Generating optical supercontinuum and frequency comb in tenuous plasmas

Qu, Kenan (ORCID:0000000261861985); Fisch, Nathaniel J. (ORCID:0000000203017380)

doi:10.1063/5.0052829

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Generating optical supercontinuum and frequency comb in tenuous plasmas

Qu, Kenan (ORCID:0000000261861985)·Fisch, Nathaniel J. (ORCID:0000000203017380)

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Abstract

There are several mechanisms by which the frequency spectrum of a laser broadens when it propagates at near-relativistic intensity in a tenuous plasma. Focusing on one-dimensional effects, we identify two strong optical nonlinearities, namely, four-wave mixing (FWM) and forward Raman scattering (FRS), for creating octave-wide spectra. FWM dominates the interaction when the laser pulse is short and intense, and its combination with phase modulation produces a symmetrically broadened supercontinuum. FRS dominates when the laser pulse is long and relatively weak, and it broadens the laser spectrum mainly toward lower frequencies and produces a frequency comb. The frequency chirping combined with group velocity dispersion compresses the laser pulse, causing higher peak intensity.

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Qu, Kenan (ORCID:0000000261861985), Fisch, Nathaniel J. (ORCID:0000000203017380). 2021-08-05. Generating optical supercontinuum and frequency comb in tenuous plasmas. https://doi.org/10.1063/5.0052829

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