Some problems of optimum focusing in the process of second harmonic generation in nonlinear crystals. Part 2. Results of numerical calculations

Аннотация

The problem of the second harmonic generation (SHG) of monochromatic spatially coherent paraxial radiation in homogeneous uniaxial quadratically nonlinear crystals upon focusing of a beam into a crystal by two crossed cylindrical lenses with different focal lengths is considered theoretically. Parameters of optimum focusing are determined as functions of the main radiation power. This part of the paper presents main results of numerical calculations. It is shown that, with an increase in the main radiation power, parameters of optimum focusing vary insignificantly at first. Then, beginning from a certain power depending on the initial conditions of the problem, the SHG efficiency maximum becomes attainable with increasingly weaker focusing. The efficiency maximum monotonically increases and probably tends to 100% with an infinite increase in the power.