Johannes Feist: Scientific Publications


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Multiscale Molecular Dynamics Simulations of Polaritonic Chemistry (PDF)
H. L. Luk, J. Feist, J. J. Toppari, and G. Groenhof
Abstract: ...When photoactive molecules interact strongly with confined light modes as found in plasmonic structures or optical cavities, new hybrid light-matter states can form, the so-called polaritons. These polaritons are coherent superpositions (in the quantum mechanical sense) of excitations of the molecules and of the cavity photon or surface plasmon. Recent experimental and theoretical works suggest that access to these polaritons in cavities could provide a totally new and attractive paradigm for controlling chemical reactions that falls in between traditional chemical catalysis and coherent laser control. However, designing cavity parameters to control chemistry requires a theoretical model with which the effect of the light-matter coupling on the molecular dynamics can be predicted accurately. Here we present a multiscale quantum mechanics/molecular mechanics (QM/ MM) molecular dynamics simulation model for photoactive molecules that are strongly coupled to confined light in optical cavities or surface plasmons. Using this model we have performed simulations with up to 1600 Rhodamine molecules in a cavity. The results of these simulations reveal that the contributions of the molecules to the polariton are time-dependent due to thermal fluctuations that break symmetry. Furthermore, the simulations suggest that in addition to the cavity quality factor, also the Stokes shift and number of molecules control the lifetime of the polariton. Because large numbers of molecules interacting with confined light can now be simulated in atomic detail, we anticipate that our method will lead to a better understanding of the effects of strong coupling on chemical reactivity. Ultimately the method may even be used to systematically design cavities to control photochemistry.
Plasmon-exciton-polariton lasing (PDF)
M. Ramezani, A. Halpin, A. I. Fernández-Domínguez, J. Feist, S. R.-K. Rodriguez, F. J. Garcia-Vidal, and J. Gómez Rivas
Abstract: ...Metallic nanostructures provide a toolkit for the generation of coherent light below the diffraction limit. Plasmonic-based lasing relies on the population inversion of emitters (such as organic fluorophores) along with feedback provided by plasmonic resonances. In this regime, known as weak light–matter coupling, the radiative characteristics of the system can be described by the Purcell effect. Strong light–matter coupling between the molecular excitons and electromagnetic field generated by the plasmonic structures leads to the formation of hybrid quasi-particles known as plasmon-exciton-polaritons (PEPs). Due to the bosonic character of these quasi-particles, exciton-polariton condensation can lead to laser-like emission at much lower threshold powers than in conventional photon lasers. Here, we observe PEP lasing through a dark plasmonic mode in an array of metallic nanoparticles with a low threshold in an optically pumped organic system. Interestingly, the threshold power of the lasing is reduced by increasing the degree of light–matter coupling in spite of the degradation of the quantum efficiency of the active material, highlighting the ultrafast dynamic responsible for the lasing, i.e., stimulated scattering. These results demonstrate a unique room-temperature platform for exploring the physics of exciton-polaritons in an open-cavity architecture and pave the road toward the integration of this on-chip lasing device with the current photonics and active metamaterial planar technologies.



Radiative heat transfer in the extreme near field (PDF)
K. Kim, B. Song, V. Fernández-Hurtado, W. Lee, W. Jeong, L. Cui, D. Thompson, J. Feist, M. T. H. Reid, F. J. García-Vidal, J. C. Cuevas, E. Meyhofer, and P. Reddy
Abstract: ...Radiative transfer of energy at the nanometre length scale is of great importance to a variety of technologies including heat-assisted magnetic recording, near-field thermophotovoltaics and lithography. Although experimental advances have enabled elucidation of near-field radiative heat transfer in gaps as small as 20-30 nanometres, quantitative analysis in the extreme near field (less than 10 nanometres) has been greatly limited by experimental challenges. Moreover, the results of pioneering measurements differed from theoretical predictions by orders of magnitude. Here we use custom-fabricated scanning probes with embedded thermocouples, in conjunction with new microdevices capable of periodic temperature modulation, to measure radiative heat transfer down to gaps as small as two nanometres. For our experiments we deposited suitably chosen metal or dielectric layers on the scanning probes and microdevices, enabling direct study of extreme near-field radiation between silica-silica, silicon nitride-silicon nitride and gold-gold surfaces to reveal marked, gap-size-dependent enhancements of radiative heat transfer. Furthermore, our state-of-the-art calculations of radiative heat transfer, performed within the theoretical framework of fluctuational electrodynamics, are in excellent agreement with our experimental results, providing unambiguous evidence that confirms the validity of this theory for modelling radiative heat transfer in gaps as small as a few nanometres. This work lays the foundations required for the rational design of novel technologies that leverage nanoscale radiative heat transfer.
Enhancement of near-field radiative heat transfer using polar dielectric thin films (PDF)
B. Song, Y. Ganjeh, S. Sadat, D. Thompson, A. Fiorino, V. Fernández-Hurtado, J. Feist, F. J. Garcia-Vidal, J. C. Cuevas, P. Reddy, and E. Meyhofer


What will it take to observe processes in 'real time'? (PDF)
S. R. Leone, C. W. McCurdy, J. Burgdörfer, L. S. Cederbaum, Z. Chang, N. Dudovich, J. Feist, C. H. Greene, M. Ivanov, R. Kienberger, U. Keller, M. F. Kling, Z.-H. Loh, T. Pfeifer, A. N. Pfeiffer, R. Santra, K. Schafer, A. Stolow, U. Thumm, and M. J. J. Vrakking


Autoionization of Molecular Hydrogen: Where do the Fano Lineshapes Go? (PDF)
A. Palacios, J. Feist, A. González-Castrillo, J. L. Sanz-Vicario, and F. Martín


Time shifts in photoemission from a fully correlated two-electron model system (PDF)
S. Nagele, R. Pazourek, J. Feist, and J. Burgdörfer



Differential cross sections for non-sequential double ionization of He by 52 eV photons from the Free Electron Laser in Hamburg, FLASH (PDF)
M. Kurka, J. Feist, D. A. Horner, A. Rudenko, Y. H. Jiang, K. U. Kühnel, L. Foucar, T. N. Rescigno, C. W. McCurdy, R. Pazourek, S. Nagele, M. Schulz, O. Herrwerth, M. Lezius, M. F. Kling, M. Schöffler, A. Belkacem, S. Düsterer, R. Treusch, B. I. Schneider, L. A. Collins, J. Burgdörfer, C. D. Schröter, R. Moshammer, and J. Ullrich





Invited Talks

  1. Modifications of molecular structure and reactions under strong light-matter coupling
  2. Extraordinary exciton transport and modifications of molecular structure under strong light-matter coupling
  3. Modifications of molecular structure and reactions under light-matter coupling
  4. Exciton Transport in Organic Microcavities in the Strong Coupling Regime
  5. Modifications of molecular structure and reactions under strong light-matter coupling
  6. Modifying molecular properties through strong coupling to confined light modes
  7. Modifying molecular properties through strong coupling to confined light modes
  8. Strong coupling of organic molecules and light: Extraordinary exciton transport and modifications of molecular structure
  9. Transport and harvesting of excitons mediated by strong coupling
  10. Transport and harvesting of excitons mediated by strong coupling
  11. Transport and harvesting of excitons mediated by strong coupling
  12. Thermalization and cooling of plasmon-exciton polaritons: towards quantum condensation
  13. Thermalization and cooling of plasmon-exciton polaritons: towards quantum condensation
  14. Thermalization and cooling of plasmon-exciton-polaritons: towards quantum condensation
  15. Correlated electron dynamics on the attosecond scale
  16. Condensation of ultralight particles: towards a quantum degenerate gas of plexcitons
  17. Accessing correlated two-electron dynamics through attosecond pump-probe and attosecond streaking
  18. Accessing correlated electron motion on the attosecond timescale
  19. Accessing correlated electron dynamics on the attosecond timescale
  20. Accessing electron dynamics on the attosecond timescale
  21. Attosecond pump-probe setups for studying doubly excited wave packets in helium
  22. Ab initio calculations of correlated electron dynamics in ultrashort pulses
  23. Ab initio Calculations of Two-electron Emission by Attosecond Pulses
  24. Correlation in double ionization of He by ultrashort pulses


  1. Modifying Chemical Structure through Cavity QED
  2. Fingerprints of Strong Coupling between Molecular Vibrations and Microcavities
  3. Modifying molecular structure through strong light-matter coupling
  4. Transport and harvesting of excitons mediated by strong coupling
  5. Quantum plasmonics: applications of plasmons for quantum optics and quantum information
  6. Signatures of quantum condensation in a diffractive array of plasmonic nanoparticles
  7. Nanoplasmonic light field synthesis for isolated attosecond pulse generation
  8. Plasmonic nanotips for spectroscopy with nanometer-scale resolution
  9. Attosecond two-photon interferometry for probing doubly excited states of helium
  10. Time-resolved photoemission by attosecond streaking: extraction of time information
  11. Probing few-body dynamics in atoms by photons and neutrons
  12. Neutron impact ionization of helium
  13. Probing Electron Correlation using Attosecond Pulses
  14. Streaking of shake-up ionization in helium
  15. Interference between nonsequential and sequential two-photon double ionization in short XUV pulses (talk given by S. Nagele)
  16. Using attosecond pulses to probe electron correlations in two-photon double ionization of He
  17. Attosecond physics in simple atomic systems
  18. Transport through quantum wires with one-sided surface disorder
  19. Nonsequential two-photon double ionization of He
  20. Angular distributions in helium photo double-ionization by ultrashort pulses
  21. Transport through nano-wires with surface disorder

Diploma thesis

Transport through quantum wires with surface disorder