TECHNOLOGY FOCUS - CERAMICS AND GLASS - Preferred Components: The matrix may be inorganic or organic glass having a viscosity of 1x 103-1x 1017 Pa.s.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The first and second components are different organic compounds, preferably carbon-containing compounds, provided that they are not hydrogen-free chalcogenide of carbon or its derivative, salt-like carbide, metallic carbide, or metal carbonyl. The first component may be an organic dye or molecule having populated triplet or mixed triplet-singlet state, two-photon-absorbing (TPA) dye, optical limiting compound, another molecule with populated triplet state, or optical limiting compound, e.g. fullerene or carbon nanotube; or the first and second components are first and second organic dyes selected from organic dyes with populated triplet states or capable of direct and/or sequential two-photon excitation, organic dyes capable of direct and/or multi-photon excitation, organic dyes capable of non-linear absorption, and organic dyes capable of hot-band absorption. The first organic dye is metal-organic complex having populated triplet states selected from porphyrin including extended porphyrin, texaphyrin, sapphyrin, orangerin (any carbon-bridged pyrrolic system), or substituted porphyrin containing lithium (Li), magnesium (Mg), aluminum (Al), titanium (Ti), vanadium (V) or vanadium oxide (VO), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), ruthenium (Ru), palladium (Pd), silver (Ag), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), lead (Pb), and/or uranium or uranium oxide (U or UO2); phthalocyanine including extended phthalocyanine or substituted phthalocyanine containing Li, Mg, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ru, Pd, Ag, Re, Os, Ir, Pt, Pb, and/or U; or optionally substituted benzopyridine, benzopyrizine, quinolate and hydroxyquinolate, and/or acetylacetonate. The second organic dye is fluorescent dye showing fluorescence emission at 360-750 nm, e.g. anthracene, tetracene, or pentacene; perylene-substituted anthracene, tetracene, or pentacene; perylene phenyl (bi-, triphenyl)-bridged anthracene, tetracene, or pentacene; perylene fluorene; thiophene; polyfluorene and oligofluorene with or without any sidechain pattern and their copolymers; polyparaphenylene including polyparaphenylene vinylene and polyphenylene ethynylene. The first and second organic dyes are chosen so that a populated triplet state of first organic dye is at an energy level allowing triplet-triplet annihilation process and subsequent transfer of energy to an excited singlet state of second dye. The combination of first and second components is green couple: 9,10-diphenylanthracene/2,7,8,12,13,17,18-octaethylporphyrin palladium (DPA/PdOEP); red couple: 9,10-bis(phenylethynyl)anthracene/meso-tetraphenyl-tetrabenzoporphyrin palladium (BPEA/PdTPTBP); near infrared couple: 9,10-bis(phenylethynyl)naphthacene/meso-tetraphenyl-octamethoxide-tetranaphtho(2,3)porphyrin palladium (BPEN/PdTPTNP); direct red-to-blue couple: perylene/PdTPTBP; direct infrared-to-green couple: 4,4'-bis(5-tetracenyl)-1,1'-biphenylene (BPBT)/PdTPTNP; or infrared-to-yellow couple: 5,6,11,12-tetraphenylnaphthacene/tetraantraporphyrin palladium. The first and second components are encapsulated in particles having average dimensions of 5 nm-999 mu m (preferably 10 nm-999 mu m). The particles are homogeneously distributed within the matrix. The particles have a surface which is functionalized by hydrogen, -(CH2)nCH3, -(CH2)n-COOR, -(CH2)n-OR, -(CH2)n-SR, -(CH2)n-NR2, or -((CH2)p-O)n-CH3.R=H, optionally substituted alkenyl or alkynyl, halo (such as Cl, Br, F, or I), NO2, NH2, CN, SO3H, or OH.    TECHNOLOGY FOCUS - POLYMERS - Preferred Properties: The matrix is transparent at 300-1600 nm. The fluid has a viscosity of 0.59x 10-3-1x 106 Pa.s. Preferred Components: The matrix is made of organic oligomer having a finite number of monomeric units, or co-oligomer comprising a mixture of monomeric units; thermoplastic polymer or copolymer including block, alternating and/or graft copolymer with molecular weight of 1x 102-1x 109 (preferably 1x 103-1x 109) including linear and branched polymer(s); thermosetting plastic including polyester resin, epoxy resin (preferably two-component epoxy resin), acrylic, polyimide, melamine resin, or phenol-formaldehyde resin; or elastic solid and polymer elastomer including polyacrylic rubber, silicone rubber, fluorosilicone rubber, fluoroelastomer, perfluoroelastomer, polyether-block-amide, or olefin rubber. The monomeric units are optionally substituted styrene, phenylene, phenylene diamine, phenylene diol, methyl methacrylate, phenol, acrylic acid, vinyl (such as vinyl alcohol or vinyl chloride), lactic acid, carbohydrate, carbonate, imide, amide (such as acryl amide), olefin (such as ethylene and propylene), olefin oxide (such as ethylene oxide or propylene oxide), olefin glycol (such as ethylene glycol and propylene glycol), terephthalic acid, epsilon -caprolactam, urethane, silane, siloxane, and/or substituted and functionalized form of these monomeric units. The matrix may be an inorganic or organic gel having a viscosity of greater than or equal to 0.1 Pa.s, preferably organic physical gel having non-covalent bonds or a chemical gel having covalent bonds and preferably crosslinked by irradiation and/or addition of crosslinking chemicals. The gel contains linear and branched polymer(s) including but not limited to polystyrene, polyphenylene, polynaphthalate, polyterephthalate, polyolefin naphthalate and polyolefin terephthalate (such as polyethylene naphthalate and polyethylene terephthalate), polyether imide, polyether ketone, polyhydroxybutyrate, polyphenylene diamine, polyphenylene diol, polymethyl methacrylate, polyphenol, polyacrylic acid, polyvinyl (such as polyvinyl alcohol or polyvinyl chloride), polylactic acid, polycarbohydrate, polycarbonate, polyimide, polyamide (such as polyacryl amide), polyolefin (such as polyethylene and polypropylene), polyolefin oxide (such as polyethylene oxide or polypropylene oxide), polyolefin glycol (such as polyethylene glycol and polypropylene glycol), polyterephthalic acid, poly- epsilon -caprolactam, polyurethane, polysilane, and/or polysiloxane. The matrix optionally and additionally includes organic solvent(s) or water to vary, adjust and control the viscosity of medium. The matrix may be a viscous liquid having a viscosity of 0.059 Pa.s. The matrix does not take part in photon energy up-conversion process upon irradiation of the medium. EXAMPLE - No suitable example given.