Single-shot carrier-envelope-phase measurement in ambient air

使用基于空气的刀刃技术对激光脉冲进行时间表征

Temporal characterization of laser pulses using an air-based knife-edge technique

本研究在环境空气中应用等离子体诱导频率分辨光开关（PI-FROSt）技术，利用电离产生的超快散焦透镜实现超短激光脉冲的高可靠时间与频谱重建，且仅需聚焦反射镜，无需额外光学元件。

Efficient self-compression of ultrashort UV pulses in air-filled hollow-core photonic crystal fiber

We report generation of ultrashort UV pulses by soliton self-compression in kagomé-style hollow-core photonic crystal fiber filled with ambient air. Pump pulses with energy 2.6 uJ and duration 54 fs at 400 nm were compressed temporally by a factor of 5, to a duration of ~11 fs. The experimental results are supported by numerical simulations, showing that both Raman and Kerr effects play a role in the compression dynamics. The convenience of using ambient air, and the absence of glass windows that would distort the compressed pulses, makes the setup highly attractive as the basis of an efficien…

穿透光学系统非线性对空气中飞秒laser灯丝的影响

Effect of nonlinearity in the pass-through optics on femtosecond laser filament in air

首次从实验和数值计算两方面分析了穿透光学对飞秒激光脉冲在大气中传播的影响。高功率飞秒激光脉冲通过固体光学元件传输时，由于克尔效应会产生时空相位调制。这种调制可能对空气中的脉冲传播产生强烈的影响。我们证明了在薄的穿透介质板中获得的相位调制减小了到灯丝起始的距离并增加了等离子体通道长度

环境空气中的等离子体加速在紧密聚焦的超短红外激光束中

Ambient air plasma acceleration in tightly-focused ultrashort infrared laser beams

研究通过PIC模拟探讨了在环境空气中紧密聚焦超短红外激光束中利用相对论性ponderomotive力加速电子的机制，并验证了在2.5μm波长时电子动能可达1.6MeV。

Enhanced broadband Terahertz radiation from two colour laser pulse interaction with thin dielectric solid target in air

We report enhanced broadband Terahertz (THz) generation and detailed characterization from the interaction of femtosecond two colour laser pulses with thin transparent dielectric tape target in ambient air. The proposed source is easy to implement, exhibits excellent scalability with laser energy. Spectral characterization using Fourier transform spectrometer reveals yield enhancement of more than 150 % in the THz region of 0.1 - 10 THz with respect to conventional two-colour laser plasma source in ambient air. Further, the source spectrum extends up to 40 THz with an enhancement of flux > 30 …

Radiation forces and confinement of neutral particles into the pulse envelope. New regime of collision ionization

The aim of this work is to find analytical expressions of the radiation force and potential densities arising from a laser pulse propagating in a dielectric media. In the femtosecond region the force becomes strong enough to confine neutral particles into the pulse envelope and translate them with the group velocity in gases. Additionally, if the trapped particles are with high density, the probability of collision with the free atoms and molecules in air become significant. The collision energies are in the range of 12 - 24 GeV and high enough to ionize the neutral atoms. Thus, a new type of …

Spectral broadening of 2 mJ femtosecond pulses in a compact air-filled convex-concave multi-pass cell

Multi-pass cell (MPC) based temporal pulse compressors have emerged in the last years as a powerful and versatile solution to the intrinsic issue of long pulses from Yb-based high-power ultrafast lasers. However, the spectral broadening of high-energy (typically more than 100 uJ) pulses has only been realized in complex setups, i.e., in large and costly, pressure-controlled vacuum chambers to avoid strong focusing, ionization, and damage on the mirrors. Here, we present spectral broadening of 2 mJ pulses in a simple and compact (60 cm long) multi-pass cell operated in ambient air. Instead of t…

相干产生与控制激光诱导空气等离子体丝中可调谐窄带太赫兹辐射

Coherent generation and control of tunable narrowband THz radiation from laser-induced air-plasma filament

本研究通过时间展宽的双色激光脉冲序列拍频诱导空气等离子体丝，实现了载波包络相位可控且频率可调谐的窄带太赫兹辐射的相干产生与控制，并经数值模拟验证了其可行性。

Simulations of the filamentation and self-channeling of spatially modulated high-power femtosecond laser pulses in air

The propagation of high-power femtosecond laser pulses in air under conditions of superposed spatial phase modulation is considered theoretically. The numerical simulations are carried out on the basis of the reduced form of nonlinear Schrodinger equation (NLSE) for time-averaged electric field envelope. Initial spatial modulations are applied to pulse wavefront profiling by a staggered (TEM33) phase plate which is simulated numerically. The dynamics of laser pulse self-focusing, filamentation, and post-filamentation self-channeling after the phase plates with variable phase jumps is studied. …

太赫兹发射光谱法测定少周期Laser脉冲的载波包络相位

Determination of the Carrier-Envelope Phase of Few-Cycle Laser Pulses with Terahertz-Emission Spectroscopy

几个周期的光脉冲的可用性打开了一个窗口，发生在阿秒时间尺度上的物理现象。为了充分利用这种脉冲，至关重要的是测量和稳定它们的载波包络（CE）相位，即，载波和包络函数之间的相位差。我们介绍了一种新的方法来确定CE阶段的激光下转换到太赫兹（THz）的频率范围内，通过在环境空气中产生等离子体，各向同性介质中的光学整流（下转换）在向前的方向是唯一可能的，如果反转对称性被打破的电气或光学手段。我们表明，几个周期的脉冲直接产生的空间电荷不对称的等离子体。与THz发射相关的不对称性取决于CE相位，这允许通过测量THz脉冲的振幅和极性来确定相位。

少周期Laser脉冲产生的空气丝波形控制太赫兹辐射

Waveform-Controlled Terahertz Radiation from the Air Filament Produced by Few-Cycle Laser Pulses

波控太赫兹辐射在太赫兹传感和量子系统相干控制中具有重要的应用价值。提出了一种利用载波包络相位（CEP）稳定的几个周期激光脉冲在大气中传播时产生的空气等离子体产生波形控制的THz辐射的新方案。我们将CEP稳定的10 fs长（约1.7光周期）的1.8 μm激光脉冲发射到空气中，发现产生的THz波形可以通过改变灯丝长度和驱动激光脉冲的CEP来控制。计算使用光电流模型，包括传播效应以及再现实验结果，并阐明了各种相移的灯丝的起源。

在空气中受限的高强度光传播

Topologically constrained high intensity light propagation in air

本研究通过时空光学涡旋控制高强度激光脉冲在大气中的长距离纤维化，揭示了拓扑约束缺陷动态在非线性波传播中的作用。