Search results for "two-photon [exchange]"
showing 10 items of 56 documents
Two-Photon Transitions in CW-ENDOR Spectra of Radicals in Fluid Solution
2002
The radical anion of duroquinone (2,3,5,6-tetramethyl-1,4-benzoquinone) was used as a model compound to describe the low-frequency (LF) ENDOR lines observed in many radical systems. These LF lines ...
Optical-sectioning improvement in two-color excitation scanning microscopy
2004
We present a new beam-shaping technique for two-color excitation fluorescence microscopy. We show that by simply inserting a properly designed shaded-ring filter in the illumination beam of smaller wavelength, it is possible to improve the effective optical sectioning capacity of such microscopes by 23%. Such an improvement is obtained at the expense of only a very small increasing of the overall energy in the point-spread-function sidelobes. The performance of this technique is illustrated by a numerical imaging simulation.
Line shape measurements of rubidium 5S-7S two-photon transition
2014
We report the use of a digital lock to measure the line profile and center frequency of rubidium 5S-7S two-photon transitions with a cw laser referenced to an optical frequency comb. The narrow, two-photon transition, 5S-7S (760 nm), insensitive to first-order in a magnetic field, is a promising candidate for frequency reference.
Testing direct neuroprotective effects of current MS therapeutic compounds with intravital two photon laser scanning microscopy
2014
Multifunctional derivatives of dimethoxy-substituted triphenylamine containing different acceptor moieties
2020
This project has received funding from the Research Council of Lithuania (LMTLT), Agreement No. [S-LZ-19-2]. This research was funded by the Région Centre, the Tunisian ministry of research, University of Monastir and the French ministry of Higher Education and Research. J. Bouclé would like to thank the Sigma-Lim LabEx environment for financial supports, and the PLATINOM facility at XLIM laboratory regarding device fabrication and characterizations. DG acknowledges the Lithuanian Academy of Sciences for the financial support.
Two-photon high-speed light-sheet volumetric imaging of brain activity during sleep in zebrafish larvae
2020
Although it is well known that zebrafish display the behavioural signature of sleep, the neuronal correlates of this state are not yet completely understood, due to the complexity of the measurements required. For example, when performed with visible excitation light, functional imaging can disrupt the day/night cycle due to the induced visual stimulation. To address this issue, we developed a custom-made two-photon light-sheet microscope optimized for high-speed volumetric imaging. By employing infra-red light (not visible to the larva) for excitation, we are able to record wholebrain neuronal activity with high temporal- and spatial-resolution without affecting the sleep state. In two-pho…
Expanding Two-Photon Intravital Microscopy to the Infrared by Means of Optical Parametric Oscillator
2010
Chronic inflammation in various organs, such as the brain, implies that different subpopulations of immune cells interact with the cells of the target organ. To monitor this cellular communication both morphologically and functionally, the ability to visualize more than two colors in deep tissue is indispensable. Here, we demonstrate the pronounced power of optical parametric oscillator (OPO)-based two-photon laser scanning microscopy for dynamic intravital imaging in hardly accessible organs of the central nervous and of the immune system, with particular relevance for long-term investigations of pathological mechanisms (e.g., chronic neuroinflammation) necessitating the use of fluorescent…
Two-photon absorption dye based on 2,5-bis(phenylacrylonitrile)thiophene with aggregration enhanced fluorescence
2016
This paper reports the synthesis and characterization of a 2,5-bis(phenylacrylonitrile) thiophene based two-photon dye, designed to show enhancement in fluorescence quantum yield in nanoaggregated form. Strong solvatochromism has been observed and explained by the favoritism of locally excited (LE) or internal charge transfer (ICT) state depending on the solvent polarity. Aqueous dispersions of nanoparticles have been prepared and investigated regarding their optical properties which were correlated to the LE and ICT state and the molecular structure of the aggregates. (C) 2016 Optical Society of America
Oscillator strengths of sulphur 3s23p34s3So-3s23p34p3P transitions measured by time resolved two-photon laser spectroscopy
1997
Oscillator strengths for the three 3s23p34s 3S1o-3s23p34p 3P0,1,2 transitions in neutral sulphur have been determined directly from lifetime measurements. Two-photon UV laser excitation and subsequent fluorescence detection have been used on atoms produced in a thermal sulphur beam or in a laser-driven plasma. A good agreement was found between data obtained in both schemes. The lifetime data obtained, τ(3P0) = 46.1(1.0) ns, τ(3P1) = 46.1(1.0) ns and τ(3P2) = 46.1(1.0) ns are compared with results of theoretical and experimental data from literature. The absorption oscillator strengths derived are f(3S1o-3P0) = 0.120(0.003), f(3S1o-3P1) = 0.360(0.008) and f(3S1o-3P2) = 0.600(0.013), respect…
Continuous-wave spontaneous lasing in mercury pumped by resonant two-photon absorption
2010
The first continuous-wave two-photon absorption laser-induced stimulated emission (CTALISE) is demonstrated. The 7^1S-6^1P transition in mercury at 1014nm wavelength is used and selective lasing of different isotopes is observed.