Fig. 3
From: Highly efficient broadband terahertz generation from ultrashort laser filamentation in liquids
Broadband terahertz spectral measurements with Michelson interferometer. a Time domain FAC traces for terahertz radiation from two-color filamentation of air (red squares), and single-color filamentation of acetone (blue circles) and ethanol (magenta up-triangle) at an input laser energy of 10 mJ. The full-width at half-maxima for air is ~86 fs, while that for acetone and ethanol is ~19 fs. b Corresponding frequency domain power spectra obtained using fast Fourier transforms for air (red line), acetone (blue line), and ethanol (magenta line). For air, 99.5% of the spectral power lies between 0.1–50 THz. Acetone and ethanol, respectively, have 72 and 64% of the spectral power in the same frequency range
