"Unexpected strong-field physics in laser filaments"

"In this talk I will discuss two topics.First, I will describe an unexpected physical mechanism of 'lasing without inversion' during filamentation of femtosecond laser pulses in the air. Importantly, realization of this mechanism requires no special effort -- it happens almost without trying.Second, I will discuss the connection between hypothetical higher order Kerr effects and the emergence of the 'Kramers-Henneberger atom' and the 'bound states of a free electron' -- stable excited electronic states dressed by a strong laser field."