Wavefront shaping of terahertz radiation using two-color flying-focus pulses with time-dependent focal velocities
arXiv:2608.20142
A. L. Elliott, H. Markland, K. G. Miller, S. W. Jolly, J. J. Pigeon, J. P. Palastro
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A two-color “flying focus” whose intensity peak can slow down turns conical THz bursts into parabolic wavefronts that are easier to collect.
Read free explainer →Properly phased two-color laser pulses drive photoionization currents that emit broadband THz radiation. With a conventional two-color pulse, the ionization front travels at a nearly constant superluminal velocity, generating THz radiation with conical wavefronts at a Cherenkov-like angle. Here we show that the dynamic intensity peak of a two-color ultrashort flying-focus pulse can be used to control the shape of the THz wavefronts. Simulations demonstrate that non-uniform motion of the intensity peak and the ionization front it drives result in a time-dependent emission angle that determines the wavefront shape. A decelerating intensity peak, in particular, enables the generation of THz radiation with parabolic wavefronts that are well suited for collection and focusing.