Photonics
 | Engineering the properties of Quantum-Light-Emitting Diodes by strainWe present the first nanomembrane Quantum-Light-Emitting Diodes (QLEDs) integrated onto piezoelectric actuators. We demonstrate that the large strain fields provided by the piezoelectric actuators can be used to engineer the whole emission properties of the quantum emitters (semiconductor quantum dots) without degrading the electrical injection operation of standard QLEDs. The hybrid device presented here has the potential to form the basis of scalable electrically-driven sources for quantum communication. R. Trotta et al., Advanced Materials (2012) DOI: 10.1002/adma.201200537 |
Slowing down single photons from quantum dotsNowadays, the vast majority of information is transferred by light in optical fibers. The single elementary particle of light is called a photon. The advantage of single photons is that they can carry and transfer quantum information over very long distances, enabling 100% secure communication, impossible to crack. We have successfully designed a new type of semiconductor material (quantum dots), which emit photons at a frequency that can be combined with rubidium atoms. By guiding the emitted light through the atoms the speed of the photons is reduced to less than 4% of the speed of light in vacuum. The breakthrough can enable the realization of quantum memories - an essential component in quantum information technology. Merging semiconductor and atomic physics in a hybrid interface opens the way to a series of novel experiments and research directions. For instance, quantum memories and quantum repeaters for quantum dot generated photons can now be fabricated. This work was carried out in close collaboration with the Kavli Institute of Nanoscience at Delft University of Technology in the Netherlands.N. Akopian et al., Nature Photonics 5, 230 (2011) URL PDF This work was highlighted in: Nature Photonics, 5, 197 (2011) (March 31, 2011) URL PDF pro-physik.de (March 28, 2011) URL | |
 | Spectral tunability of microtube resonators on glassThe tunability of optical resonant modes of spiral microtube cavities, rolled-up from square patterned SiO/SiO2 thin nanomembranes on glass substrates, is demonstrated experimentally by coating the tube walls by atomic layer deposition. Transverse-electric modes are observed for Al2O3 coatings thicker than approximately 20 nm, as revealed by linear polarization analysis of the emitted light. Such fine tunability, which is essential for realizing optical microdevices, brings a better understanding of the resonant modes in microtubular cavities, suggesting that the microtubes could be used in potential applications for on-chip components like filters and sensors.V. A. Bolaños Quiñones et al., Optics Letters 34, 2345 (2009) URL PDF |
 | Shaped tubular optical microcavitiesWe have fabricated tubular optical microcavities by releasing pre-defined stressed SiO/SiO2 bilayer nanomembranes from polymer sacrificial layers. Optical measurements at room temperature demonstrate that the resonant optical modes can be accurately tuned along the tube axes. The resonant modes shift to higher energies with decreasing number of tube wall rotations and thickness, which is well-described by simulations. Rolled-up tubular optical microcavities can be produced in large periodic arrays on arbitrary substrates and are therefore highly attractive for on-chip integration technologies.G. S. Huang et al., Applied Physics Letters 94, 141901 (2009) URL PDF |
Si/SiO microtube optical ring resonatorsRolled-up Si/SiO tubes show optically resonant emission in the visible spectral range at room temperature. The mode spacings are inversely proportional to the tube diameter, and the resonant modes recorded are strictly polarized along the tube axis. The Si/SiO microtube optical ring resonators can easily be integrated on a single chip and represent a major step towards Si-based optical signal processing.R. Songmuang et al., Applied Physics Letters 90, 091905 (2007) URL PDF | |