Resonant, broadband, and highly efficient optical frequency conversion in semiconductor nanowire gratings at visible and UV wavelengths

Abstract

Using a hydrodynamic approach we examine bulk-and surface-induced second and third harmonic generation from semiconductor nanowire gratings having a resonant nonlinearity in the absorption region. We demonstrate resonant, broadband and highly efficient optical frequency conversion: contrary to conventional wisdom, we show that harmonic generation can take full advantage of resonant nonlinearities in a spectral range where nonlinear optical coefficients are boosted well beyond what is achievable in the transparent, long-wavelength, nonresonant regime. Using femtosecond pulses with approximately 500 MW/cm 2 peak power density, we predict third harmonic conversion efficiencies of approximately 1% in a silicon nanowire array, at nearly any desired UV or visible wavelength, including the range of negative dielectric constant.We also predict surface second harmonic conversion efficiencies of order 0.01%, depending on the electronic effective mass, bistable behavior of the signals as a result of a reshaped resonance, and the onset fifth order nonlinear effects. These remarkable findings, arising from the combined effects of nonlinear resonance dispersion, field localization, and phase-locking, could significantly extend the operational spectral bandwidth of silicon photonics, and strongly suggest that neither linear absorption nor skin depth should be motivating factors to exclude either semiconductors or metals from the list of useful or practical nonlinear materials in any spectral range.The advent of metamaterials and the search for efficient nonlinear frequency converters have mediated the growth of theoretical and experimental studies of second and third harmonic generation (SHG and THG) from all types of metallic, semiconductor, and all-dielectric

Study of second and third harmonic generation from an indium tin oxide nanolayer: Influence of nonlocal effects and hot electrons

“…On the right side of Eq. (4) we have the bound electron plasma frequency, followed by surface and magnetic Lorentz contributions [23,24].…”

Second-Harmonic Generation in Mie-Resonant GaAs Nanowires

“…The usual metrics for SH conversion efficiency involves the SH light that one may collect in a certain direction in the far-field region, or the total light scattered Q SH in all directions in the far-field, as defined in Equation (16). However, a portion of SH energy is inexorably dissipated in the near field via one-photon absorption.…”

“…Cubic nonlinearities are very large both in the bulk of Si and GaAs. Enhanced nonlinear optical effects have been predicted and experimentally observed in a variety of nanoscale structures based on semiconductors: At the band-edge of photonic crystals [3][4][5][6][7], in leaky-mode-resonant gratings or photonic-crystal slabs [8][9][10], and more recently in Mie-resonant nanoantennas [11,12] and metasurfaces [13][14][15][16]. Besides the large nonlinearity, the fabrication processes of nanoscale semiconductor devices are mature and reliable, and in some cases compatible with existing technologies for photonic integrated circuits, e.g., silicon photonics.…”

Harmonic generation in the opaque region of GaAs: the role of the surface and magnetic nonlinearities

“…α i,j,k P j P k and P i NL (3) = j=1,3 k=1,3 l=1,3 β i,j,k,l P j P k P l , respectively, where P j = n 0 er j are the Cartesian components of the macroscopic polarization and n 0 is the dipole density. We note that the present method differs from our previous theoretical analysis found in [4][5][6][7][8] in that our current approach includes the effects of combined linear and nonlinear material dispersions, which turn out to be critical to accurately portray both qualitative and quantitative aspects of nonlinear frequency conversion in nanoscale systems [12]. Specifically, in Ref.…”

“…Specifically, in Ref. [12] a similar model is applied to Si, GaAs, and GaP nanowire arrays, and predictions are made of enhanced surface and bulk SHG and THG (0.001% and 1%, respectively, with power densities of order 1GW/cm 2 ) using the combined action of Mie resonances and dispersive, resonant nonlinearities in the opacity range. Expanding the summations for isotropic GaAs or GaP having (001) symmetry leads to the following simplified vector components: (2) P NL (2) y P NL (2)…”