Calculation of high-order harmonic generation spectrum and Floquet resonance states using the dynamical symmetry

The Floquet resonance states of a periodically driven system are obtained using a special weighted power method which forces the dynamical symmetry into regular wave propagation methods. We demonstrate the utility of this method for the calculation of high harmonic generation spectra in rare gases. By using this method the resonance Floquet state which dominates the spectrum is obtained directly at a low computational cost. This may allow the calculation of resonance Floquet states in parameter regimes not accessible before. Implementation involves only slight adjustments to the standard wave propagation codes. The method's unique advantage is explained and demonstrated.