Characterization of the supercontinuum radiation generated by self-focusing of few-cycle 800 nm pulses in argon

摘要: Self-focusing of few-cycle pulses in atmospheric-pressure argon results a supercontinuum which differs remarkably from the case longer pulses: under single-filament conditions it extends to 200 nm and 250 with 6 fs 10 pulses, respectively; radiation, including shortest wavelengths, is collimated shows no conical emission. The short-wavelength part intrinsically at least as short incoming fundamental pulse. These features make attractive source widely tunable pump for spectroscopic applications. We present extensive experimental dependence spectrum on pulse energy, duration chirp, filament length, gas pressure comparison nitrogen air. discuss them other role third harmonic identify required get single highly stable filament. also model, based self-guiding, predicts useful scaling rules.