94,531 research outputs found
The Josephson light-emitting diode
We consider an optical quantum dot where an electron level and a hole level
are coupled to respective superconducting leads. We find that electrons and
holes recombine producing photons at discrete energies as well as a continuous
tail. Further, the spectral lines directly probe the induced superconducting
correlations on the dot. At energies close to the applied bias voltage eV, a
parameter range exists, where radiation proceeds in pairwise emission of
polarization correlated photons. At energies close to 2eV, emitted photons are
associated with Cooper pair transfer and are reminiscent of Josephson
radiation. We discuss how to probe the coherence of these photons in a SQUID
geometry via single photon interference.Comment: Main text: 4 pages, 4 figures, Supplementary material: 8 pages, 4
figure
Surface plasmon enhanced light-emitting diode
A method for enhancing the emission properties of light-emitting diodes, by coupling to surface plasmons, is analyzed both theoretically and experimentally. The analyzed structure consists of a semiconductor emitter layer thinner than λ/2 sandwiched between two metal films. If a periodic pattern is defined in the top semitransparent metal layer by lithography, it is possible to efficiently couple out the light emitted from the semiconductor and to simultaneously enhance the spontaneous emission rate. For the analyzed designs, we theoretically estimate extraction efficiencies as high as 37% and Purcell factors of up to 4.5. We have experimentally measured photoluminescence intensities of up to 46 times higher in fabricated structures compared to unprocessed wafers. The increased light emission is due to an increase in the efficiency and an increase in the pumping intensity resulting from trapping of pump photons within the microcavity
A Cooper pair light emitting diode
We demonstrate Cooper-pair's drastic enhancement effect on band-to-band
radiative recombination in a semiconductor. Electron Cooper pairs injected from
a superconducting electrode into an active layer by the proximity effect
recombine with holes injected from a p-type electrode and dramatically
accelerate the photon generation rates of a light emitting diode in the
optical-fiber communication band. Cooper pairs are the condensation of
electrons at a spin-singlet quantum state and this condensation leads to the
observed enhancement of the electric-dipole transitions. Our results indicate
the possibility to open up new interdisciplinary fields between
superconductivity and optoelectronics.Comment: 5 pages (4 figures
Composite cavity for enhanced efficiency of up conversion.
Methods, apparatus and systems for an up-converter resonant cavity light emitting diode device includes a semiconductor light source, an up-converter to form the light emitter with up-converting materials and an electrical source coupled with the semiconductor light source for providing electrical energy to the semiconductor light source to provide a desired wavelength emitted light. The semiconductor light source is a resonant cavity light emitting diode or laser that emits an approximately 975 nm wavelength to provide electrical and optical confinement to the semiconductor light source to fonn a resonant cavity up-converting light emitting diode (UCIRCLED). Rows and columns of electrodes provide active matrix addressing of plural sets of UC/RCLEDs for display devices. The up-converter resonant cavity light emitting diode device has applications in head mounted projection display optical system using spectrally selective beam splitters to eliminate spectral overlap between colors a
Combination of up-converting materials with semiconductor light sources
Methods, apparatus and systems for an up-converter resonant cavity light emitting diode device includes a semiconductor light source, an up-converter to form the light emitter with up-converting materials and an electrical source coupled with the semiconductor light source for providing electrical energy to the semiconductor light source to provide a desired wavelength emitted light. The semiconductor light source is a resonant cavity light emitting diode or laser that emits an approximately 975 nm wavelength to provide electrical and optical confinement to the semiconductor light source to form an up-converting resonant cavity light emitting diode (UCIRCLED). Rows and columns of electrodes provide active matrix addressing of plural sets of UCIRCLEDs for display devices. The up-converter resonant cavity light emitting diode device has applications in head mounted projection display optical system using spectrally selective beam splitters to eliminate spectral overlap between colors a
Composite cavity for enhanced efficiency of up conversion.
Methods, apparatus and systems for an up-converter resonant cavity light emitting diode device includes a semiconductor light source, an up-converter to form the light emitter with up-converting materials and an electrical source coupled with the semiconductor light source for providing electrical energy to the semiconductor light source to provide a desired wavelength emitted light. The semiconductor light source is a resonant cavity light emitting diode or laser that emits an approximately 975 nm wavelength to provide electrical and optical confinement to the semiconductor light source to fonn a resonant cavity up-converting light emitting diode (UCIRCLED). Rows and columns of electrodes provide active matrix addressing of plural sets of UC/RCLEDs for display devices. The up-converter resonant cavity light emitting diode device has applications in head mounted projection display optical system using spectrally selective beam splitters to eliminate spectral overlap between colors a
10 Mb/s visible light transmission system using a polymer light-emitting diode with orthogonal frequency division multiplexing
We present a newly designed polymer light-emitting diode with a bandwidth of ∼350 kHz for high-speed visible light communications. Using this new polymer light-emitting diode as a transmitter, we have achieved a record transmission speed of 10 Mb/s for a polymer light-emitting diode-based optical communication system with an orthogonal frequency division multiplexing technique, matching the performance of single carrier formats using multitap equalization. For achieving such a high data-rate, a power pre-emphasis technique was adopted
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