Optomechanische Hohlraumresonator-Quantenelektrodynamik mit Farbzentren in Diamant

• Antragstellerin: Professorin Dr. Giovanna Morigi, seit 1/2015
• Fachliche Zuordnung: Theoretische Physik der kondensierten Materie ; Optik, Quantenoptik und Physik der Atome, Moleküle und Plasmen
• Förderung: Förderung von 2013 bis 2017
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 236935559

• Erstellungsjahr: 2018

Zusammenfassung der Projektergebnisse

Color centers in diamond mono-crystals are single defects, which can scatter photons in the visible spectrum. These quantum emitters can be confined within a photonic crystal’s cavity, where strong coupling between NV center and light can be realized at the single photon level. The mechanical excitation of these nano-structures alters the optical properties of the cavity. In turn, the mechanical effects of light can exert radiation forces on the shaped diamond crystal. Within this research project we developed a consistent theoretical model for the description of the quantum dynamics of this hybrid quantum system, which systematically includes the effects of noise and dissipation due to coupling with external sources. Our model allows one to predict the full coupled dynamics of NV center, mechanical resonator, and optical field. By these means we can determine the spectrum of resonance fluorescence of the system and in particular calculate and identify the effects due to the strong coupling with localized vibrational modes of the bulk. Using this theoretical framework we analyzed the dynamics of the mechanical resonator emerging from the interplay between noise and the coherent coupling of the NV center with a high-Q mode of an optical cavity. Our focus was to develop protocols for radiative cooling the mechanical resonator down to ultralow temperatures. This research provided the theoretical characterization of the parameter regime where radiative cooling of the mechanical resonator is efficient. Moreover, it lead to two unexpected results. In first place, the addition of an optical cavity in general does not improve the cooling efficiency for the setup we considered. A further unexpected result is that noise, and in particular pure dephasing of the NV center’s electronic transitions, can lead to an improvement of the cooling efficiency by making the performance more robust against parameter fluctuations. The theoretical models and tools we developed allow one to predict the full dynamics, including the coherence properties of the light emitted by this system, which can be experimentally measured. They further provide a solid basis for developing the theoretical description of the collective properties of ensembles of NV centers which both couple to the bulk and to the optical resonators, where lasing and synchronization are expected.

Projektbezogene Publikationen (Auswahl)

• Quantum optical master equation for solid-state quantum emitters, Phys. Rev A 90, 063818 (2014)
  Ralf Betzholz, Juan Mauricio Torres, and Marc Bienert
  
• Optomechanical laser cooling with mechanical modulations, Phys. Rev. A 91, 023818 (2015)
  Marc Bienert and Pablo Barberis-Blostein
  
• Suppression of Rabi oscillations in hybrid optomechanical systems, Phys. Rev. A 92, 043822 (2015)
  Timo Holz, Ralf Betzholz and Marc Bienert
  
• Laser and cavity cooling of a mechanical resonator with a Nitrogen-Vacancy center in diamond, Phys. Rev. A 94, 053835 (2016)
  Luigi Giannelli, Ralf Betzholz Laura Kreiner, Marc Bienert, and Giovanna Morigi
  
• Resonance fluorescence of a laser-cooled atom in a non-harmonic potential, Eur. Phys. J. D 20, 215 (2016)
  Ralf Betzholz and Marc Bienert