Fig. 10. Energy, temporal, and spectral characteristics of THz pulses generated by 3.9 μm filaments.

a Dependence of THz energy W_THz and the corresponding THz conversion efficiency Q_THz on the input laser energy W_in. b THz signals E_THz measured by electro-optic sampling (inset, blue) and by a Michelson interferometer (red). c THz power spectra S_THz (solid lines) obtained by the above techniques together with the noise levels of each technique (dashed lines). Reprinted from ref. ⁹⁰ under the terms of the Creative Commons CC BY license