Fig. 2
From: Highly efficient broadband terahertz generation from ultrashort laser filamentation in liquids
Broadband terahertz energy and polarization measurements by PED. a Energy measured by the PED (with filter and spectral corrections) from two-color filamentation in air (red square) and single color filamentation in various liquids: ethanol (magenta up-triangle), methanol (olive down-triangle), acetone (blue circle), dichloroethane (purple diamond), deionized water (dark-red right-triangle), carbon disulfide (green left-triangle), as a function of laser energy. Each data point is averaged over 32 acquisitions and the error bars indicate the standard deviation from the average. For an input laser energy of 28 mJ before the cuvette, an integrated terahertz energy of 76 µJ is obtained from the filamentation in acetone. b Polarization measurement of terahertz radiation from air (red square) and acetone (blue circle) at a laser energy of 10 mJ. The theoretical cosine square fits to the plots are shown by red dashed line for air, and blue dashed line for acetone. The polarization of the incident laser is shown by a black dash-dot arrow. The polarization of the terahertz radiation from air (two-color) is shown by a red dash-dot arrow, which is rotated by 151° with respect to the incident laser polarization. The terahertz polarization for acetone (single color) is shown by a blue dash-dot arrow, rotated by 84° with respect to the laser polarization
