Flying Focus: Spatiotemporal Control of Laser Intensity
An advanced focusing scheme called a “flying focus” has been demonstrated in which a diffractive lens combined with a chirped laser pulse enables a small-diameter laser focus to propagate nearly 100× its Rayleigh length . Furthermore, the speed at which the focus—and therefore the peak intensity—moves is decoupled from the group velocity of the laser; it was demonstrated to co- or counter-propagate along the laser axis at any velocity. In addition to plasma amplifiers , the spatiotemporal control of laser intensity achieved by the flying focus has the potential to change the way other plasma devices are optimized, including photon accelerators, laser wakefield accelerators, high-harmonics generation, and THz generation.
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