Sub-poissonian light in third-harmonic generation: Quantum predictions via classical trajectories

Sub-Poissonian light in the third-harmonic generation process is studied numerically and analytically. Special regime exhibiting the time-stable maximum sub-Poissonian behaviour with the Fano factorF ≈ 0.81 is found and analyzed. Theoretical prediction of the Fano factor and explanation of the extraordinary time stability of the sub-Poissonian behaviour are given using the semiclassical method of classical trajectories.