Detection of laser-induced

Using the same PAbs an optical biosensor system has been developed for 2,4,6-TCP [224]. The principle is the detection of laser-induced fluorescence (LIF) in single microdroplets by a homogeneous quenching fluorescence immunoassay (QFIA). The competitive immunoassay occurs in microdroplets (d=58.4 mm) produced by a piezoelectric generator system. A continuous Ar ion laser (488 nm) excites the fluorescent tracer and its fluorescence is detected by a spectrometer attached to a cooled, charge-coupled device (CCD) camera... 

At York University, Toronto, microwave measurements have been revived by Storry and Hessels [9,10], that could benefit of lasers to excite the 23P level, instead of the lamps used by Hughes and coworkers. Also, the detection of laser-induced fluorescence from 23P levels makes another basic difference with respect to Hughes experiments, which, together with a microwave frequency scan, eliminated the lineshape asymmetries. In this experiment, a moderate magnetic field is also used to select the transitions between the desidered Mj sublevels. The... 

Maznev AA, Nelson KA, Rogers JA. Optical heterodyne detection of laser-induced gratings. Opt Lett 1998 23(16) 1319. 

FTLIF = Fourier transform detection of laser induced fluorescence. 

The majority of femtosecond time-resolved PP experiments is performed in the condensed phase and is based on the detection of photons. For these experiments, the calculation of the nonlinear electric polarization represents the central task of the theoretical description. While femtosecond time-resolved measurements with detection of photons are possible also in the gas phase, e.g. by the detection of laser-induced fluorescence (LIF) or with background-free four-wave-mixing schemes, the detection of charged particles (i.e. photoelectrons or ions) has the advantage of the extremely high collection efficiency. By mass-selected detection of the ions, additional information on the photoinduced fragmentation... 

F. E. Hoge, R.N. Swift Airborne simultaneous spectroscopic detection of laser-induced water Raman backscatter and fluorescence from chlorophyll a and other naturally occuring pigments. Appl. Opt. 20, 3197 (1981)... 

Bundschuh, T., W. Hauser, J.L. Kim, R. Knopp, and F.J. Scherbaum. 2001. Determination of colloid size by two-dimensional optical detection of laser induced plasma. Coll. Surf. A, 180 285-293. 

In the higher atmosphere the aerosol density decreases rapidly with altitude and other detection schemes may become more advantageous. Raman spectroscopy or detection of laser-induced fluorescence excited by frequency-doubled pulsed lasers has been utilized [14.22]. Both Raman and fluorescence intensities excited by the laser at a location x are proportional to the density n. (x) of scattering particles. However, because of the high pressure (p latm) the fluorescence is quenched if the collisional deactivation na v becomes faster than the spontaneous decay A. = 1/t. (see Sect. 12.2). Transition probabilities and quenching cross sections must therefore be known if quantitative results are to be obtained from measurements of the fluorescence intensity. 

K. A., Rogers, J.A. (1998). Optical heterodyne detection of laser-induced gratings. Opt. Lett. 23 1319-1321 Fecko,C.J.,Eaves, J.D.,Tokmakoff, A. (2002). Isotropic and anisotropic Raman scattering from molecular liquids measured by spatially masked optical Kerr effect spectroscopy. J. Chem. Phys. 117 1139-1154. 

However, with the advent of lasers, the teclmique of laser-induced fluorescence (LIF) has probably become the single most popular means of detennining product-state distributions an early example is the work by Zare and co-workers on Ba + FLT (X= F, Cl, Br, I) reactions [25]. Here, a tunable laser excites an electronic transition of one of the products (the BaX product in this example), and the total fluorescence is detected as a... 

New to the fourth edition are the topics of laser detection and ranging (LIDAR), cavity ring-down spectroscopy, femtosecond lasers and femtosecond spectroscopy, and the use of laser-induced fluorescence excitation for stmctural investigations of much larger molecules than had been possible previously. This latter technique takes advantage of two experimental quantum leaps the development of very high resolution lasers in the visible and ultraviolet regions and of the supersonic molecular beam. 

Since TIRF produces an evanescent wave of typically 80 nm depth and several tens of microns width, detection of TIRF-induced fluorescence requires a camera-based (imaging) detector. Hence, implementing TIRF on scanning FLIM systems or multiphoton FLIM systems is generally not possible. To combine it with FLIM, a nanosecond-gated or high-frequency-modulated imaging detector is required in addition to a pulsed or modulated laser source. In this chapter, the implementation with of TIRF into a frequency-domain wide-field FLIM system is described. 

Luminescence of Mn " is well known in the steady-state luminescence spectra of feldspars (Tarashchan 1978 Waychunas 1989 White 1990 GOtze 2000 Goro-bets and Rogojine 2001). Its green luminescence is predominantly detected in plagioclases. In K-feldspars the Mn " " emission is less common because of the difficulty of the Mn " - K" " substitution. Its band is also very well detected in laser-induced time-resolved spectra peaking at 550-560 nm (Eig. 4.43a). It is characterized by an extremely long decay time of 10-12 ms. 

K. Yamanouchi In the VUV-PHOFEX measurements, the photofragment of S( S) was monitored by exciting it to the S(3D]) state by the UV laser light and by detecting die laser-induced fluorescence emitted from S(3D]). Since only the fluorescence from the S fragments produced in the central region of the free-jet expansion was collected, the photoabsorption of ultracold (-5 K) OCS was selectively detected. 

Miller et al. (8) report the CN(X E ) nascent vibrational populations detected by laser induced fluorescence after flash photolysis of C2N2 under collisionless conditions at 164, 158, and 154 nm. They report only the ratio of the CN(X2Z+, v = 1) to CN(X2E+, v = 0) populations. In all cases, they find this ratio to be less than 1, but increasing with higher photon energy. 

Abbreviations DNA, deoxyribose nucleic acid ECD, electrochemical detection LIF, laser induced fluorescence LOD, limit of detection PDMS, poly(dimethylsiloxane) PSA, prostate specific antigen TOF-MS, time-of-flight mass spectrometer TNT, 2,4,6-trinitrotoluene. 

Figure 8.12 Chromatography of anthracene derivatives with different detection modes (A) laser-induced fluorescence (B) UV absorbance. Conditions capillary, 115.1 cm X 10 /un I.D. with 1.27-/im coating stationary phase, silicone acrylate/ethylhexyl acrylate Vy Vm = 0.65 mobile phase, acetonitrile detection, (A) laser-induced fluorescence (AeX 325 nm, Aem 380 nm), pressure 13.8 bar, (B) UV (258 nm), pressure 13.0 bar. Peaks 1, salicylate 2, anthracene-methanol 3, anthracenecarbonitrile 4, anthracene 5, fluoranthracene 6,1,2-benzanthracene 7, 9-phenylanthracene. (Reprinted from Ref. 11 with permission.)...

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