Coherently tunable third-order nonlinearity in a nanojunction

Abstract

Abstract. A possibility of tuning the phase of the third-order Kerr-type nonlinear susceptibility in a system consisting of two interacting metal nanospheres and a nonlinearly polarizable molecule is investigated theoretically and numerically. It is shown that by varying the relative inter-sphere separation, it is possible to tune the phase of the effective nonlinear susceptibility χ (3) (ω; ω, ω, −ω) in the whole range from 0 to 2π.

Decay Dynamics of 3‐methyl‐3‐pentene‐2‐one from the light absorbing S2(ππ*) state ‐ Resonance Raman Spectroscopy and CASSCF Study

“…In this case, overtones and combination bands through A-term enhancement are strong and will reach maximum at full resonance with the vibronic band. [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] For example, the A-band resonance Raman spectra of methyl iodide [25][26][27][28][29] are dominated by the very intense overtones progression of nν C-I because of the C-I bond breaking in the excited state. Another example comes from pyrene and anthracene, [34] whose resonance Raman spectra are wavelength dependent and display very strong overtones and combination bands when the laser excitation overlaps with the vibronic band.…”

“…The very strong nν 9 overtone progression of 3M3P2O consists with the electronic nature of the π HÀ1 → π L * transition that weakens the C¼C bond greatly, as is indicated by the molecular orbitals 26 and 28 in Table 1, and suggests that the S 2 (ππ*) PES along the C¼C reaction coordinates possesses the largest slope in FC, [21][22][23][24] to the intense overtone progression of C-I stretch fundamental mode of iodomethane, where iodomethane undergoes a direct C-I bond breaking because of n I → σ C-I transition. [25][26][27][28][29] Similarly, the very strong combination band progression (nν 9 + mν 8 ) of 3M3P2O suggests that the C 2 ¼O 7 double bond of 3M3P2O also undergoes bond order change in so far as the degree of the intensity of a FC active stretch mode correlates the degree of the bond length change in the repulsive PES. In order to speculate the possible intermediate structures such as S 2,min (ππ*), the conical intersection point between S 2 (ππ*) and S 1 (nπ*), we recall the CT-band resonance Raman spectra of the benzene-I 2 and olefin-I 2 complexes, [30][31][32][33] where the displayed intensity pattern is to some extent similar to that of the A-band resonance Raman spectra of 3M3P2O.…”

Diffractive arrays of gold nanoparticles near an interface: Critical role of the substrate

“…[1][2][3] The subject has recently received renewed attention 4,5 with the prediction 6,7 and experimental observation [8][9][10][11][12] of interesting optical phenomena that result from the interaction between the geometrical resonance associated with light diffraction and the excitation of localized surface-plasmon resonances in metallic nanoparticles, which play the role of plasmonic nanoantennas. 13 In addition to the interesting physics revealed in such systems, a number of applications have been proposed, including nanoscale energy transport, 14,15 sensing, 16,17 and modifying spontaneous emission, 18 which rely on the improved quality factor resulting from the reduction in radiative damping of the array as compared to localized plasmons excited in isolated particles.…”

Theory of energy transfer interactions near sphere and nanoshell based plasmonic nanostructures

“…Isolated spherical metallic nanoparticle and coupled metallic nanoparticle pair (dimer) has attracted a great deal of attention to investigate various phenomena occurring in the world of plasmonics. In addition to the nanoparticle monomer, coupled nanoparticles have also been widely investigated and proved to be useful in e.g., surface enhanced Raman scattering (SERS), nano-scale optical wave-guiding, detection, nanolensing, phase tuning of the nonlinear susceptibility, enhancement of molecular fluorescence, and quantum-dots (QDs) photoluminescence [3][4][5][6]. Coupled nanoparticle dimers have widely been investigated using hybridization theory where ________________________________________________________________________________ * Corresponding author E-Mail: manmohaniitd@gmail.com SP modes of a complex nanostructure are expressed as the bonding (symmetric) and the antibonding (asymmetric) interaction of SPs belonging to the constituents [7,8].…”