Abstract

Modern laser sources deliver intense, ultrashort pulses containing a few optical cycles only. This progress paved the way to the quickly-developing field of ”extreme nonlinear optics”, for which the position of the carrier wave with respect to the envelope, the so-called carrier-envelope phase (CEP), matters. The CEP is expected to modify the pulse dynamics when the pulse duration becomes comparable to the oscillation cycle of the carrier wave [1]. Here we report on changes induced over remote distances by an initial phase offset along the self-compression of infrared and near-infrared femtosecond pulses mediated by filamentation. Few-cycle pulses can indeed be obtained by filamentary compression [2] and they have interesting properties, e.g., the self-guiding process acts as a spatial filter producing an excellent mode quality. In Ref. [3], energy variations at the percent level were observed to keep the filament CEP rather stable, as measured by f − 2 f spectral interferometry. In Ref. [4], simulated ultrashort filaments were even proposed to maintain a nearly constant CEP upon meter-range distances.

© 2011 Optical Society of America