Atomic-like high-harmonic generation from two-dimensional materials.

摘要: The generation of high-order harmonics from atomic and molecular gases enables the production high-energy photons ultrashort isolated pulses. Obtaining efficiently similar photon energy solid-state systems could lead, for instance, to more compact extreme ultraviolet soft x-ray sources. We demonstrate ab initio simulations that it is possible generate free-standing monolayer materials, with an cutoff gases. In limit in which electrons are driven by pump laser perpendicularly monolayer, they behave qualitatively same as responsible high-harmonic (HHG) atoms, where their trajectories described widely used semiclassical model, exhibit real-space those case. Despite similarities, first last steps well-established three-step model HHG remarkably different two-dimensional materials Moreover, we show electron-electron interaction plays important role harmonic because strong local-field effects, modify how material ionized. recombination accelerated electron wave packet also found be modified infinite extension plane, thus leading a favorable wavelength scaling yield than HHG. Our results establish novel efficient way generating based on device, Two-dimensional offer unique platform both bulk can investigated, depending angle incidence. Devices extend existing