[1] Bloembergen N. Solid state infrared quantum counters[J]. Physical Review Letters, 2, 84-85(1959).
[2] Auzel F. Upconversion and anti-Stokes processes with f and d ions in solids[J]. Chemical Reviews, 104, 139-173(2004).
[3] Ovsyakin V V, Feofilov P P. Cooperative sensitization of luminescence in crystals activated with rare earth ions[J]. Soviet Journal of Experimental and Theoretical Physics Letters, 4, 317-318(1966).
[4] Muhr V, Wilhelm S, Hirsch T et al. Upconversion nanoparticles: from hydrophobic to hydrophilic surfaces[J]. Accounts of Chemical Research, 47, 3481-3493(2014).
[5] Esterowitz L, Noonan J, Bahler J. Enhancement in a Ho3+-Yb3+ quantum counter by energy transfer[J]. Applied Physics Letters, 10, 126-127(1967).
[6] Gnach A, Lipinski T, Bednarkiewicz A et al. Upconverting nanoparticles: assessing the toxicity[J]. Chemical Society Reviews, 44, 1561-1584(2015).
[7] Suyver J F, Aebischer A, García-Revilla S et al. Anomalous power dependence of sensitized upconversion luminescence[J]. Physical Review B, 71, 125123(2005).
[8] Xu L, Zhang J Z, Yin L F et al. Recent progress in efficient organic two-photon dyes for fluorescence imaging and photodynamic therapy[J]. Journal of Materials Chemistry C, 8, 6342-6349(2020).
[9] Venkatakrishnarao D, Narayana Y S L V, Mohaiddon M A et al. Two-photon luminescence and second-harmonic generation in organic nonlinear surface comprised of self-assembled frustum shaped organic microlasers[J]. Advanced Materials, 29, 1605260(2017).
[10] Auzel F. Multiphonon-assisted anti-Stokes and Stokes fluorescence of triply ionized rare-earth ions[J]. Physical Review B, 13, 2809-2817(1976).
[11] Zhou B, Shi B Y, Jin D Y et al. Controlling upconversion nanocrystals for emerging applications[J]. Nature Nanotechnology, 10, 924-936(2015).
[12] Liu D M, Xu X X, Du Y et al. Three-dimensional controlled growth of monodisperse sub-50 nm heterogeneous nanocrystals[J]. Nature Communications, 7, 10254(2016).
[13] Liao J Y, Zhou J J, Song Y L et al. Preselectable optical fingerprints of heterogeneous upconversion nanoparticles[J]. Nano Letters, 21, 7659-7668(2021).
[14] Dong H, Sun L D, Yan C H. Energy transfer in lanthanide upconversion studies for extended optical applications[J]. Chemical Society Reviews, 44, 1608-1634(2015).
[15] Zheng W, Huang P, Tu D T et al. Lanthanide-doped upconversion nano-bioprobes: electronic structures, optical properties, and biodetection[J]. Chemical Society Reviews, 44, 1379-1415(2015).
[16] Krämer K W, Biner D, Frei G et al. Hexagonal sodium yttrium fluoride based green and blue emitting upconversion phosphors[J]. Chemistry of Materials, 16, 1244-1251(2004).
[17] Zhou J, Liu Q, Feng W et al. Upconversion luminescent materials: advances and applications[J]. Chemical Reviews, 115, 395-465(2015).
[18] Wang F, Liu X G. Upconversion multicolor fine-tuning: visible to near-infrared emission from lanthanide-doped NaYF4 nanoparticles[J]. Journal of the American Chemical Society, 130, 5642-5643(2008).
[19] Chivian J S, Case W E, Eden D D. The photon avalanche: a new phenomenon in Pr3+-based infrared quantum counters[J]. Applied Physics Letters, 35, 124-125(1979).
[20] Liang Y S, Zhu Z M, Qiao S Q et al. Migrating photon avalanche in different emitters at the nanoscale enables 46th-order optical nonlinearity[J]. Nature Nanotechnology, 17, 524-530(2022).
[21] Liu Y J, Lu Y Q, Yang X S et al. Amplified stimulated emission in upconversion nanoparticles for super-resolution nanoscopy[J]. Nature, 543, 229-233(2017).
[22] Hao S W, Shao W, Qiu H L et al. Tuning the size and upconversion emission of NaYF4∶Yb3+/Pr3+ nanoparticles through Yb3+ doping[J]. RSC Advances, 4, 56302-56306(2014).
[23] Dong H, Sun L D, Wang Y F et al. Photon upconversion in Yb3+-Tb3+ and Yb3+-Eu3+ activated core/shell nanoparticles with dual-band excitation[J]. Journal of Materials Chemistry C, 4, 4186-4192(2016).
[24] Qin W P, Liu Z Y, Sin C N et al. Multi-ion cooperative processes in Yb3+ clusters[J]. Light: Science & Applications, 3, e193(2014).
[25] Zhou B, Yang W F, Han S Y et al. Photon upconversion through Tb3+-mediated interfacial energy transfer[J]. Advanced Materials, 27, 6208-6212(2015).
[26] Wang F, Deng R R, Wang J et al. Tuning upconversion through energy migration in core-shell nanoparticles[J]. Nature Materials, 10, 968-973(2011).
[27] Zuo J, Sun D P, Tu L P et al. Cover picture: precisely tailoring upconversion dynamics via energy migration in core-shell nanostructures (angew. chem. int. Ed. 12/2018)[J]. Angewandte Chemie: International Edition, 57, 2979(2018).
[28] Hell S W, Sahl S J, Bates M et al. The 2015 super-resolution microscopy roadmap[J]. Journal of Physics D: Applied Physics, 48, 443001(2015).
[29] Shi S, Yin Z S, Wang L. Dark channel and cross channel based multi-prior combined multi-spectral super-resolution algorithm[J]. Acta Optica Sinica, 42, 1010001(2022).
[30] Hell S W, Wichmann J. Breaking the diffraction resolution limit by stimulated emission: stimulated-emission-depletion fluorescence microscopy[J]. Optics Letters, 19, 780-782(1994).
[31] Willig K I, Harke B, Medda R et al. STED microscopy with continuous wave beams[J]. Nature Methods, 4, 915-918(2007).
[32] Kuang C F, Li S, Liu W et al. Breaking the diffraction barrier using fluorescence emission difference microscopy[J]. Scientific Reports, 3, 1441(2013).
[33] Han K Y, Kim S K, Eggeling C et al. Metastable dark states enable ground state depletion microscopy of nitrogen vacancy centers in diamond with diffraction-unlimited resolution[J]. Nano Letters, 10, 3199-3203(2010).
[34] Deka G, Sun C K, Fujita K et al. Nonlinear plasmonic imaging techniques and their biological applications[J]. Nanophotonics, 6, 149(2017).
[35] Lee C, Xu E Z, Liu Y W et al. Giant nonlinear optical responses from photon-avalanching nanoparticles[J]. Nature, 589, 230-235(2021).
[36] Wang B J, Zhan Q Q, Zhao Y X et al. Visible-to-visible four-photon ultrahigh resolution microscopic imaging with 730-nm diode laser excited nanocrystals[J]. Optics Express, 24, A302-A311(2016).
[37] Gustafsson M G L. Nonlinear structured-illumination microscopy: wide-field fluorescence imaging with theoretically unlimited resolution[J]. Proceedings of the National Academy of Sciences of the United States of America, 102, 13081-13086(2005).
[38] Wang G C, Chen T S. Super-resolution structural characteristics of subcellular organelles in living cells[J]. Chinese Journal of Lasers, 49, 2007203(2022).
[39] Gao L, Gao B B, Wang F. Applications of super-resolution microscopy techniques in living brain imaging[J]. Chinese Journal of Lasers, 49, 2007301(2022).
[40] Sahl S J, Hell S W, Jakobs S. Fluorescence nanoscopy in cell biology[J]. Nature Reviews Molecular Cell Biology, 18, 685-701(2017).
[41] Drees C, Raj A N, Kurre R et al. Engineered upconversion nanoparticles for resolving protein interactions inside living cells[J]. Angewandte Chemie: International Edition, 55, 11668-11672(2016).
[42] Yao C, Wang P Y, Li X M et al. Near-infrared-triggered azobenzene-liposome/upconversion nanoparticle hybrid vesicles for remotely controlled drug delivery to overcome cancer multidrug resistance[J]. Advanced Materials (Deerfield Beach, Fla.), 28, 9341-9348(2016).
[43] He M, Pang X C, Liu X Q et al. Monodisperse dual-functional upconversion nanoparticles enabled near-infrared organolead halide perovskite solar cells[J]. Angewandte Chemie: International Ed. in English, 55, 4280-4284(2016).
[44] Wang F, Banerjee D, Liu Y S et al. Upconversion nanoparticles in biological labeling, imaging, and therapy[J]. The Analyst, 135, 1839-1854(2010).
[45] Zhan Q Q, Liu H C, Wang B J et al. Achieving high-efficiency emission depletion nanoscopy by employing cross relaxation in upconversion nanoparticles[J]. Nature Communications, 8, 1058(2017).
[46] Chmyrov A, Keller J, Grotjohann T et al. Nanoscopy with more than 100000 ‘doughnuts’[J]. Nature Methods, 10, 737-740(2013).
[47] Liang L L, Feng Z W, Zhang Q M et al. Continuous-wave near-infrared stimulated-emission depletion microscopy using downshifting lanthanide nanoparticles[J]. Nature Nanotechnology, 16, 975-980(2021).
[48] Wu Q S, Huang B R, Peng X Y et al. Non-bleaching fluorescence emission difference microscopy using single 808-nm laser excited red upconversion emission[J]. Optics Express, 25, 30885-30894(2017).
[49] Chen C H, Wang F, Wen S H et al. Multi-photon near-infrared emission saturation nanoscopy using upconversion nanoparticles[J]. Nature Communications, 9, 3290(2018).
[50] Chen C H, Liu B L, Liu Y T et al. Heterochromatic nonlinear optical responses in upconversion nanoparticles for super-resolution nanoscopy[J]. Advanced Materials, 33, e2008847(2021).
[51] Liu Y T, Wang F, Lu H X et al. Super-resolution mapping of single nanoparticles inside tumor spheroids[J]. Small, 16, e1905572(2020).
[52] Denkova D, Ploschner M, Das M et al. 3D sub-diffraction imaging in a conventional confocal configuration by exploiting super-linear emitters[J]. Nature Communications, 10, 3695(2019).
[53] Plöschner M, Denkova D, de Camillis S et al. Simultaneous super-linear excitation-emission and emission depletion allows imaging of upconversion nanoparticles with higher sub-diffraction resolution[J]. Optics Express, 28, 24308-24326(2020).
[54] Bednarkiewicz A, Chan E M, Kotulska A et al. Photon avalanche in lanthanide doped nanoparticles for biomedical applications: super-resolution imaging[J]. Nanoscale Horizons, 4, 881-889(2019).
[55] Shen S H, Du E, Zhang M et al. Confocal rescan structured illumination microscopy for real-time deep tissue imaging with superresolution[J]. Advanced Photonics Nexus, 2, 016009(2023).
[56] Liu B L, Chen C H, Di X J et al. Upconversion nonlinear structured illumination microscopy[J]. Nano Letters, 20, 4775-4781(2020).
[57] Liu B L, Liao J Y, Song Y L et al. Multiplexed structured illumination super-resolution imaging with lifetime-engineered upconversion nanoparticles[J]. Nanoscale Advances, 4, 30-38(2022).
[58] Ding L, Chen C H, Shan X C et al. Optical nonlinearity enabled super-resolved multiplexing microscopy[J]. Advanced Materials, 36, e2308844(2024).
[59] Wang F, Wen S H, He H et al. Microscopic inspection and tracking of single upconversion nanoparticles in living cells[J]. Light, Science & Applications, 7, 18007(2018).
[60] Garfield D J, Borys N J, Hamed S M et al. Enrichment of molecular antenna triplets amplifies upconverting nanoparticle emission[J]. Nature Photonics, 12, 402-407(2018).
[61] Gargas D J, Chan E M, Ostrowski A D et al. Engineering bright sub-10-nm upconverting nanocrystals for single-molecule imaging[J]. Nature Nanotechnology, 9, 300-305(2014).
[62] Kraft M, Würth C, Muhr V et al. Particle-size-dependent upconversion luminescence of NaYF4∶Yb, Er nanoparticles in organic solvents and water at different excitation power densities[J]. Nano Research, 11, 6360-6374(2018).
[63] Ma C S, Xu X X, Wang F et al. Optimal sensitizer concentration in single upconversion nanocrystals[J]. Nano Letters, 17, 2858-2864(2017).
[64] Sedlmeier A, Gorris H H. Surface modification and characterization of photon-upconverting nanoparticles for bioanalytical applications[J]. Chemical Society Reviews, 44, 1526-1560(2015).
[65] Sun T Y, Li Y H, Ho W L et al. Integrating temporal and spatial control of electronic transitions for bright multiphoton upconversion[J]. Nature Communications, 10, 1811(2019).
[66] Lee C, Xu E Z, Kwock K W C et al. Indefinite and bidirectional near-infrared nanocrystal photoswitching[J]. Nature, 618, 951-958(2023).
[67] Zhou J J, Chizhik A I, Chu S et al. Single-particle spectroscopy for functional nanomaterials[J]. Nature, 579, 41-50(2020).