The evolution of terahertz (THz) waveform in air plasma driven by low-energy few-cycle laser pulses is investigated to improve the accuracy of the carrier envelope phase (CEP) determination. Based on the transient photocurrent model, a balanced spatial distribution of the Kerr and free-electron effects in the plasma is found at 109 \mu J input energy. THz inversion occurs only once at the initial CEP of 0.5\pi, in which high-precision measurement of the CEP of few-cycle laser pulses is achieved.
© 2013 Chinese Optics Letters
Rongjie Xu, Ya Bai, Liwei Song, Na Li, Peng Peng, and Peng Liu, "Terahertz emission by balanced nonlinear effects in air plasma," Chin. Opt. Lett. 11, 123002-123002 (2013)