Second Harmonic Light Manipulation with Vertical Split Ring Resonators

Abstract

inducing electromagnetic fields. [9,10] In general, SHG conversion efficiency relies on several factors: inversion asymmetry of the hosting media, spatial overlap of the fundamental and second-harmonic (SH) modes, quality factor (Q-factor) of the involved modes, and the field intensity of the fundamental resonant mode. [11][12][13][14][15][16] Among these factors, plasmonic nanostructures [17][18][19][20][21][22][23] have a clear advantage of being particularly effective in inducing strong electromagnetic field that can increase the SHG conversion efficiency. For instance, the large field confinement associated with the magnetic resonances of split-ring resonators (SRRs) has led to a significant SHG enhancement. [23][24][25][26][27][28] While these prior results have been a major step forward in demonstrating SHG in plasmonic structures, further improvement is needed if they were to become a competitive alternative. Take SRR metasurface as an example, most of fabricated SRRs are of planar subwavelength structures, in which they lay flat on a high index dielectric substrate as illustrated in the inset of Figure 1a. While such planar SRRs (PSRRs) are relatively easy to fabricate, the strong fields present in PSRR gaps are inevitably exposed to the underlying substrate, resulting in leakage of the electromagnetic energy into the substrate, reducing the exposure of enhancedThe second harmonic generation (SHG) of vertical and planar split-ring resonators (SRRs) that are broken centro-symmetry configurations at the interface of metal surface and air is investigated. Strong interactions, better electromagnetic field confinements, and less leakage into the substrate for vertical SRRs are found. Experimental results show a 2.6-fold enhancement of SHG nonlinearity, which is in good agreement with simulations and calculations. Demonstrations of 3D metastructures and vertical SRRs with strong SHG nonlinearity majorly result from magnetic dipole and electric quadrupole clearly provides potential applications for photonics and sensing. StereometamaterialsSince its discovery soon after the invention of the laser, the second harmonic generation (SHG) as a prominent nonlinear optical effect has played an important role in various photonic applications ranging from light source, [1] high-resolution imaging, to spectroscopy. [2][3][4] Fundamentally, SHG is prohibited in bulk noble metals such as gold and silver occasionally used in metamaterials because of their centrosymmetric crystal lattices. Recently, the phenomenon of SHG has been widely studied in various metallic nanostructures, such as nanorods, nanoparticles, multiresonant, nanoantennas, etc. [5][6][7][8] In plasmonic systems, nonlinearity was mainly attributed to either the broken centro-symmetry at the metal surface or to the high degree of the asymmetric spatial variation of the

Nonlinear optics of two‐dimensional transition metal dichalcogenides

“…A careful design of the incidence light path and the crystal angle is necessary to optimize the nonlinear effect. However, if the size of the medium is scaled down to the sub‐wavelength regime and shorter than the coherence length, the phase‐matching condition is not necessary to achieve strong nonlinear effect, which has been demonstrated in the nanophotonic and plasmonic systems . For TMDs we discuss here, the phase‐matching issue can also be ignored due to their atomic thin nature.…”

Exciting Magnetic Dipole Mode of Split-Ring Plasmonic Nano-Resonator by Photonic Crystal Nanocavity

“…Therefore, we use the finite difference time domain (FDTD) technique to verify the simulation and find that the results of the two algorithms are consistent. Our approach may open the way for the on-chip applications of a magnetic field component in the optical field, such as a magnetic sensor [ 30 ], magneto-optic modulator [ 31 , 43 , 44 , 45 ], second harmonic manipulation [ 46 ], all-optical switch [ 47 ], microwave sensor [ 48 ], plasmonic nanolasers, and spacer [ 49 , 50 , 51 ].…”

Nonlinear Optical Characterization of 2D Materials

“…To optimize the nonlinear effect, the path of the incident light and crystal orientation must be carefully designed. However, if the size of the medium is reduced to the sub-wavelength range and is shorter than the coherence length, the phase-matching condition is easily reached for achieving strong nonlinear effects, which has been demonstrated in nanoscale metamaterials [ 11 , 12 ].…”