Enhancement of peak intensity in a filament core with spatiotemporally focused femtosecond laser pulses

We demonstrate that the peak intensity in the filament core, which is inherently limited by the intensity clamping effect during femtosecond laser filamentation, can be significantly enhanced using spatiotemporally focused femtosecond laser pulses. In addition, the filament length obtained by spatiotemporally focused femtosecond laser pulses is similar to 25 times shorter than that obtained by a conventional focusing scheme, resulting in improved high spatial resolution.