Polarization-resolved second harmonic generation microscopy of chiral G-shaped metamaterials

Abstract

Chiral planar metamaterials are known for their possibility to show strong nonlinear optical effects such as second harmonic generation (SHG) circular dichroism or asymmetric SHG. The underlying mechanisms are commonly discussed in terms of local field effects and formation of localized SHG sources (so called "hotspots") that are sensitive to the shape and size of meta-atoms. Nevertheless, a full characterization of the polarization state of the nonlinear optical radiation from the hotspots has not been performed until now. Here we present the results of the polarization-resolved second harmonic generation microscopy studies of planar chiral G-shaped metamaterials. We demonstrate that the SHG radiation coming from the hotspots that are localized within a single meta-atom is partially polarized; moreover, the SHG polarization state reveals the chirality of the structure. The observed effects are attributed to the induced plasmonic current oscillations at the fundamental frequency along with the local field distribution.

Chirality‐Dependent Second‐Order Nonlinear Optical Effect in 1D Organic–Inorganic Hybrid Perovskite Bulk Single Crystal

“…[28] Subsequently,t he research on SHG-CD mainly focused on biological tissues (collagen), [29] nanoparticle dimers, [30] plasmonic metasurfaces, [31] metamaterials. [32,33] In addition, as we known that, growing high quality single crystal with large size for the study of nonlinear optics is crucial necessary,w hich can be achieved available length in the phase matching direction. [34] Nevertheless, through comprehensive research, we find that the SHG-CD effect in chiral OIHPs bulk single crystals is rarely investigated.…”

Second-Harmonic Generation Optical Rotation Solely Attributable to Chirality in Plasmonic Metasurfaces

“…Whereas SHG-CD has been demonstrated from numerous chiral nano/metamaterials, − far less attention has been devoted to SHG-OR. Previous studies have demonstrated SHG-OR in plasmonic nanostructures, where the origin of the effect can be ambiguous. − Indeed, SHG-OR can be due to both intrinsic structural chirality and sample anisotropy.…”

High‐Efficiency Spatial‐Wave Frequency Multiplication Using Strongly Nonlinear Metasurface

“…[ 20 , 21 ] Therefore various optical metasurfaces have been proposed for enhancing SHG, and the intensity, phase, and polarization states of the induced SHG can be precisely manipulated by optimizing the sizes, shapes, and orientations of the metallic nanostructures. [ 10 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]…”

“…[20,21] Therefore various optical metasurfaces have been proposed for enhancing SHG, and the intensity, phase, and polarization states of the induced SHG can be precisely manipulated by optimizing the sizes, shapes, and orientations of the metallic nanostructures. [10,[22][23][24][25][26][27][28][29][30] The traditional optical buck metamaterial can generate second harmonic nonlinearity with efficient conversion by using phase matching techniques. The optical metasurfaces have exhibited novel nonlinear properties that were not found in the natural nonlinear buck optical crystals, and they provide a promising venue for enhancing and manipulate SHGs.…”