High-harmonic generation in a driven triangular well: The implications of chaos

We compute the spectrum of emitted radiation for a particle in a triangular potential well and driven by an electromagnetic field. For intense fields, the spectrum exhibits a plateau structure, a series of harmonic peaks of comparable strength up to some high-harmonic order, similar to that found in experiments and similar theoretical models. By comparing the quantum and classical dynamics, we see that the onset of high-harmonic generation in the quantum system appears to be correlated to the onset of chaos in the classical system. We also consider the effect of a slow turn on of the field and show why the acceleration should be used instead of the induced dipole moment to compute the spectrum. © 1996 The American Physical Society.