研究了温度梯度控制成丝中的自压缩现象。以充有2.0×105 Pa氩气的密闭气体作为成丝介质,在焦点处加热,由热传导形成温度梯度。25 ℃,0.8 mJ能量入射输出脉冲在没有任何色散补偿手段的情况下自压缩到17 fs,其傅里叶脉冲变换极限为5.5 fs。将脉冲能量提高到2.7 mJ,在中心为450 ℃的温度梯度下,输出脉冲自压缩到19 fs,其傅里叶脉冲变换极限为14.5 fs。通过温度控制将自压缩的能量提高了近2 mJ,实现了从脉冲自压缩到单丝脉冲展宽继而多丝的过程。

The phenomenon of pulse self-compression in temperature gradient controlled filamentation is demonstrated. 2.0×105 Pa argon gas sealed in quartz tube as the propagation medium,heating up at the focus,forms temperature gradient because of the heat conduction. At 25 ℃,the input pulse energy is 0.8 mJ,the output pulse self-compresses to 17 fs without dispersion compensation,and the Fourier transform limit pulse is 5.5 fs. When the energy is up to 2.7 mJ,and temperature gradient at the center is 450 ℃,the output pulse self-compresses to 19 fs and the Fourier transform limit pulse is 14.5 fs. The energy of self-compression increasees by nearly 2 mJ through temperature control,achieves the process from self-compression to single-filament pulse broadening and then multi-filamentation.