CEP stabilized high power ultrashort pulse laser system

脉冲宽度在100ps范围内的超短脉冲激光器现已在许多研究实验室建立，并已成为不可或缺的工具。然而，只有极短的脉冲宽度小于10fs，才能对原子或分子过程进行时间分辨分析，如化学反应或热化过程，或以选择性的方式影响它们。这为研究和控制超短光脉冲与纳米结构、分子甚至单个原子的相互作用提供了无数的可能性。然而，对于这些所谓的少周期脉冲，仅基于包络对脉冲的描述不再足够。相反，电场和绝对相位(所谓的载波包络相位-CEP)是光-物质相互作用的关键。为此，位于耶拿的阿贝光子学中心将安装一个载波包络相位(CEP)稳定的超短脉冲激光系统，提供高脉冲能量和高平均功率，以及时间和光谱脉冲整形的可能性。该系统将使几个研究小组能够进行不同的调查和应用。主要研究内容如下：1.研究CEP、光谱和时间脉冲特性对大面积共振纳米结构的光致隧穿效应、超快开关和非线性光学效应(如高效频率转换)的影响。这就要求在近红外(约800 nm)中产生脉冲长度小于10fS的相位稳定光脉冲。重复频率必须从单次发射调整到至少50 kHz，以区分慢热效应和快电子效应。CEP稳定、时间和光谱形状的脉冲应用于控制气体和光催化系统中的化学反应。在激光系统中，产生一个额外的探测脉冲，允许用CARS光谱(CARS相干反斯托克斯拉曼散射)对反应产物进行时间和空间分辨的定量分析。检测所有可能的中间体需要泵浦脉冲的光谱宽度大于4200厘米-1。时间同步探测脉冲的波长明显更短(515 Nm)，其光谱宽度小于10 cm-1，这定义了测量的光谱分辨率。在二维材料中，应通过泵浦-探测实验对自由载流子的时空动力学进行基础性研究。这些系统的典型热化时间在所应用系统的脉冲持续时间范围内(约10fS)。通过改变CEP，我们将研究结构的几何对称性与脉冲的时间对称性之间的关联。

Ultra-short pulse lasers with pulse durations in the range of 100 fs are now established in many research laboratories and have become indispensable tools. However, only extremely short pulse durations of less than 10 fs allow the time-resolved analysis of atomic or molecular processes such as chemical reactions or thermalization processes or to influence them in a selective manner.This opens up numerous possibilities to study and control the interaction of ultrashort light pulses with nanostructures, molecules and even individual atoms. However, for these so-called few cycle pulses, a description of the pulses based only on the envelope is no longer sufficient. Instead, the electric field and the absolute phase (so-called carrier envelope phase - CEP) are crucial for the light-matter interaction.For this reason, a carrier envelope phase (CEP)-stabilized ultrashort pulse laser system will be installed at the Abbe Center of Photonics in Jena, providing both high pulse energies and high average powers as well as the possibility of temporal and spectral pulse shaping. The system will enable several research groups to perform different investigations and applications. In particular, the following topics will be addressed:1. Investigations on the influence of CEP and spectral as well as temporal pulse properties on photoinduced tunneling effects, ultrafast switching and nonlinear optical effects (such as efficient frequency conversion) in large area resonant nanostructures. This requires phase-stabilized light pulses in the NIR (about 800 nm) with a pulse length smaller than 10 fs. The repetition rate must be adjustable from single shot to at least 50 kHz to distinguish between slow thermal and fast electronic effects.2. The CEP stabilized, temporally and spectrally shaped pulses shall be used to control chemical reactions in gases and photocatalytic systems. In the laser system an additional probe pulse is generated that allows the temporally and spatially resolved quantitative analysis of reaction products by CARS-spectroscopy (CARS – coherent Anti-Stokes Raman Scattering). The detection of all possible intermediates requires a spectral width of the pump pulse greater than 4200 cm-1. The temporally synchronized probe pulse at a significant shorter wavelength (515 nm) has a spectral width smaller than 10 cm-1, which defines the spectral resolution of the measurement.3. In 2D-materials fundamental research on spatio-temporal dynamics of free charge carriers by means of pump-probe experiments shall be performed. Typical thermalization times of these systems are in the range of the pulse duration of the applied system (ca. 10fs). By varying the CEP, the correlation of the geometric symmetry of the structures with the temporal symmetry of the pulse will be investigated.