Abstract:
An embodiment of the invention relates to single-photon source for emitting single photons, comprising a cavity having a first mirror and a second mirror and exhibiting a longitudinal resonance frequency between the first and second mirror; at least one quantum dot arranged inside said cavity, said quantum dot being strain-dependent and configured to generate radiation at a strain-dependent radiation frequency; a device capable of exciting the quantum dot to generate radiation;a piezoelectric crystal being arranged outside the cavity and mechanically coupled to the second mirror's outer surface, said piezoelectric crystal configured to receive a control voltage and capable of applying either a laterally tensile and vertically compressive strain to both the cavity and the quantum dot, or a laterally compressive and vertically tensile strain to both the cavity and the quantum dot, depending on the control voltage's polarity;wherein, in response to said strain, the resonance frequency and the radiation frequency shift in opposite directions.
Abstract:
The invention provides, inter alia, a method for sampling an individual optical pulse (LP) and for forming samples (AW1-AW5) which characterize the pulse profile of the optical pulse to be sampled, in which a sequence of temporally successive optical sampling pulses (AP1-AP5) having different optical wavelengths (1-5) is formed when the pulse to be sampled is sampled by means of the sampling pulses with the formation of modulated sampling pulses (AP1'-AP5') and the modulated sampling pulses (AP1'-AP5') are measured wavelength-individually with the formation of the samples.
Abstract:
An embodiment of the invention relates to a device comprising a laser and a waveguide stripe or netlike hexagonal stripe structure, which allows propagation of multitude of the lateral modes in the waveguide stripe or stripe structure, wherein the waveguide stripe has at least one corrugated edge section along its longitudinal axis to provide preferable amplification of the fundamental lateral mode or in-phase supermode and to obtain high brightness of the emitted radiation.
Abstract:
An embodiment of the invention relates to a memory comprising a strained double-heterostructure (110) having an inner semiconductor layer (115) which is sandwiched between two outer semiconductor layers, (120, 125) wherein the lattice constant of the inner semiconductor layer differs from the lattice constants of the outer semiconductor layers, the resulting lattice strain in the double-heterostructure inducing the formation of at least one quantum dot inside the inner semiconductor layer, said at least one quantum dot being capable of storing charge carriers therein, and wherein, due to the lattice strain, the at least one quantum dot has an emission barrier (Eb) of 1,15 eV or higher, and provides an energy state density of at least three energy states per 1000 nm3, all said at least three energy states (186) being located in an energy band (DeltaWb) of 50 meV or less.
Abstract:
Erfindungsgemäß vorgesehen ist u. a. ein Verfahren zum Abtasten eines einzelnen optischen Pulses (LP) und zum Bilden von Abtastwerten (AW1-AW5), die den Pulsverlauf des abzutastenden optischen Pulses kennzeichnen, bei dem eine Abfolge zeitlich aufeinander folgender optischer Abtastpulse (AP1-AP5) gebildet wird, die unterschiedliche optische Wellenlängen (1-5) aufweisen, mit den Abtastpulsen der abzutastende Puls unter Bildung modulierter Abtastpulse (AP1'-AP5') abgetastet wird und die modulierten Abtastpulse (AP1'-AP5') wellenlängenindividuell unter Bildung der Abtastwerte gemessen werden.
Abstract:
The invention relates to a memory cell (10) comprising at least one binary memory area for storing an item of bit information and to a method for storing an item of bit information. According to the invention, it is provided that the memory area (SB), e.g. a quantum dot layer of In(Ga)As quantum dots, can optionally store holes or electrons and allows a recombination of holes and electrons, the charge carrier type of the charge carriers stored in the memory area defines the bit information of the memory area and a charge carrier injection device (PN) is present, by means of which optionally holes or electrons can be injected into the memory area (SB) and the bit information can thus be changed. The holes and electrons come from a hole reservoir (LR) or electron reservoir (ER) which consist e.g. of p-doped or n-doped GaAs. The readout layer (AS) is a two-dimensional hole or electron gas layer.
Abstract:
An embodiment of the invention relates to single-photon source for emitting single photons, comprising a cavity having a first mirror and a second mirror and exhibiting a longitudinal resonance frequency between the first and second mirror; at least one quantum dot arranged inside said cavity, said quantum dot being strain-dependent and configured to generate radiation at a strain-dependent radiation frequency; a device capable of exciting the quantum dot to generate radiation;a piezoelectric crystal being arranged outside the cavity and mechanically coupled to the second mirror's outer surface, said piezoelectric crystal configured to receive a control voltage and capable of applying either a laterally tensile and vertically compressive strain to both the cavity and the quantum dot, or a laterally compressive and vertically tensile strain to both the cavity and the quantum dot, depending on the control voltage's polarity;wherein, in response to said strain, the resonance frequency and the radiation frequency shift in opposite directions.
Abstract:
Die Erfindung bezieht sich u. a. auf eine Speicherzelle (10) zum Speichern mindestens einer Bitinformation, wobei die Speicherzelle eine Halbleiterstruktur (11) mit einem zumindest einen Potentialtopf (200) aufweisenden Bandverlauf (EL) und zumindest zwei elektrische Anschlüsse (40, 130) umfasst, wobei sich durch Anlegen einer elektrischen Einspeisespannung (Us=Uspeis) an die zwei Anschlüsse der Beladungszustand des Potentialtopfes mit Ladungsträgern vergrößern, durch Anlegen einer Entladespannung (Us=Usperr) verkleinern und durch Anlegen einer Beibehaltespannung (Us=Ubei) beibehalten lässt und wobei der jeweilige Beladungszustand des Potentialtopfes die Bitinformation der Speicherzelle festlegt. Erfindungsgemäß ist vorgesehen, dass die Halbleiterstruktur eine Raumladungszone (Wn) aufweist und der Potentialtopf durch eine Halbleiterheterostruktur (80) gebildet ist, wobei die Halbleiterheterostruktur und die Raumladungszone relativ zueinander räumlich derart angeordnet sind, dass sich die Halbleiterheterostruktur bei Anliegen der Beibehaltespannung innerhalb der Raumladungszone, bei Anliegen der Einspeisespannung am Rand oder außerhalb der Raumladungszone und bei Anliegen der Entladespannung innerhalb der Raumladungszone befindet.
Abstract:
An embodiment of the invention relates to a device comprising a laser and a waveguide stripe or netlike hexagonal stripe structure, which allows propagation of multitude of the lateral modes in the waveguide stripe or stripe structure, wherein the waveguide stripe has at least one corrugated edge section along its longitudinal axis to provide preferable amplification of the fundamental lateral mode or in-phase supermode and to obtain high brightness of the emitted radiation.
Abstract:
The invention relates to a method for the production of a photon pair source, which generates entangled photon pairs, having at least one quantum dot, wherein in the method the operational behaviour of the photon pair source is determined by adjusting the fine structure splitting of the excitonic energy level of the at least one quantum dot. It is provided according to the invention for the fine structure splitting of the excitonic energy level to be adjusted by depositing the at least one quantum dot on a {111} crystal surface of a semiconductor substrate.