We have investigated the photophysics of the luminescent polymer poly~1,3-phenylenevinylene-alt-2,5dioctyloxy-1,4-phenylenevinylene! by a variety of optical spectroscopies. The incorporation of alternating meta-phenylene and para-phenylene rings restricts conjugation with respect to poly~para-phenylenevinylene! derivatives. As a consequence, excited states are blueshifted and the nonlinear susc...

This work investigates the structural and nonlinear optical properties of a D-A type 1-[4-({(E)-[4-(methylsulfanyl)phenyl]methylidene}amino)phenyl]ethanone, MMP in which charge transfer occurs from -SCH3 donor to -COCH3 acceptor group through methylidene backbone; and some of its modeled analogues using quantum chemical calculations with pure BLYP and hybrid B3LYP correlation with high basis se...

We demonstrate second order optical nonlinearity in a silicon architecture through heterogeneous integration of single-crystalline gallium nitride (GaN) on silicon (100) substrates. By engineering GaN microrings for dual resonance around 1560 nm and 780 nm, we achieve efficient, tunable second harmonic generation at 780 nm. The χ2 nonlinear susceptibility is measured to be as high as 16 ± 7 pm/...

We present the first study of nonlinear optical third-harmonic generation (THG) in the strongly correlated charge-transfer insulator Sr(2)CuO(2)Cl(2). For fundamental excitation in the near infrared, the THG spectrum reveals a strongly resonant response for photon energies near 0.7 eV. Polarization analysis reveals this novel resonance to be only partially accounted for by three-photon excitati...

In recent years there has been excessive progress in the ‘green’ chemistry approach for the synthesis of gold and silver nanoparticles. Bimetallic nanoparticles have gained special significance due to their unique tunable optical properties. Herein we report a facile one-pot, ecofriendly synthesis of Au–Ag bimetallic core–shell nanoparticles using gripe water as reducing as well as stabilizing ...

We report quasi-phase-matched second-harmonic generation in periodically poled lithium niobate (PPLN), where both fundamental and second-harmonic waves are ordinary waves. It provides a lower-limit value for d22 of 1.1 pm/V. The measured temperature and wavelength bandwidth of the second-harmonic signal are in good agreement with the theoretical predictions. Since the d22 = dYYY nonlinear coeff...

We demonstrate a new, nonlinear optical effect of electric currents. First, a steady current is generated by applying a voltage on a doped GaAs crystal. We demonstrate that this current induces second-harmonic generation of a probe laser pulse. Second, we optically inject a transient current in an undoped GaAs crystal by using a pair of ultrafast laser pulses and demonstrate that it induces the...

In this paper, for the first time to our knowledge, we investigate the optical bi-stability in a compact parallel array of micro- ring resonators with 5μm radius, induced by optical nonlinearity. Due to the nature of perfect light confinement, resonance and accumulation process in a ring resonator, optical nonlinear effects, even at small optical power of a few milliwatts in this structure are ...

Experimental measurements of the second order susceptibilities for the second harmonic generation are reported for YAl3(BO3)4 (YAB) single crystals for the two principal tensor components xyz and yyy. First principle's calculation of the linear and nonlinear optical susceptibilities for Yttrium Aluminum Borate YAl3(BO3)4 (YAB) crystal have been carried out within a framework of the full-potenti...

We investigate whether microscopic cascading of second-order nonlinearities of two molecules in the side-byside configuration can lead to a third-order molecular nonlinear-optical response that exceeds the fundamental limit. We find that for large values of the second hyperpolarizability, the side-by-side configuration has a cascading contribution that lowers the direct contribution. However, w...