An imaging system comprises a light source generating a pump beam, and an optical coupling system for receiving an input beam of infrared light from a scene and combining the input beam with the pump beam, wherein an intensity of the pump beam is higher than an intensity of the input beam. The imaging system further comprises a crystal configured for adiabatically mixing the beams and providing an output beam having a frequency which is a sum of frequencies of the input and pump beams, and a visible, near-infrared or ultraviolet light imager configured for collecting and to spectrally resolving the output beam.

A third-harmonic conversion arrangement includes a second-harmonic generating crystal and a third-harmonic generating crystal arranged in a polarization loop. The polarization loop, which includes a plurality of mirrors, a polarization-selective reflector, and a polarization rotator, causes plane-polarized fundamental-wavelength radiation being converted to make two passes through the crystals in orthogonally-opposed polarization orientations.

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.

A difference frequency generation optical transmitter and sum frequency generation optical receiver operating in the mid-infrared wavelength range for use in free space optical satellite communications are described. By using mid-infrared light, the transmitter/receiver can mitigate atmospheric scintillation, scattering, and other non-ideal optical effects in the communication channel. This is achieved through the use of nonlinear optical crystals designed for difference frequency generation in the case of the transmitter and sum frequency generation for the receiver. High-speed modulated communication signals can thus be frequency converted to the mid-infrared wavelength range by a relatively low cost, compact and high-power optical communication system.

The invention relates to an apparatus for generating laser pulses. It is an object of the invention to provide a method for generating synchronized laser pulse trains at variable wavelengths (e.g., for coherent Raman spectroscopy/microscopy), wherein the switching time for switching between different wavelengths should be in the sub-s range. For this purpose the apparatus according to the invention comprises a pump laser (1), which emits pulsed laser radiation at a specified wavelength, an FDML laser (3), which emits continuous wave laser radiation at a cyclically variable wavelength, and a nonlinear conversion medium (4), in which the pulsed laser radiation of the pump laser (1) and the continuous wave laser radiation of the FDML laser (3) are superposed. In the nonlinear conversion medium (4) the pulsed laser radiation of the pump laser (1) and the continuous wave laser radiation of the FDML laser (3) are converted in an optical parametric process into pulsed laser radiation at a signal wavelength and an idler wavelength that differs therefrom. Furthermore the invention relates to a method for generating laser pulses.

A frequency electromagnetic radiation generation system including: a non linear crystal producing THz frequency electromagnetic radiation; a fundamental beam that interacts with the non linear crystal thereby emitting a THz frequency electromagnetic radiation emission; a silicon intermediary coupled to the non linear crystal for output channeling the THz frequency electromagnetic radiation emission to an output environment; the system utilising a fundamental beam which has a photon energy below the bandgap energy of silicon.

A device for high-speed real-time sampling of mid-infrared ultrafast light signals includes a time domain amplification unit and a detection unit. The time domain amplification unit is used to perform sampling and time domain amplification on signal light incident to the time domain amplification unit, and convert the signal light of a mid-infrared band into a near-infrared/visible band. The detection unit is used to receive and record information of the to-be-detected signal light processed by the time domain amplification unit to realize high-speed real-time sampling and measurement of the mid-infrared ultrafast light signal. The present disclosure can accurately obtain subpicosecond transient characteristics of the light signal, breaks through the capacity limit to the response rate of a traditional photoelectric detector, the bandwidth of the oscilloscope and the like, and is applicable to femtosecond-level mid-infrared ultrafast light signals.

A nonlinear crystal comprising a first curved face and an opposing second curved face is described. The first and second curved faces are arranged to provide the nonlinear crystal with rotational symmetry about at least one axis of the nonlinear crystal. The nonlinear crystal allows for frequency tuning of a generated optical field that is generated by propagating a fundamental optical field through the nonlinear crystal by rotation of the nonlinear crystal about an axis of rotation without any significant, or minimal, deviation being introduced to the generated optical field. These nonlinear crystals can therefore be incorporated into an external cavity frequency doubler or mixer without any need for the employment of optical compensation optics or servo control electronics to automatically realign the cavity mirrors.

Apparatus include an optical cavity including an optical coupling portion situated to couple an optical signal input field to an intracavity optical signal field and an optical control input field to an intracavity optical control field, wherein the optical cavity includes a nonlinear optical medium that mediates a selective exchange of at least one predetermined temporal mode between the intracavity optical signal field and an intracavity optical register field based on a nonlinear phase-matched interaction between the intracavity optical signal, control, and register fields and selectable field characteristics of the optical control input field.

A method for providing a detection-signal for objects to be detectedat least a first and second light-beam including different frequencies being generated with a first optical non-linear 3-wave-process from a light-beam of a light-source including an output-frequency, and the first light-beam including a reference-frequency being detected, and the second light-beam including an object-frequency being emitted and received after reflection on an object, and the light-beam including the output-frequency and the second light-beam including the object-frequency being superposed, and a reference-beam including a reference-frequency being generated with a second optical non-linear 3-wave-process from the two superposed light-beams including the output-frequency and including the object-frequency, and a detection-signal being generated so that the object-distance is determinable due to the aforementioned superposition based on the time-difference between the detection of the first light-beam including the reference-frequency and a detection of a change of the reference-beam including the reference-frequency.