Nonlinear Optics in Guided Geometries - Abstract
Husakou, Anton
We consider supercontinuum generation in dielectric-coated metallic hollow waveguides filled with a noble gas, and study two aspects of this process: solitonic pulse compression in the single-cycle region, and coherence preservation due to plasma contribution. We predict the compression of a 20-fs pulse to a duration of 1.7 fs with an energy of 6 microjoule by soliton-effect compression, without external chirp compensation. We study the physical factors determining the limitations on shortest pulses in the single-cycle regime. It is shown that a small but nonzero value of the third-order group velocity dispersion is the key factor to achieve the compression below one optical cycle. We also show that the carrier-offset phase is preserved during the compression in spite of the short output pulse duration. The suppression of coherence degradation in high-power soliton-induced supercontinuum generation is shown to be caused by the influence of plasma contributions. It is related to the formation of coherent seed components by the abruptly rising plasma density at the peak of the pulse. In contrast, in the low-intensity regime the strong coherence degradation is caused by the generation of seed components from noise by four-wave-mixing. The coherence properties of white light are studied for different input pulse durations and GVD regimes.