Nonlinear spectrometer for collinear four-wave mixing

我们申请了具有光栅扫描功能的共线非线性光谱仪和相应的宽带相干激光源，其使得可以在570 nm和930 nm之间的全波长范围内产生超短激光脉冲。非线性谱仪将用于进行高空间分辨率的共线四波混频，主要用于二维傅里叶变换光谱，这使得可以快速有效地记录光谱、非均匀线宽、均匀线宽以及状态之间的耦合和相干。作为一种现代光谱工具，非线性光谱仪将为回答基础前沿研究问题做出重大贡献，同时也将提供一种有效表征材料和样品的手段。相关的研究问题包括：（a）氧化亚铜中里德伯激子之间的耦合以及里德伯激子沿不同主量子数沿着态的级联弛豫。(b)在钝化的镧系氧化物薄膜中超灵敏跃迁的起源和确切行为，其已经显示出非常强的变化，以响应其周围环境的微小变化，因此是量子传感应用的理想候选者。(c)名义上暗激子态对极化激元凝聚的影响。由于对称性的破坏，到这种状态的光学跃迁可能变得非常弱。对称性破缺的大小与周围环境的状态之间的相互作用，以及亮态和暗态之间的耦合和相互作用，很难使用传统的光谱技术来解决。(d)钙钛矿中亮激子能级退相速率的研究和优化。在某些材料类别中，已知在钙钛矿结构的空间延伸、激子能级的结构和退相速率之间存在复杂的相互作用。环境对这种复杂相互作用的影响是钙钛矿应用的一个高度相关的问题。(e)胶体纳米片中非马尔可夫声子相互作用的影响问题。(f)二维傅里叶变换光谱在化学问题弗拉姆中的应用。获得激子态的均匀线宽和状态之间的耦合和相干性的可能性在短的集成时间和高空间分辨率将带来新的光谱专业知识，以TU多特蒙德大学，这将增加可以彻底解决的科学问题的范围。

We apply for a collinear nonlinear spectrometer with raster scanning functionality and a corresponding broadband coherent laser source that renders it possible to create ultrashort laser pulses in the full wavelength range between 570 nm and 930 nm. The nonlinear spectrometer will be applied to perform collinear four-wave mixing with high spatial resolution and mainly for two-dimensional Fourier transform spectroscopy whichrenders it possible to record the spectrum, inhomogeneous linewidths, homogeneous linewidths and couplings and coherences between states in a quick and efficient manner. As a modern spectroscopy tool, the nonlinear spectrometer will provide a significant contribution towards answering fundamental cutting-edge research questions, but will also provide a means to characterize materials and samples efficiently. Relevant research questions include (a) the coupling between Rydberg excitons in bulk Cuprous Oxide and the cascaded relaxation of Rydberg excitons along states with different principal quantum number. (b) the origin and the exact behavior of hypersensitive transitions in passivated Lanthanide Oxide thin films which show very strong shifts already in response to tiny changes of their surroundings and are therefore ideal candidates for quantum sensing applications. (c) the influence of nominally dark exciton states on polariton condensates. Due to broken symmetries optical transitions to such states may become very weakly allowed. The interplay between the magnitude of symmetry breaking and the state of the surrounding and also the couplings and interactions between bright and dark states are hard to address using conventional spectroscopic techniques. (d) the investigation and optimization of dephasing rates of bright exciton levels in perovskites. In some material classes, it is already known that there is a complex interplay between the spatial extension of the perovskite structure, the structure of the exciton energy levels and the dephasing rates. The influence of the surrounding on this complex interplay is a highly relevant question for applications of perovskites. (e) the question of the influence of non-Markovian phonon interactions in colloidal nanoplatelets. (f) applications of two-dimensional Fourier transform spectroscopy within the fram of questions in Chemistry. The possibility to obtain the homogeneous linewidths of exciton states and the couplings and coherences between states within short integration times and with high spatial resolution will bring fundamental new spectroscopic expertise to TU Dortmund university, which will increase the range of scientific questions that can be addressed drastically.