A cleansing lighting device includes a laser light source configured to emit light in the visible light spectrum or in the infrared light spectrum. The cleansing lighting device also includes a light frequency up-converter to convert longer wavelength light from the laser light source to shorter wavelength light. The converted light has a dominant wavelength in the portion of the ultraviolet range at or below 380 nm, suitable for the cleansing application. An example cleansing lighting device may also include an optical element, such as a beam shaping lens or a variable optical beam deflector, to distribute the resulting ultraviolet light from the up-converter for the cleansing application. Such a cleansing lighting device may be a standalone device, although the device or individual components for light-based cleansing may be incorporated in a luminaire, for example, together with an artificial light source adapted to general illumination.

A laser adjustment method includes a first adjustment step and a second adjustment step. In the first adjustment step, using a light detector detecting a second harmonic light, optical intensity and wavelength of the second harmonic light is detected and a first temperature adjuster is adjusted to adjust temperatures of a Nd:YVO.sub.4 crystal and a KTP crystal such that the detected wavelength of the second harmonic light approaches a desired wavelength and such that the optical intensity of the second harmonic light reaches at least a predetermined value. In the second adjustment step, after the first adjustment step, a temperature of an etalon is adjusted by a second temperature adjuster such that the detected wavelength of the second harmonic light approaches the desired wavelength and such that the optical intensity of the second harmonic light reaches at least a predetermined value.

A hybrid photonic chip comprising a plurality of semiconductor materials arranged to define a chip providing a function, wherein at least a first part of the chip is formed of materials which can be fabricated using a CMOS technique; and at least a second part of the chip which comprises non-linear crystal material and is not subjected to etching process; wherein the second part of the chip in conjunction with the first part is configured to support a propagating low loss single mode.

A third-harmonic generation method includes frequency-quadrupling a fundamental optical beam via cascaded second-harmonic generation to yield a fourth-harmonic optical beam. The method also includes down-converting the fourth-harmonic optical beam to yield a third-harmonic optical beam. A third harmonic generator includes a monolithic optical element having nonzero quadratic electric susceptibility to (i) frequency-quadruple a fundamental optical beam via cascaded second-harmonic generation, and (ii) down-convert a fourth-harmonic optical beam to yield a third-harmonic optical beam.

A laser light source includes a nonlinear optical medium and a pump laser source configured to generate a pump laser beam to form a signal beam and an idler beam in the nonlinear optical medium by parametric down conversion. The laser light source further includes a seed light source configured to generate a seed signal beam and/or a seed idler beam having a coherence length lesser than a coherence length of the pump laser beam, and a superpositioning device configured to superposition the seed signal beam and/or the seed idler beam with the pump laser beam for joint coupling into the nonlinear optical medium.

There is presented an optical apparatus comprising first and second photon pair sources configured to convert at least one pump light photon into a first and second correlated signal and idler photon pairs. In one example, the apparatus is configured to use one of the signal and idler photons from the first correlated photon pair for controlling the conversion of the pump light photon in the second photon pair source. The apparatus may configured such that, at least one of the signal and idler photons from the first correlated photon pair is output from the first photon pair source onto an optical path wherein at least one of the signal and idler photons from the second correlated photon pair is output from the second photon pair source onto the optical path. A method is also provided for outputting one or more photons using the optical apparatus.

Embodiments of the present disclosure include techniques for forming nanotextured surfaces on various materials. In certain embodiments, a nanotextured surface of a wafer is formed in a processing chamber, such as a semiconductor processing chamber. A flat surface opposite the nanotextured surface is attached to a flat surface of a bulk material. In some embodiments the bulk material and the wafer are optical materials. In some embodiments, a second surface of the bulk material is also attached to a wafer having a nanotextured surface and a light may pass through the first nanotextured surface, the bulk optical material, and the second nanotextured surface with low reflection.

There is presented an optical apparatus comprising first and second photon pair sources configured to convert at least one pump light photon into a first and second correlated signal and idler photon pairs. In one example, the apparatus is configured to use one of the signal and idler photons from the first correlated photon pair for controlling the conversion of the pump light photon in the second photon pair source. The apparatus may configured such that, at least one of the signal and idler photons from the first correlated photon pair is output from the first photon pair source onto an optical path wherein at least one of the signal and idler photons from the second correlated photon pair is output from the second photon pair source onto the optical path. A method is also provided for outputting one or more photons using the optical apparatus.

A method of generation of a random symbol sequence using quantum opto-electronic devices A and B with device-independent security is disclosed. The method is characterized by the two sources each producing entangled two-beam, pulsed multiphoton quantum states of light and sending one beam to a quantum interference and measurement device C. Before being sent, the beams are multiplexed with coherent beams. Quantum interference and measurement device C demultiplexes them and uses coherent beams for compensating the fluctuations in the quantum beams. Then, it interferes quantum beams on a beam splitter, measures the output and sends results back. Subsequently, A and B share an entangled state. They interfere local beams with coherent light on beam splitters and measure on detectors. A fraction of measurements are kept secret and used as the source of symbols forming the cryptographic key, while others are used to establish the security using an entanglement test.

A wavelength conversion device includes a nonlinear optical crystal, a guide light source configured to provide a guide light traveling in a first direction within the nonlinear optical crystal such that a thermal waveguide penetrating the nonlinear optical crystal is formed, a signal light source configured to provide a signal light having a first wavelength (1) and traveling in a second direction opposite to the first direction through the thermal waveguide, and a pump light source configured to provide a pump light having a second wavelength (2) and traveling in the second direction through the thermal waveguide, wherein an output light including a wavelength component corresponding to a sum of energies of the first wavelength (1) and the second wavelength (2) is provided from the thermal waveguide.