wavefront engineering with artificial nanostructures has important applications in laser manufacturing, bioimaging, optical communications, etc. In the linear optical regime, metasurfaces are widely utilized to realize wavefront engineering functionalities, such as imaging with a flat lens and generation of vortex beams and holographic images. On the other hand, it is highly desirable to directly control the wavefront of light during nonlinear optical processes. Here, the nonlinear optical wavefront engineering with geometric phase controlled all‐dielectric metadevices is experimentally demonstrated. This is realized by integrating the multifunctional dielectric metasurface with the conventional nonlinear optical crystals. It is demonstrated that the nonlinear metadevice can be used to generate optical vortices and nonreciprocal holographic images at second harmonic frequencies. The proposed all‐dielectric metadevice represents an important strategy to develop compact and multifunctional nonlinear optical sources.