A device for producing an electromagnetic radiation of predetermined properties is configured as a layered structure and includes a light interacting layer, in communication with at least one light emitting source, and having one or more light interacting regions, each configured to define a closed-loop light mixing path for optically coupling a pair of input coherent light components of predetermined first and second frequencies to create an output radiation component of a third beating frequency of a predetermined high-frequency profile. The device further includes a control layer interfacing with said light interacting layer and configured for controllable switching between inoperative opaque and operative transparent states with respect to the at least one third beating frequency, to selectively prevent and allow transmission of the at least one output radiation component of the third frequency towards a medium in the vicinity of the layered structure.

A quantum EIT-based optical switch includes a first waveguide, linear or nonlinear, a separate nonlinear waveguide evanescently coupled to the first waveguide, and a pump coupled to the nonlinear waveguide. A quantum STIRAP-based optical transduction device, which includes an auxiliary, intermediate spectral state for the quantum signal that aids efficient transduction of the quantum signal from the input spectral state to the output spectral state in a single device.

An apparatus and method for wavelength conversion of a signal, for example, a dual-polarization signal, is disclosed. The apparatus implements a single-loop counter-propagating wavelength conversion scheme which provides both up-conversion and down-conversion of the signal within the same loop. Nonlinear wavelength conversion devices in the loop provide both up-conversion and down-conversion of the polarization components of the signal within the loop depending on whether the polarization component travels through the nonlinear conversion device in a clockwise or a counter-clockwise direction. The wavelength-converted signal is available to be extracted from the wavelength-conversion loop. An all-optical wavelength-division multiplexing transponder based on the wavelength-conversion scheme is also disclosed.

A wavelength conversion system according to an aspect of the present disclosure includes a first crystal holder holding a first non-linear crystal, a second crystal holder holding a second non-linear crystal, a third crystal holder holding a third non-linear crystal, and a container housing the holders. The container has an entrance window and an emission window. The first non-linear crystal, the second non-linear crystal, and the third non-linear crystal are disposed in this order on an optical path of a laser beam traveling from the entrance window to the emission window. The crystal holders are rotatable. A first rotational axis that is a rotational axis of the first crystal holder is orthogonal to a second rotational axis that is a rotational axis of the second crystal holder, and the first rotational axis is parallel to a third rotational axis that is a rotational axis of the third crystal holder.

A quantum communications system may include a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The receiver node may be configured to arrange a received bit stream of optical pulses from the transmitter node into time bins, convert the optical pulses in the time bins into corresponding optical pulses in frequency bins, and detect respective optical pulse values from each of the frequency bins.

An optical frequency mixing module is described that comprises a nonlinear medium for frequency mixing the photons of one or more input optical fields to generate an output optical field; a nonlinear medium tuner for automatically phase matching the nonlinear medium to the one or more input optical fields to select the wavelength of the output optical field generated by the nonlinear medium; and a first direction correcting optic. The position of the first direction correcting optic relative to the nonlinear medium is dependent upon the selected wavelength of the output optical field and therefore ensures that the position and angle of propagation of this field remains constant and independent of its wavelength of. The optical frequency mixing modules therefore provides a means for automatically selecting the wavelength of the output field with no deviation being imparted onto the position or angle of propagation of the output field.

A wavelength conversion system including: A. a first nonlinear optical crystal to which first pulsed laser light having a first polarization state and a first wavelength and second pulsed laser light having a second polarization state and a second wavelength are inputted and which is configured to output in response to the input the second pulsed laser light and first sum frequency light having the second polarization state and a third wavelength produced by sum frequency mixing of the first wavelength with the second wavelength; and B. a second nonlinear optical crystal to which the first sum frequency light and the second pulsed laser light outputted from the first nonlinear optical crystal are inputted and which is configured to output in response to the input third pulsed laser light having a fourth wavelength.

A technique to generate terahertz radiation is disclosed, where a pump beam (12) is coupled into an optical element (50) made of a medium with non-linear optical properties having plane-parallel front and rear boundary surfaces (51, 52), wherein the pump beam (12) is split into a set of partial pump beams (121) by reflection and/or diffraction on a periodic relief structure (53) of said optical element (50). The partial pump beams travels along a direction at an angle γ that satisfies the velocity matching condition of v.sub.p,cs, cos(γ)=v.sub.THz,f within the given medium, where v.sub.p;cs is the group velocity of the pump beam, v.sub.THz;f is the phase velocity of the terahertz radiation and the speed a planar envelope (212) travels toward the front boundary surface (51) of the optical element (50), and γ is the angle formed by the pulse front envelope and the phase front of the pump beam.

An optical quantum state converter comprises an optical fiber input port configured to receive an optical signal comprising an optical quantum state at a first wavelength from an optical source. An optical combiner having a first input is coupled to the optical fiber input port. An optical pump source having an output that is coupled to a second input of the optical combiner provides an optical pump signal at a pump signal wavelength to a second input of the combiner. A nonlinear optical waveguide having an input that is coupled to an output of the optical combiner converts the optical quantum state at the first wavelength to an optical quantum state at a second wavelength determined by the optical pump signal.

The invention relates to a frequency conversion arrangement (100) for optimising properties of a harmonic of a laser, in particular a beam profile and/or a long-term stability, the arrangement comprising:—a first non-linear crystal (X1), which is designed to convert a first wavelength (λ1) partially into a second wavelength (λ2); and—an optical unit, which in particular comprises at least one prism (P), which is designed in such a way as to influence the main axes (x1, y1, x2, y2) of the beam profiles of the first wavelength (λ1) and/or the second wavelength (λ2) differently; and—a second non-linear crystal (X2), which is designed in such a way as to generate a third wavelength (λ3) from the unconverted part of the first wavelength (λ1) and/or the second wavelength (λ2), the second non-linear crystal (X2) having an entry face (A1) and an exit face (A2), and the exit face (A2) running obliquely to the entry face (A1).