Abstract: This invention provides a method of detecting a photon in a first frequency range, the method comprising the steps of: exciting a first transmission medium by a first probe signal at a first probe frequency, wherein the first probe signal excites electrons of the first transmission medium from a ground state of the first transmission medium to a first excited state of the first transmission medium; exciting the first transmission medium by a first coupling signal at a first coupling frequency, wherein the first coupling signal overlaps with the first probe signal in the first transmission medium and excites electrons of the first transmission medium to a predetermined excited state of the first transmission medium such that a first photon in the first frequency range and having a first polarisation incident upon the first transmission medium excites an electron in the predetermined excited state of the first transmission medium to a further excited state of the first transmission medium, wherein a first photo

Abstract: This disclosure provides a method of controlling an electromagnetic field detector by causing a first phase shift to be applied to a second probe signal path so as to cause a variation in a change in intensity of combined first and second paths of a probe signal; obtaining data indicating a second phase shift to be applied to the second probe signal path so as to increase the change in intensity of the combined first and second paths of the probe signal, wherein the second phase shift is determinable from a variation in the change in intensity of the combined first and second paths of the probe signal caused by the first phase shift; and causing the second phase shift to be applied to the second probe signal path.

Abstract: This disclosure provides a first wireless transceiver for a wireless telecommunications network, and a method of operating the first wireless transceiver, such that a combination of a phase-modulated signal and a local oscillator signal cause a detectable change of a probe signal from which a phase state of the phase-modulated signal can be detected.

Abstract: This invention provides a method of detecting an electromagnetic field, and a device for 5 performing said method, the method comprising the steps of: transmitting a probe signal at a probe frequency in a first probe signal path and a second probe signal path to an optical receiver, wherein the first probe signal path passes through a transmission medium and the probe frequency is set to excite electrons of the transmission medium from a ground state to a first excited state; transmitting a coupling signal at a coupling frequency in a first coupling signal path, wherein the first coupling signal path overlaps with the first probe signal path in the transmission medium in a first overlapping section, wherein the coupling frequency is set to excite electrons of the transmission medium to a predetermined excited state so as to induce an Electromagnetic Induced Transparency, EIT, effect in the transmission medium such that an incident electromagnetic field at the transmission medium causes a change in refractive

Abstract: This disclosure provides an electromagnetic field detector, and a method of operating the electromagnetic field detector in a wireless telecommunications network, the electromagnetic field detector including a first optical transmitter, a second optical transmitter, and a transmission medium, wherein the first optical transmitter is configured to transmit a probe signal at a probe frequency and the second optical transmitter is configured to transmit a coupling signal at a coupling frequency, wherein the probe frequency is set to excite electrons of the transmission medium from a ground state to a first excited state and the coupling frequency is set to excite electrons of the transmission medium to a predetermined excited state so as to induce an Electromagnetic Induced Transparency (EIT) effect such that an incident electromagnetic field at the transmission medium causes a detectable change in the probe signal.

Abstract: This disclosure provides a method of operating a central node in a telecommunications network, the telecommunications network including an optical network and a plurality of distributed nodes each configured to use a first optical signal at a first wavelength, the method including producing a first optical signal at a second wavelength; directing the first optical signal into a first path for the first optical signal and a second path for the first optical signal, wherein the first path for the first optical signal is connected to a first optical stabilizer to stabilize the first optical signal produced by the central node, and the second path for the first optical signal provides the first optical signal to the optical network for distribution to each of the plurality of distributed nodes, wherein the second wavelength has a lower transmission loss than the first wavelength.

Abstract: This invention relates to an electromagnetic field receiver controller including a first and second optical transmitter, a transmission medium and an optical receiver. The first optical transmitter is configured to transmit a probe signal to the optical receiver via the transmission medium at a probe frequency and the second transmitter is configured to transmit a coupling signal via the transmission medium at a coupling frequency, wherein the probe frequency is set to excite electrons of the transmission medium from a ground state to a first excited state and the coupling frequency is set to excite electrons of the transmission medium to a predetermined excited state so as to induce an Electromagnetic Induced Transparency (EIT) effect in the electromagnetic field receiver such that an incident electromagnetic field at the transmission medium causes a detectable change in power of the probe signal at the optical receiver.

Abstract: This disclosure provides a waveguide including a sequence of variable transparency segments, wherein each variable transparency segment of the sequence of variable transparency segments is configured to vary its transparency by the electromagnetically Induced Transparency (EIT) effect and further vary its transparency in response to an incident electromagnetic field; and a plurality of separator segments interspersed within the sequence of variable transparency segments so that each variable transparency segment: has a first separation distance from a first other variable transparency segment being a first predetermined number of variable transparency segments preceding or succeeding in the sequence of variable transparency segments, has a second separation distance from a second other variable transparency segment being a second predetermined number of variable transparency segments preceding or succeeding in the sequence of variable transparency segments, and is uniquely identified by a combination of separ