Intensity and wavelength scaling of laser-driven electron transition radiation: toward a table-top source of electromagnetic pulses

Abstract

The low-frequency transition-radiation output generated by laser-driven relativistic electrons is analyzed as a function of the intensity I and the wavelength λ0 of an ultrashort laser driver pulse. This analysis reveals the significance of the product as the key scaling parameter of the problem, suggesting that the requirements to the field intensity needed to produce a bright transition-radiation output can be significantly loosened by resorting to ultrashort driver pulses in the mid-infrared. The low-frequency part of the spectrum of transition radiation emitted by relativistic electrons driven by high-power mid-infrared pulses can span, as our analysis shows, well beyond the terahertz region, reaching the spectral range typical of electromagnetic pulses, thus opening a route toward a table-top source of such pulses.