All-dielectric χ<sup>(2)</sup> metasurfaces: recent progress

Fig. 1. Simplified scheme of SHG in a leaky cavity. FF (SH) beam is represented in red (blue), κ_in (κ_out) denotes the input (output) coupling coefficient and $ζ$ the spatial overlap between the dominant modes at the two frequencies.

Download full size

View in Article

Fig. 2. Comparison between isolated (top) and arrayed (bottom) air-suspended GaAs nanoantennas with radius r = 200 nm and height h=400 nm. A normally impinging beam is linearly polarized along x, and the array (bottom) has a period of p=1 μm. (a) Scattering cross section decomposed in electric (blue) and magnetic (red) multipolar contributions, computed by projecting the field inside a nanoparticle onto vector spherical harmonics⁹⁵. The scattering cross section from the isolated particle has been scaled by a factor 6 to be compared with the plot on the bottom. The black dashed curve (bottom) displays the array transmission. (b) Near-field enhancement corresponding to the magnetic-dipole resonance.

Download full size

View in Article

$Arrays of quasi-independent dielectric χ(2) Mie-type resonators. (a) SHG from a GaAs metasurface radiated into different diffraction orders vs. pump polarization angle. Green: total; blue: (0,±1) orders; red: (±1,0) orders; black: (0,0) order98. (b) SH back-focal plane (BFP) imaging of a LiNbO3 metasurface for horizontally (center) or vertically (right) polarized pump101. (c) Mechanism to partially redirect SHG from an AlGaAs metasurface close to normal direction99. (d) Controlling SH polarization. BFP imaging of SH from isolated (left) or arrayed (right) AlGaAs nanoantennas with elliptical basis100. (e) Broadband frequency generation in a GaAs metasurface through multiple nonlinear processes96.$

Fig. 3. Arrays of quasi-independent dielectric χ⁽²⁾ Mie-type resonators. (a) SHG from a GaAs metasurface radiated into different diffraction orders vs. pump polarization angle. Green: total; blue: (0,±1) orders; red: (±1,0) orders; black: (0,0) order⁹⁸. (b) SH back-focal plane (BFP) imaging of a LiNbO₃ metasurface for horizontally (center) or vertically (right) polarized pump¹⁰¹. (c) Mechanism to partially redirect SHG from an AlGaAs metasurface close to normal direction⁹⁹. (d) Controlling SH polarization. BFP imaging of SH from isolated (left) or arrayed (right) AlGaAs nanoantennas with elliptical basis¹⁰⁰. (e) Broadband frequency generation in a GaAs metasurface through multiple nonlinear processes⁹⁶.

Download full size

View in Article

$Nonlinear wavefront shaping in dielectric metasurfaces.(a) Si metasurface implementing the first Kerker condition and funneling THG into the (-1)-diffraction order106. (b) Top: TH focusing from a Si metasurface. Bottom: Nonlinear imaging and spatial correlation for two apertures107. (c) SH beam-steering (left) and focusing (right) from an AlGaAs metasurface108. (d) SH geometric phase control in a Si metasurface109.$

Fig. 4. Nonlinear wavefront shaping in dielectric metasurfaces.(a) Si metasurface implementing the first Kerker condition and funneling THG into the (-1)-diffraction order¹⁰⁶. (b) Top: TH focusing from a Si metasurface. Bottom: Nonlinear imaging and spatial correlation for two apertures¹⁰⁷. (c) SH beam-steering (left) and focusing (right) from an AlGaAs metasurface¹⁰⁸. (d) SH geometric phase control in a Si metasurface¹⁰⁹.

Download full size

View in Article

Fig. 5. Quasi-BIC mode generation in nonlinear metasurfaces. A few ways to break the symmetry and reveal the high-Q resonance are sketched in the top row. Yellow (blue) color denotes a material addition (removal). (a) L-shaped GaAs/AlGaO heterostructures¹²⁴. (b) Asymmetric Si nanodimers made of two rods with different widths¹²⁵. (c) T-shaped Si resonators¹²⁶. (d) Asymmetric GaP nanodimers made of two elliptical-basis cylinders rotated by an angle θ¹²⁷.

Download full size

View in Article

Fig. 6. SHG efficiency vs. Q-factor of the dominant FF mode for different resonant devices (markers’ color) and materials (markers’ shape).

Download full size

View in Article

Table 1. Most common materials for χ⁽²⁾ nonlinear nano-optics. Refractive index n and second-order nonlinear coefficient d all refer to a wavelength λ = 1550 nm but for LiNbO₃ for which we consider λ = 1313 nm.
View table
View in Article
Table 1. Most common materials for χ⁽²⁾ nonlinear nano-optics. Refractive index n and second-order nonlinear coefficient d all refer to a wavelength λ = 1550 nm but for LiNbO₃ for which we consider λ = 1313 nm.
Material Point group $n$ $d_{eff}$ $(pm / V)$ $λ_{TPA} (nm)$ Refs.
GaAs $\bar{4} 3 m$ 3.38 110 1720 ref.^{58, 59}
Al_0.18Ga_0.82As $\bar{4} 3 m$ 3.30 100 1480 ref.^{60, 61}
GaP $\bar{4} 3 m$ 3.10 82 1100 ref.⁵⁹
AlN $6 m m$ 2.10 4.7 440 ref.⁶²
LiNbO₃ $3 m$ 2.30, 2.21 19.5 620 ref.⁵⁹

Tools

Get Citation

Copy Citation Text

Carlo Gigli, Giuseppe Leo. All-dielectric χ⁽²⁾ metasurfaces: recent progress[J]. Opto-Electronic Advances, 2022, 5(7): 210093

Download Citation

EndNote(RIS)BibTex Plain Text

Set citation alerts for article

Save article for my favorites

Paper Information

Category: Research Articles

Received: Jul. 14, 2021

Accepted: Oct. 15, 2021

Published Online: Aug. 19, 2022

The Author Email:

DOI:10.29026/oea.2022.210093

Topics

laser devices and laser physics

Lasers and Laser Optics

Laser physics

laser manufacturing

Instrumentation, Measurement and Metrology

Table 1. Most common materials for χ(2) nonlinear nano-optics. Refractive index n and second-order nonlinear coefficient d all refer to a wavelength λ = 1550 nm but for LiNbO3 for which we consider λ = 1313 nm.

Table 1. Most common materials for χ(2) nonlinear nano-optics. Refractive index n and second-order nonlinear coefficient d all refer to a wavelength λ = 1550 nm but for LiNbO3 for which we consider λ = 1313 nm.

微信扫一扫：分享

Table 1. Most common materials for χ⁽²⁾ nonlinear nano-optics. Refractive index n and second-order nonlinear coefficient d all refer to a wavelength λ = 1550 nm but for LiNbO₃ for which we consider λ = 1313 nm.

Table 1. Most common materials for χ⁽²⁾ nonlinear nano-optics. Refractive index n and second-order nonlinear coefficient d all refer to a wavelength λ = 1550 nm but for LiNbO₃ for which we consider λ = 1313 nm.