Topic
Spontaneous emission
About: Spontaneous emission is a research topic. Over the lifetime, 12855 publications have been published within this topic receiving 323684 citations.
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TL;DR: In this article, the influence of external charges on the radiative recombination rate of an electron−hole pair in a CdSe quantum dot was investigated via atomistic empirical pseudopotential calculations.
Abstract: The influence of external charges on the radiative recombination rate of an electron−hole pair in a CdSe quantum dot is investigated via atomistic empirical pseudopotential calculations. It is found that, when a negative external charge is near the surface of a CdSe quantum dot, its Coulomb potential could be strong enough to pull the hole away from the electron and results in a reduction of the radiative recombination rate by a factor of 70. Distance, direction, charge number, and charge type dependences of this effect are investigated.
77 citations
TL;DR: In this paper, the in-plane polarization of wurtzite GaN/(Al, Ga)N multiple quantum wells was studied and the luminescence was polarized normal to [0001] and showed no spectral shift with polarization angle, i.e., it originates solely from A excitons.
Abstract: We study the in-plane polarization of wurtzite GaN/(Al, Ga)N multiple quantum wells. Identical M-plane (1100) and C-plane (0001) structures are grown by plasma-assisted molecular-beam epitaxy on γ-LiAlO2(100) and 6H–SiC(0001), respectively. While the emission from the conventional [0001] oriented wells is isotropic within the growth plane, we observe a strong polarization anisotropy of over 90% for the M-plane sample. The luminescence is polarized normal to [0001] and shows no spectral shift with polarization angle, i.e., it originates solely from A excitons (px and py valence band states). The deviation of the polarization degree from unity is attributed to the mixing with pz valence band states due to quantum confinement.
77 citations
TL;DR: In this article, the role of the Purcell effect in the stimulated and spontaneous emission rates of semiconductor lasers is investigated, taking into account the carriers' spatial distribution in the volume of the active region over a wide range of cavity dimensions and emitter/cavity linewidths, enabling the detailed modeling of the static and dynamic characteristics of either micro- or nano-scale lasers using singlemode rate-equations analysis.
Abstract: Nanoscale semiconductor lasers have been developed recently using either metal, metallo-dielectric, or photonic crystal nanocavities. While the technology of nanolasers is steadily being deployed, their expected performance for on-chip optical interconnects is still largely unknown due to a limited understanding of some of their key features. Specifically, as the cavity size is reduced with respect to the emission wavelength, the stimulated and the spontaneous emission rates are modified, which is known as the Purcell effect in the context of cavity quantum electrodynamics. This effect is expected to have a major impact in the “threshold-less” behavior of nanolasers and in their modulation speed; but its role is poorly understood in practical laser structures, characterized by significant homogeneous and inhomogeneous broadening and by a complex spatial distribution of the active material and cavity field. In this paper, we investigate the role of the Purcell effect in the stimulated and spontaneous emission rates of semiconductor lasers taking into account the carriers’ spatial distribution in the volume of the active region over a wide range of cavity dimensions and emitter/cavity linewidths, enabling the detailed modeling of the static and dynamic characteristics of either micro- or nano-scale lasers using single-mode rate-equations analysis. The ultimate limits of scaling down these nanoscale light sources in terms of Purcell enhancement and modulation speed are also discussed showing that the ultrafast modulation properties predicted in nanolasers are a direct consequence of the enhancement of the stimulated emission rate via reduction of the mode volume.
77 citations
TL;DR: In this paper, the steady-state spontaneous emission of a V-type three-level atom was investigated, with the coherence between the two upper levels modified and controlled via incoherent pumping to a fourth auxiliary level.
Abstract: We investigate the steady-state spontaneous emission of a V-type three-level atom, with the coherence between the two upper levels modified and controlled via incoherent pumping to a fourth auxiliary level. The external pumping gives us an easily controllable handle in manipulating the spontaneous emission to such an extent that, under certain conditions, complete quenching of spontaneous emission is possible. We also show that even the interference between the decay channels, which is considered a key requirement in spontaneous emission quenching through quantum interference, is not essential to achieve near 100% trapping and almost complete suppression of spontaneous emission. Thus we provide a scheme for spontaneous emission quenching which can be easily realized experimentally.
77 citations
TL;DR: In this paper, the spectrum and the linear polarization of photoluminescence of hot electrons in GaAs crystals were investigated and the radiative recombination of hot electron created in the central Γ-valley via the subsidiary L-valleys was observed.
77 citations