Abstract: The invention relates to a device for the frequency analysis of a signal, comprising a diamond crystal having NV centers defining sub-regions, an excitation unit for optically or electrically exciting each sub-region, an injection unit for injecting a signal so that the sub-region is in the presence of the signal, a magnetic field generator designed so as to generate a magnetic field on each sub-region, the magnetic field having a spatial variation of amplitude in a first direction, and a detector for detecting the resonance frequency of each sub-region of the region, the detector comprising an electrical contact for detecting the charges created in a sub-region, and a reading circuit.

Abstract: The invention relates to a device for the frequency analysis of a signal, comprising a diamond crystal having NV centers defining sub-regions, an excitation unit for optically or electrically exciting each sub-region, an injection unit for injecting a signal so that the sub-region is in the presence of the signal, a magnetic field generator designed so as to generate a magnetic field on each sub-region, the magnetic field having a spatial variation of amplitude in a first direction, and a detector for detecting the resonance frequency of each sub-region of the region, the detector comprising an electrical contact for detecting the charges created in a sub-region, and a reading circuit.

Abstract: A system for analyzing a microwave-frequency signal by imaging is provided, comprising: a solid material at least one optical property of which is modifiable in at least one zone of the material, when the zone is simultaneously in the presence of an optical excitation or electrical excitation and a microwave-frequency signal having at least one frequency coinciding with a resonant frequency of the material, the material furthermore being such that a value of the resonant frequency varies as a function of the amplitude of a magnetic field, a magnetic field generator configured to generate a magnetic field having, in the interior of a portion of the zone, a spatial amplitude variation in a direction X, the material then having a resonant frequency that is dependent on a position in the direction X, and a detector configured to receive an image of the zone in said direction X.

Abstract: A system for analyzing a microwave-frequency signal by imaging is provided, comprising: a solid material at least one optical property of which is modifiable in at least one zone of the material, when the zone is simultaneously in the presence of an optical excitation or electrical excitation and a microwave-frequency signal having at least one frequency coinciding with a resonant frequency of the material, the material furthermore being such that a value of the resonant frequency varies as a function of the amplitude of a magnetic field, a magnetic field generator configured to generate a magnetic field having, in the interior of a portion of the zone, a spatial amplitude variation in a direction X, the material then having a resonant frequency that is dependent on a position in the direction X, and a detector configured to receive an image of the zone in said direction X.

Abstract: A continuous variable quantum encryption key distribution system comprises a sender (Alice) able to randomly choose the phase and the amplitude of each coherent light pulse of a signal, to provide a coherent state defined by a first quadrature and a second quadrature that are random, and to transmit to a receiver (Bob) the signal pulses (S) and a local oscillator (LO), the receiver comprising a homodyne detector (36) for measuring a randomly chosen quadrature of a signal pulse. The sender comprises a device for time-division multiplexing the pulses of the signal (S) and of the local oscillator (LO) to handle the transmission over an optical fiber (10) of the signal and local oscillator pulses to the receiver. The receiver comprises a demultiplexer (31), able to send the received pulses over a first channel (32), or over a second channel (33). The channels are applied as inputs to the homodyne detector (36).

Abstract: Encoding digital data intended for transmission by a particle flow of single particles, includes: encoding digital data on a parameter x of said particle flow, wherein the parameter x has a conjugated parameter y of said particle flow; and ensuring that said parameter x and said conjugated parameter y are in a minimum state (?x. ?y=1).

Abstract: A continuous variable quantum encryption key distribution system comprises a sender (Alice) able to randomly choose the phase and the amplitude of each coherent light pulse of a signal, to provide a coherent state defined by a first quadrature and a second quadrature that are random, and to transmit to a receiver (Bob) the signal pulses (S) and a local oscillator (LO), the receiver comprising a homodyne detector (36) for measuring a randomly chosen quadrature of a signal pulse. The sender comprises a device for time-division multiplexing the pulses of the signal (S) and of the local oscillator (LO) to handle the transmission over an optical fiber (10) of the signal and local oscillator pulses to the receiver. The receiver comprises a demultiplexer (31), able to send the received pulses over a first channel (32), or over a second channel (33). The channels are applied as inputs to the homodyne detector (36).

Abstract: Quantum cryptography by polarization ambiguity is generally used but it involves polarization-maintained fibers. This invention proposes an alternative: quantum cryptography by ambiguity in time. It comprises the conversion of K bits to be transmitted into a train of K pulses of particle flows of time width ?T and whose frequency Tb, is predetermined knowing that each of the K pulses being shifted or not in time such that the kth pulse is shifted by a duration t0 respectively t1, with respect to the initial instant of the period depending on the value “0”, respectively “1” of the kth bit, where k is an integer such that 0?k<K and the shifts t0 and t1 are such that 0?t0,t1?Tb??T and 0<|t1?t0|<?T.

Abstract: This invention proposes an alternative: quantum cryptography by ambiguity in time. It comprises the conversion of K bits to be transmitted into a train of K pulses of particle flows of time width &Dgr;T and whose frequency Tb, is predetermined knowing that each of the K pulses being shifted or not in time such that the kth pulse is shifted by a duration t0 respectively t1, with respect to the initial instant of the period depending on the value “0”, respectively “1” of the kth bit, where k is an integer such that 0≦k<K and the shifts t0 and t1 are such that 0≦t0,t1≦Tb−&Dgr;T and 0<It1−t0I<&Dgr;T.

Abstract: Quantum cryptography uses the basic principles of quantum mechanics to secure the transmission of an encryption key. It does not prevent spying on the transmission channel. If a spy intercepts the message, however, errors are inevitably introduced. These errors are used by the transmitter and the authorized receiver to detect spying on the channel with absolute certainty. In this case, the transmission is not validated and the spy has no exploitable information.

Abstract: Quantum cryptography by polarization ambiguity is generally used but it involves polarization-maintained fibers.

Abstract: An unstable optical cavity for laser beams, having at least 3 deflection means for making a beam created in the cavity undergo at least three changes in direction so to form an optical ring path, and an optical magnification set disposed among the deflecting means. The at least 3 deflection means are prisms, each of which has an air-glass reflecting interface that provides one of the changes in direction by total reflection. A first of the at least 3 prims is positioned at an output of the cavity and has an air-glass reflecting interface with an insufficient size for a total reflection of the beam in the cavity, and remaining ones of the prisms have an air-glass reflecting interface with a sufficient size for a total reflection of the beam in the cavity.

Abstract: Disclosed is a compact optical source capable of emitting wavelengths (notably in the blue spectrum) which it is difficult for standard laser diodes to achieve. This source has a laser (or laser diode) emitting at a wavelength .lambda.oi, a non-linear medium (NLM) in which the phase matching condition is achieved at a wavelength .lambda.o.sub.a belonging to the set of .lambda.o.sub.i values, a mirror M.sub.l transparent at .lambda.o.sub.i /2 and reflective at .lambda.oi placed at output of the medium (NLM) By reinjecting wavelengths .lambda.oi.noteq..lambda.oa into the laser, it is possible to lock the emission of the laser to .lambda.oa and thus set up a high-powered optical source .lambda.o.sub.a /2. Application: blue sources.

Abstract: Disclosed is a non-linear optical device in which the non-linear medium comprises a circular surface on which the light beam to be processed gets reflected. A structure such as this can be used to resolve the difficulties of making mirrors of the cavity containing the non-linear medium.