Terahertz acoustics in hot dense laser plasmas.
Terahertz acoustics in hot dense laser plasmas.
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DOI：
10.1103/physrevlett.114.115001
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发表时间：
2015-03
影响因子：
8.6
通讯作者：
A. Adak;A. Robinson;P. Singh;G. Chatterjee;A. D. Lad;J. Pasley;G. Kumar
中科院分区：
文献类型：
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作者：
A. Adak;A. Robinson;P. Singh;G. Chatterjee;A. D. Lad;J. Pasley;G. Kumar
我们提出了迄今为止未观察到的流体动力学方面，即在太赫兹频率范围内产生超高频声扰动，其起源本质上是纯粹的流体动力学。这种扰动是由 30 fs、800 nm 高强度激光 (∼5×10(16) W/cm(2)）产生的等离子体中密度梯度的流速差引起的。皮秒级的观测使我们能够捕获这些高频振荡（1.9±0.6 THz），这些振荡是由于激光快速加热介质而产生的。采用两种互补技术，即泵浦探头反射测量法和泵浦探头多普勒光谱测量技术，可以明确识别这种太赫兹声扰动。流体动力学模拟很好地再现了观察结果，提供了对该过程的深入了解。
We present a hitherto unobserved facet of hydrodynamics, namely the generation of an ultrahigh frequency acoustic disturbance in the terahertz frequency range, whose origins are purely hydrodynamic in nature. The disturbance is caused by differential flow velocities down a density gradient in a plasma created by a 30 fs, 800 nm high-intensity laser (∼5×10(16) W/cm(2)). The picosecond scale observations enable us to capture these high frequency oscillations (1.9±0.6 THz) which are generated as a consequence of the rapid heating of the medium by the laser. Adoption of two complementary techniques, namely pump-probe reflectometry and pump-probe Doppler spectrometry provides unambiguous identification of this terahertz acoustic disturbance. Hydrodynamic simulations well reproduce the observations, offering insight into this process.