Second-harmonic generation from plasmon polariton excitation on silver diffraction gratings: comparisons of theory and experiment

Abstract

We present a comparison between experimental and theoretical results for the diffraction efficiencies of the secondharmonic light produced in the orders of silver diffraction gratings. The gratings considered are sinusoidal, have depths of a few nanometers, and can produce significant surface plasmon polariton excitation at fundamental and second-harmonic frequencies. The calculations are based on a general expression for the nonlinear polarization of the surface of a homogeneous and isotropic medium, and the diffraction problems at the fundamental and harmonic frequencies are solved using a Rayleigh method. The silver gratings were fabricated using holographic lithography and evaporative metal deposition techniques. The samples were illuminated with picosecond pulses of wavelength 1064 nm, and photon-counting techniques were used to study the diffracted orders at 532 nm, with absolute normalization provided by a quartz reference. The diffracted orders exhibit anomalies and other features, many of which are related to plasmon polariton excitation at both fundamental and second-harmonic frequencies. Employing previously measured values for the nonlinear susceptibilities of a flat silver surface, remarkably good comparisons of theory and experiment are obtained for the second-harmonic order efficiencies.

Second harmonic generation under doubly resonant lattice plasmon excitation

“…Generating a maximum average output power of 190 pW with a maximum SHG conversion efficiency of 1.06 × 10 −9 . Taking the metasurface thickness into account, the maximum second order nonlinearity is 1.0 pm V −1 (see Supporting Information), which is of the same order of magnitude with respect to state-of-the-art metasurfaces [11,24,39]. Polynomial best-fitting finds a linear slope in the dou- ble log scale of 2.35.…”

“…In 1985 Coutaz et al showed that, as the incidence angle is changed, SHG undergoes strong enhancement in metallic mono-dimensional gratings when the im-pinging beam is resonant with the nonlocal surface plasmon [10], what is today known as SLR. However, in the same structure the SHG is also enhanced when the SLR condition is fullfield at the second harmonic frequency [11]. Similarly, for two-dimensional (2D) nanoparticle arrays the SHG is enhanced for the SLR at the fundamental frequency [12,13] and at the second harmonic [14].…”

Giant Second-Harmonic Generation in Cantor-like Metamaterial Photonic Superlattices

“…1−6 Other approaches to realize high-efficiency SHG employ the field amplification in the structure because of the slow light effect (high density of modes) at photonic band edges, 7−9 or the strong light confinement in photonic cavities, defective and disordered superlattices, and plasmonic systems. 10−27 The incorporation of artificial materials with a negative refractive index has led to striking phenomena in photonic superlattices. The so-called metamaterials with simultaneous negative dielectric permittivity (ε B ) and magnetic permeability (μ B ) 28−34 yield superlattices with a gap under oblique incident light, i.e., θ ≠ 0, known as the magnetic/electric bulklike plasmon-polariton (PP) gap.…”

“…Dielectric superlattices, in particular, can be designed to have reciprocal lattice vectors, G n , to compensate the phase mismatch Δ k = k 2ω – 2 k ω , where k ω and k 2ω are the wavevectors of the fundamental field (FF) and second-harmonic (SH) waves, respectively. This enhances the second-harmonic (SH) conversion efficiency in a mechanism known as the quasi-phase-matching condition. − Other approaches to realize high-efficiency SHG employ the field amplification in the structure because of the slow light effect (high density of modes) at photonic band edges, − or the strong light confinement in photonic cavities, defective and disordered superlattices, and plasmonic systems. − The incorporation of artificial materials with a negative refractive index has led to striking phenomena in photonic superlattices. The so-called metamaterials with simultaneous negative dielectric permittivity (ε B ) and magnetic permeability (μ B ) − yield superlattices with a gap under oblique incident light, i.e., θ ≠ 0, known as the magnetic/electric bulklike plasmon-polariton (PP) gap.…”