An optical element includes an optical crystal and an antireflection film coating the surface of the optical crystal. The antireflection film contains an organic compound that includes, as a structural unit, at least one of a compound containing a cyclic structure to which a fluorine atom is bound and a compound containing a cyclic olefin structure.

Provided is a wavelength conversion element capable of achieving highly efficient wavelength conversion, without relying on a method of applying electric fields. A wavelength conversion element is formed of a second-order nonlinear optical crystal and has a z-axis, running along a direction of spontaneous polarization, within a substrate plane. The wavelength conversion element includes a waveguide in which, when a plurality of circles having their centers on a straight line parallel to the z-axis and having the same radius are depicted so that circumferences of the plurality of circles contact each other, semicircular waveguides corresponding to one semicircles of the circumferences with the straight line as a boundary, are alternately connected.

A method for joining an optical crystal to a substrate includes radiating a pulsed laser beam through the optical crystal or through the substrate onto a surface of an intermediate layer between the optical crystal and the substrate, and forming a fusion zone in the intermediate layer between the optical crystal and the substrate by the radiation of the pulsed laser beam, thereby integrally joining the optical crystal and the substrate.

Disclosed are an optical member and a display device having the same. The optical member includes a first substrate, a plurality of wavelength conversion parts provided on the first substrate while being spaced apart from each other, and a sealing layer on a top surface of the wavelength conversion parts and at a lateral side of the wavelength conversion parts. Each of the wavelength conversion parts includes a host on the first substrate, and a plurality of wavelength conversion particles in the host.

A broadband light source device for creating broadband light pulses includes a hollow-core fiber and a pump laser source device. The hollow-core fiber is configured to create the broadband light pulses by an optical non-linear broadening of pump laser pulses. The hollow-core fiber includes a filling gas, an axial hollow light guiding fiber core configured to support core modes of a guided light field, and an inner fiber structure surrounding the fiber core and configured to support transverse wall modes of the guided light field. The pump laser source device is configured to create and provide the pump laser pulses at an input side of the hollow-core fiber. The transverse wall modes include a fundamental transverse wall mode and second and higher order transverse wall modes.

A broadband light source device for creating broadband light pulses includes a hollow-core fiber and a pump laser source device. The hollow-core fiber is configured to create the broadband light pulses by an optical non-linear broadening of pump laser pulses. The hollow-core fiber includes a filling gas, an axial hollow light guiding fiber core configured to support core modes of a guided light field, and an inner fiber structure surrounding the fiber core and configured to support transverse wall modes of the guided light field. The pump laser source device is configured to create and provide the pump laser pulses at an input side of the hollow-core fiber. The transverse wall modes include a fundamental transverse wall mode and second and higher order transverse wall modes.

Described embodiments include a plasmonic apparatus and method. The plasmonic apparatus includes a substrate having a first negative-permittivity layer comprising a first plasmonic surface. The plasmonic apparatus includes a plasmonic nanoparticle having a base with a second negative-permittivity layer comprising a second plasmonic surface. The plasmonic apparatus includes a dielectric-filled gap between the first plasmonic surface and the second plasmonic surface. The plasmonic apparatus includes a plasmonic cavity created by an assembly of the first plasmonic surface, the second plasmonic surface, and the dielectric-filled gap, and having a spectrally separated first fundamental resonant cavity wavelength λ.sub.1 and second fundamental resonant cavity wavelength λ.sub.2. The plasmonic apparatus includes a plurality of fluorescent particles located in the dielectric-filled gap. Each fluorescent particle of the plurality of fluorescent particles having an absorption spectrum including the first fundamental resonant cavity wavelength λ.sub.1 and an emission spectrum including the second fundamental resonant cavity wavelength λ.sub.2.

Described embodiments include a plasmonic apparatus and method. The plasmonic apparatus includes a substrate having a first negative-permittivity layer comprising a first plasmonic surface. The plasmonic apparatus includes a plasmonic nanoparticle having a base with a second negative-permittivity layer comprising a second plasmonic surface. The plasmonic apparatus includes a dielectric-filled gap between the first plasmonic surface and the second plasmonic surface. The plasmonic apparatus includes a plasmonic cavity created by an assembly of the first plasmonic surface, the second plasmonic surface, and the dielectric-filled gap, and having a spectrally separated first fundamental resonant cavity wavelength λ.sub.1 and second fundamental resonant cavity wavelength λ.sub.2. The plasmonic apparatus includes a plurality of fluorescent particles located in the dielectric-filled gap. Each fluorescent particle of the plurality of fluorescent particles having an absorption spectrum including the first fundamental resonant cavity wavelength λ.sub.1 and an emission spectrum including the second fundamental resonant cavity wavelength λ.sub.2.

Provided are a wavelength converting particle, a method for manufacturing a wavelength converting particle, and a light-emitting diode containing a wavelength converting particle. The wavelength converting particle comprises a hybrid OIP nanocrystal that converts a wavelength of light generated by an excitation light source into a specified wavelength. Accordingly, it is possible to optically stabilize and improve color purity and light-emission performance without changes in a light-emitting wavelength range.

A miniaturized PPKTP crystal-based entanglement source system using multi-mode reception is provided, which includes a pump light source, a pump light transmission module, an entanglement device, a first collection device, and a second collection device. In the entanglement source system, entangled lights are received by using multi-mode optical fibers, and an entangled light processing scheme of combining a temporal filtering technology and a spatial filtering technology is applied into a collecting device at one side of the entanglement source system, to form asymmetric device structures in the entanglement source system, to enable multi-mode reception.