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Phase-modulated nonlinear coherent spectroscopy (PHANCY)

Phase-modulated nonlinear coherent spectroscopy (PHANCY)

PHANCY

The goal of this project is to study isolated nanosystems with coherent two-dimensional (2D) spectroscopy in order to gain a better understanding of microscopic processes taking place on the atomic and molecular level. From a bottom-up approach, we study energy and charge transfer reactions in molecular systems, ranging from isolated molecules, to molecular aggregates and larger molecular networks. These processes are of general importance as they form the building blocks in photosynthesis, photovoltaics and photocatalysis.
2D spectroscopy (Fig 1a) is a unique experimental technique which provides both, high time and frequency resolution. As no other technique, it is capable of directly revealing couplings and energy transfer mechanisms in 2D frequency-correlation maps (Fig. 1b), which makes it the ideal method to investigate molecular dynamics on ultrafast (femtosecond) time scales.
While 2D spectroscopy has been mainly applied to condensed phase systems, we are the first group who uses this method to study well-controlled nanosystems prepared in molecular and cluster beam experiments in the gas phase [1,2]. We investigate the ultrafast photodynamics of organic chromophore ensembles expanded in seeded supersonic beams, embedded in superfluid helium nanodroplets or attached to solid rare gas clusters. The influence of environmental perturbations on the molecular dynamics is controlled in a systematic manner by co-doping with additional solvent molecules. This approach strongly reduces the complexity of the spectroscopic probes while providing high flexibility for the synthesis of individual molecular model systems. The unique combination of the well-controlled systems with 2D spectroscopy and selective detection schemes, available in the gas phase, enables us to deduce a precise and comprehensive picture of the ultrafast photodynamics taking place in the probed systems.

This work is part of the ERC advanced grant "Coherent multidimensional spectroscopy of controlled isolated systems (COCONIS)".

2D-spectroscopy

Figure. 1: a) Experimental scheme to record two-dimensional frequency-correlations maps of a doped cluster/droplet beam. b) Comparison of 2 D and 1D spectrum. Off-diagonal features, clearly separated in 2D spectra, are difficult to identify in 1D spectra. These off-diagonal signals provide information about couplings and energy relaxation pathways.

 

Relevant publications:

[8] Bruder L, Bangert U, Binz M, Uhl D, Stienkemeier F:
Coherent multidimensional spectroscopy in the gas phase
J Phys B-at Mol Opt, 2019; 52: 183501-(19pp).: abstract - pdf - arXiv

[7] Bruder L, Eisfeld A, Bangert U, Binz M, Jakob M, Uhl D, Schulz-Weiling M, Grant E R, Stienkemeier F:
Delocalized excitons and interaction effects in extremely dilute thermal ensembles
Physical Chemistry Chemical Physics, 2019; 21 (5): 2276- 2282.: abstract - pdf

[6] Bruder L, Bangert U, Binz M, Uhl D, Vexiau R, Bouloufa-Maafa N, Dulieu O, Stienkemeier F:
Coherent multidimensional spectroscopy of dilute gas-phase nanosystems
Nat Commun, 2018; 9: 4823-(7pp): abstract - pdf - arXiv

[5] Bruder L, Binz M, Stienkemeier F:
Phase-synchronous undersampling in nonlinear spectroscopy
Opt Lett, 2018; 43 (4): 875-878.: abstract - pdf - arXiv

[4] Li Z Z, Bruder L, Stienkemeier F, Eisfeld A:
Probing weak dipole-dipole interaction using phase-modulated nonlinear spectroscopy
Phys Rev A, 2017; 95 (5): 052509-1-052509-12.: abstract - pdf - arXiv

[3] Bruder L, Bangert U, Stienkemeier F:
Phase-modulated harmonic light spectroscopy
Opt Express, 2017; 25 (5): 5302-5315.: abstract - pdf

[2] Bruder L, Binz M, Stienkemeier F:
Efficient isolation of multiphoton processes and detection of collective resonances in dilute samples
Phys Rev A, 2015; 92 (5): 053412-1-053412-6.: abstract - pdf - arXiv

[1] Bruder L, Mudrich M, Stienkemeier F:
Phase-modulated electronic wave packet interferometry reveals high resolution spectra of free Rb atoms and Rb*He molecules
Phys Chem Chem Phys, 2015 (37); 17: 23877-23885.: abstract - pdf - arXiv

 

Contact:

Dr. Lukas Bruder, lukas.bruder[at]physik.uni-freiburg.de

 

Funding:

Deutsche Forschungsgemeinschaft

International Research Training Group (IRTG 2079) "Cold Controlled Ensembles in Physics and Chemistry"

European Research Council

 

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