Journal articles: 'Laser Fluorescence Imaging'

1

Hanson, Ronald K. "Planar laser-induced fluorescence imaging." Journal of Quantitative Spectroscopy and Radiative Transfer 40, no. 3 (September 1988): 343–62. http://dx.doi.org/10.1016/0022-4073(88)90125-2.

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Saitoh, Naoki, and Norimitsu Akiba. "Ultraviolet Fluorescence Imaging of Fingerprints." Scientific World JOURNAL 6 (2006): 691–99. http://dx.doi.org/10.1100/tsw.2006.143.

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We studied fluorescence imaging of fingerprints on a high-grade white paper in the deep ultraviolet (UV) region with a nanosecond-pulsed Nd-YAG laser system that consists of a tunable laser and a cooled CCD camera.Clear fluorescence images were obtained by time-resolved imaging with a 255- to 425-nm band-pass filter, which cuts off strong fluorescence of papers. Although fluorescence can be imaged with any excitation wavelength between 220 and 290 nm, 230 and 280 nm are the best in terms of image quality. However, the damage due to laser illumination was smaller for 266-nm excitation than 230- or 280-nm excitation.Absorption images of latent fingerprints on a high-grade white paper are also obtained with our imaging system using 215- to 280-nm laser light. Shorter wavelengths produce better images and the best image was obtained with 215 nm. Absorption images are also degraded slightly by laser illumination, but their damage is smaller than that of fluorescence images.

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Cappelli, M. A., P. H. Paul, and R. K. Hanson. "Laser‐induced fluorescence imaging of laser‐ablated barium." Applied Physics Letters 56, no. 18 (April 30, 1990): 1715–17. http://dx.doi.org/10.1063/1.103124.

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Gupta, Neelam. "Spectropolarimetric Imaging of Laser-Induced Fluorescence." IEEE Sensors Journal 10, no. 3 (March 2010): 503–8. http://dx.doi.org/10.1109/jsen.2009.2038189.

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Grönlund, Rasmus, Jenny Hällström, Ann Johansson, Kerstin Barup, and Sune Svanberg. "Remote Multicolor Excitation Laser-Induced Fluorescence Imaging." Laser Chemistry 2006 (January 10, 2006): 1–6. http://dx.doi.org/10.1155/2006/57934.

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Remote laser-induced fluorescence of stone materials was performed with application towards cultural heritage. Fluorescence was induced in targets ∼60 m from a mobile lidar laboratory by ultraviolet laser light, either from a frequency-tripled Nd:YAG laser or from an optical parametric oscillator system. Analysis was performed on combined spectra from the different excitation wavelengths and it was noted that important additional information can be gained when using several excitation wavelengths.

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Clark Brelje, T., and Robert L. Sorenson. "Multi-color laser scanning confocal microscopy with a krypton/argon ion laser." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 406–7. http://dx.doi.org/10.1017/s0424820100086337.

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Fluorescence is presently the most important imaging mode in biological confocal microscopy. The optical properties of laser scanning confocal microscopy (LSCM) are particularly favorable for fluorescence microscopy since the generally high signal-to-background ratio is enhanced by LSCM by rejecting out-of-focus fluorescent emissions. In addition, this improved imaging capability along the optical (z-)axis allows the optical sectioning of specimens by adjusting the plane of focus. This removes one of the most severe limitations of convential fluorescence microscopy, the necessity to examine monolayers of cells or thin sections of tissues.However, the advantages of LSCM for multi-color fluorscence microscopy are critically dependent on the availability of suitable light sources and fluorophores. By far the most commonly used light source is a small, air-cooled argon ion laser with emission wavelengths at 488 and 514 nm. Although the most frequently used fluorophores, fluorescein (FITC) and tetramethylrhodamine, can be excited by these wavelengths, it is impossible to specifically excite each fluorophore in the presence of the other fluorophore.

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Tan, Weihong, Philip G. Haydon, and Edward S. Yeung. "Imaging Neurotransmitter Uptake and Depletion in Astrocytes." Applied Spectroscopy 51, no. 8 (August 1997): 1139–43. http://dx.doi.org/10.1366/0003702971941656.

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An ultraviolet (UV) laser-based optical microscope and charge-coupled device (CCD) detection system was used to obtain chemical images of biological cells. Subcellularstructures can be easily seen in both optical and fluorescence images. Laser-induced native fluorescence detection provides high sensitivity and low limits of detection, and it does not require coupling to fluorescent dyes. We were able to quantitatively monitor serotonin that has been taken up into and released from individual astrocytes on the basis of its native fluorescence. Different regions of the cells took up different amounts of serotonin with a variety of uptake kinetics. Similarly, we observed different serotonin depletion dynamics in different astrocyte regions. There were also some astrocyte areas where no serotonin uptake or depletion was observed. Potential applications include the mapping of other biogenic species in cells as well as the ability to image their release from specific regions of cells in response to external stimuli.

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Häkkänen, H. J., and J. E. I. Korppi-Tommola. "Laser-Induced Fluorescence Imaging of Paper Surfaces." Applied Spectroscopy 47, no. 12 (December 1993): 2122–25. http://dx.doi.org/10.1366/0003702934066307.

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Laser-induced fluorescence imaging has been used to study the microstructure of paper surfaces. Pulses from a XeCl-excimer laser, 10 ns in duration at 308 nm, were used for excitation, and fluorescence was collected at 420 nm. The excitation spot diameter was approximately 20 µm, and the sampling interval 0.15 mm. Within an area of 5*5 mm2, 1023 sampling points were recorded to generate 3D fluorescence maps of paper surfaces. Papers containing fluorescence whitening agents (FWAs) gave the highest average fluorescence signals. Coated papers with no FW As show weaker signals than the base sheet. For some thirty different paper samples, an obvious correlation between the amount of coating and the average intensity of the fluorescence signal was observed. Signal fluctuations around the average intensity values were sensitive to (1) the chemical pulp content in super calantered (SC) paper, (2) the amount of recycled fiber in newsprint, and (3) the amount of coating on the light-weight coated (LWC) paper surface. An effort was made to correlate fluorescence imaging results to predict mottling (diffusion of printing ink after printing) in various paper brands.

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Schneckenburger, Herbert. "Lasers in Live Cell Microscopy." International Journal of Molecular Sciences 23, no. 9 (April 30, 2022): 5015. http://dx.doi.org/10.3390/ijms23095015.

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Due to their unique properties—coherent radiation, diffraction limited focusing, low spectral bandwidth and in many cases short light pulses—lasers play an increasing role in live cell microscopy. Lasers are indispensable tools in 3D microscopy, e.g., confocal, light sheet or total internal reflection microscopy, as well as in super-resolution microscopy using wide-field or confocal methods. Further techniques, e.g., spectral imaging or fluorescence lifetime imaging (FLIM) often depend on the well-defined spectral or temporal properties of lasers. Furthermore, laser microbeams are used increasingly for optical tweezers or micromanipulation of cells. Three exemplary laser applications in live cell biology are outlined. They include fluorescence diagnosis, in particular in combination with Förster Resonance Energy Transfer (FRET), photodynamic therapy as well as laser-assisted optoporation, and demonstrate the potential of lasers in cell biology and—more generally—in biomedicine.

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Leppert, Jan, Jochen Krajewski, Sven Rainer Kantelhardt, Sven Schlaffer, Nadine Petkus, Erich Reusche, Gerion Hüttmann, and Alf Giese. "Multiphoton Excitation of Autofluorescence for Microscopy of Glioma Tissue." Neurosurgery 58, no. 4 (April 1, 2006): 759–67. http://dx.doi.org/10.1227/01.neu.0000204885.45644.22.

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Abstract OBJECTIVE: Intraoperative detection of residual tumor tissue in glioma surgery remains an important challenge because the extent of tumor removal is related to the prognosis of the disease. Multiphoton excited fluorescence tomography of living tissues provides high-resolution structural and photochemical imaging at a subcellular level. In this conceptual study, we have used multiphoton microscopy and fluorescence lifetime imaging (4D microscopy) to image cultured glioma cell lines, solid tumor, and invasive tumor cells in an experimental mouse glioma model and human glioma biopsy specimens. MATERIAL AND METHODS: A laser imaging system containing a mode-locked 80 MHz titanium:sapphire laser with a tuning range of 710 to 920 nm, a scan unit, and a time correlated single photon counting board was used to generate autofluorescence intensity images and fluorescence lifetime images of cultured cell lines, experimental intracranial gliomas in mouse brain, and biopsies of human gliomas. RESULTS: Multiphoton microscopy of native tumor bearing brain provided structural images of the normal brain anatomy at a subcellular resolution. Solid tumor, the tumor-brain interface, and single invasive tumor cells could be visualized. Fluorescence lifetime imaging demonstrated significantly different decay of the fluorescent signal in tumor versus normal brain, allowing a clear definition of the tumor-brain interface based on this parameter. Distinct fluorescence lifetimes of endogenous fluorophores were found in different cellular compartments in cultured glioma cells. The analysis of the relationship between the laser excitation wavelength and the lifetime of excitable fluorophores demonstrated distinct profiles for cells of different histotypes. CONCLUSION: Multiphoton excited fluorescence of endogenous fluorophores allows structural imaging of tumor and central nervous system histo-architecture at a subcellular level. The analysis of the decay of the fluorescent signal within specific excitation volumes by fluorescent lifetime imaging discriminates glioma cells and normal brain, and the excitation/lifetime profiles may further allow differentiation of cellular histotypes. This technology provides a noninvasive optical tissue analysis that may potentially be applied to an intraoperative analysis of resection plains in tumor surgery.

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Da Silva, E., B. Lenain, and M. Manfait. "Fluorescence imaging by confocal microspectrometry." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1520–21. http://dx.doi.org/10.1017/s0424820100132236.

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Confocal microfluorometry possesses many advantages. In particular, it provides the possibility to control the size of the analyzed surface and the depth of focus.The laser focussed on a line under microscope has been achieved either with cylindrical optics or by spot deflection (to conserve the Gaussian distribution of the laser beam).Associated with a 2D detector, this focussed line gives the spectral distribution for all the points of the line. A motorized stage in the direction perpendicular to the line gives all the data to rebuild a spectral image.We present a new scanning method rigorously confocal and giving, in addition, the possibility to change continuously the spread factor (defined by the number of pixels of the detector divided by the dimension of the line onto the sample under microscope), from few pixels by micrometer up to 20 pixels by micrometer.Figure 1 shows the principle of the system; a first optical scanner scans a line onto the sample under microscope.

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Raarup, Merete Krog, and Jens Randel Nyengaard. "QUANTITATIVE CONFOCAL LASER SCANNING MICROSCOPY." Image Analysis & Stereology 25, no. 3 (May 3, 2011): 111. http://dx.doi.org/10.5566/ias.v25.p111-120.

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This paper discusses recent advances in confocal laser scanning microscopy (CLSM) for imaging of 3D structure as well as quantitative characterization of biomolecular interactions and diffusion behaviour by means of one- and two-photon excitation. The use of CLSM for improved stereological length estimation in thick (up to 0.5 mm) tissue is proposed. The techniques of FRET (Fluorescence Resonance Energy Transfer), FLIM (Fluorescence Lifetime Imaging Microscopy), FCS (Fluorescence Correlation Spectroscopy) and FRAP (Fluorescence Recovery After Photobleaching) are introduced and their applicability for quantitative imaging of biomolecular (co-)localization and trafficking in live cells described. The advantage of two-photon versus one-photon excitation in relation to these techniques is discussed.

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Fisher, Wait G., and Eric A. Wachter. "Improved Signal Processing in Multi-Photon Imaging." Microscopy and Microanalysis 6, S2 (August 2000): 800–801. http://dx.doi.org/10.1017/s1431927600036497.

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Multi-photon excitation has been used in microscopy for nearly a decade, providing a number of demonstrated advantages over other methods for fluorescence imaging. Because excitation is achieved using longer, less energetic light, photodamage and photobleaching of the sample are reduced. Furthermore, since excitation occurs only at the focal point, this approach allows the practical collection of three-dimensionally resolved fluorescence images of live cells. However, due to the small two-photon cross-section of most fluorophores, pulsed lasers are required to generate detectable signal levels. This is due to the quadratic dependence of twophoton absorption on the instantaneous power of the laser. Typically, these lasers are pulsed at very high repetition frequencies, on the order of 106 pulses per second with pulse durations of a few hundreds of femtoseconds. For example, a titanium:sapphire (Ti:S) laser mode-locked at 76 Mhz can provide up to 100,000 watts of instantaneous power and is ideal for exciting two-photon events.

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Kwok, Alfred S., Carol F. Wood, and Richard K. Chang. "Fluorescence imaging of CO_2 laser-heated droplets." Optics Letters 15, no. 12 (June 15, 1990): 664. http://dx.doi.org/10.1364/ol.15.000664.

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Hanson, Ronald K., Jerry M. Seitzman, and Phillip H. Paul. "Planar laser-fluorescence imaging of combustion gases." Applied Physics B Photophysics and Laser Chemistry 50, no. 6 (June 1990): 441–54. http://dx.doi.org/10.1007/bf00408770.

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Ni, T. Q., and L. A. Melton. "Fuel Equivalence Ratio Imaging for Methane Jets." Applied Spectroscopy 47, no. 6 (June 1993): 773–81. http://dx.doi.org/10.1366/0003702934066910.

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A 2-D fuel/oxygen equivalence ratio imaging system has been developed. The technique exploits the efficient quenching of the fluorescence of organic molecules by molecular oxygen in order to determine the fuel and oxygen partial pressures simultaneously. Following pulsed planar laser excitation of fluoranthene—a specially selected fluorescent dopant—two images of the fluorescence were recorded, with the second image being delayed by several nanoseconds. Use of a rapid lifetime determination algorithm yielded first a fluorescence lifetime image, and subsequently, with the assumption of Stern-Volmer quenching, an intensity image corrected for quenching. Images of the air pressure, fuel pressure, and the equivalence ratio were obtained. The technique, which uses dual gated intensifiers coupled to a sensitive CCD camera, requires only two integrated fluorescence intensities to calculate the fluorescence lifetime accurately. In the current work, images of the turbulence-induced mixing of a methane jet into quiescent air are displayed. Images can also be obtained in flames, but the analysis of the data is uncertain because the fluorescence lifetime of fluoranthene is temperature dependent.

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Zhang, Wenmei, Lei Liu, Qi Zhang, Dongtang Zhang, Qin Hu, Yanan Wang, Xiayan Wang, Qiaosheng Pu, and Guangsheng Guo. "Visual and real-time imaging focusing for highly sensitive laser-induced fluorescence detection at yoctomole levels in nanocapillaries." Chemical Communications 56, no. 16 (2020): 2423–26. http://dx.doi.org/10.1039/c9cc09594b.

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We developed a highly sensitive laser-induced fluorescence detection system, involving visual and real-time imaging focusing instead of the use of fluorescent reagents, for the detection of analytes in nanocapillaries.

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Sosna, Barbara, Dorota Bartusik-Aebisher, Grzegorz Cieślar, Aleksandra Kawczyk-Krupka, and Wojciech Latos. "New fluorescent imaging technics in gastrology." European Journal of Clinical and Experimental Medicine 19, no. 3 (2021): 251–54. http://dx.doi.org/10.15584/ejcem.2021.3.7.

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Introduction. There is a need to develop a new imaging technique in medicine. Gastroenterology is the branch of medicine focused on the digestive system and its disorders therefore for this branch is needed to detect all problems affecting the gastrointestinal tract. Aim. The aim of this article is to complete discuss the possibility of the new fluorescent imaging technics in gastrology to use innovative screening to identify individuals at an early stage. Material and methods. We discuss here imaging techniques such as include x-rays, computed tomography, scans, and magnetic resonance imaging in gastrology. Spectroscopy is the study of the formation and interpretation of spectra resulting from the interaction of all types of radiation on matter understood as a community of atoms and molecules. Various spectroscopic techniques are obtained by combining different types of radiation with different ways of its interaction with the test sample. They provide the opportunity to obtain detailed information about the tested substance – from its atomic composition, through its chemical structure, to its surface structure. Analysis of the literatue. The tissue fluorescence spectrum can be obtained by: (1) autofluorescence, or natural or primary fluorescence, i.e. by direct irradiation of the tissue with laser radiation (laser-induced fluorescence – LIF) and (2) photodynamic diagnosis (PDD), where spectrum analysis is preceded by systemic or local administration of the photosensitizer. Conclusion. The use of fluorescence imaging in colon cancer patient has potential to improve quality of treatment and diagnosis.

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Dellis, Polychronis. "Laser-induced fluorescence measurements in a single-ring test rig: Evidence of cavitation and the effect of different operating conditions and lubricants in cavitation patterns and initiation." International Journal of Engine Research 21, no. 9 (January 14, 2019): 1597–611. http://dx.doi.org/10.1177/1468087418819254.

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The laser-induced fluorescence technique is based on the excitation of molecules of a fluorescent material by a light source. The main advantage of this technique is that it has the potential to quantify the lubricant film thickness throughout the cycle. Similar to all the other optical techniques, it has this major advantage compared to the electrical techniques where the oil film can be measured only under the piston rings. In this work, experimental data from a simulating single-ring test rig are presented and further parametric analysis is given regarding cavitation in lubricants that was, at first, in the case of the single-ring test rig, evident in laser-induced fluorescence measurements. Different lubricants are used for the laser-induced fluorescence experiments and the different laser-induced fluorescence signals are analysed and interpreted compared to their physical and chemical properties and, furthermore, with the aid of imaging through a glass liner, a clearer picture is given regarding the cavitation shapes together with the respective laser-induced fluorescence measurements and cavitation initiation.

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Fernandez, J. M. "Pulsed Laser Imaging Techniques: Calcium and Exocytosis in Excitable Cells." Microscopy and Microanalysis 3, S2 (August 1997): 807–8. http://dx.doi.org/10.1017/s1431927600010928.

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A rapid Ca++ signal is known to be the main trigger for exocytosis in excitable cells. However, its mode of action is unknown. Recently, it has become clear that the spatial distribution of a Ca++ stimulus is important for exocytosis. To investigate this question we have developed a novel instrument capable of imaging Ca++ gradients in patch clamped cells. We have equipped a standard fluorescence microscope with a CCD camera and an image processing station. This combination can generate a thin section view of the fluorescence of a single cell. We have equipped this microscope with a pulsed laser illumination system. The distribution of intracellular calcium can be obtained by exciting the Ca++ indicator dye (e.g., rhod-2) with a brief laser pulse [300 ns long at 525 nm ], then an image can be formed with the light emitted by the dye. by synchronizing the laser pulse with a depolarizing stimulus in a patch-clamped chromaffin cell loaded with the fluorescent Ca++ indicator rhod-2, we could easily obtain snapshots of the Ca++ distribution at known times after a stimulus.

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Bhartia, Rohit, Everett C. Salas, William F. Hug, Ray D. Reid, Arthur L. Lane, Katrina J. Edwards, and Kenneth H. Nealson. "Label-Free Bacterial Imaging with Deep-UV-Laser-Induced Native Fluorescence." Applied and Environmental Microbiology 76, no. 21 (September 3, 2010): 7231–37. http://dx.doi.org/10.1128/aem.00943-10.

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ABSTRACT We introduce a near-real-time optical imaging method that works via the detection of the intrinsic fluorescence of life forms upon excitation by deep-UV (DUV) illumination. A DUV (<250-nm) source enables the detection of microbes in their native state on natural materials, avoiding background autofluorescence and without the need for fluorescent dyes or tags. We demonstrate that DUV-laser-induced native fluorescence can detect bacteria on opaque surfaces at spatial scales ranging from tens of centimeters to micrometers and from communities to single cells. Given exposure times of 100 μs and low excitation intensities, this technique enables rapid imaging of bacterial communities and cells without irreversible sample alteration or destruction. We also demonstrate the first noninvasive detection of bacteria on in situ-incubated environmental experimental samples from the deep ocean (Lo'ihi Seamount), showing the use of DUV native fluorescence for in situ detection in the deep biosphere and other nutrient-limited environments.

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Gurfinkel, Michael, Shi Ke, Xiaoxia Wen, Chun Li, and Eva M. Sevick-Muraca. "Near-Infrared Fluorescence Optical Imaging and Tomography." Disease Markers 19, no. 2-3 (2004): 107–21. http://dx.doi.org/10.1155/2004/474818.

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The advent of recent advances in near-infrared laser diodes and fast electro-optic detection has spawned a new research field of diagnostic spectroscopy and imaging based on targeting and reporting exogenous fluorescent agents. This review seeks to concisely address the physics, instrumentation, advancements in tomography, and near-infrared fluorescent contrast agent development that promises selective and specific molecular targeting of diseased tissues. As an example of one area of the field, recent work focusing on pharmacokinetic analysis of fluorophores targeting the epidermal growth factor receptor (EGFR) is presented in a human breast cancer xenograft mouse model to demonstrate specificity of molecularly targeted contrast agents. Finally, a critical evaluation of the limitations and the opportunities for future translation of fluorescence-enhanced optical imaging of deep tissues is presented.

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Tong, Wei, and Edward S. Yeung. "Direct Visualization of Secretion from Single Bovine Adrenal Chromaffin Cells by Laser-Induced Native Fluorescence Imaging Microscopy." Applied Spectroscopy 52, no. 3 (March 1998): 407–13. http://dx.doi.org/10.1366/0003702981943590.

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Direct visualization of the secretion process of individual bovine adrenal chromaffin cells was achieved with laser-induced native fluorescence imaging microscopy. By monitoring the native fluorescence of catecholamines excited by the 275 nm laser line with an intensified charge-coupled-device (CCD) camera, we obtained good temporal and spatial resolution simultaneously without using additional fluorescent probes. Large variations were found among individual cells in terms of the amounts of catecholamines secreted and the rates of secretion. Different regions of a cell also behave differently during the secretion process. However, the degree of this local heterogeneity is smaller than in neurons and neuralgia. The influence of deep-ultraviolet (UV) laser excitation on cells is also discussed. This quantitative imaging technique provides a useful noninvasive approach for the study of dynamic cellular changes and the understanding of the molecular mechanisms of secretory processes.

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Kwaśny, Alicja, Jakub Bogusławski, and Grzegorz Soboń. "Multiphoton scanning laser microscope based on femtosecond fiber laser." Photonics Letters of Poland 14, no. 4 (December 31, 2022): 74–76. http://dx.doi.org/10.4302/plp.v14i4.1182.

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We present a multiphoton scanning laser microscope based on a femtosecond frequency-doubled erbium-doped fiber laser. The laser used in the epi-illumination microscope setup generated 95 fs pulses at the wavelength of 780 nm with 44.3 mW average power at 100 MHz pulse repetition rate. The imaging process was controlled by custom software developed in the NI LabVIEW environment. Detection of two-photon fluorescence was proven by acquiring a series of images from various biological samples. Full Text: PDF ReferencesJ.W. Lichtman, J.A. Conchello, "Fluorescence microscopy", Nature methods 2(12), 910 (2005). CrossRef W. Zipfel, R. Williams, W. Webb, "Nonlinear magic: multiphoton microscopy in the biosciences", Nat. Biotechnol. 21, 1369 (2003). CrossRef Coherent, Chameleon Ultra Datasheet (2019). DirectLink J. Boguslawski et al., "In vivo imaging of the human eye using a 2-photon-excited fluorescence scanning laser ophthalmoscope", J. Clin. Invest. 132(2), e154218 (2022). CrossRef M.J. Marzejon et al., "Two-photon microperimetry with picosecond pulses", Biomed. Opt. Expr. 12, 462 (2021). CrossRef A. Fast et al., "Institutional Drivers Influence on CSR Engagement: A Comparison of Developed & Developing Economies", Sci. Rep. 10, 18093 (2020). CrossRef D. Stachowiak et al., "Femtosecond Er-doped fiber laser source tunable from 872 to 1075 nm for two-photon vision studies in humans", Biomed. Opt. Expr. 13, 1899 (2022). CrossRef MenloSystems, T-light Femtosecond Fiber Laser 1560 nm (2013). DirectLink J. Yao, L.V. Wang, "Photoacoustic microscopy", Laser and Photonics Rev. 7, 758 (2013). CrossRef D. Stachowiak et al., "Frequency-doubled femtosecond Er-doped fiber laser for two-photon excited fluorescence imaging", Biomed. Opt. Expr. 11, 4431 (2020). CrossRef B.R. Masters et al., "Mitigating thermal mechanical damage potential during two-photon dermal imaging", J. Biomed. Opt. 9, 1265 (2004). CrossRef

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Yamanaka, Masahito, Kenta Saito, Nicholas I. Smith, Satoshi Kawata, Takeharu Nagai, and Katsumasa Fujita. "Saturated excitation of fluorescent proteins for subdiffraction-limited imaging of living cells in three dimensions." Interface Focus 3, no. 5 (October 6, 2013): 20130007. http://dx.doi.org/10.1098/rsfs.2013.0007.

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We report, for the first time, the saturated excitation (SAX) of fluorescent proteins for subdiffraction-limited imaging of living cells in three-dimensions. To achieve saturation, a bright yellow and green fluorescent protein (Venus and EGFP) that exhibits a strong nonlinear fluorescence response to the high excitation intensity at the laser focus is used. Harmonic demodulation of the fluorescence signal produced by a modulated excitation light extracts the nonlinear fluorescence signals. After constructing the image from the nonlinear components, we obtain fluorescence images of living cells with spatial resolution beyond the diffraction limit. We also applied linear deconvolution to SAX microscopy and found it effective in further enhancing the contrast of small intracellular structures in the SAX image, confirming the expansion of the optical transfer function in SAX microscopy.

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CHEN, CHAO-WEI, TIFFANY R. BLACKWELL, RENEE NAPHAS, PAUL T. WINNARD, VENU RAMAN, KRISTINE GLUNDE, and YU CHEN. "DEVELOPMENT OF NEEDLE-BASED MICROENDOSCOPY FOR FLUORESCENCE MOLECULAR IMAGING OF BREAST TUMOR MODELS." Journal of Innovative Optical Health Sciences 02, no. 04 (October 2009): 343–52. http://dx.doi.org/10.1142/s1793545809000747.

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Fluorescence molecular imaging enables the visualization of basic molecular processes such as gene expression, enzyme activity, and disease-specific molecular interactions in vivo using targeted contrast agents, and therefore, is being developed for early detection and in situ characterization of breast cancers. Recent advances in developing near-infrared fluorescent imaging contrast agents have enabled the specific labeling of human breast cancer cells in mouse model systems. In synergy with contrast agent development, this paper describes a needle-based fluorescence molecular imaging device that has the strong potential to be translated into clinical breast biopsy procedures. This microendoscopy probe is based on a gradient-index (GRIN) lens interfaced with a laser scanning microscope. Specifications of the imaging performance, including the field-of-view, transverse resolution, and focus tracking characteristics were calibrated. Orthotopic MDA-MB-231 breast cancer xenografts stably expressing the tdTomato red fluorescent protein (RFP) were used to detect the tumor cells in this tumor model as a proof of principle study. With further development, this technology, in conjunction with the development of clinically applicable, injectable fluorescent molecular imaging agents, promises to perform fluorescence molecular imaging of breast cancers in vivo for breast biopsy guidance.

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Dunsby, C., P. M. P. Lanigan, J. McGinty, D. S. Elson, J. Requejo-Isidro, I. Munro, N. Galletly, et al. "An electronically tunable ultrafast laser source applied to fluorescence imaging and fluorescence lifetime imaging microscopy." Journal of Physics D: Applied Physics 37, no. 23 (November 20, 2004): 3296–303. http://dx.doi.org/10.1088/0022-3727/37/23/011.

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Yang, Jiemin, and Lynn A. Melton. "Fluorescence-Based Method Designed for Quantitative Measurement of Fuel Film Thickness during Cold-Start of Engines." Applied Spectroscopy 54, no. 4 (April 2000): 565–74. http://dx.doi.org/10.1366/0003702001949744.

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The liquid fuel that accumulates in the engine manifold and cylinders during cold start conditions is thought to contribute significantly to excess hydrocarbon emissions. Two fluorescent dopants, cyclohexanone and 2-methyl-cyclopentanone, have been tested for use as fluorescent markers for quantitative two-dimensional (2D) imaging of the thickness of automotive fuel films in the range 0–1 mm. These dopants are co-evaporative with synthetic automotive fuel and have fluorescence that is virtually independent of oxygen concentration equivalent to saturation under 5 atm air at temperatures of 20–200 °C. Selection, calibration procedures, and (nonengine) demonstration laser-induced-fluorescence (LIF) imaging experiments are discussed.

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Sitter, David N. "Laser-induced fluorescence imaging of the ocean bottom." Optical Engineering 40, no. 8 (August 1, 2001): 1545. http://dx.doi.org/10.1117/1.1385510.

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Que, I., L. Zerrillo, Y. Li, A. B. Chan, and L. J. Cruz. "Fluorescence-based confocal laser endomicroscopy for imaging osteoarthritis." Osteoarthritis and Cartilage 26 (April 2018): S468—S469. http://dx.doi.org/10.1016/j.joca.2018.02.884.

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Grib, Stephen W., Paul S. Hsu, Naibo Jiang, Josef J. Felver, S. Alexander Schumaker, Campbell D. Carter, and Sukesh Roy. "100 kHz krypton planar laser-induced fluorescence imaging." Optics Letters 45, no. 14 (July 6, 2020): 3832. http://dx.doi.org/10.1364/ol.395389.

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Johansson, O., J. Bood, B. Li, A. Ehn, Z. S. Li, Z. W. Sun, M. Jonsson, A. A. Konnov, and M. Aldén. "Photofragmentation laser-induced fluorescence imaging in premixed flames." Combustion and Flame 158, no. 10 (October 2011): 1908–19. http://dx.doi.org/10.1016/j.combustflame.2011.02.021.

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Hosoi, Rie, Sota Sato, Miho Shukuri, Yuka Fujii, Kenichiro Todoroki, Yasushi Arano, Toshihiro Sakai, and Osamu Inoue. "A Simple Ex Vivo Semiquantitative Fluorescent Imaging Utilizing Planar Laser Scanner: Detection of Reactive Oxygen Species Generation in Mouse Brain and Kidney." Molecular Imaging 18 (January 1, 2019): 153601211882042. http://dx.doi.org/10.1177/1536012118820421.

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Objective: Oxidative stress plays an important role in the onset of many neuronal and peripheral disorders. We examined the feasibility of obtaining semiquantitative fluorescent images of reactive oxygen species (ROS) generation in mouse brain and kidney utilizing a planar laser scanner and dihydroethidium (DHE). Methods: To investigate ROS generation in brain, sodium nitroprusside was injected into the striatum. Dihydroethidium was injected into the tail vein. After DHE injection, tissue slices were analyzed utilizing a planar laser scanner. For kidney study, cis-diamminedichloroplatinum [II] (cisplatin) was intraperitoneally administrated into mice. Results: Clear and semiquantitative fluorescent images of ROS generation in the mouse brain and kidney were obtained. Furthermore, the fluorescence intensity was stable and not affected by fading. Sodium nitroprusside induced approximately 6 times the fluorescence accumulation in the brain. Cisplatin caused renal injury in all mice, and in comparison with control mice, more than 10 times fluorescence accumulation was observed in the renal medulla with tubular necrosis and vacuolization. Conclusions: We successfully obtained ex vivo semiquantitative fluorescent images of ROS generation utilizing a planar laser scanner and DHE. This simple method is useful for ROS detection in several ROS-related animal models and would be applicable to a variety of biochemical processes.

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Serafino, Michael J., and Javier A. Jo. "Direct frequency domain fluorescence lifetime imaging using simultaneous ultraviolet and visible excitation." Biomedical Optics Express 14, no. 4 (March 23, 2023): 1608. http://dx.doi.org/10.1364/boe.480287.

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Due to the complexity, limited practicality, and cost of conventional fluorescence lifetime imaging/microscopy (FLIM) instrumentation, FLIM adoption has been mostly limited to academic settings. We present a novel point scanning frequency-domain (FD) FLIM instrumentation design capable of simultaneous multi-wavelength excitation, simultaneous multispectral detection, and sub-nanosecond to nanosecond fluorescence lifetime estimation. Fluorescence excitation is implemented using intensity-modulated CW diode lasers that are available in a selection of wavelengths spanning the UV-VI-NIR range (375-1064 nm). Digital laser intensity modulation was adopted to enable simultaneous frequency interrogation at the fundamental frequency and corresponding harmonics. Time-resolved fluorescence detection is implemented using low-cost, fixed-gain, narrow bandwidth (100 MHz) avalanche photodiodes, thus, enabling cost-effective fluorescence lifetime measurements at multiple emission spectral bands simultaneously. Synchronized laser modulation and fluorescence signal digitization (250 MHz) is implemented using a common field-programmable gate array (FPGA). This synchronization reduces temporal jitter, which simplifies instrumentation, system calibration, and data processing. The FPGA also allows for the implementation of the real-time processing of the fluorescence emission phase and modulation at up to 13 modulation frequencies (processing rate matching the sampling rate of 250 MHz). Rigorous validation experiments have demonstrated the capabilities of this novel FD-FLIM implementation to accurately measure fluorescence lifetimes in the range of 0.5-12 ns. In vivo endogenous, dual-excitation (375nm/445nm), multispectral (four bands) FD-FLIM imaging of human skin and oral mucosa at 12.5 kHz pixel rate and room-light conditions was also successfully demonstrated. This versatile, simple, compact, and cost-effective FD-FLIM implementation will facilitate the clinical translation of FLIM imaging and microscopy.

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Zoladek, A., F. Pascut, P. Patel, and I. Notingher. "Development of Raman Imaging System for time-course imaging of single living cells." Spectroscopy 24, no. 1-2 (2010): 131–36. http://dx.doi.org/10.1155/2010/521962.

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Development of novel inverted Raman micro-spectrometer with the ability to perform multi-hours spectral measurements on living cells is presented. Our system combines a Confocal Raman Micro-Spectrometer and Fluorescence Microscope with cell incubator enclosure allowing measurement of cells in extended time period. To illustrate the feasibility of this Raman micro-spectroscopy system forin vitrotime-course studies of cells we performed an experiment where the same group of cells were scanned with the laser at 2 hours intervals between the scans over 8 hours to build Raman spectral images and ensure that no changes occur due to laser damage or environmental conditions. Cell viability test was performed with fluorescence microscopy on exactly the same cells at the end of the time-course Raman measurements.

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Jovin, Thomas M., Michel Robert-Nicoud, Donna J. Arndt-Jovin, and Thorsten Schormann. "3-D imaging of cells using a confocal laser scanning microscope and digital image processing." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 96–97. http://dx.doi.org/10.1017/s0424820100102560.

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Light microscopic techniques for visualizing biomolecules and biochemical processes in situ have become indispensable in studies concerning the structural organization of supramolecular assemblies in cells and of processes during the cell cycle, transformation, differentiation, and development. Confocal laser scanning microscopy offers a number of advantages for the in situ localization and quantitation of fluorescence labeled targets and probes: (i) rejection of interfering signals emanating from out-of-focus and adjacent structures, allowing the “optical sectioning” of the specimen and 3-D reconstruction without time consuming deconvolution; (ii) increased spatial resolution; (iii) electronic control of contrast and magnification; (iv) simultanous imaging of the specimen by optical phenomena based on incident, scattered, emitted, and transmitted light; and (v) simultanous use of different fluorescent probes and types of detectors.We currently use a confocal laser scanning microscope CLSM (Zeiss, Oberkochen) equipped with 3-laser excitation (u.v - visible) and confocal optics in the fluorescence mode, as well as a computer-controlled X-Y-Z scanning stage with 0.1 μ resolution.

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Ding, He, Lin Yang, Hongshang Peng, Xiaohui Wang, Fangtian You, and Lingling Hou. "Intracellular Temperature Imaging in Gold Nanorod-Assisted Photothermal Therapy with Luminescent Eu(III) Chelate Nanoparticles." Journal of Nanoscience and Nanotechnology 16, no. 4 (April 1, 2016): 3877–82. http://dx.doi.org/10.1166/jnn.2016.11819.

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Eu-tris(dinaphthoylmethane)-bis-(trioctylphosphine oxide) (Eu-DT) molecules encapsulated by Polystyrene and bis(trimethoxysilyl)decane nanoparticles were prepared via a modified encapsulation-reprecipitation method and show a high sensitivity to sense temperature. After surface modification with poly-L-lysine, the fluorescent nanoparticles obtained a well biocompatibility and low toxicity at a certain concentration. In the physiological temperature range (25–45 °C), the fluorescence of the nanoparticles is rather sensitive to temperature with a sensitivity of −2.6%/°C. The temperature nanosensors and gold nanorods were internalized into living HepG2 cells. The fluorescence intensity of phagocytic nanoparticles decreased with the irradiation of 808-nm laser, which were captured by Epi-fluorescence microscope.

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Taylor, Adam Thomas, and Edward P. C. Lai. "Current State of Laser-Induced Fluorescence Spectroscopy for Designing Biochemical Sensors." Chemosensors 9, no. 10 (September 27, 2021): 275. http://dx.doi.org/10.3390/chemosensors9100275.

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Laser-induced fluorescence (LIF) has been a valuable analytical technique since the 1970s that has only been made more useful through advances in other scientific fields such as biochemistry. Moreover, advances in laser and detector technology have seen a decrease in LIF detector costs and an increase in their ease of use. These changes have allowed for LIF technology to be widely adopted for various sensor designs in combination with advanced instruments. With advances in biochemistry necessitating the detection of complex metabolites, labelling with fluorescent chemical reagents may be necessary to improve detection sensitivity. Furthermore, advances made in fluorescent labeling technologies have allowed for the use of LIF in the detection of nanoparticles as well as for imaging techniques using nanoparticles as signal amplifiers. This technology has become invaluable in the detection of environmental pollutants, monitoring of biological metabolites, biological imaging, and cancer diagnosis, making it one of the most valuable analytical science techniques currently available.

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Wokosin, D., V. F. Centonze, and J. G. White. "UV-excited fluorophore images obtained with IR excitation." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 906–7. http://dx.doi.org/10.1017/s0424820100166993.

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The widespread use of two-photon excitation fluorescence imaging has been somewhat inhibited by the necessity to use large, expensive, high-power, short-pulse lasers. These ultra-short pulse lasers are used as an excitation source in a raster scanning configuration to provide sufficient peak power density in a lens focal volume to generate detectable two-photon absorption events for rapid imaging. Biological studies often benefit from multiple fluorescent labels and multi-labelled samples often require different excitation wavelengths for adequate excitation of the various colored fluorophores. This is achieved inexpensively with the three Krypton Argon laser lines in standard confocal imaging systems, but multiple two-photon excitation lasers--if available-- would be a very expensive system. The lasers commonly used for two-photon imaging are tuneable, but this is not a non-trivial and time consuming process. The tuning range on these lasers allows good access to the blue-emitting and green-emitting fluorophores via two-photon excitation; however, we have found that a fixed-wavelength, compact,

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Seidenari, Stefania, Federica Arginelli, Sara Bassoli, Jennifer Cautela, Paul M. W. French, Mario Guanti, Davide Guardoli, Karsten König, Clifford Talbot, and Chris Dunsby. "Multiphoton Laser Microscopy and Fluorescence Lifetime Imaging for the Evaluation of the Skin." Dermatology Research and Practice 2012 (2012): 1–8. http://dx.doi.org/10.1155/2012/810749.

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Multiphoton laser microscopy is a new, non-invasive technique providing access to the skin at a cellular and subcellular level, which is based both on autofluorescence and fluorescence lifetime imaging. Whereas the former considers fluorescence intensity emitted by epidermal and dermal fluorophores and by the extra-cellular matrix, fluorescence lifetime imaging (FLIM), is generated by the fluorescence decay rate. This innovative technique can be applied to the study of living skin, cell cultures andex vivosamples. Although still limited to the clinical research field, the development of multiphoton laser microscopy is thought to become suitable for a practical application in the next few years: in this paper, we performed an accurate review of the studies published so far, considering the possible fields of application of this imaging method and providing high quality images acquired in the Department of Dermatology of the University of Modena.

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Merrigan, Tony L., C. Adam Hunniford, David J. Timson, Martin Catney, and Robert W. McCullough. "Development of a novel mass spectrometric technique for studying DNA damage." Biochemical Society Transactions 37, no. 4 (July 22, 2009): 905–9. http://dx.doi.org/10.1042/bst0370905.

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An experimental system, based upon UV and IR laser desorption, has been constructed to enable the production and characterization of neutral biomolecular targets. These targets are to be used for interaction experiments investigating radiation-induced damage to DNA. The viability of the laser-desorption techniques of MALDI (matrix-assisted laser-desorption ionization), SALDI (surface-assisted laser-desorption ionization) and DIOS (desorption/ionization on silicon), for production of these gas targets is discussed in the present paper. Fluorescent dye tagging and LIF (laser-induced fluorescence) imaging has been used to characterize the biomolecular plumes, revealing their spatial density profiles and temporal evolution.

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Bagh, Sangram, and Matthew F. Paige. "Construction and application of a single-molecule fluorescence microscope." Canadian Journal of Chemistry 83, no. 5 (May 1, 2005): 435–42. http://dx.doi.org/10.1139/v05-053.

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In this paper, we describe the construction, optimization, and testing of an epifluorescence microscope that has single-molecule (SM) resolution and sensitivity. The microscope makes use of a novel new type of wide-area charge-coupled device (CCD) photodetector with on-chip multiplier gain. Sensitivity and spatial resolution of the instrument are demonstrated by imaging individual Rhodamine 6G (R6G) molecules and characterizing their basic photophysical behaviour under a variety of imaging conditions. A simple, general method for calibrating the photodetector (correlating CCD counts with incident photons) using a highly attenuated laser beam is presented, and the performance of the photodetector is compared with that of other detectors commonly used in SM fluorescence imaging applications. We also demonstrate the versatility of the microscope system by characterizing the SM photophysical behaviour of several other fluorescent molecules, including bodipy-FL and the enhanced green fluorescent protein (EGFP). Key words: single molecule, fluorescence, microscopy, CCD camera, calibration, photobleaching.

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Pallister, David M., and Michael D. Morris. "Laser Koehler Epi-Illumination for Raman and Fluorescence Microscopic Imaging." Applied Spectroscopy 48, no. 10 (October 1994): 1277–81. http://dx.doi.org/10.1366/0003702944027480.

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A comparison of microscopic Raman images acquired with an optical-fiber critical (Nelson) illumination system, an optical-fiber Koehler laser illumination system, and Koehler laser illumination without an optical fiber demonstrates performance differences between the three illumination methods. Best images are obtained with optical-fiber Koehler illumination.

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Liu, Chao, Xinwei Wang, Yan Zhou, and Yuliang Liu. "Timing and Operating Mode Design for Time-Gated Fluorescence Lifetime Imaging Microscopy." Scientific World Journal 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/801901.

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Steady-state fluorence imaging and time-resolved fluorescence imaging are two important areas in fluorescence imaging research. Fluorescence lifetime imaging is an absolute measurement method which is independent of excitation laser intensity, fluorophore concentration, and photobleaching compared to fluorescence intensity imaging techniques. Time-gated fluorescence lifetime imaging microscopy (FLIM) can provide high resolution and high imaging frame during mature FLIM methods. An abstract time-gated FLIM model was given, and important temporal parameters are shown as well. Aiming at different applications of steady and transient fluorescence processes, two different operation modes, timing and lifetime computing algorithm are designed. High resolution and high frame can be achieved by one-excitation one-sampling mode and least square algorithm for steady imaging applications. Correspondingly, one-excitation two-sampling mode and rapid lifetime determination algorithm contribute to transient fluorescence situations.

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Xu, Huantian, Shu Chen, Kaijun Mu, Junqiao Wang, Yongzhi Tian, Shilei Su, Yanchao Mao, and Erjun Liang. "Investigation of nondegenerate two-photon absorption in common fluorescent dyes." Journal of Nonlinear Optical Physics & Materials 27, no. 03 (September 2018): 1850027. http://dx.doi.org/10.1142/s0218863518500273.

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The nondegenerate two-photon excited fluorescence (ND-TPEF) and nondegenerate two-photon absorption (ND-TPA) cross-sections of two common fluorescent dyes were investigated using the femtosecond pump-probe technique at several wavelength combinations. Time-resolved and laser intensity dependent fluorescence revealed that the fluorescence was originated from the ND-TPA effect. Experimental ND-TPA cross-section exhibited larger values than corresponding degenerate two-photon absorption case. Additionally, an improved essential-state model involving multiple TPA excited states was proposed to evaluate the TPA cross-section of organic molecules, which showed good agreement with experimental results. This study indicates that the investigated fluorescent dyes would play important roles in multicolor two-photon imaging.

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Fritzky, Luke, and David Lagunoff. "Advanced Methods in Fluorescence Microscopy." Analytical Cellular Pathology 36, no. 1-2 (2013): 5–17. http://dx.doi.org/10.1155/2013/569326.

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It requires a good deal of will power to resist hyperbole in considering the advances that have been achieved in fluorescence microscopy in the last 25 years. Our effort has been to survey the modalities of microscopic fluorescence imaging available to cell biologists and perhaps useful for diagnostic pathologists. The gamut extends from established confocal laser scanning through multiphoton and TIRF to the emerging technologies of super-resolution microscopy that breech the Abbé limit of resolution. Also considered are the recent innovations in structured and light sheet illumination, the use of FRET and molecular beacons that exploit specific characteristics of designer fluorescent proteins, fluorescence speckles, and second harmonic generation for native anisometric structures like collagen, microtubules and sarcomeres.

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Lin, Jia, and Adam D. Hoppe. "Uniform Total Internal Reflection Fluorescence Illumination Enables Live Cell Fluorescence Resonance Energy Transfer Microscopy." Microscopy and Microanalysis 19, no. 2 (March 11, 2013): 350–59. http://dx.doi.org/10.1017/s1431927612014420.

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AbstractFluorescence resonance energy transfer (FRET) microscopy is a powerful technique to quantify dynamic protein-protein interactions in live cells. Total internal reflection fluorescence (TIRF) microscopy can selectively excite molecules within about 150 nm of the glass-cell interface. Recently, these two approaches were combined to enable high-resolution FRET imaging on the adherent surface of living cells. Here, we show that interference fringing of the coherent laser excitation used in TIRF creates lateral heterogeneities that impair quantitative TIRF-FRET measurements. We overcome this limitation by using a two-dimensional scan head to rotate laser beams for donor and acceptor excitation around the back focal plane of a high numerical aperture objective. By setting different radii for the circles traced out by each laser in the back focal plane, the penetration depth was corrected for different wavelengths. These modifications quell spatial variations in illumination and permit calibration for quantitative TIRF-FRET microscopy. The capability of TIRF-FRET was demonstrated by imaging assembled cyan and yellow fluorescent protein–tagged HIV-Gag molecules in single virions on the surfaces of living cells. These interactions are shown to be distinct from crowding of HIV-Gag in lipid rafts.

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Kuznetsov, Andrey V., Oleg Mayboroda, Dagmar Kunz, Kirstin Winkler, Walter Schubert, and Wolfram S. Kunz. "Functional Imaging of Mitochondria in Saponin-permeabilized Mice Muscle Fibers." Journal of Cell Biology 140, no. 5 (March 9, 1998): 1091–99. http://dx.doi.org/10.1083/jcb.140.5.1091.

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Confocal laser-scanning and digital fluorescence imaging microscopy were used to quantify the mitochondrial autofluorescence changes of NAD(P)H and flavoproteins in unfixed saponin-permeabilized myofibers from mice quadriceps muscle tissue. Addition of mitochondrial substrates, ADP, or cyanide led to redox state changes of the mitochondrial NAD system. These changes were detected by ratio imaging of the autofluorescence intensities of fluorescent flavoproteins and NAD(P)H, showing inverse fluorescence behavior. The flavoprotein signal was colocalized with the potentiometric mitochondria-specific dye dimethylaminostyryl pyridyl methyl iodide (DASPMI), or with MitoTracker™ Green FM, a constitutive marker for mitochondria. Within individual myofibers we detected topological mitochondrial subsets with distinct flavoprotein autofluorescence levels, equally responding to induced rate changes of the oxidative phosphorylation. The flavoprotein autofluorescence levels of these subsets differed by a factor of four. This heterogeneity was substantiated by flow-cytometric analysis of flavoprotein and DASPMI fluorescence changes of individual mitochondria isolated from mice skeletal muscle. Our data provide direct evidence that mitochondria in single myofibers are distinct subsets at the level of an intrinsic fluorescent marker of the mitochondrial NAD–redox system. Under the present experimental conditions these subsets show similar functional responses.

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Lee, Michael P., Phillip H. Paul, and Ronald K. Hanson. "Laser-fluorescence imaging of O_2 in combustion flows using an ArF laser." Optics Letters 11, no. 1 (January 1, 1986): 7. http://dx.doi.org/10.1364/ol.11.000007.

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Olesik, John W., and Eric J. Williamsen. "Simultaneous Detection of One-Dimensional Laser-Induced Fluorescence or Laser Light Scattering Images in Plasmas." Applied Spectroscopy 43, no. 6 (August 1989): 933–40. http://dx.doi.org/10.1366/0003702894203787.

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An instrumental system to simultaneously detect one-dimensional atomic or ionic fluorescence images is described. The instrument can also be used to acquire laser light scattering images or laterally resolved emission images. The fluorescence, scattering, or emission image passes through a monochromator and is re-imaged on an intensified diode array detector. Measurement of spatially resolved ground-state populations in inductively coupled plasmas is discussed. Interpretation of the fluorescence data obtained under different plasma operating conditions is considered. Results with the use of laser-induced fluorescence imaging to study the effect of sample transport rate, concomitant species-induced matrix effects, and modulated power plasmas are discussed. Comparison of fluorescence and emission images shows the complementary nature of the information provided by each. Laser light scattering off intact droplets or particles in a 1.0-kW inductively coupled plasma is discussed. Means to minimize the scattering signal are evaluated. Detection of laser light scattering images is discussed.

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Journal articles on the topic 'Laser Fluorescence Imaging'

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