Femtosecond laser with frequency conversion, pulse shaping, and detection at 100 kHz repetition rate

我们要求一种重复频率为100 kHz的新飞秒激光器，这将使我们能够开发和应用各种快速扫描瞬态吸收，二维（2D）光谱和2D显微镜技术，快速数据采集，提高速度高达100倍，并允许新的测量模式。特别是，我们计划在100 kHz重复率下实现瞬态吸收、三阶和五阶激子-激子相互作用二维光谱、二维光谱电化学、多维多量子荧光光谱、二维荧光显微镜、超快单分子光谱和量子控制景观分析的拍摄到拍摄调制和检测。我们建议整个系统的所有组件的重复率为100 kHz，即，激光器、通过非共线光学参量放大的频率转换、飞秒脉冲整形器、单像素荧光检测器、用于探测脉冲的瞬态吸收检测的光谱仪和照相机系统以及数据采集系统。通过100 kHz的脉冲整形和相关的测量时间加速来使用快速扫描方法，将有助于研究动力学不稳定的化学物质，提高信噪比的额外平均值，扫描3D、4D和5D光谱的额外参数，访问更高阶（第四至第十）的响应函数，具有300纳米空间分辨率的异质材料系统的显微光谱学，以及其他测量概念。据估计，高达十亿个不同的非线性信号（即，脉冲序列时延和相位组合）可以在三小时的数据采集中获得。目前正在通过人工智能方法（神经网络和遗传算法的结合）对大量数据进行评估。要解决的科学课题包括功能有机材料中激子输运的分辨率，激子湮灭，激子在1D，2D和3D材料中扩散的系统比较，双自由基中的动力学过程和电荷转移，2D材料中的激子-声子耦合，以及光子混合结构中强耦合的研究。目前，该集团没有具备所需技术参数的激光系统。拟议的设备将成为维尔茨堡大学“纳米系统化学中心”（CNC）新实验室的核心。用于超快、空间分辨2D实验的专用显微镜低温恒温器将由单独的基金资助，以降低当前提案的总体成本。

We request a new femtosecond laser at 100 kHz repetition rate that will allow us to develop and apply various rapid-scan transient absorption, two-dimensional (2D) spectroscopy, and 2D microscopy techniques with fast data acquisition, improving speed by a factor of up to 100 and allowing new measurement modalities. In particular, we plan to realize shot-to-shot modulation and detection at 100 kHz repetition rate for transient absorption, third-order and fifth-order exciton–exciton-interaction 2D spectroscopy in pump–probe geometry, 2D spectroelectrochemistry, multidimensional multiquantum fluorescence spectroscopy, 2D fluorescence microscopy, ultrafast single-molecule spectroscopy, and quantum control landscape analysis. We propose the 100 kHz repetition rate for all components of the total system, i.e., the laser, frequency conversion via noncollinear optical parametric amplification, a femtosecond pulse shaper, a single-pixel fluorescence detector, a spectrometer-and-camera system for transient absorption detection of probe pulses, and the data acquisition system. Employing rapid-scan methods through 100-kHz shot-to-shot pulse shaping and the associated speed-up in measurement time will facilitate the investigation of kinetically unstable chemical species, additional averaging for improved signal-to-noise ratio, scanning of additional parameters for 3D, 4D, and 5D spectroscopy, accessing higher orders (fourth to tenth) of the response function, micro-spectroscopy of heterogeneous material systems with 300 nm spatial resolution, and other measurement concepts. It is estimated that up to one billion distinct nonlinear signals (i.e., pulse-train time-delay and phase combinations) can be obtained in three hours of data acquisition. Evaluation of the massive data volume is being developed via artificial intelligence approaches (a combination of neural networks and genetic algorithms). Scientific topics to be addressed include the resolution of exciton transport in functional organic materials, exciton annihilation, systematic comparison of exciton diffusion in 1D, 2D, and 3D materials, dynamic processes and charge transfer in biradicals, exciton–phonon coupling in 2D materials, and the investigation of strong coupling in photonic hybrid structures. Currently, the group has no laser system available with the required technical parameters. The proposed device shall form the core of a new laboratory in the “Center for Nanosystems Chemistry” (CNC) at the University of Würzburg. A dedicated microscopy cryostat for ultrafast, spatially resolved 2D experiments will be financed by separate funds to reduce the overall cost of the current proposal.