An efficient control of ultrashort laser filament location in air for the purpose of remote sensing

摘要: The unavoidable hot spots in a practical terawatt level laser pulse will self-focus air at short distance. distance cannot be changed significantly by only controlling the chirp or divergence. We overcome such early self-focusing using telescope, which enlarges diameter of beam, thus that spots. telescope’s effective focal length is much shorter than both enlarged beam and Then, resulting filaments merge into geometrical focus whose position controllable telescope. This technique also minimizes generation white light.