For a superconducting qubit driven to perform Rabi oscillations and coupled to a slow electromagnetic or nanomechanical oscillator we describe previously unexplored quantum optics effects. When the Rabi frequency is tuned to resonance with the oscillator, the latter can be driven far from equilibrium. Blue detuned driving leads to a population inversion in the qubit and a bistability with lasing behavior of the oscillator; for red detuning the qubit cools the oscillator. This behavior persists at the symmetry point where the qubit-oscillator coupling is quadratic and decoherence effects are minimized. There the system realizes a "single-atom-two-photon laser."

Superconducting qubits coupled to electric or nanomechanical resonators display effects previously studied in quantum electrodynamics (QED) and extensions thereof. Here we study a driven qubit coupled to a low-frequency tank circuit with particular emphasis on the role of dissipation. When the qubit is driven to perform Rabi oscillations, with Rabi frequency in resonance with the oscillator, the latter can be driven far from equilibrium. Blue detuned driving leads to a population inversion in the qubit and lasing behavior of the oscillator ("single-atom laser"). For red detuning the qubit cools the oscillator. This behavior persists at the symmetry point where the qubit-oscillator coupling is quadratic and decoherence effects are minimized. Here the system realizes a "single-atom-twophoton laser". Φ Φ x (t) ac J J J M M C L U

We describe a cost-efficient and large area scalable production process of organic light-emitting diodes (OLEDs) with photonic crystals (PCs) as extraction elements for guided modes. Using laser interference lithography and physical plasma etching, we texture the indium tin oxide (ITO) electrode layer of an OLED with one- and two-dimensional PC gratings. By optical transmission measurements, the resonant mode of the grating is shown to have a drift of only 0.4% over the 5mm length of the ITO grating. By changing the lattice constant between 300 and 600nm, the OLED emission angle of enhanced light outcoupling is tailored from −24.25° to 37°. At these angles, the TE emission is enhanced up to a factor of 2.14.

We fabricated organic light-emitting diodes with one-dimensional Bragg gratings as light extraction elements for substrate and waveguide modes. A Ta2O5 layer was introduced to obtain a high refractive index contrast to the subsequent anode layer. As anode we employed a highly conductive polymer. Laser interference lithography and physical plasma etching were used to pattern gratings into the Ta2O5 layer with a lattice constant of 370 nm and various grating depths. Mainly attributed to the outcoupling of the substrate modes, the structured devices exhibit a luminous flux which is up to four times higher compared to the unstructured reference devices.

Bragg gratings incorporated into organic light-emitting diodes (OLEDs) establish a coupling between waveguide modes and useful light (leaky modes). Here we demonstrate that the net coupling direction depends on the OLED stack design. We fabricated two different device structures with gold Bragg gratings. Angle resolved electroluminescence spectra were recorded. For the first device peaks of enhanced emission due to the Bragg grating are observed corresponding to a net energy transfer in direction of the leaky modes. The second device, on the other hand, exhibits dips in the emission spectrum. This reversed direction of energy transfer from the leaky modes to the waveguide modes is explained considering transfer matrix simulations of modal intensity distributions and device emission simulations. An OLED efficiency enhancement is only achieved, if the waveguide mode extraction is dominant.