Excited fluorescence

B1.18.5.5 CONTRAST ENHANCEMENT AND PRACTICAL LIMITS TO CONFOCAL ONE-PHOTON-EXCITATION FLUORESCENCE MICROSCOPY... 

B1.18.5.6 CONFOCAL MICROSCOPY WITH MULTIPHOTON-EXCITATION FLUORESCENCE... 

Wokosin D L, Centonze V, White J G, Armstrong D, Robertson G and Ferguson A I 1996 All-solid-state ultrafast lasers facilitate multiphoton excitation fluorescence imaging IEEE J. Sel. Top. Quantum Electron. 21051-65... 

Two-photon excited fluorescence detection at the single-molecule level has been demonstrated for cliromophores in cryogenic solids [60], room-temperature surfaces [61], membranes [62] and liquids [63, 64 and 65]. Altliough multiphoton excited fluorescence has been embraced witli great entluisiasm as a teclmique for botli ordinary confocal microscopy and single-molecule detection, it is not a panacea in particular, photochemical degradation in multiphoton excitation may be more severe tlian witli ordinary linear excitation, probably due to absorjDtion of more tlian tire desired number of photons from tire intense laser pulse (e.g. triplet excited state absorjDtion) [61],... 

Mertz J, Xu C and Webb W W 1995 Single-molecule detection by two-photon-excited fluorescence Opt Lett. 20 2532-4... 

Other techniques to inspect bonding surfaces for contamination have also been proposed, including ultraviolet fluorescence [162], Pulsed ultraviolet light incident on the surface excites fluorescence of organic contamination, which can... 

The same UV lamps discussed in Section 2.2.3.1 are employed to excite fluorescence. Excitation is usually performed using long-wavelength radiation (2 = 365 nm), shorter wavelengths are occasionally employed (e.g. 2 = 302 nm, DNA analysis). 

A qualitatively different approach to probing multiple pathways is to interrogate the reaction intermediates directly, while they are following different pathways on the PES, using femtosecond time-resolved pump-probe spectroscopy [19]. In this case, the pump laser initiates the reaction, while the probe laser measures absorption, excites fluorescence, induces ionization, or creates some other observable that selectively probes each reaction pathway. For example, the ion states produced upon photoionization of a neutral species depend on the Franck-Condon overlap between the nuclear configuration of the neutral and the various ion states available. Photoelectron spectroscopy is a sensitive probe of the structural differences between neutrals and cations. If the structure and energetics of the ion states are well determined and sufficiently diverse in... 

Nonlinear optical phenomena, as well as near-field optics, provide us with super resolving capability [20]. The probability of nonlinear optical phenomena is proportional to the number of photons which participate in the phenomenon. For example, the intensity distribution of two-photon excited fluorescence corresponds to the square of the excitation light. Thus, we proposed a combination of the field... 

Swift, J. L., Heuff, R. F. and Cramb, D. T. (2006) A two-photon excitation fluorescence cross-correlation assay for a model ligand-receptor binding system using quantum dots. Biophys. J., 90, 1396-1410. 

FIG. 12 Principal component analysis similarity map defined by the principal components 1 and 2 for vitamin A excitation fluorescence spectral data. Sample coding L, R, and X stand for the GDL, rennet, and mixed systems, respectively the digits are for the time elapsed since the beginning of the kinetics. 

Itoh, M. Adachi, T. Transient absorption and two-step laser excitation fluorescence studies of the excited-state proton transfer and relaxation in the methanol solution of 7-hydroxyflavone. J. Am. Chem. Soc. 1984, 106, 4320 -324. 

Itoh, M. Hasegawa, K. Fujiwara, Y. Two-step laser excitation fluorescence study of the ground- and excited-state proton transfer in alcohol solutions of 7-hydroxyisoflavone. J. Am. Chem. Soc. 1986, 108, 5853-5857. 

Principles and Characteristics Atomic fluorescence spectrometry (AFS) is based on excitation of atoms by radiation of a suitable wavelength (absorption), and detection and measurement of the resultant de-excitation (fluorescence). The only process of analytical importance is resonance fluorescence, in which the excitation and fluorescence lines have the same wavelength. Nonresonance transitions are not particularly analytically useful, and involve absorption and fluorescence photons of different energies (wavelength). 

Fluorescence Lifetimes. Fluorescence lifetimes were determined by the phase shift method, utilizing a previously-described phase fluorimeter. The emission from an argon laser was frequency doubled to provide a 257 nm band for excitation. Fluorescence lifetimes of anisole and polymer 1 in dichloro-methane solution were 2.2 and 1.4 nsec, respectively. Fluorescence lifetimes of polymer films decreased monotonically with increasing DHB concentration from 1.8 (0) to 0.7 nsec (9.2 x 10 3 MDHB). Since fluorescence lifetimes (in contrast to fluorescence intensities) are unaffected by absorption effects of the stabilizer, these results provide direct evidence in support of the intensity measurements for RET from polymer to stabilizer. 

Sun W-C, Gee KR, Haugland RP (1998) Synthesis of novel fluorinated coumarins excellent UV light-excitable fluorescent dyes. Bioorg Med Chem Lett 8 3107-3110... 

Fig. 5 Linear absorption (1, 2) and one-photon-excited fluorescence (1, 2 ) for the quantum yield standard Cresyl Violet (1, 1 ) and the proposed standard PD 2631 (2, 2 ) for NIR wavelengths. Molecular structures are shown to the left...

So PT, Dong CY, Masters BR, Berland KM (2000) Two-photon excitation fluorescence microscopy. Annu Rev Biomed Eng 2 399-429... 

Lee LG, Berry GM, Chen CH (1989) Vita blue a new 633-nm excitable fluorescent dye for cell analysis. Cytometry 10 151-164... 

Personov RI, AT shits LA, Bykovskaja LA (1972) The effect of fine structure appearance in laser-excited fluorescence spectra of organic compounds in solid solutions. Opt Commun 6 169-173... 

The fluorescent components are denoted by I (intensity) followed by a capitalized subscript (D, A or s, for respectively Donors, Acceptors, or Donor/ Acceptor FRET pairs) to indicate the particular population of molecules responsible for emission of/and a lower-case superscript (d or, s) that indicates the detection channel (or filter cube). For example, / denotes the intensity of the donors as detected in the donor channel and reads as Intensity of donors in the donor channel, etc. Similarly, properties of molecules (number of molecules, N quantum yield, Q) are specified with capitalized subscript and properties of channels (laser intensity, gain, g) are specified with lowercase superscript. Factors that depend on both molecular species and on detection channel (excitation efficiency, s fraction of the emission spectrum detected in a channel, F) are indexed with both. Note that for all factorized symbols it is assumed that we work in the linear (excitation-fluorescence) regime with negligible donor or acceptor saturation or triplet states. In case such conditions are not met, the FRET estimation will not be correct. See Chap. 12 (FRET calculator) for more details. 

LaMorte, Y. J., Zoumi, A. and Tromberg, B. J. (2003). Spectroscopic approach for monitoring two-photon excited fluorescence resonance energy transfer from homodimers at the subcellular level. J. Biomed. Opt. 8, 357-61. 

Volkmer, A., Subramaniam, V., Birch, D. J. and Jovin, T. M. (2000). One- and two-photon excited fluorescence lifetimes and anisotropy decays of green fluorescent proteins. Biophys. J. 78, 1589-98. 

Tada, J., Kono, T., Suda, A., Mizuno, H., Miyawaki, A., Midorikawa, K. and Kannari, F. (2007). Adaptively controlled supercontinuum pulse from a micro structure fiber for two-photon excited fluorescence microscopy. Appl. Opt. 46, 3023-30. 

Fisz, J. J. (2007). Fluorescence polarization spectroscopy at combined high-aperture excitation and detection Application to one-photon-excitation fluorescence microscopy. J. Phys. Chem. A 111, 8606-21. 

---