Abstract:
An optical system including: a photon source; first directing elements configured to direct photons to follow a first path through the optical system; second directing elements configured to direct photons to follow a second path through the optical system, wherein the second path is the reverse of the first path, photons travelling through the first path having a different polarization to those travelling through the second path; and a mechanism varying the relative phase shift between photons following the first path and photons following the second path.
Abstract:
An optical device comprising a quantum dot provided in a resonant confinement structure, an output from said confinement structure and a pulsed excitation source for said quantum dot, wherein the quantum dot is configured to allow the emission of photons having a first energy in response to a pulse from said excitation source, said resonant confinement structure providing optical confinement, the first energy being different to the resonant energy of the resonant confinement structure, the optical device further comprising a timing unit, said timing unit being configured to select photons which have been emitted from the quantum dot due to excitation by a pulse, the timing unit selecting photons emitted after the duration of the pulse which caused the emission of the photons.
Abstract:
A photon source comprising a photon source body, said photon source body comprising at least one quantum dot; carrier injection means for injecting carriers into said at least one quantum dot and change of state means for changing the state of the carriers within the quantum dot after a predetermined time duration, the carrier injection means injecting carriers which are configured to allow emission of radiation by radiative recombination
Abstract:
An optical component comprising an emitter and a solid reflector, said reflector having a convex outer surface, said emitter being located within the solid reflector, the emitter being configured to emit radiation via an electric dipole transition, the dipole having a dipole axis being orientated at an angle of 45 degrees or less to the surface normal at the apex of the reflector.
Abstract:
According to one embodiment, a quantum information system includes a source of time dependent entangled photons and an indicating unit. The indicating unit indicates the entangled state of the entangled photons based on the emission time of one or more of the entangled photons.
Abstract:
A photon source comprising a semiconductor heterostructure, said semiconductor heterostructure comprising a quantum well, a barrier region adjacent said quantum well and a quantum dot provided in said quantum well, the photon source further comprising electrical contacts and a power supply coupled to first and second electrical contacts configured to apply a tuneable electric field across said quantum dot to control the emission energy of said quantum dot, said electric field being tuneable across an operating range an wherein the tunneling time of carriers from said quantum dot to said first electrical contact and the tunneling time of carriers from said quantum dot to said second electrical contact are greater than the radiative decay time of an exciton in said quantum dot over said operating range for controlling the emission energy, said photon source being configured such that emission from a single quantum dot exits said photon source.
Abstract:
A photon source comprising a photon source body, said photon source body comprising at least one quantum dot; carrier injection means for injecting carriers into said at least one quantum dot and change of state means for changing the state of the carriers within the quantum dot after a predetermined time duration, the carrier injection means injecting carriers which are configured to allow emission of radiation by radiative recombination.
Abstract:
A component comprising a qubit and a controller for said qubit, said component comprising a quantum dot and an excitation portion configured to produce a neutral exciton state in said quantum dot to form said qubit, the component further comprising a measuring unit to make an optical measurement relating to the orientation of said state, wherein said controller comprises voltage source coupled to electrical contacts configured to apply a modulated electric field across said quantum dot, wherein the modulation is faster than the decay time of said neutral exciton state.
Abstract:
A quantum memory component including a quantum dot molecule having first and second quantum dots provided in respective first and second layers separated by a barrier layer; an exciton comprising an electron and hole bound state in said quantum dot molecule, the spin state of said exciton forming a qubit; first and second electrical contacts respectively provided below the first quantum dot and above the second quantum dot; a voltage source to apply an electric field across said quantum dot molecule; a controller to modulate the electric field across the quantum dot molecule, including an information acquiring circuit to acquire information concerning the relationship between fine structure splitting of the exciton and the applied electric field and a timing circuit to allow switching of the exciton from an indirect configuration to a direct configuration at predetermined times derived from the fine structure splitting.
Abstract:
A semiconductor structure with a waveguide, the semiconductor structure has a plurality of layers, at least one of which being partially laterally oxidised, said laterally oxidised material modifying the lateral effective refractive index with said structure in order to form a waveguide within the structure, the structure also has a quantum dot, said quantum dot being configured to emit photons into said waveguide, the waveguide being configured such that it guides the output from a single quantum dot.