Time-resolved investigation of low-density plasma channels produced by a kilohertz femtosecond laser in air
Time-resolved investigation of low-density plasma channels produced by a kilohertz femtosecond laser in air
复制标题
DOI：
10.1103/physreve.72.026412
复制
发表时间：
2005-08-01
影响因子：
2.4
通讯作者：
Chin, SL
中科院分区：
文献类型：
--
作者：
Liu, JS;Duan, ZL;Chin, SL
利用泵浦-探测后纵向衍射法，研究了1 kHzps激光在空气中产生的弱等离子体通道的电子密度和衰减动力学。在50fs的超短激光脉冲和0.6mJ的低能量下，我们在空气中观察到了长度接近2 cm的弱等离子体通道。分析了一种对相移和沟道尺寸敏感的电子密度的解析重构方法。弱等离子体通道中的电子密度约为4×10(16)cm(-3)。等离子体通道直径约50微米，灯丝直径约150微米，可测电子密度可扩展至10(15)cm(-3)以下。此外，还提出了一种不同的时频技术，称为线性啁啾纵向衍射法，用于时间分辨地研究激光辐照气体的超快电离动力学、激光与团簇光束的相互作用等。
By employing pump-probe back longitudinal diffractometry, the electron density and decay dynamics of a weak plasma channel created by a 1-KHz fs laser in air has been investigated. With ultrashort laser pulses of 50 fs and low energy of 0.6 mJ, we observe weak plasma channels with a length similar to 2 cm in air. An analytical reconstruction method of electron density has been analyzed, which is sensitive to the phase shift and channel size. The electron density in the weak plasma channel is extracted to be about 4x10(16) cm(-3). The diameters of the plasma channel and the filament are about 50 and 150 mu m, respectively, and the measurable electron density can be extended to less than 10(15) cm(-3). Moreover, a different time-frequency technique called linearly chirped longitudinal diffractometry is proposed to time-resolved investigate ultrafast ionization dynamics of laser-irradiated gas, laser interaction with cluster beam, etc.