论文信息 - Spectral dependences of conical emission in gases: Minimization of scattering for ultra-short pulsed laser ablation

Spectral dependences of conical emission in gases: Minimization of scattering for ultra-short pulsed laser ablation

Parameters of conical emission (CE), at focusing of femtosecond and short picosecond pulses in ambient gases, are characterized in a wide range of experimental conditions. Scattered and absorbed energy, the beam profiles and spectra are compared for different duration and wavelengths of laser radiation (harmonics of Ti:Sa and Yb:YAG laser). Shorter wavelengths were found to be most beneficial for elimination of CE. Nearly no scattering of short picosecond pulses was observed at 515 nm in the energy density range up to 300 J/cm2. The results are analyzed in terms of the contributing ultra-fast phenomena effecting refraction index of gases (the Kerr effect, different mechanisms of ionization). Advantages of the visible pulses are illustrated in deep drilling experiments.

[1] G. Mourou,et al. Self-channeling of high-peak-power femtosecond laser pulses in air. , 1995, Optics letters.

[2] S. Chin,et al. Conical emission from laser plasma interactions in the filamentation of powerful ultrashort laser pulses in air. , 1997, Optics letters.

[3] Holger Lubatschowski,et al. Femtosecond Technology for Technical and Medical Applications , 2010 .

[4] V. Krainov,et al. Atoms in Strong Light Fields , 1985 .

[5] V. P. Kandidov,et al. Influence of transient self-defocusing on the propagation of high-power femtosecond laser pulses in gases under ionisation conditions , 1994 .

[6] O. Kosareva,et al. NONLINEAR OPTICAL PHENOMENA: Nonlinear-optical transformation of a high-power femtosecond laser pulse in air , 2003 .

[7] Spectral blueshifting and spatial defocusing of intense laser pulses in dense gases , 1994 .