An object is to provide a new type of near-infrared ray-emitting phosphor which exhibits excellent emission intensity. A near-infrared ray-emitting phosphor is represented by a general formula, (Y, Lu, Gd).sub.3-x-y (Ga,Al,Sc).sub.5O.sub.12:(Cr.sub.x,(Yb,Nd).sub.y) (0.05<x<0.3, 0≤y<0.3).

The present invention relates to a polysulfide upconversion phosphor, and belongs to the field of new optical function materials. The phosphor uses polysulfide as a substrate and rare earth ions as activators, and has a general formula of composition: mA.sub.2S.Math.nBS.Math.kC.sub.2-xS.sub.3:D.sub.x. The upconversion phosphor provided by the present invention can emit ultraviolet, blue, blue-green, green, red and near-infrared light when excited by near infrared light at 750-1650 nm. Because the upconversion phosphor provided by the present invention uses polysulfide with low phonon energy and symmetry as a substrate material, and optimizes rare earth ions to be doped into the matrix material as luminescence centers, the upconversion phosphor has higher upconversion luminescence efficiency and safety and wider application range compared with industrial NaYF.sub.4:Yb, Er material.

A nanoparticle containing monoclinic lutetium oxide. A method of: dispersing a lutetium salt solution in a stream of oxygen gas to form droplets, and combusting the droplets to form nanoparticles containing lutetium oxide. The combustion occurs at a temperature sufficient to form monoclinic lutetium oxide in the nanoparticles. An article containing lutetium oxide and having an average grain size of at most 10 microns.

An object is to provide a new type of near-infrared ray-emitting phosphor which exhibits excellent emission intensity. A near-infrared ray-emitting phosphor is represented by a general formula, (Y,Lu,Gd).sub.3-x-y (Ga,Al,Sc).sub.5O.sub.12:(Cr.sub.x,(Yb,Nd).sub.y) (0.05<x<0.3, 0≤y<0.3).

A phosphor of an embodiment has a composition represented by a composition formula: Na.sub.xRM.sub.yS.sub.zO.sub.a, where R represents at least one element selected from the group consisting of Y, La, Gd, and Lu, M represents at least one element selected from the group consisting of Bi, Ce, Eu, and Pr, x is an atomic ratio satisfying 0.93<x<1.07, y is an atomic ratio satisfying 0.00002<y<0.01, z is an atomic ratio satisfying 1.9<z<2.1, and a is an atomic ratio satisfying 0.001<a<0.05.

Provided are a polycrystalline phosphor film applicable to a high-power optical device, a preparation method therefor, and a vehicle lamp device using the same, wherein the polycrystalline phosphor film comprises a plurality of phosphor crystals and pores formed between the phosphor crystals, and the phosphor crystal can be a synthesized product comprising at least one rare earth material and cerium (Ce). In addition, the method for preparing a polycrystalline phosphor film can comprise the steps of: preparing a phosphor powder comprising a plurality of phosphor particles; injecting the phosphor powder into a predetermined mold so as to mold the same into a predetermined shape; generating a sintered body by primarily sintering, at a first temperature, the phosphor powder having the predetermined shape; secondarily sintering the sintered body, having been primarily sintered, at a second temperature lower than the first temperature; and forming a polycrystalline phosphor film by processing the sintered body having been secondarily sintered.

A method for checking an authenticity feature having an optical storage phosphor, to an apparatus for checking, an authenticity feature and to a value document having an authenticity feature. The authenticity feature has an optical storage phosphor. In one step, the optical storage phosphor is subjected to at least one query sequence, respectively comprising at least a first readout process and a second readout process. At least a first and a second readout measurement value are captured, which respectively are based on the detection of an optical emission in response to the respectively first or the respectively second associated readout process. A readout measurement value time series is created and is respectively associated with the at least one query sequence, comprising at least the first readout measurement value respectively associated with the first readout process and the second one respectively associated with the second readout process.

A phosphor of an embodiment has a composition represented by a composition formula: Na.sub.xRM.sub.yS.sub.zO.sub.a, where R represents at least one element selected from the group consisting of Y, La, Gd, and Lu, M represents at least one element selected from the group consisting of Bi, Ce, Eu, and Pr, x is an atomic ratio satisfying 0.93<x<1.07, y is an atomic ratio satisfying 0.00002<y<0.01, z is an atomic ratio satisfying 1.9<z<2.1, and a is an atomic ratio satisfying 0.001<a<0.05.

A nanoparticle containing monoclinic lutetium oxide. A method of: dispersing a lutetium salt solution in a stream of oxygen gas to form droplets, and combusting the droplets to form nanoparticles containing lutetium oxide. The combustion occurs at a temperature sufficient to form monoclinic lutetium oxide in the nanoparticles. An article containing lutetium oxide and having an average grain size of at most 10 microns.