State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China.
Phys Rev Lett. 2012 Jun 22;108(25):255004. doi: 10.1103/PhysRevLett.108.255004. Epub 2012 Jun 20.
Waveform-controlled terahertz (THz) radiation is of great importance due to its potential application in THz sensing and coherent control of quantum systems. We demonstrated a novel scheme to generate waveform-controlled THz radiation from air plasma produced when carrier-envelope-phase (CEP) stabilized few-cycle laser pulses undergo filamentation in ambient air. We launched CEP-stabilized 10 fs-long (~1.7 optical cycles) laser pulses at 1.8 μm into air and found that the generated THz waveform can be controlled by varying the filament length and the CEP of driving laser pulses. Calculations using the photocurrent model and including the propagation effects well reproduce the experimental results, and the origins of various phase shifts in the filament are elucidated.
由于在太赫兹传感和量子系统相干控制方面的潜在应用，波形控制太赫兹（THz）辐射具有重要意义。我们展示了一种新方案，通过在环境空气中进行载波包络相位（CEP）稳定的少周期激光脉冲的细丝化来产生空气等离子体，从而产生波形可控的太赫兹辐射。我们将 CEP 稳定的 10fs 长（~1.7 光学周期）1.8μm 激光脉冲发射到空气中，并发现通过改变细丝长度和驱动激光脉冲的 CEP 可以控制所产生的太赫兹波形。使用光电流模型进行的计算并包括传播效应很好地再现了实验结果，并阐明了细丝中各种相移的起源。
