Zusammenfassung
We investigate intensity of the parametric down conversion of ultrashort,
ultraviolet pulse both in a low- and high-conversion regime. In the first
regime, we develop a simple analytical expressions for the photon flux of the
fluorescence. Numerical simulations using three-dimensional stochastic Wigner
method provide results in the latter regime. We find that the perturbative
approximation for the photon flux as a function of the wavelength of the signal
and the observation angle, quantitatively describes even the non-perturbative
regime. For short pump pulses the intensity of the fluorescence is highest at
frequencies where the group velocities of the pump and the down-conversion are
equal. For longer pump pulses this requirement is gradually relaxed.
Additionally, for small pump beams, the intensity strongly depends on the
spatial divergence between interacting fields.
Nutzer