Up-to-Five-Photon Upconversion from Near-Infrared to Ultraviolet Luminescence Coupled to Aluminum Plasmonic Lattices

Abstract

The incorporation of upconversion luminescence (UCL) materials into various plasmonic structures promotes light−matter interactions in nanophotonic systems. It has been experimentally demonstrated that UCL enhancement entailing two photons exhibits a quadratic dependence on the excitation intensity. However, in the field of plasmonics, there have not been sufficient studies on highorder multi-photon upconversion processes. We report up-to-five-photon UCL, wherein λ = 1550 nm near-infrared light is converted to 382 nm ultraviolet light, from core−inert shell nanoparticles coupled to aluminum plasmonic lattices. The fivephoton UCL intensity of nanoparticles on the plasmonic lattice is over 800 times stronger than that on the flat glass. We demonstrate that the enhancement of UCL scales with the nth power of the local field enhancement for n-photon process. These findings give a strategy to obtain high-order multi-photon UPL with aluminum plasmonic nanostructures and can contribute to anti-counterfeiting application.

Effect of concentration of Er3+ on up‐conversion luminescence in NaYF4 containing oxy‐fluoride glass‐ceramics

“…At low Er 3+ contents, the Er 3+ ion under 980 nm excitation undergoes processes of ground state energy absorption and excited state absorption, which pumped electrons from 4 I 15/2 → 4 I 11/2 → 4 F 7/2 , and then continues with a non-radiative relaxation to 2 H 11/2 and 4 S 3/2 energy levels, because the energy level difference from 4 F 7/2 to 4 F 9/2 is much greater than that from 4 F 7/2 to 4 S 3/2 , so the main consequence is green light emission by 4 S 3/2 → 4 I 15/2 ; at high Er 3+ contents, CR effect occurs among Er 3+ ions, in which CR1: 4 F 7/2 + 4 I 11/2 → 4 F 9/2 + 4 F 9/2 and CR2: 4 F 9/2 + 4 I 15/2 → 4 I 9/2 + 4 I 13/2 among Er 3+ ions promote more electrons undergoing transition to the 4 F 9/2 energy level, resulting in a greatly increased probability of red light emission. [41][42][43][44][45][46][47][48] The change of up-conversion color is cause by the phenomenon of cross relaxation among Er ions, which are determined by the distance of nearby Er ions and the intermediate energy levels of the exited Er 3+ ions. In this regard, high contents of Er ions shorten the distance among Er ions, which favors the cross relaxation, but not directly goes to ground state, resulting in a higher probability of electrons occupying other excited states, which provides a basis for the adjustment of the range of red-to-green ratio of the UCL.…”

Strategy of Charge Compensation for High-Performance Ni2+-Activated MgAl2O4 Spinel Near-Infrared Phosphor Synthesis via the Sol–Gel Combustion Method

“…Most semiconductor chip-based NIR pc-LEDs emit the NIR-I region, and their emission peaks are generally very narrow. The broadband NIR phosphor-based NIR pc-LED devices with ultraviolet/blue LED chips as the excitation light source emerge as the mainstream NIR devices due to their low cost, high luminous efficiency, and good spectrum turnability. − Rare earth ions (Pr 3+ , Nd 3+ , Ho 3+ , Er 3+ , and Tm 3+ ) and transition metal ions (Mn 5+ , Mn 6+ , Ni 2+ , and Cr 3+ ) are known to emit NIR above 1000 nm. − Ni 2+ has a 3d 8 electronic configuration, and its 3 T 2 (3F) → 3 A 2 (3F) leads to a broadband NIR-II (1000–1700 nm) emission with a large full width at half-maximum (fwhm) of ∼300 nm. Its emission is known to be sensitive to the microenvironment of the crystal field it occupies in the octahedron of the host material.…”

Enhancing Up-Conversion Luminescence Using Dielectric Metasurfaces: Role of the Quality Factor of Resonance at a Pumping Wavelength

“…By combining optical emitters with plasmonic metasurfaces, a strong enhancement of photoluminescence (PL) has been demonstrated. − In Figure a, we summarize the examples of PL enhancement, both down- and upconversions, of the explored optical emitters in combination with plasmonic metasurfaces, including organic dyes, fluorescence proteins, quantum dots, and up-converters. In each category, the PL enhancement factor varies depending on the configurations.…”

“…(a) Survey of the plasmonic enhancement of luminescence intensity of the emitters reported since 2005, including organic dye (red), − fluorescence protein (green), − quantum dot (orange), − and up-conversion materials (blue). − (b) Schematic of the sample consisting of an Si metasurface, an UCNP layer, and a polymer layer on the top. (c, d) Top-view SEM images of (c) an as-made Si metasurface and (d) that coated by a monolayer of UCNPs.…”