ABSTRACT
Nonlinear optical processes are an essential tool in modern optics, with a broad spectrum of applications, including signal processing, frequency conversion, spectroscopy and quantum optics. Ordinary parametric devices nevertheless still suffer from relatively low gains and wide spectral emission. Here we demonstrate a unique configuration for phase-matching multiple nonlinear processes in a monolithic 2D nonlinear photonic crystal, resulting in the coherent parametric emission of four signal and idler modes, featuring an exponential gain enhancement equal to the Golden Ratio. The results indicate a new route towards compact high-brightness and coherent sources for multi-photon generation, manipulation and entanglement, overcoming limitations of conventional parametric devices.
ABSTRACT
We develop a general model, based on a (2+1)D unidirectional pulse propagation equation, for describing broadband noncollinear parametric interactions in 2D quadratic lattices. We apply it to the analysis of twin-beam optical parametric generation in hexagonally poled LiTaO3, gaining further insights into experimental observations.
ABSTRACT
We theoretically and experimentally investigate multistep parametric processes in broadband optical parametric generators (OPGs) based on periodically poled 1 mol. % MgO-doped stoichiometric LiTaO3. We demonstrate that parametric collateral processes may deplete or enhance spectral portions of the OPG output, depending on pump pulse duration.
ABSTRACT
We report on broadband gain in an optical parametric generator based on periodically poled 1 mol% magnesium-doped stoichiometric LiTaO3 (PPMg:SLT). More than an octave-spanning parametric gain, stretching from near to mid-infrared, is generated by pumping the crystals close to the point where, at parametric degeneracy, the waves experience zero group-velocity dispersion. Using a picosecond Ti:sapphire source, we measured the broadest parametric gain bandwidths, 180 THz at 10 dB, in PPMg:SLT gratings with a period of 25 µm pumped at 860 nm.
