Setup for coherent multidimensional electronic spectroscopy

我们希望建立一个在可见光谱范围内可调的相干多维光谱仪，以研究纳米尺度系统的电子结构和动力学，例如量子点，纳米管，2D材料，J-聚集体或异质结构中的组合。为了实现这样的设置，目标是产生在450-750 nm范围内可调谐的10飞秒、光谱宽（> 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光谱，其中电子耦合直接表现为交叉峰，并且对光谱线型的均匀和非均匀贡献可以被分离。这些独特的功能，2DES将被利用，以提供定量信息的微观之间的电子激发，声子和自旋纳米材料的耦合。这些耦合产生了一系列准粒子，如激子，多激子，极化子和极化激元。我们希望揭示的数量，如准粒子结合能（例如双激子，极化子结合能），均匀线宽，退相时间和寿命。这些量提供了与应用直接相关的设备功能起源的基本物理信息。需要以下关键项目来构建这样的设置：（i）宽带（> 100 nm）脉冲可调在可见光范围内与几个微焦耳的能量（ii）用于表征和引导脉冲到样品的组件，（iii）组件，以产生可控的相位锁定脉冲序列，以及（iv）组件的信号的低噪声检测。（i）的实现需要放大的Ti：Sapph激光系统（脉冲能量~5 mJ，脉冲持续时间100 fs，重复率1 kHz，中心波长800 nm）、可见光参量放大器（OPA，波长范围475-750 nm）和空芯光纤设置以在光谱上加宽OPA脉冲。为了实现（ii），需要一个自制的瞬态光栅频率分辨光学选通（TG-FROG）设置，功率计，便携式光谱仪，一个小相机，和各种光学元件。由于可编程商业脉冲整形技术，可以实现第（iii）项。最后，项目（iv）需要能够以1 kHz连续采集的摄谱仪和低噪声CCD/CMOS传感器。所要求的测量站将构成AG Seiler的启动基础设施。不仅必须在申请人的任期内确立其独立的科学生涯，而且还必须实施申请的和计划的第三方资助的项目，如社区研究中心。由于负责发言人在博士工作期间拥有构建类似多维光谱仪器的丰富经验，我们希望以有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.