Search results for " Harmonic Generation and Mixing"
showing 3 items of 3 documents
High-order harmonic generation via bound-bound transitions in an elliptically polarized laser field
2016
We use a simplified five-level system to investigate the high-order harmonic generation (HHG) spectrum emitted by an atom driven by a linearly or elliptically polarized laser field. For this model, the Schrödinger equation is exactly analytically reduced to the system of ordinary differential equations, which is solved numerically. Studying the intensity and polarization of the emitted radiation, we find that under high laser ellipticity the harmonic emission is suppressed. However, the harmonic intensity typically depends nonmonotonously on the laser ellipticity. Such anomalous behavior is very pronounced for the resonant harmonic. We offer an explanation of this behavior based on the incr…
Random quasi-phase-matched second-harmonic generation in periodically poled lithium tantalate
2010
We observe second harmonic generation via random quasi-phase-matching in a 2.0 micron periodically poled, 1-cm-long, z-cut lithium tantalate. Away from resonance, the harmonic output profiles exhibit a characteristic pattern stemming from a stochastic domain distribution and a quadratic growth with the fundamental excitation, as well as a broadband spectral response. The results are in good agreement with a simple model and numerical simulations in the undepleted regime, assuming an anisotropic spread of the random nonlinear component. (C) 2010 Optical Society of America
Backward second-harmonic generation of near infrared picosecond pulses
2014
We report on backward second-harmonic generation using picosecond laser pulses in congruent lithium niobate with 3.2 µm periodic poling. By tuning both the pump wavelength and the sample temperature, we observed three resonant peaks in the range 1530-1730 nm, corresponding to 16th, 17th and 18th quasi-phase-matching orders, respectively. A maximum conversion efficiency of 0.475% was achieved at the 16th order with a 10 kW peak pump power. The latter is the highest conversion reported in bulk to date, for the backward configuration, with an improvement greater than 50% with respect to those previously achieved with nanosecond pulses for the same order of resonance.