AbstractThis thesis concerns theoretical and experimental work on spatio-temporal instabilities in c(2) frequency conversion processes. The theoretical activities are centered around modeling second harmonic generation in the presence of a competing parametric process both in singly and doubly resonant configurations. The employed techniques constitute a combination of linear stability analyses, multiple-scales calculations, and numerical simulations. The parametric conversion is found to modify the dynamics considerably and leads to new types of spatio-temporal structures such as intensity spiral patterns, dark solitons, and negative hexagons. Furthermore, the spatial distribution of quantum noise in second harmonic generation is investigated based on Langevin equations. The spatial spectrum of squeezing and the two-point correlation function are calculated in the far-field, and the clear non-classical signatures are pointed out. The first experimental results on pattern formation and temporal instabilities in second harmonic generation are presented. Clear evidence for hexagon formation is observed in addition to a new type of self-pulsing instability observed due to interaction between the second harmonic and competing parametric processes. Good agreement between theory and experiment is obtained.
Finally, an experiment on quantum tomography on new quantum states of light is discussed. The succesful reconstruction of the Wigner function for a single-photon Fock state with an overall measurement efficiency of 33% is established. |