@article{EstrechoGaoBrodbecketal.2016,
  author    = {Estrecho, E. and Gao, T. and Brodbeck, S. and Kamp, M. and Schneider, C. and H{\"o}fling, S. and Truscott, A. G. and Ostrovskaya, E. A.},
  title     = {Visualising Berry phase and diabolical points in a quantum exciton-polariton billiard},
  series = {Scientific Reports},
  volume    = {6},
  journal   = {Scientific Reports},
  number    = {37653},
  doi       = {10.1038/srep37653},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167496},
  year      = {2016},
  abstract  = {Diabolical points (spectral degeneracies) can naturally occur in spectra of two-dimensional quantum systems and classical wave resonators due to simple symmetries. Geometric Berry phase is associated with these spectral degeneracies. Here, we demonstrate a diabolical point and the corresponding Berry phase in the spectrum of hybrid light-matter quasiparticles—exciton-polaritons in semiconductor microcavities. It is well known that sufficiently strong optical pumping can drive exciton-polaritons to quantum degeneracy, whereby they form a macroscopically populated quantum coherent state similar to a Bose-Einstein condensate. By pumping a microcavity with a spatially structured light beam, we create a two-dimensional quantum billiard for the exciton-polariton condensate and demonstrate a diabolical point in the spectrum of the billiard eigenstates. The fully reconfigurable geometry of the potential walls controlled by the optical pump enables a striking experimental visualization of the Berry phase associated with the diabolical point. The Berry phase is observed and measured by direct imaging of the macroscopic exciton-polariton probability densities.},
  language  = {en}
}
@article{SuchomelBrodbeckLiewetal.2017,
  author    = {Suchomel, H. and Brodbeck, S. and Liew, T. C. H. and Amthor, M. and Klaas, M. and Klembt, S. and Kamp, M. and H{\"o}fling, S. and Schneider, C.},
  title     = {Prototype of a bistable polariton field-effect transistor switch},
  series = {Scientific Reports},
  volume    = {7},
  journal   = {Scientific Reports},
  number    = {5114},
  doi       = {10.1038/s41598-017-05277-1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158323},
  year      = {2017},
  abstract  = {Microcavity exciton polaritons are promising candidates to build a new generation of highly nonlinear and integrated optoelectronic devices. Such devices range from novel coherent light emitters to reconfigurable potential landscapes for electro-optical polariton-lattice based quantum simulators as well as building blocks of optical logic architectures. Especially for the latter, the strongly interacting nature of the light-matter hybrid particles has been used to facilitate fast and efficient switching of light by light, something which is very hard to achieve with weakly interacting photons. We demonstrate here that polariton transistor switches can be fully integrated in electro-optical schemes by implementing a one-dimensional polariton channel which is operated by an electrical gate rather than by a control laser beam. The operation of the device, which is the polariton equivalent to a field-effect transistor, relies on combining electro-optical potential landscape engineering with local exciton ionization to control the scattering dynamics underneath the gate. We furthermore demonstrate that our device has a region of negative differential resistance and features a completely new way to create bistable behavior.},
  language  = {en}
}
@article{CzerniukBrueggemannTepperetal.2014,
  author    = {Czerniuk, T. and Br{\"u}ggemann, C. and Tepper, J. and Brodbeck, S. and Schneider, C. and Kamp, M. and H{\"o}fling, S. and Glavin, B. A. and Yakovlev, D. R. and Akimov, A. V. and Bayer, M.},
  title     = {Lasing from active optomechanical resonators},
  series = {Nature Communications},
  volume    = {5},
  journal   = {Nature Communications},
  doi       = {10.1038/ncomms5038},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121559},
  pages     = {4038},
  year      = {2014},
  abstract  = {Planar microcavities with distributed Bragg reflectors (DBRs) host, besides confined optical modes, also mechanical resonances due to stop bands in the phonon dispersion relation of the DBRs. These resonances have frequencies in the 10- to 100-GHz range, depending on the resonator's optical wavelength, with quality factors exceeding 1,000. The interaction of photons and phonons in such optomechanical systems can be drastically enhanced, opening a new route towards the manipulation of light. Here we implemented active semiconducting layers into the microcavity to obtain a vertical-cavity surface-emitting laser (VCSEL). Thereby, three resonant excitations--photons, phonons and electrons--can interact strongly with each other providing modulation of the VCSEL laser emission: a picosecond strain pulse injected into the VCSEL excites long-living mechanical resonances therein. As a result, modulation of the lasing intensity at frequencies up to 40 GHz is observed. From these findings, prospective applications of active optomechanical resonators integrated into nanophotonic circuits may emerge.},
  language  = {en}
}