Polarization-controlled terahertz generation by bicircular longer-wavelength laser fields

When compared with other laser configurations, stronger terahertz (THz) waves can be generated from gaseous plasmas driven using two-color omega + 2 omega circularly polarized laser fields with the same helicity (CP-S), but consideration of the THz polarization state shows that these waves are linearly polarized. Here, we show that polarization-controlled THz radiation, including circularly polarized radiation, can be generated using CP-S pump fields. Unlike the conventional multi-cycle 800 nm + 400 nm combination, we use longer-wavelength or few-cycle laser pulses to generate nonzero net currents along two orthogonal directions with a similar to +/-pi/2 phase difference between them because of laser field symmetry breaking. When the current distribution's axis of symmetry is ascertained, the THz polarization direction can be confirmed. (C) 2022 Optica Publishing Group

Automated summary

It is discovered that polarization-controlled THz radiation, including circularly polarized radiation, can be generated using two-color circularly polarized laser fields. This study demonstrates that by adjusting the symmetry of the laser field, circularly polarized THz radiation can be achieved.