Optical nonlinearities of a high concentration of small metal particles dispersed in glass: copper and silver particles

Electrically tunable nonlinear plasmonics in graphene nanoislands

“…The latter correspond to light wavelengths that are much larger than the size of the islands 10 , and therefore, we characterize their optical response in the electrostatic limit, so they contribute to the far field with their induced dipole moment p. In our numerical simulations, we consider light incident along the direction normal to the carbon In a we show second-harmonic data for roughly spherical gold and silver MNPs measured at fundamental wavelengths of 800 and 780 nm, respectively (solid circles) 7,8 ; roughly spherical gold MNPs measured at a fundamental wavelength of 1,064 nm (open circles) 30 ; gold decahedra measured at a fundamental wavelength of 790 nm (solid diamonds) 31 ; and silver triangles measured at a fundamental wavelength of 1,064 nm (solid triangles) 32 . In b we show degenerate four-wave mixing data for roughly spherical silver and copper MNPs measured at wavelengths of B420 and B570 nm, respectively (solid circles) 33 , as well as THG data for silver MNPs measured at a fundamental wavelength of 1,230 nm (open circle at the bottom) 34 plane, which we take asẑ. As we are interested in the enhanced optical response due to plasmons, armchair-edged nanoislands are preferred because they support intense and highly tunable modes, whereas zigzag-edged islands host near-zeroenergy electronic states that are detrimental to the strength and tunability of optical excitations 28 , particularly when the plasmon energy is above the Fermi level 12 (see Supplementary Fig.…”

“…In particular, we show the reported experimental values of |a (2) | acquired through hyper-Rayleigh scattering of various types of gold and silver nanoparticles in aqueous suspensions 7,8,[30][31][32] . In addition, we show values of the reported third-order susceptibility |w (3) | obtained from degenerate four-wave mixing measurements of glasses doped with silver and copper nanoparticles 33 and from THG measurements of dispersed silver colloids on quartz 34 , converted into |a (3) | upon multiplication by the particle volume.…”

Classical Theory of Optical Nonlinearity in Conducting Nanoparticles

“…We, however, note that the quantity measured in Ref. [9] cannot be easily related to the nonlinear polarizability derived here. On the other hand, one can argue on physical grounds that any nonlinearity that is a consequence of electron confinement should vanish in the limit a !…”

“…j2E 0 j=4 a. To obtain the nonlinear correction to the refractive index n, we retain only the k 1 term in the Fourier series (9). For a transparent medium of refractive index n 0 doped with randomly and sparsely distributed metal nanospheres, we have n 2 n 2 0 1 3p…”

“…In Ref. [9], degenerate four wave mixing was used to measure the effective nonlinear susceptibility 3 for glasses doped with Ag and Cu nanospheres of varying sizes (see also Ref. [10] where these data were compared to the analytical model of Ref.…”