Extended filamentation with temporally chirped femtosecond Bessel-Gauss beams in air.
Extended filamentation with temporally chirped femtosecond Bessel-Gauss beams in air.
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DOI：
10.1364/oe.17.000575
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发表时间：
2009-01
期刊：
影响因子：
3.8
通讯作者：
P. Polynkin;M. Kolesik;J. Moloney
中科院分区：
文献类型：
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作者：
P. Polynkin;M. Kolesik;J. Moloney
报道了时间啁啾飞秒贝塞尔-高斯光束超快衍射的实验结果。我们发现，通过啁啾的脉冲，所产生的等离子体通道的纵向范围可以扩展相对于完全压缩，变换限制的飞秒脉冲产生的灯丝。我们发现飞秒贝塞耳-高斯光束的轴上发射的强度和平行度之间存在明显的相关性。对于完全压缩的脉冲，轴上发射可以忽略不计，但当使用啁啾脉冲时，它可以变得相当可观（高达输入脉冲能量的10%）。在某些条件下，轴上发射变得足以产生其自身的等离子体通道，从而导致扩展的双折射。这种效应可以提供远程控制的手段，在细丝的形成与飞秒贝塞尔-高斯beams.We确定一个四波混频过程中，增强，这是可能导致在轴上发射的最大值，并推导出一个简单的表达式，用于估计的啁啾脉冲的持续时间，这是需要这种增强。我们的估计与实验符合得很好。
We report experimental results on ultrafast filamentation with temporally chirped femtosecond Bessel-Gauss beams. We find that by chirping the pulses, the longitudinal range of the generated plasma channels can be extended relative to filaments generated by fully compressed, transform-limited femtosecond pulses. We find a clear correlation between the extent of filamentation and the intensity of the on-axis emission by the femtosecond Bessel-Gauss beam. The on-axis emission is negligible for fully compressed pulses, but it can become quite substantial (up to 10% of the input pulse energy) when chirped pulses are used. Under certain conditions, the on-axis emission becomes sufficient for generating its own plasma channel thus resulting in extended filamentation. This effect may offer means of remote control over filament formation with femtosecond Bessel-Gauss beams.We identify a four-wave mixing process, enhancement of which is likely to result in a maximum of the on-axis emission, and derive a simple expression for estimating the duration of the chirped pulse that is required for such enhancement. Our estimations are in good agreement with the experiment.