Setup for coherent multidimensional electronic spectroscopy

我们希望建立一个可在可见光谱范围内调谐的相干多维光谱仪，以研究异质结构中纳米尺度系统的电子结构和动力学，如量子点、纳米管、2D材料、J-聚集体或它们的组合。为了实现这种设置，目标是产生10飞秒、可在450-750 nm范围内调谐的光谱宽(&gt；100 nm)脉冲的锁相序列。在二维电子光谱(2DES)实验中，样品的非线性光学响应被表示为二维谱，其中的电子耦合直接表现为交叉峰，并且可以区分对谱线形状的均匀和非均匀贡献。2DES的这些独特功能将被用来提供有关纳米材料中电子激发、声子和自旋之间微观耦合的定量信息。这些耦合产生了一系列准粒子，如激子、多激子、极化子和极化子。我们希望揭示准粒子结合能(如双激子、极化子结合能)、均匀线宽、退相时间和寿命等量。这些量在设备功能的起源处提供基本物理信息，与应用程序直接相关。建立这样的设置需要以下关键部件：(I)可在可见范围内调谐的具有几个微焦耳能量的宽带(100 Nm)脉冲，(Ii)用于表征脉冲并将其引导到样品的组件，(Iii)用于产生可控锁相脉冲序列的组件，以及(Iv)用于低噪声信号检测的组件。(I)的实现需要一个放大的钛：萨普夫激光系统(脉冲能量~5mJ，脉冲宽度100fs，重复频率1 kHz，中心波长800 nm)，一个可见光参量放大器(OPA，波长范围475-750 nm)，以及一个空芯光纤装置来对OPA脉冲进行光谱展宽。为了实现(II)，人们需要自制的瞬变光栅频率分辨光学门(TG-FROG)装置、功率计、便携式光谱仪、小型相机和各种光学元件。项目(Iii)可以实现，这要归功于可编程的商业脉冲整形技术。最后，第(4)项需要一台摄谱仪和能够在1千赫频率下连续采集的低噪声电荷耦合器件/cmos传感器。所请求的测量站将构成AG Seiler的启动基础设施。不仅必须在申请人的终身任期内确立其独立的科学生涯，而且对于执行所要求的和计划的第三方资助的项目，如CRCs，也是至关重要的。由于负责发言人在她的博士工作期间在构建类似的多维光谱仪器方面拥有丰富的经验，我们希望以一种高效的方式构建该设置。

We wish to build a coherent multidimensional spectrometer tunable over the visible spectral range to investigate the electronic structure and dynamics of nanoscale systems, such as quantum dots, nanotubes, 2D materials, J-aggregates or combination thereof in heterostructures. To realize such a setup, the aim is to produce phase-locked sequences of 10 femtosecond, spectrally broad (> 100 nm) pulses tunable in the 450-750 nm range. In a two-dimensional electronic spectroscopy (2DES) experiment, the sample’s nonlinear optical response is represented as a 2D spectrum, where electronic couplings directly show as cross-peaks and the homogeneous and inhomogeneous contributions to spectroscopic lineshapes can be separated. These unique features of 2DES will be exploited to provide quantitative information about the microscopic couplings between electronic excitations, phonons and spins in nanomaterials. These couplings give rise to a range of quasiparticles such as excitons, multi-excitons, polarons, and polaritons. We wish to reveal quantities like quasiparticle binding energies (e.g. biexciton, polaron binding energies), homogeneous linewidths, dephasing times and lifetimes. These quantities inform on the basic physics at the origin of functionality in devices, of direct relevance for applications. The following key items are needed to build such a setup: (i) broadband (> 100 nm) pulses tunable over the visible range with several microjoules energy (ii) components for the characterisation and guiding of pulses to the sample, (iii) components to generate controllable phase-locked sequences of pulses, and (iv) components for low-noise detection of the signals. The implementation of (i) requires an amplified Ti:Sapph laser system (pulse energy ~5 mJ, pulse duration 100 fs, repetition rate 1 kHz, central wavelength 800 nm), a visible optical parametric amplifier (OPA, wavelength range 475-750 nm), and a hollow-core fiber setup to spectrally broaden the OPA pulses. For the realization of (ii), one needs a home-built transient-grating frequency resolved optical gating (TG-FROG) setup, powermeters, a portable spectrometer, a small camera, and various optical components. Item (iii) can be realized thanks to programmable commercial pulse shaping technology. Finally, item (iv) requires a spectrograph and low-noise CCD/CMOS sensor capable of continuous acquisition at 1 kHz. The requested measuring station would form the starting infrastructure for the AG Seiler. Not only would it be essential to establish the independent scientific career of the applicant during her tenure-track period, but it would also be essential for the implementation of requested and planned third-party funded projects, such as CRCs. Since the responsible spokesperson has extensive experience with building a similar multidimensional spectroscopy instrument during her PhD work, we expect the setup to be built in an efficient manner.