Impact of a static magnetic field on high-order harmonic spectra

We have studied the influence of a static magnetic field on the high harmonic radiation that is caused by the motion of an atomic electron along the laser propagation direction. Different from the ordinary high harmonic spectrum which has been studied under the influence of a static magnetic field, we found that the spectrum of the harmonic radiation polarized in the laser propagation direction is quite sensitive to an additional static magnetic field. The signal heights of this spectrum can be substantially affected by a relatively weak static magnetic field of the order of 30 T directed along the magnetic-field vector of the linearly polarized laser pulse. This dependence of the signal strength on the external magnetic field has clear potential to be employed as a means to measure magnetic fields.