Efficient single-photon emission from electrically driven InP quantum dots epitaxially grown on Si(001)

The heteroepitaxy of III-V semiconductors on silicon is a promising approach for making silicon a photonic platform for on-chip optical interconnects and quantum optical applications. Monolithic integration of both material systems is a long-time challenge, since different material properties lead to high defect densities in the epitaxial layers. In recent years, nanostructures however have shown to be suitable for successfully realising light emitters on silicon, taking advantage of their geometry. Facet edges and sidewalls can minimise or eliminate the formation of dislocations, and due to the reduced contact area, nanostructures are little affected by dislocation networks. Here we demonstrate the potential of indium phosphide quantum dots as efficient light emitters on CMOS-compatible silicon substrates, with luminescence characteristics comparable to mature devices realised on III-V substrates. For the first time, electrically driven single-photon emission on silicon is presented, meeting the wavelength range of silicon avalanche photo diodes' highest detection efficiency

Parameter study on phase I of the VUV-FEL at the TESLA test facility

Currently, a SASE-FEL in the VUV, driven by the TESLA test facility accelerator, is under construction at DESY. As a first phase of the project, three of the eight TTF accelerator modules will be installed to deliver an electron beam with a nominal energy of approximately 380 MeV with a peak current of 500 A. With this energy, employing an undulator with the same parameters as for the final design, the resonant wavelength is around 44 nm. For this wavelength, the transverse beam emittance and energy spread conditions can be relaxed as compared to the design wavelength of 6 nm in the final stage. The proposed length of the planar undulator with the integrated FODO lattice is about 15 m.In this paper, we present a detailed study on how the performance around 300 MeV depends on the electron beam and undulator parameters. Also, the status of the project is briefly sketched