  Coherent control of harmonic generation was studied theoretically. A specific
harmonic order was targeted. An optimal control theory was employed to find the
driving field where restrictions were imposed on the frequency band. Additional
restrictions were added to suppress undesired outcomes such as ionization and
dissociation. The method was formulated in the frequency domain. An update
procedure for the field based on relaxation was employed. The method was tested
on several examples demonstrating generation of high frequencies from a driving
field with a restricted frequency band.
