Fig. 1: Air lasing generation by CEP-stabilized near-single-cycle light pulses.
From: Controlling rotational air lasing lineshape by carrier-envelope offset phase
a Photo of a gas tube filled with 1 bar N2, where the laser beam is propagating from left to right and focused in the tube center. b Measured lasing spectra after a short-pass UV filter (<450 nm) at the gas pressure of 1 bar and 1 mbar, respectively. In the 1 bar case, the pedestal is corresponding to the supercontinuum labeled with SPM. c High-energy-resolution lasing spectra around 428 nm, where the rotational quantum number of the \({{{{{\rm{X}}}}}}^{2}{\Sigma }_{g}^{+}(\nu=1)\) state is assigned on the top of the peaks in the spectrum at 1 mbar. In the high-pressure case, the peak positions and lineshapes are both varied and dependent on the laser CEP.
