Two-photon luminescence

The mercury-free fluorescent lamps and plasma display panels require alternative luminescent materials for efficient conversion of ultraviolet radiation to visible light. The quantum cutting (two photon luminescence or photon-cascade emission) was demonstrated in famous "Eu -Gd " pair" containing system employing the concept of down-conversion, which means that two visible photons are emitted after... 

Durr, N. J., Larson, T., Smith, D. K., Korgel, B. A., Sokolov, K. and Ben-Yakar, A. (2007). Two-photon luminescence imaging of cancer cells using molecularly targeted gold nanorods. Nano Lett. 7 941-945. 

The excitation of the surface plasmon effect also induces strongly enhanced fluorescence properties of gold nanoparticles due to the enhanconent in the radiative rate of the inter-band electronic transitions relative to that in bulk metals. Metal nanoparticles, especially gold nanorods exhibit enhanced two-photon luminescence (TPL) and multi-photon luminescoice (MPL) [7, 8]. Strongly-enhanced TPL has been observed from individual particles [9, 10] and particle solutions [11] under femtosecond NIR laser excitation. This observation raises the possibility of nonlinear optical imaging in the NIR region, where water and biomolecules have... 

FIGURE 98 Structure of the [Eu(L15 )3] complex used for two-photon luminescence microscopy (Picot et al., 2008a). 

Gold nanorods exhibit intense two-photon luminescence. Two-photon imaging of tissue phantoms treated with 50 x 15 nm gold nanorods functionalized with EGFR antibodies increased intensity by three orders of magnitude compared with cellular autofluorescence with 760 nm excitation [48]. 

Sommerdijk JL, Bril A, de Jager AW (1974) Two photon luminescence with ultraviolet excitation of trivalent praseodymium. J Lumin 8 341-344... 

Many other techniques have been used in addition to those discussed. For example, additional absorption techniqnes, generally beyond the scope of this article inclnde two-photon luminescence (287), thermal leasing (288), photoacoustic techniques (289), and white-light continuum spectroscopy (290). For further information, the reader is referred particnlarly to Reference 1. 

H. Wang et al.. In vitro and in vivo two-photon luminescence imaging of single gold nanorods. Proceedings of the National Academy of Sciences, 102(44), 15752-15756 (2005). 

L. Tong et al, Visualizing systemic clearance and cellular level biodistribution of gold nanorods by intrinsic two-photon luminescence, Langmuir, 25(21), 12454-12459 (2009). 

In some fluorides (e.g. YF3, LaFs, NaYF4) the lowest crystal-field component of the 4f5d state of Pr is situated above the So level. Excitation with short-wavelength ultraviolet radiation (e.g. 185 nm) or cathode-rays excites the Pr + ion from the H4 ground state into the 4f5d level, from where it decays radiationless to the So level. From here the Pr ion returns to the ground state by two-photon luminescence (Piper et al., 1974, Sommerdijk et al., 1974a) the... 

A. (2007) Two-photon luminescence imaging of cancer cells using molecularly targeted gold nanorods. Nano Letters, 7,... 

In 2007, Beeby et al. nicely showed that two-photon time gated luminescence spectra of complexes could be measured using a cavity-dumped mode locked Ti-sapphire laser with two un-optimised Eu(III) complexes (complexes potential candidates for future time-gated two-photon microscopy studies. The next generation of functionalised Ln(III) complexes will permit the in cellulo study of biologically relevant analytes by two-photon luminescence microscopy. Multi-photon excitation microscopy has established itself as a powerfiil tool in the life sciences the... 

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