Efficient Ultraviolet Nanosources Based on Third‐Harmonic Generation in Dielectric–Metal Composite Nanodisks

Abstract

Dielectric materials with high indices have recently attracted much attention in the community of nanophotonics. Severe optical losses in visible–ultraviolet (UV) region, however, limit their applications. This article proposes dielectric–metal nanocomposites as alternative high‐index materials for Mie‐resonance‐based applications. Such composite materials have high indices in the range of wavelength longer than plasmon resonance of inclusion metal nanoparticles, while they have much lower losses in the range from blue‐violet down to near‐UV compared with commonly used high‐index materials such as silicon, enabling near‐UV generation with high efficiency based on third‐harmonic generation (THG). The numerical results show that ZnO nanodisk containing silver nanoparticles can generate near‐UV radiation at 351.3 nm via THG with an efficiency about 20 times higher compared with silicon nanodisk under same pumping condition. Significantly high THG efficiency of 0.015% has been predicted with such a composite nanodisk supported by aluminum substrate under pumping with a peak intensity of 20 GW cm−2, a spot size of 0.8 , a duration of 50 fs at 1054 nm, respectively.

Dielectric Chiral Metasurfaces for Second‐Harmonic Generation with Strong Circular Dichroism

“…[21] The above metamaterials and metasurfaces can be made of both plasmonic and dielectric materials, the latter of which are preferable due to lower optical losses and stronger CD. [9,10] Over the past decade, nonlinear nanostructures and metasurfaces [22] have extensively investigated for diverse practical applications, including efficient harmonic generation, [23][24][25][26][27][28] four-wave mixing, [29] high-order stimulated Raman scattering, [30] and nonlinear beam shaping. [31] In particular, nonlinear optical processes in chiral metasurfaces [32][33][34][35][36][37][38][39] have great importance for nonlinear chiral sensing and nonlinear metasurface holography.…”

Giant Nonlinear Circular Dichroism from High Q‐Factor Asymmetric Lithium Niobate Metasurfaces

“…Recently, chiral metamaterials have attracted much attention because of their unique circular dichroism (CD), [1][2][3][4][5][6][7][8][9] i.e., incident lights with different polarization states have different responses, which can be used for polarimetric detection, [10] biosensors, [11][12][13] optical communications, chiral nonlinearity, [14][15][16][17][18] and chiral meta-holography. [19][20][21][22] Compared with 3D bulk materials, metamaterials and metasurfaces have sub-wavelength scale volume, which is more conducive to the integration of ultra-compact optical elements, and can effectively reduce the requirements for phase matching.…”