scholarly journals Direct Two-Photon Excitation of Isomeric Transition in Thorium-229 Nucleus

2021 ◽  
Vol 57 (11) ◽  
pp. 1119
Author(s):  
V.I. Romanenko ◽  
Ye.G. Udovitskaya ◽  
L.P. Yatsenko ◽  
A.V. Romanenko ◽  
A.N. Litvinov ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Monochromatic Light ◽  
Fluorescence Emission ◽  
Isomeric Transition ◽  
Absorption Saturation ◽  
Two Photon ◽  
Photon Excitation ◽  
Polychromatic Radiation ◽  
Electromagnetic Trap ◽  
Two Photon Excitation

A possibility of the two-photon excitation of an isomeric state in a nucleus of thorium-229 has been discussed. The fluorescence intensity of the excitation is demonstrated to be identical for the irradiation of nuclei with either monochromatic light or polychromatic radiation consisting of a sequence of short lightpulses of the same intensity. The two-photon excitation of Th3+ ion in an electromagnetic trap with a focused laser beam with a wavelength of about 320 nm and power of 100 mW can lead to the absorption saturation, at which the fluorescence emission with the frequency of the transition in a nucleus is maximal. In crystals doped with Th4+ to a concentration of about 1018 cm-3 and irradiated with a laser radiation 10 W in power, the emission of several photons persecond with a wavelength of about 160 nm becomes possible.

Side illumination fluorescence emission characteristics from a dye doped polymer optical fiber under two-photon excitation

2008 ◽  
Vol 47 (11) ◽  
pp. 1913 ◽  
Author(s):  
M. Sheeba ◽  
M. Rajesh ◽  
S. Mathew ◽  
V. P. N. Nampoori ◽  
C. P. G. Vallabhan ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Fluorescence Emission ◽  
Emission Characteristics ◽  
Polymer Optical Fiber ◽  
Two Photon ◽  
Photon Excitation ◽  
Doped Polymer ◽  
Side Illumination ◽  
Two Photon Excitation

scholarly journals A novel method for observing proteins in vivo using a small fluorescent label and multiphoton imaging

2005 ◽  
Vol 390 (3) ◽  
pp. 787-790 ◽  
Author(s):  
Stanley W. Botchway ◽  
Ignasi Barba ◽  
Randolf Jordan ◽  
Rebecca Harmston ◽  
Peter M. Haggie ◽  
...  
Keyword(s):  
Fluorescence Detection ◽  
Fluorescence Emission ◽  
Yeast Cells ◽  
Fluorescent Label ◽  
Multiphoton Imaging ◽  
Two Photon ◽  
Photon Excitation ◽  
Novel Method ◽  
Two Photon Excitation

A novel method for the fluorescence detection of proteins in cells is described in the present study. Proteins are labelled by the selective biosynthetic incorporation of 5-hydroxytryptophan and the label is detected via selective two-photon excitation of the hydroxyindole and detection of its fluorescence emission at 340 nm. The method is demonstrated in this paper with images of a labelled protein in yeast cells.

Fluorescence Anisotropies of 4-Dimethylamino-ω- diphenylphosphinyl-trans-Styrene in Isotropic Media in the Case of One-and Two-Photon Excitation

1993 ◽  
Vol 48 (4) ◽  
pp. 551-556 ◽  
Author(s):  
A. Kawski ◽  
J. Gryczyński ◽  
Z. Gryczyński
Keyword(s):  
Excited State ◽  
Rotational Diffusion ◽  
Fluorescence Emission ◽  
Excited State Lifetime ◽  
Two Photon ◽  
Photon Excitation ◽  
Isotropic Media ◽  
Different Temperatures ◽  
Initial Shock ◽  
Two Photon Excitation

Abstract Fluorescence emission anisotropies, r, and mean lifetimes of 4-dimethylamino-ω-diphenylphosphinyl-trans-styrene (DDPS) were measured in n-butanol at different temperatures from 20 to 80 °C for one-and two-photon excitation. When increasing the temperature, the lifetime decreased from 32 to 12 ps, the r values, however, remained constant (0.315 and 0.445 for one-and two-photon excitation, respectively) and were found to be temperature independent. For DDPS in glycerol at - 5°C, where rotational diffusion does not occur during the excited state lifetime, the limiting emission anisotropies were r0 = 0.382 and r0 = 0.545 for one-and two-photon excitation, respectively, very little differing from the fundamental emission anisotropies rf = 2/5 and rf = 4/7. The small differences rf - r0 can be due to vibrations performed after excitation by the DDPS molecule as a result of the initial shock.

Two-photon excitation microscopy in cellular biophysics

1995 ◽  
Vol 53 ◽  
pp. 62-63
Author(s):  
David W. Piston ◽  
Brian D. Bennett ◽  
Robert G. Summers
Keyword(s):  
Confocal Microscopy ◽  
Laser Beam ◽  
Duty Cycle ◽  
Excited Electronic State ◽  
Input Power ◽  
Two Photon ◽  
Simultaneous Absorption ◽  
Photon Excitation ◽  
Very High ◽  
Two Photon Excitation

Two-photon excitation microscopy (TPEM) provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging and photochemistry. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10-5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.

Two-photon excitation fluorescence microscopy in living systems

1993 ◽  
Vol 51 ◽  
pp. 154-155 ◽  
Author(s):  
David W. Piston
Keyword(s):  
Confocal Microscopy ◽  
Fluorescence Microscopy ◽  
Singlet State ◽  
Excited Electronic State ◽  
Input Power ◽  
Two Photon ◽  
Simultaneous Absorption ◽  
Photon Excitation ◽  
Very High ◽  
Two Photon Excitation

Two-photon excitation fluorescence microscopy provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In our fluorescence experiments, the final excited state is the same singlet state that is populated during a conventional fluorescence experiment. Thus, the fluorophore exhibits the same emission properties (e.g. wavelength shifts, environmental sensitivity) used in typical biological microscopy studies. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10−5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.

Two‐photon excitation fluorescence microscopy using a semiconductor laser

Bioimaging ◽  
1995 ◽  
Vol 3 (2) ◽  
pp. 70-75 ◽  
Author(s):  
Pekka E Hänninen ◽  
Martin Schrader ◽  
Erkki Soini ◽  
Stefan W Hell
Keyword(s):  
Fluorescence Microscopy ◽  
Semiconductor Laser ◽  
Two Photon ◽  
Photon Excitation ◽  
Two Photon Excitation

Two-Photon Excitation Imaging of Glucose Metabolism in Living Tissue

1997 ◽  
Vol 3 (S2) ◽  
pp. 305-306
Author(s):  
David W. Piston
Keyword(s):  
Confocal Microscopy ◽  
Collection Efficiency ◽  
Three Dimensional ◽  
Spatial Filter ◽  
Input Power ◽  
Photon Absorption ◽  
Focal Volume ◽  
Two Photon ◽  
Photon Excitation ◽  
Two Photon Excitation

Two-photon excitation microscopy (TPEM) provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging and photochemistry. It provides three-dimensional resolution and eliminates background equivalent to an ideal confocal microscope without requiring a confocal spatial filter, whose absence enhances fluorescence collection efficiency. This results in inherent submicron optical sectioning by excitation alone. In practice, TPEM is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10−5 limits the average input power to less than 10 mW, only slightly greater than the power normally used in confocal microscopy. Because of the intensity-squared dependence of the two-photon absorption, the excitation is limited to the focal volume.

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