Principal frequency of an ultrashort laser pulse

Abstract

We introduce an alternative definition of the main frequency of an ultrashort laser pulse, the principal frequency ${\omega }_P$. This parameter is complementary to the most accepted and widely used carrier frequency ${\omega }_0$. Given the fact that these ultrashort pulses, also known as transients, have a temporal width comprising only few cycles of the carrier wave, corresponding to a spectral bandwidth $\Delta \omega$ covering several octaves, ${\omega }_P$ describes, in a more precise way, the dynamics driven by these sources. We present examples where, for instance, ${\omega }_P$ is able to correctly predict the high-order harmonic cutoff independently of the carrier envelope phase. This is confirmed by solving the time-dependent Schrödinger equation in reduced dimensions, supplemented with the time-analysis of the quantum spectra, where it is possible to observe how the sub-cycle electron dynamics is better described using ${\omega }_P$. The concept of ${\omega }_P$, however, can be applied to a large variety of scenarios, not only within the strong field physics domain.

11 pages, 6 figures, accepted in PRA

References in corpus (1)

• Bright Coherent Ultrahigh Harmonics in the keV X-Ray Regime from Mid-Infrared Femtosecond Lasers

Cited by in corpus (4)

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