We demonstrate complete all-optical and phase-stable control of the linear optical polarization and the nonlinear coherent response (third-harmonic generation) of a hybrid nanoplasmonic-photonic system. A few tens of femtoseconds after the excitation, we turn the response on and off at any given point in time and probe its temporal evolution throughout the control process with a three-pulse non...

We study heat transfer between conductors, mediated by the excitation of a monomodal harmonic oscillator. Using a simple model, we show that the onset of rectification in the system is directly related to the nonlinearity of the electron gas dispersion relation. When the metals have a strictly linear dispersion relation, a Landauer-type expression for the thermal current holds, symmetric with r...

We introduce and demonstrate a new approach to measuring coherent electron wave packets using high-harmonic spectroscopy. By preparing a molecule in a coherent superposition of electronic states, we show that electronic coherence opens previously unobserved high-harmonic-generation channels that connect distinct but coherently related electronic states. Performing the measurements in dynamicall...

We report on the dispersion of the third-order nonlinear susceptibility (chi(3) or "Chi 3") in planar Ta2O5 waveguides in the telecommunications spectral window. We utilize the observation of third-harmonic generation under ultrashort pulsed excitation as a reference-free characterization method of chi(3) and obtain a large nonlinear coefficient, 2x10(-13) esu, at 1550 nm. Our observation of ef...

Third harmonic generation (THG) imaging using a near-field scanning optical microscope (NSOM) is demonstrated for the first time. A femtosecond, tunable near-infrared laser was used to generate both nonresonant and resonantly enhanced third harmonic radiation in human red blood cells. We show that resonantly enhanced THG is a chemically specific bulk probe in NSOM imaging by tuning the excitati...

Current-voltage characteristics of suspended single-wall carbon nanotube quantum dots show a series of steps equally spaced in voltage. The energy scale of this harmonic, low-energy excitation spectrum is consistent with that of the longitudinal low-k phonon mode (stretching mode) in the nanotube. Agreement is found with a Franck-Condon-based model in which the phonon-assisted tunneling process...

We use an harmonic technique to probe the dynamics of a liquid-liquid interface in a capillary. The capillary pressure drop induced by a harmonic displacement of the fluids is recorded as a function of the excitation amplitude and frequency. At low frequency there is an amplitude threshold above which the contact line depins and slides, and this threshold is related to the static hysteresis of ...

We develop a green light source with low spatial coherence via intracavity frequency doubling of a solid-state degenerate laser. The second-harmonic emission supports many more transverse modes than the fundamental emission, and exhibits lower spatial coherence. A strong suppression of speckle formation is demonstrated for both fundamental and second-harmonic beams. Using the green emission for...

Frequency-scanned excitation profiles of coherent second harmonic generation (SHG) were measured for silver nanoparticle arrays prepared by nanosphere lithography. The frequency of the fundamental beam did not coincide with the localized surface plasmon resonance (LSPR) of the nanoparticles and was tuned so that the coherent second harmonic (SH) emission was in the region of the LSPR at 720-750...

Over the past twenty years, in ultrasound contrast imaging, new physiological information are obtained by the detection of non-linearities generated by the microbubbles. One of the most used techniques is the pulse inversion imaging. The usual command of this system is a fixed-frequency sinus wave. An optimal choice of this command requires the knowledge of the transducer and of the medium to o...