An apparatus is disclosed herein. The apparatus comprises a non-linear photonic element for outputting a signal and idler photon pair. The apparatus further comprises a module configured to, based on receiving one or more control signals, controllably store photons and controllably output stored photons. The apparatus further comprises a detector arrangement comprising one or more detectors for detecting light. The module is further configured to receive at least one of the signal and idler photons of the pair. The module is further configured to at least partially store one of the signal or idler photons of the pair. The module is further configured to output the said at least partially stored signal or idler photon along an optical path towards the at least one detectors. The apparatus is configured to direct the other of the signal or idler photon towards the detector arrangement.

Methods and apparatuses for manipulating and modulating of laser beams. The methods and apparatuses enable activating and deactivating of laser beams, while the laser systems maintain their operating power. Further, a hybrid pump module configured to be coupled to an optical fiber having a core and at least one clad, comprising: at least one focusing lens in optical with the optical fiber; plurality of diode modules, each configured to output a multi-mode beam in optical path with the clad; and at least one core associated module, in optical path with the core, configured to provide selected functions. Further, apparatus and methods configured for frequency doubling of optical radiation.

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 quantum source includes: a quantum source generator dividing a pump beam into a plurality of channels and generating a plurality of signals and a plurality of idlers using nonlinear crystals respectively located optical paths of the plurality of channels; and an entangled photon pair combiner outputting an enhanced signal by combining the plurality of signals and outputting an enhanced idler by combining the plurality of idlers.

A nonlinear fiber interferometer is disclosed suitable for fiber sensor and other applications. A first nonlinear fiber section amplifies probe and conjugate sidebands of a pump through four-wave mixing. A second section introduces a phase shift to be measured, for example from a sensor. A third nonlinear fiber section amplifies with phase-sensitive gain to increase signal-to-noise ratio. Based on phase-sensitive output power of probe and/or conjugate components, the phase shift can be measured. Superior performance can be obtained by balancing gain between the (first and third) nonlinear sections. Non-fiber, for example photonic integrated circuit, embodiments are disclosed. Differential sensing, alternative detection schemes, sensing applications, associated methods, and other variations are disclosed.

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).

A quasi-deterministic single-photon source and method of generating single photons on demand are disclosed. The single-photon source includes photon pair generation for generating a heralding and heralded photon in a frequency-correlated photon pair, a single-photon spectrometer adapted to detect the heralding photon and to generate an output signal that is indicative of the frequency of the detected heralding photon, a pulse shaper arrangement for reshaping a broadband pulse, and an optical frequency conversion means for converting, upon irradiation with a reshaped pulse, a heralded photon into a single output photon with deterministic source frequency. The pulse shaper arrangement is configured to select, based on the spectrometer output signal, only frequency components of the broadband pulse that substantially coincide with the heralding photon frequency or with a constant detuning thereof.

A mid-infrared broadband laser including: a femtosecond laser configured to generate a near-infrared light; nonlinear waveguide configured to broaden and/or shift a spectrum of the light from the femtosecond laser; and a nonlinear medium configured to generate a broadband light by mixing spectral components of the output from the non-linear waveguide. Optionally, at least one dispersion compensation element may be placed between the femtosecond laser and the nonlinear waveguide and/or between the nonlinear waveguide and the nonlinear medium.

A nonlinear crystal grating assembly including two integral nonlinear crystal grating structures having inverted crystal axes and having parallel spaced-apart mesas with predetermined mesa widths arranged such that, when assembled in an interdigitated configuration, the mesas of the two grating structures form an alternating grating pattern that is aligned with a propagation direction of input light, thereby creating a periodic structure for quasi-phase-matching (QPM). The nonlinear crystal grating structures are formed using strontium tetraborate, lithium triborate or another nonlinear crystal material. The nonlinear crystal grating assembly is utilized in a laser assembly in which fundamental wavelengths are doubled and/or summed using intermediate frequency conversion stages, and then a final frequency converting stage utilizes the nonlinear crystal grating assembly to double or sum one or more intermediate light beam frequencies to generate laser output light at high power and photon energy levels. A method and inspection system are also described.

A quantum source includes: a quantum source generator dividing a pump beam into a plurality of channels and generating a plurality of signals and a plurality of idlers using nonlinear crystals respectively located optical paths of the plurality of channels; and an entangled photon pair combiner outputting an enhanced signal by combining the plurality of signals and outputting an enhanced idler by combining the plurality of idlers.