摘要
Supercontinuum generation in atmospheric-pressure nitrogen by a focused intense femtosecond Ti:sapphire laser was studied at various pulse durations and energies.The generated supercontinuum was greatly blue-broadened due to self-phase modulation in the plasma produced.The measured blue-broadening△ωis proportional to pulse intensity for fixed pulse duration,and values up to 0.7ω(ωbeing the originaI laser frequency)was obtained with a pulse energy of 9.5 mJ and minimum duration of 100 fs.
基金
Supported by the National Climbing Project of China,and the National Natural Science Foundation of China under Grant Nos 19884001 and 19525412.
