Towards graphene plasmon-based free-electron infrared to X-ray sources

Abstract

Rapid progress in nanofabrication methods has fuelled a quest for ultra-compact photonic integrated systems and nanoscale light sources. The prospect of small-footprint, highquality emitters of short-wavelength radiation is especially exciting due to the importance of extreme ultraviolet and X-ray radiation as research and diagnostic tools in medicine, engineering, and the natural sciences. Here, we propose a highly-directional, tunable, and monochromatic radiation source based on electrons interacting with graphene plasmons (GPs). Our complementary analytical theory and ab-initio simulations demonstrate that the high momentum of the strongly-confined GPs enables the generation of high-frequency radiation from relatively low-energy electrons, bypassing the need for lengthy electron acceleration stages or extreme laser intensities. For instance, highly-directional 20 keV photons could be generated in a table-top design using electrons from conventional radiofrequency (RF) electron guns. The conductive nature and high damage threshold of graphene make it especially suitable for this application. Our electron-plasmon scattering

Spectrally and Spatially Resolved Smith-Purcell Radiation in Plasmonic Crystals with Short-Range Disorder

“…Consequently, we can learn more about the interplay between collective and resonant effects in electron-photon interactions. Such interactions of free electrons with specially designed nanophotonic structures can lead to tunable radiation sources from the terahertz [7], infrared and visible [15], to the x ray [46], as well as provide new sensing and diagnostics tools.…”

Terahertz-optical intensity grating for creating high-charge, attosecond electron bunches

“…The first case involved the compression of a lower-charge electron cloud into attobunches with durations of about 20 (FWHM), containing about 246 electrons. Such short-duration bunches could be used, for instance, as sources of high-quality coherent radiation through processes like inverse Compton scattering [13], Smith-Purcell radiation [57], transition radiation [58], and through electron-plasmon scattering [59,60]. We find that the realization of this scenario depends on having KE spreads which are extremely low but feasible [53].…”

Broadband negative refraction of hyperbolic highly squeezed graphene plasmons

“…Realizing negative refraction of highly squeezed polaritons, especially that supported by twodimensional (2D) materials (1)(2)(3)(4)(5)(6), such as graphene plasmon polaritons, is an important step toward the active manipulation of light at the extreme nanoscale (7)(8)(9), and can promise many photonic and optoelectronic applications (10)(11)(12)(13)(14)(15)(16)(17). In 2017, the phenomenon of all-angle negative refraction between highly squeezed isotropic graphene plasmons and hexagonal boron nitride's (BN) phonon polaritons, with their in-plane polaritonic wavelengths squeezed by a factor over 100, is theoretically shown possible in the graphene-BN heterostructures (18).…”