A lighting device 1 has phosphors, a porous material (5), and emitters 4. The emitters are interposed between the phosphors and surfaces (2a) to be irradiated with light of the lighting device. The porous material has heat conductivity and is impregnated with the phosphors.

To improve startability in a UV irradiation apparatus equipped with excimer lamps. The UV irradiation apparatus includes a plurality of excimer lamps each having a light-emitting tube filled with a discharge gas containing a noble gas. The plurality of excimer lamps includes a first excimer lamp filled with the discharge gas at a first enclosed gas pressure and a second excimer lamp filled with the discharge gas at a second enclosed gas pressure lower than the first enclosed gas pressure. The first excimer lamp is placed in a position such that at least part of light emitted from the second excimer lamp is allowed to enter the first excimer lamp.

To improve startability in a UV irradiation apparatus equipped with excimer lamps. The UV irradiation apparatus includes a plurality of excimer lamps each having a light-emitting tube filled with a discharge gas containing a noble gas. The plurality of excimer lamps includes a first excimer lamp filled with the discharge gas at a first enclosed gas pressure and a second excimer lamp filled with the discharge gas at a second enclosed gas pressure lower than the first enclosed gas pressure. The first excimer lamp is placed in a position such that at least part of light emitted from the second excimer lamp is allowed to enter the first excimer lamp.

A short-arc discharge lamp includes a pair of electrodes disposed facing each other inside a light-emitting tube, a scale-like structure being formed on an outer surface of at least one electrode of the pair of electrodes, and a coating film covering the outer surface on which the scale-like structure is formed. The scale-like structure includes a plurality of flaky protrusions protruding from the outer surface in a direction inclined with respect to a normal direction of the outer surface, each flaky protrusion having a front surface whose angle formed with the outer surface is an obtuse angle and a back surface whose angle formed with the outer surface is an acute angle. The coating film contains at least one of metal oxides, metal carbides, metal borides, metal silicides, and metal nitrides. A part of the coating film enters a space sandwiched between the back surface and the outer surface.

A short-arc discharge lamp includes a pair of electrodes disposed facing each other inside a light-emitting tube, a scale-like structure being formed on an outer surface of at least one electrode of the pair of electrodes, and a coating film covering the outer surface on which the scale-like structure is formed. The scale-like structure includes a plurality of flaky protrusions protruding from the outer surface in a direction inclined with respect to a normal direction of the outer surface, each flaky protrusion having a front surface whose angle formed with the outer surface is an obtuse angle and a back surface whose angle formed with the outer surface is an acute angle. The coating film contains at least one of metal oxides, metal carbides, metal borides, metal silicides, and metal nitrides. A part of the coating film enters a space sandwiched between the back surface and the outer surface.

A discharge chamber for a deep ultraviolet (DUV) light source includes a housing; and a first electrode and a second electrode in the housing, the first electrode and the second electrode being separated from each other to form a discharge region between the first electrode and the second electrode, the discharge region being configured to receive a gain medium including at least one noble gas and a halogen gas. At least one of the first electrode and the second electrode includes a metal alloy including more than 33% and less than 50% zinc by weight.

To improve startability in a UV irradiation apparatus equipped with excimer lamps. The UV irradiation apparatus includes a plurality of excimer lamps each having a light-emitting tube filled with a discharge gas containing a noble gas. The plurality of excimer lamps includes a first excimer lamp filled with the discharge gas at a first enclosed gas pressure and a second excimer lamp filled with the discharge gas at a second enclosed gas pressure lower than the first enclosed gas pressure. The first excimer lamp is placed in a position such that at least part of light emitted from the second excimer lamp is allowed to enter the first excimer lamp.

To improve startability in a UV irradiation apparatus equipped with excimer lamps. The UV irradiation apparatus includes a plurality of excimer lamps each having a light-emitting tube filled with a discharge gas containing a noble gas. The plurality of excimer lamps includes a first excimer lamp filled with the discharge gas at a first enclosed gas pressure and a second excimer lamp filled with the discharge gas at a second enclosed gas pressure lower than the first enclosed gas pressure. The first excimer lamp is placed in a position such that at least part of light emitted from the second excimer lamp is allowed to enter the first excimer lamp.

A discharge chamber for a deep ultraviolet (DUV) light source includes a housing; and a first electrode and a second electrode in the housing, the first electrode and the second electrode being separated from each other to form a discharge region between the first electrode and the second electrode, the discharge region being configured to receive a gain medium including at least one noble gas and a halogen gas. At least one of the first electrode and the second electrode includes a metal alloy including more than 33% and less than 50% zinc by weight.

There is provided a photoreactor for the remediation of gaseous emissions and/or contaminated water using ultraviolet (UV) or vacuum ultraviolet (VUV). There is also provided an emission source for generating UV and/or VUV, the source comprising: a microwave generator; a chamber arranged to receive microwaves generated by the microwave generator, the chamber comprising: a gas comprising species for forming excimers; a resonator arranged to receive the microwaves in the chamber and generate a plasma; a first electrode spaced apart from the resonator; and a voltage source configured to generate an electric field between the resonator and the first electrode, wherein, on application of the electric field, the electric field drives electrons and/or ions from the plasma to generate excimers and produce vacuum ultraviolet or ultraviolet emission. There are also provided methods of generating UV and/or VUV, and methods of remediating fluids.