Efficient Second-Harmonic Generation in Nanocrystalline Silicon Nanoparticles

Abstract

Recent trends to employ high-index dielectric particles in nanophotonics are motivated by their reduced dissipative losses and large resonant enhancement of nonlinear effects at the nanoscale. Because silicon is a centrosymmetric material, the studies of nonlinear optical properties of silicon nanoparticles have been targeting primarily the third-harmonic generation effects. Here we demonstrate, both experimentally and theoretically, that resonantly excited nanocrystalline silicon nanoparticles fabricated by an optimized laser printing technique can exhibit strong second-harmonic generation (SHG) effects. We attribute an unexpectedly high yield of the nonlinear conversion to a nanocrystalline structure of nanoparticles supporting the Mie resonances. The demonstrated efficient SHG at green light from a single silicon nanoparticle is 2 orders of magnitude higher than that from unstructured silicon films. This efficiency is significantly higher than that of many plasmonic nanostructures and small silicon nanoparticles in the visible range, and it can be useful for a design of nonlinear nanoantennas and silicon-based integrated light sources.

Second-harmonic generation in dielectric nanoparticles with different symmetries

“…The absence of phase matching conditions at the subwavelength scales results in significant drop of the generation efficiency, making the exploitation of resonances in such nanoscale structures the only way to enhance SHG. During the last few decades, metallic nanostructures supporting localized surface plasmon esonances have been actively studied -while the lattice of typical plasmonic materials has a center of inversion, second harmonic (SH) generation is still possible by surface and nonlocal volume effects [12][13][14][15][16]. In more recent developments, nanoparticles from dielectrics and semiconductors with a non-centrosymmetric crystalline lattice and bulk second order non-linearity [17][18][19][20] have been extensively studied.…”

The conformation of bovine serum albumin adsorbed to the surface of single all‐dielectric nanoparticles following light‐induced heating

“…All‐dielectric nanophotonics have opened a new era in optics with the multitude of Mie‐type optical resonances governing various linear and nonlinear optical properties of non‐metallic NPs (silicon, germanium, gallium arsenide or phosphide, etc.) greater than 100 nm in diameter.…”

Active meta-optics and nanophotonics with halide perovskites

“…Second-harmonic generation from halide perovskite (CsPbX 3 or MAPbX 3 , where MA=CH 3 NH 3 ) structures is not so effective due to the centrosymmetric crystalline structure. However, lead-free perovskites (such as CsGeI 3 and MAGeI 3 ) exhibit giant secondharmonic generation with the second-order nonlinear coefficient χ (2) exceeding the values of 150 pm V −1 , being comparable with those for GaAs and exceeding by many orders the coefficients observed for silicon 33,41 .…”

“…Moreover, in situ chemical variation of the perovskites band gap 24,25 and, thus, the spectrum of their luminescence, opens up unprecedented opportunities for reconfigurable nanophotonic devices not achievable with the use of the conventional GaAs platform. As a result, halide perovskite nanoparticles 26 , nanowires 27,28 , microdisks 29 , microplates 30 , nanoscale gratings 31 , and metasurfaces 32,33 are easy to fabricate and process, and they can become a convenient and cheap part of optical circuitry in the near future 34 . Nevertheless, the existing silicon-based platform is much more developed for on-chip integrated photonics 35 , but it is expected to be outperformed by the perovskites in the future.…”