Theory for Bose-Einstein condensation of light in nanofabricated semiconductor microcavities

Abstract

We construct a theory for Bose-Einstein condensation of light in nano-fabricated semiconductor microcavities. We model the semiconductor by one conduction and one valence band which consist of electrons and holes that interact via a Coulomb interaction. Moreover, we incorporate screening effects by using a contact interaction with the scattering length for a Yukawa potential and describe in this manner the crossover from exciton gas to electron-hole plasma as we increase the excitation level of the semiconductor. We then show that the dynamics of the light in the microcavities is damped due to the coupling to the semiconductor. Furthermore, we demonstrate that on the electron-hole plasma side of the crossover, which is relevant for the Bose-Einstein condensation of light, this damping can be described by a single dimensionless damping parameter that depends on the external pumping. Hereafter, we propose to probe the superfluidity of light in these nanofabricated semiconductor microcavities by making use of the differences in the response in the normal or superfluid phase to a sudden rotation of the trap. In particular, we determine frequencies and damping of the scissors modes that are excited in this manner. Moreover, we show that a distinct signature of the dynamical Casimir effect can be observed in the density-density correlations of the excited light fluid.

Decondensation in Nonequilibrium Photonic Condensates: When Less Is More

“…The model we have used is applicable to a wide range of systems which need only satisfy a few criteria: an optical environment with a well-defined ground state, a fluorescent gain medium, and re-scattering of light faster than loss resulting in thermalization. We thus expect that multimode condensation and decondensation both inside and outside the lasing regime will be observable in plasmonic lattices coupled to dyes, which have recently shown condensation [31], semiconductors in photonic crystal resonators [32], and also more conventional laser systems. Excitonpolariton condensates (both semi-conductor and organic), however, differ from photon condensates in that the mixed light-matter excitations relax directly through their matter component, whereas in photon and plasmon condensates equilibration occurs via exchanges between weakly-coupled light and molecular excitations.…”

“…The rich interplay between the different modes observed in Fig. 2 also offers great opportunities for the creation of tailored states of light [33], since the mode structure can easily be influenced through the shape of the cavity [34], lattice [31] or crystal structure [32], and the spatial pump profile can be varied. Since fluctuations are most relevant near phase transitions, we expect this rich phase diagram to be a fruitful tool in the search for unusual quantum correlations.…”

Analogue gravitational lensing in optical Bose-Einstein condensates

“…Consequently, in the whole process, the system should be kept in a steady state without small scaled perturbations below healing length scale, which is also consistent with the analogue gravity research requirement [24]. For possible experimental implementations, the BEC of light in a semiconductor microcavity or dye-based setups might be used, in particular due to the fact that the semiconductor microcavity setup can have stronger interactions [44].…”

Bose-Einstein condensation of photons from the thermodynamic limit to small photon numbers

“…Its solu-tions are Bogoliubov modes of sound [55,56] or collective breathing [57] or scissors [58] modes. It can be derived from Maxwell's equations [59], and coincides with the mean of the equations coming from quantum field treatments [46,47].…”

“…For example, planar photonic crystals filled with semiconductors have been proposed for photon thermalization and condensation [58], as have arrays of superconducting qubits [73].…”