Project Details
Projekt
Titanium-sapphire femtosecond laser amplifier system
Subject Area
Condensed Matter Physics
Term
Funded in 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 460729500
The laser amplifier system requested by the group of Prof. Lange provides ultrashort optical pulses with a duration of 35 fs, a pulse energy of 4.5 mJ, a center wavelength of 800 nm, and a repetition rate of 3 kHz. Using the laser’s fundamental, strong terahertz (THz) pulses consisting only of a single oscillation cycle, and with peak fields exceeding 1 MV/cm will be generated by tilted pulse-front optical rectification. Moreover, strong, phase-locked mid-infrared pulses with peak fields of up to 100 MV/cm and tuneable center frequencies ranging from 15 to 100 THz will be generated using the requested dual optical parametric amplifier. Time domain spectroscopy tracing the amplitude and phase of THz pulses simultaneously will enable linear characterization as well as strong-field measurements including amplitude-resolved, two-dimensional spectroscopy. In addition, a custom-cut magnet cryostat system, requested in a separate proposal, will enable spectroscopy at magnetic fields and cryogenic temperatures.Our group investigates extreme limits of light-matter interaction in which optical nonlinearities occur on time scales significantly shorter than a single cycle of light. Recent achievements include the observation of dynamical Bloch oscillations and high-harmonics generation, lightwave acceleration of Dirac electrons in topological insulators, minimally dissipative switching of spins by strong, antenna-enhanced THz near fields, non-perturbative nonlinearities beyond Kohn’s theorem, and non-adiabatic switching of deep-strongly light-matter coupled electrons in specialized THz resonators.The requested laser system will allow us to continue this research and explore novel directions of THz subcycle physics in condensed matter systems. Recent experiments in cavity quantum electrodynamics (cQED) have utilized the vacuum modes of optical resonators to control electronic transport, chemical reactions, or superconductivity. While these studies have focused on strong or ultrastrong light-matter coupling in equilibrium, we will investigate high-field dynamics in general, and in particular for previously inaccessible coupling strengths, where the vacuum Rabi frequency exceeds the oscillation period of light. To this end, we will further boost the coupling strength of our established cavity-coupled Landau electrons, investigate nonlinearities of deep-strongly coupled semiconductor intersubband transitions, and explore novel concepts for cQED including superconducting resonators or atomically thin electronic systems such as transition metal dichalcogenides. As we systematically explore the transition from linear to nonlinear to non-perturbative dynamics, we expect a wealth of novel phenomena including high-order nonlinearities, generation of non-classical light, novel resonances generated by nonlinear interactions, and phase transitions to unfold. Subcycle resolution will play a key role in unravelling the relevant quantum dynamics.
DFG Programme
Major Research Instrumentation
Major Instrumentation
Titan-Saphir-basiertes Femtosekundenlaserverstärkersystem
Instrumentation Group
5700 Festkörper-Laser
Applicant Institution
Technische Universität Dortmund
