Imprinting spiral Higgs waves onto superconductors with vortex beams

A vortex beam, akin to a quantized vortex in superfluids, possesses inherent orbital angular momentum (OAM), resulting in the propagation of a spiral-shaped wavefront. Here, we demonstrate that a pulsed vortex beam with OAM in the terahertz frequency band can induce a spiral Higgs wave, which is a spiral-shaped oscillation mode of the superconducting order parameter. By utilizing the gauge-invariant theory for the super-conducting order, we demonstrate that the phase mode is driven to screen the longitudinal magnetic field of the vortex beam, which facilitates the imprinting of the spiral-shaped wavefront and the transfer of OAM to the condensate. Furthermore, we find that increasing the OAM of light amplifies the intensity of the third-harmonic generation. These findings highlight the potential of terahertz vortex beams as a spectroscopic probe of collective modes.