Bridging the Gap between Dielectric Nanophotonics and the Visible Regime with Effectively Lossless Gallium Phosphide Antennas

Abstract

We present all-dielectric gallium phosphide (GaP) nanoantennas as an e cient nanophotonic platform for surface-enhanced second harmonic generation (SHG) and uorescence (SEF), showing negligible losses in the visible range. Employing single GaP nanodisks, we observe an increase of more than three orders of magnitude in the SHG signal in comparison with the bulk. This constitutes an SHG e ciency as large as 0.0002%, which is, to the best of our knowledge, the highest yet achieved value produced by a single nano-object in the optical region. Furthermore, we show that GaP dimers with 35 nm gap can enhance up to 3600 times the uorescence emission of dyes located in the gap of the nanoantenna. This is accomplished by a uorescence lifetime reduction of, at least, 22 times, accompanied by a high intensity eld con nement in the gap region. These results open new avenues for low-loss nanophotonics in the optical regime.

Growth and Characterization of GaP/GaPAs Nanowire Heterostructures with Controllable Composition

“…First of all, compared with other III–V zinc‐blende (ZB) semiconductors, GaP is nearly lattice matched (0.37% mismatch) with Si and can be used as a buffer layer material for integration of polar III–V direct bandgap materials (e.g., GaAs) on Si platform . Due to its broad transparency range, from visible to IR (0.6–11 μm) and high second‐order nonlinear susceptibility, GaP plays an important role in modern nanophotonics as an all‐dielectric material for fabrication of nanoantennas with disc or columnar morphology acting as an efficient platform for second‐harmonic‐generation devices providing several orders of magnitude conversion efficiency compared with the bulk materials …”

“…[2] Due to its broad transparency range, from visible to IR (0.6-11 μm) and high second-order nonlinear susceptibility, GaP plays an important role in modern nanophotonics as an all-dielectric material for fabrication of nanoantennas with disc or columnar morphology acting as an efficient platform for second-harmonic-generation devices providing several orders of magnitude conversion efficiency compared with the bulk materials. [3] Indirect band structure of ZB GaP (E g ¼ 2.27 eV at 300 K) is one of the limiting factors for the development of efficient GaP-based light-emitting and photovoltaic devices on Si. [4] Transition to direct-gap structure can be observed in ternary alloys such as GaP 1 À x As x with high arsenic content x ≥ 55.56%, which is accompanied by a bandgap narrowing.…”

Hybrid Metal-Dielectric Nano-Aperture Antenna for Surface Enhanced Fluorescence

“…The periodic grating structures usually surround the nano-aperture to both enhance the excitation rate and converge the emission for high collection efficiency [38,39]. Meanwhile, the silicon layer can be replaced with a lower loss dielectric material in the spectral region (e.g., GaP [40] in visible region). This would increase the antenna quantum yield.…”

Low‐Loss Hybrid High‐Index Dielectric Particles on a Mirror for Extreme Light Confinement

“…High‐index dielectric (HID) nanophotonics is rapidly becoming a mature field and may supplant plasmonics in specific applications due to reduced Ohmic losses and CMOS (complementary metal–oxide–semiconductor) compatibility . Dielectric nanostructures support multiple Mie resonances of both electric and magnetic character enabling efficient coupling to far‐field radiation .…”

“…[32] High-index dielectric (HID) nanophotonics is rapidly becoming a mature field and may supplant plasmonics in specific applications due to reduced Ohmic losses and CMOS (complementary metal-oxide-semiconductor) compatibility. [33][34][35][36][37] Dielectric nanostructures support multiple Mie resonances of both electric and magnetic character enabling efficient coupling to far-field radiation. [33] This existence of multiple modes has made it possible to use their relative interaction within a single nanoantenna to tailor the cavity modes or to utilize multiple antennas to manipulate light over large areas by so-called metasurfaces.…”