A three-dimensional model of GaAs/A1GaAs quantum double rings in the lateral static electric field is investigated theoretically. The eigenvalue problem with the effective-mass approximation is solved by means of the ...A three-dimensional model of GaAs/A1GaAs quantum double rings in the lateral static electric field is investigated theoretically. The eigenvalue problem with the effective-mass approximation is solved by means of the finite-element method. The energy levels and wave functions of quantum-confined electrons and heavy holes are obtained and show an agreement with our previous theoretical and experimental studies. It is shown in the approximation of neglecting the Coulomb attraction between the electron and heavy hole that a relatively large Stark shift of exciton emission of 4 meV is attainable with an applied electric field of 0.7 kV/cm.展开更多
We demonstrate third harmonic generation in plasmonic antennas consisting of highly doped germanium grown on silicon substrates and designed to be resonant in the mid-infrared frequency range that is inaccessible with...We demonstrate third harmonic generation in plasmonic antennas consisting of highly doped germanium grown on silicon substrates and designed to be resonant in the mid-infrared frequency range that is inaccessible with conventional nonlinear plasmonic materials.Owing to the near-field enhancement,the result is an ultrafast,subdiffraction,coherent light source with a wavelength tunable between 3 and 5μm,and ideally overlapping with the fingerprint region of molecular vibrations.To observe the nonlinearity in this challenging spectral window,a highpower femtosecond laser system equipped with parametric frequency conversion in combination with an all-reflective confocal microscope setup is employed.We demonstrate spatially resolved maps of the linear scattering cross section and the nonlinear emission of single isolated antenna structures.A clear third-order power dependence as well as mid-infrared emission spectra prove the nonlinear nature of the light emission.Simulations support the observed resonance length of the double-rod antenna and demonstrate that the field enhancement inside the antenna material is responsible for the nonlinear frequency mixing.展开更多
基金supported by a Grant-in-Aid for Scientific Research from the Ministry of Education,Science,Sports,and Culture of Japan (No.20340080).
文摘A three-dimensional model of GaAs/A1GaAs quantum double rings in the lateral static electric field is investigated theoretically. The eigenvalue problem with the effective-mass approximation is solved by means of the finite-element method. The energy levels and wave functions of quantum-confined electrons and heavy holes are obtained and show an agreement with our previous theoretical and experimental studies. It is shown in the approximation of neglecting the Coulomb attraction between the electron and heavy hole that a relatively large Stark shift of exciton emission of 4 meV is attainable with an applied electric field of 0.7 kV/cm.
基金support from the European Commission via the Marie Curie Carrier Integration Grant and the Seventh Framework Programme under Grant No.613055the Deutsche Forschungsgemeinschaft through the Emmy Noether programme and the EPSRC under Grant No.EP/N003225/1。
文摘We demonstrate third harmonic generation in plasmonic antennas consisting of highly doped germanium grown on silicon substrates and designed to be resonant in the mid-infrared frequency range that is inaccessible with conventional nonlinear plasmonic materials.Owing to the near-field enhancement,the result is an ultrafast,subdiffraction,coherent light source with a wavelength tunable between 3 and 5μm,and ideally overlapping with the fingerprint region of molecular vibrations.To observe the nonlinearity in this challenging spectral window,a highpower femtosecond laser system equipped with parametric frequency conversion in combination with an all-reflective confocal microscope setup is employed.We demonstrate spatially resolved maps of the linear scattering cross section and the nonlinear emission of single isolated antenna structures.A clear third-order power dependence as well as mid-infrared emission spectra prove the nonlinear nature of the light emission.Simulations support the observed resonance length of the double-rod antenna and demonstrate that the field enhancement inside the antenna material is responsible for the nonlinear frequency mixing.
