Generation of optical harmonics from quantum light

High-gain parametric down-conversion enables the generation of so-called bright squeezed vacuum states. These states of light, on the one hand, are nonclassical, i.e., have features that are inconsistent with the classical description. On the other hand, they contain huge numbers of photons and are therefore efficient for nonlinear interactions. One of the key features of bright squeezed vacuum is photon-number correlations resulting in the high efficiency for optical harmonic generation. For instance, squeezed vacuum can be 15 times more efficient for third harmonic generation than coherent light of the same mean intensity. Moreover, optical harmonics generated from bright squeezed vacuum can have unusual statistical properties, such as non-Gaussian Wigner function. The generation process can manifest interesting symmetry features as, for instance, invariance to the orientation of the nonlinear medium.
The PhD project is aimed at obtaining second and third optical harmonics from bright squeezed vacuum and studying their statistical and symmetry properties. The work will include (1) engineering bright squeezed vacuum for the efficient generation of harmonics; (2) obtaining the harmonics and measuring the efficiencies and (3) study of the polarization properties of the harmonic generation.