Ultrashort laser pulse propagation in materials with strong-coupling carriers

超短激光脉冲在强耦合载流子材料中的传播

• 批准号: 388268385
• 负责人: Professor Dr. Mirco Imlau
• 金额: --
• 依托单位: Fach Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/388268385?language=en
• 关键词: Ultrashort; laser; pulse; propagation; materials

The propagation of ultrashort, intense femtosecond laser pulses in optical materials is determined by light-matter-interactions. It results in a spatial and temporal development of energy density, phase and polarisation and in technologically relevant effects, such as self-phase modulation and self-focussing.Only recently, it has been shown that additional, non-instantaneous contributions to the nonlinear polarisation appear in materials with strong-coupling carriers, that rely on a carrier-induced lattice deformation. Characteristically, the formation dynamics is found in the sub-500-fs time regime, i.e. typical for modern, commercial ultrashort laser pulse systems. Thereby, an interaction with propagating femtosecond laser pulses becomes possible, that result in self-contained nonlinear optical effects and pulse coupling phenomena.From the viewpoint of solid state physics, the non-instantaneous, nonlinear polarisation relies on the self-trapping of carriers by strong coupling to the crystal lattice as self-trapped excitons or small, strong-coupling polarons and the resulting change of the electronic dipole moment. For the understanding of propagating ultrashort pulses, a comprehensive knowledge on the nonlinear interaction of coupled charge carriers with light is necessary, that is missing in literature, so far. Established, ultrafast measurement techniques rely on fixed pulse durations, that hinder the selective resolution of pulse propagation influence due to quasi-instantaneous and non-instantaneous contributions to the nonlinear polarisation. Multiscale modelling of nonlinear optical effects dependent on the pulse duration are missing; a complete control of pulse propagation in materials with strong-coupling carriers is not possible.The project aims to fill this gap and a systematic experimental and numeric study of pulse propagation and coupling using the pulse duration as central parameter will be performed.By combination of spectroscopic and nonlinear optical methods, a selective assignment of contributions of the non-instantaneous nonlinear polarisation to self-trapped excitons and small, strong-coupling polarons and their separation to the quasi-instantaneous polarization becomes possible. Due to pronounced resonant interactions of ultrashort laser pulses with these quasiparticles, it is necessary to precisely characterize the complex spectral signature over a broad spectral range. We expect that our results, with lithium niobate as a model system, will bring important information about pulse propagation in the applicationary field of ultrafast photonics, such as e.g. for optical parametric amplifiers, but also may trigger novel applications.

超短、强飞秒激光脉冲在光学材料中的传输是由光-物质相互作用决定的。它导致能量密度、相位和偏振的空间和时间发展，以及技术相关的效应，例如自相位调制和自聚焦。直到最近，人们才发现，在具有强耦合载流子的材料中出现了对非线性偏振的额外的、非瞬时的贡献，这种贡献依赖于载流子诱导的晶格变形。典型地，形成动力学被发现在子500-fs的时间制度，即典型的现代商业超短激光脉冲系统。从固体物理学的观点来看，非瞬时的非线性极化依赖于载流子的自陷，载流子通过强耦合到晶格中成为自陷激子或小的强耦合极化子，以及由此产生的电子偶极矩的变化。为了更好地理解超短脉冲的传输特性，需要对耦合载流子与光的非线性相互作用有一个全面的了解，而这在文献中是缺失的。已建立的超快测量技术依赖于固定的脉冲持续时间，由于准瞬时和非瞬时对非线性偏振的贡献，这阻碍了脉冲传播影响的选择性分辨率。缺少依赖于脉冲持续时间的非线性光学效应的多尺度模拟;由于强耦合载流子的存在，脉冲在材料中的传输无法完全控制，本项目旨在填补这一空白，以脉冲宽度为中心参数，对脉冲的传输和耦合进行系统的实验和数值研究，结合光谱和非线性光学方法，将非瞬时非线性极化的贡献选择性地分配给自陷激子和小的强耦合极化子，并且将它们分离到准瞬时极化成为可能。由于超短激光脉冲与这些准粒子的共振相互作用，有必要在很宽的光谱范围内精确地表征复杂的光谱特征。我们期望，我们的结果，与锂离子作为一个模型系统，将带来重要的信息脉冲传播的超快光子学的应用领域，例如光学参量放大器，但也可能引发新的应用。

项目成果

Superposed picosecond luminescence kinetics in lithium niobate revealed by means of broadband fs-fluorescence upconversion spectroscopy

• DOI: 10.1038/s41598-020-68376-6
• 发表时间: 2020-07-09
• 期刊: SCIENTIFIC REPORTS
• 影响因子: 4.6
• 作者: Krampf, A.;Messerschmidt, S.;Imlau, M.
• 通讯作者: Imlau, M.

Excitonic hopping-pinning scenarios in lithium niobate based on atomistic models: different kinds of stretched exponential kinetics in the same system

基于原子模型的铌酸锂激子跳跃钉扎场景：同一系统中的不同种类的拉伸指数动力学

• DOI: 10.1088/1361-648x/ab9c5b
• 发表时间: 2020
• 期刊: Journal of Physics: Condensed Matter
• 作者: Gabor Corradi;Andreas Krampf;Simon Messerschmidt;Laura Vittadello;Mirco Imlau
• 通讯作者: Mirco Imlau

Pulse-induced transient blue absorption related with long-lived excitonic states in iron-doped lithium niobate

脉冲诱导的瞬态蓝色吸收与铁掺杂铌酸锂中的长寿命激子态相关

• DOI: 10.1364/ome.9.002748
• 发表时间: 2019
• 期刊: Optical Materials Express
• 影响因子: 2.8
• 作者: Simon Messerschmidt;Björn Bourdon;David Brinkmann;Andreas Krampf;Laura Vittadello;Mirco Imlau
• 通讯作者: Mirco Imlau

The role of self-trapped excitons in polaronic recombination processes in lithium niobate

自俘获激子在铌酸锂极化复合过程中的作用

• DOI: 10.1088/1361-648x/aaf4df
• 发表时间: 2019
• 期刊: Journal of Physics: Condensed Matter
• 作者: Simon Messerschmidt;Andreas Krampf;Felix Freytag;Mirco Imlau;Laura Vittadello;Marco Bazzan ;Gabor Corradi
• 通讯作者: Gabor Corradi