An ultraviolet light emitting device includes: a first substrate; a second substrate; a gas in a space between the first substrate and the second substrate; electrodes directly or indirectly on a first main surface of the first substrate; a dielectric layer that is located in a first region directly or indirectly on the first main surface of the first substrate and covers the electrodes, the dielectric layer being not located in a second region directly or indirectly on the first main surface of the first substrate, the second region being different from the first region, the first region including regions in which the electrodes are located; and a light-emitting layer that is located in the second region and/or located directly or indirectly on at least one of second and third main surfaces of the second substrate and emits the ultraviolet light in the gas due to electrical discharge between the electrodes.

An ultraviolet light emitting device includes: a first substrate; a second substrate; a gas in a space between the first substrate and the second substrate; electrodes directly or indirectly on a first main surface of the first substrate; a dielectric layer that is located in a first region directly or indirectly on the first main surface of the first substrate and covers the electrodes, the dielectric layer being not located in a second region directly or indirectly on the first main surface of the first substrate, the second region being different from the first region, the first region including regions in which the electrodes are located; and a light-emitting layer that is located in the second region and/or located directly or indirectly on at least one of second and third main surfaces of the second substrate and emits the ultraviolet light in the gas due to electrical discharge between the electrodes.

An ultraviolet light emitting device comprises: a first substrate having a main surface; a second substrate facing the main surface of the first substrate; a gas in a space between the first substrate and the second substrate; electrodes directly or indirectly on the main surface of the first substrate; a dielectric layer that is located directly or indirectly on the main surface of the first substrate and covers the electrodes; and a first light-emitting layer. The first light-emitting layer is located directly or indirectly on the dielectric layer and emits ultraviolet light in the gas due to electrical discharge between the electrodes. The first light-emitting layer is thicker in first regions on the dielectric layer than in second regions. The second regions include at least part of regions directly above the electrodes.

An ultraviolet light emitting device comprises: a first substrate having a main surface; a second substrate facing the main surface of the first substrate; a gas in a space between the first substrate and the second substrate; electrodes directly or indirectly on the main surface of the first substrate; a dielectric layer that is located directly or indirectly on the main surface of the first substrate and covers the electrodes; and a first light-emitting layer. The first light-emitting layer is located directly or indirectly on the dielectric layer and emits ultraviolet light in the gas due to electrical discharge between the electrodes. The first light-emitting layer is thicker in first regions on the dielectric layer than in second regions. The second regions include at least part of regions directly above the electrodes.

A fluid treatment device includes an inner tube; an outer tube that is provided so as to surround the inner tube; a discharge space in which a discharge gas is filled in a space sandwiched between the inner tube and the outer tube; a first electrode and a second electrode that are configured to apply a voltage to the discharge space; a flow path that is provided inside the inner tube and through which a treatment target fluid flows. The flow path includes a fluid control part that guides the treatment target fluid so as to approach an inner peripheral wall of the inner tube.

A system for forming a laser-sustained plasma includes a gas containment element, an illumination source configured to generate pump illumination, and a collector element. The gas containment element is configured to contain a volume of a gas mixture. The collector element is configured to focus the pump illumination from the pumping source into the volume of the gas mixture contained within the gas containment element in order to generate a plasma within the volume of the gas mixture that emits broadband radiation. The gas mixture filters one or more selected wavelengths of radiation emitted by the plasma.

A system for forming a laser-sustained plasma includes a gas containment element, an illumination source configured to generate pump illumination, and a collector element. The gas containment element is configured to contain a volume of a gas mixture. The collector element is configured to focus the pump illumination from the pumping source into the volume of the gas mixture contained within the gas containment element in order to generate a plasma within the volume of the gas mixture that emits broadband radiation. The gas mixture filters one or more selected wavelengths of radiation emitted by the plasma.

A production method for an ultraviolet light-emitting body containing Sc:YPO.sub.4 crystals, the method containing: subjecting a raw material to a hydrothermal reaction to obtain a precursor, the raw material containing a Sc source, a Y source, and a PO.sub.4 source; and firing the precursor.

A production method for an ultraviolet light-emitting body containing Sc:YPO.sub.4 crystals, the method containing: subjecting a raw material to a hydrothermal reaction to obtain a precursor, the raw material containing a Sc source, a Y source, and a PO.sub.4 source; and firing the precursor.

Disclosed herein is a device capable of irradiating a narrower area than ever before with ultraviolet light to inactivate bacteria or viruses. This device includes a first light source that emits ultraviolet light having a principal wavelength band overlapping a range of 200 nm or more and less than 240 nm; a housing body that houses the first light source; and a light guide body that has an elongated shape and guides the ultraviolet light emitted from the light source in a longitudinal direction, part of the light guide body, including a first end that is an end on a side close to the light source, being positioned in the housing body. The light guide body is disposed in such a manner that the second end, which is an end on a side opposite to the first end, projects outside the housing body.