The exact harmonic-generation (HG) spectrum is obtained analytically for a one-band one-dimensional conductor for both ac and ac + dc external fields. It is shown that even and odd harmonics can be created and controlled depending on the initial-state conditions and the field amplitudes E. The HG spectrum forms a single plateau with a cutoff defined by a maximum HG order ${\mathit{N}}_{\mathit{m}}$ corresponding to the maximum energy acquired by the electron in the laser field. This maximum energy corresponds to single transfer between neighboring sites, i.e., ${\mathit{N}}_{\mathit{m}}$=eEa/ħω, where a is the lattice constant and ω the field frequency.

• Received 18 May 1994

DOI:https://doi.org/10.1103/PhysRevB.50.3473