Calorimetric detection of the conical THz radiation from femtosecond laser filaments in air

Abstract : The spectral distribution of the conical terahertz (THz) emission from a femtosecond laser filament in air is measured with a bolometric detector and a set of filters, confirming that the main part of the emission lies between 0.5 and 3 THz. The efficiency of this THz emission is compared with that obtained in air via Four Waves Mixing of femtosecond laser pulses at ω and 2 ω in the presence of a plasma.