In the process of optical second-harmonic generation an X-wave, travelling at the group velocity of the fundamental frequency, spontaneously forms. Its parameters, as well as the angular spectrum, are directly correlated to the group velocity mismatch and to the wavevector mismatch between the two harmonics. A novel mechanism for spatio-temporal localized waves generation is thus proposed. ∗Ele...

Chiral-selective non-linear optics and optoelectronic signal generation are demonstrated in an electrically active photonic metamaterial. The metamaterial reveals significant chiroptical responses in both harmonic generation and the photon drag effect, correlated to the resonance behavior in the linear regime. The multifunctional chiral metamaterial with dual electrical and optical functionalit...

We present a practical scheme to separate the contributions of the electric quadrupole-like and the magnetic dipole-like effects to the forbidden second order optical nonlinear response of graphene, and give analytic expressions for the second order optical conductivities, calculated from the independent particle approximation, with relaxation described in a phenomenological way. We predict str...

Recent experimental developments in material sciences have generated hope that it will be possible to devise optical media where the difference in group velocity between the fundamental and third harmonic may be strongly suppressed. Under these circumstances both pulses would travel together over a long distance. This would lead to an enhancement of the generation process, and hence strong focu...

Kramers-Krönig (K-K) analysis of harmonic generation optical data is usually greatly limited by the technical inability to measure data over a wide spectral range. Data inversion for real and imaginary part of χ(nω;ω, ..., ω) can be more efficiently performed if the knowledge of one of the two parts of the susceptibility in a finite spectral range is supplemented with a single measurement of th...

The nonlinear optical response of porous InPs100d membranes was examined and compared to that of bulk crystalline s100d-oriented InP. Measurements of optical rectification and optical second-harmonic generation have been carried out in reflection under excitation by 120 fs, 800 nm Ti:Sapphire laser beam pulses. A significant enhancement in both the radiated terahertz field and second-harmonic r...

We report the experimental demonstration of all-optical format conversion by exploiting the cascaded second-harmonic generation and difference-frequency generation (cSHG/DFG) in a periodically poled lithium niobate (PPLN) waveguide assisted by the reflective semiconductor optical amplifier (RSOA)-based active mode-locking. 10 and 20 Gbit/s format conversions from non-return-to-zero (NRZ) to ret...

High-harmonic generation is shown to be capable of providing time-resolved information about the particle density of a complex system. As an example, we study numerically high-harmonic generation from expanding xenon clusters in a pump-probe laser scheme, where the pump laser pulse induces the cluster explosion and the probe pulse generates harmonics in the expanding cluster. We show that the h...

Multiferroicity can be induced in strontium titanate by applying biaxial strain. Using optical second harmonic generation, we report a transition from 4/mmm to the ferroelectric mm2 phase, followed by a transition to a ferroelastic-ferroelectric mm2 phase in a strontium titanate thin film. Piezoelectric force microscopy is used to study ferroelectric domain switching. Second harmonic generation...

High efficiency of the second-harmonic and sum-frequency generation can be obtained in optical superlattice by using the conventional quasi-phase-matched (QPM) method. Although this trick can be played on the acoustic wave, the media with negative nonlinear parameters are not common in acoustics. Furthermore, the QPM method used in acoustic metamaterials has been less studied. In this work, a p...