Engineered nonlinear materials using gold nanoantenna array

Abstract

Gold dipole nanoantennas embedded in an organic molecular film provide strong local electromagnetic fields to enhance both the nonlinear refractive index (n2) and two-photon absorption (2PA) of the molecules. An enhancement of 53× for 2PA and 140× for nonlinear refraction is observed for BDPAS (4,4′-bis(diphenylamino)stilbene) at 600 nm with only 3.7% of gold volume fraction. The complex value of the third-order susceptibility enhancement results in a sign change of n2 for the effective composite material relative to the pure BDPAS film. This complex nature of the enhancement and the tunability of the nanoantenna resonance allow for engineering the effective nonlinear response of the composite film.

Nonlinear Refraction and Absorption of Ag29 Nanoclusters: Evidence for Two-Photon Absorption Saturation

“…Interaction of intense light beams with matter can induce various nonlinear optical effects and phenomena. Among them, nonlinear absorption and refraction, two processes describing the change of the optical absorption and refraction index of a material with the incident light intensity, have received considerable attention. − This interest lies in the numerous applications offered in a wide range of fieldsfrom spectroscopy, laser science, and microscopy to functional material design. − Recently, the search for materials with large nonlinear absorption or nonlinear refraction has turned toward nanomaterials and heterogeneous materials with embedded nanoscale structures. − Matrices incorporating metallic nanoparticles have in particular been shown to possess extremely large nonlinear absorption or refraction due to the presence of confined conduction band electrons. Besides, for particles with diameters smaller than about 100 nm in particular, surface plasmon resonances (SPR), namely resonances associated with the collective excitation of these conduction band electrons, provide further enhancements of these nonlinear optical properties.…”

Coupling light and sound: giant nonlinearities from oscillating bubbles and droplets

“…A large and growing body of research investigates high-quality factor (high-Q) nonlinear photonic microresonators [9,[48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63], integrated optical waveguides [64][65][66][67], optical nanoantennas [42,[68][69][70][71][72][73][74][75][76][77][78][79][80], and metasurfaces [81][82][83][84]. A judicious design of such structures enables large local enhancements of the optical field intensity, which in turn leads to strong nonlinear optical effects.…”

“…By analogy with a conventional roof-top antenna, an optical nanoantenna emits, receives and, more broadly, controls light with nanoscale elements that are much smaller than the wavelength of the incident light [78,103,104]. In particular, nanoscale dimensions and subwavelength operating regime allow using optical nanoantennas to enhance lightmatter interaction which, along with other many interesting phenomena useful for sensing, spectroscopy and imaging, leads to strong nonlinear optical effects [42,[68][69][70][71][72][73][74][75][76][77][78][79][80]. Optical nanoantennas may be made of metals (most often of gold and silver) or dielectric and semiconductor materials.…”

Plasmonics for Telecommunications Applications

“…The most simple nanoantenna one can imagine is a single or two-coupled metallic nanoscatterers (dipole nanoantenna) [80][81][82][83][84][85][86], as illustrated in Figure 2a. The scattering properties of these systems have been extensively investigated (from the numerical and experimental points of view) as a function of the nanoparticles geometry and the input impedance [82,85], demonstrating that it can be designed analogous to dipoles in RF domain [80,81,84]. These concepts have also opened up the possibility to design and develop optical nanocircuit elements analogous to radiation resistance, radiation efficiency, and conduction losses [83,87].…”