Controlling the spectrum of high-power terahertz radiation from a laser-driven plasma wave

Generation of strong THz waves is a very important and difficult research issue. We performed particle-in-cell (PIC) simulation studies to investigate the possibility of powerful THz generation and spectrum controllability by using a laser-driven plasma wave. Our results show that it is possible to produce spectrum-controllable high-power (>1 MV/cm) THz waves by manipulating the plasma density profiles. This method may provide a good way for coherent high-power THz radiation sources, of which the spectrum ranges from a narrow bandwidth to a wide bandwidth.

► We propose a method of spectrum-controllable THz generation.
► The method using a density gradient and a laser was demonstrated by PIC simulations.
► Changing the density gradient and the peak density can produce different THz spectra.
► It can produce ultrashort THz wave pulses with a field strength of cB>>1cB>>1 MV/cm.