Long-lived cation radical formation of aromatic amines in poly(methyl methacrylate) matrix at room temperature by two-photon excitation

1988 ◽  
Vol 20 (3) ◽  
Author(s):  
Akira Tsuchida ◽  
Mitsuru Nakano ◽  
Masaaki Yoshida ◽  
Masahide Yamamoto ◽  
Yoshio Wada
Keyword(s):  
Methyl Methacrylate ◽  
Aromatic Amines ◽  
Room Temperature ◽  
Cation Radical ◽  
Radical Formation ◽  
Poly Methyl Methacrylate ◽  
Two Photon ◽  
Photon Excitation ◽  
Two Photon Excitation

scholarly journals Optical bistability in InSb at room temperature with two‐photon excitation

1983 ◽  
Vol 42 (4) ◽  
pp. 334-336 ◽  
Author(s):  
A. K. Kar ◽  
J. G. H. Mathew ◽  
S. D. Smith ◽  
B. Davis ◽  
W. Prettl
Keyword(s):  
Optical Bistability ◽  
Room Temperature ◽  
Two Photon ◽  
Photon Excitation ◽  
Two Photon Excitation

Room-Temperature Fluorescence Imaging and Spectroscopy of Single Molecules by Two-Photon Excitation

1997 ◽  
Vol 101 (38) ◽  
pp. 7019-7023 ◽  
Author(s):  
Erik J. Sánchez ◽  
Lukas Novotny ◽  
Gary R. Holtom ◽  
X. Sunney Xie
Keyword(s):  
Fluorescence Imaging ◽  
Room Temperature ◽  
Single Molecules ◽  
Two Photon ◽  
Photon Excitation ◽  
Imaging And Spectroscopy ◽  
Two Photon Excitation

Two-photon excitation of alkyl-substituted magnesium phthalocyanine: radical formation via higher excited states

1994 ◽  
Vol 80 (1-3) ◽  
pp. 289-298 ◽  
Author(s):  
Holger Stiel ◽  
Klaus Teuchner ◽  
Andrea Paul ◽  
Wolfgang Freyer ◽  
Dieter Leupold
Keyword(s):  
Excited States ◽  
Radical Formation ◽  
Two Photon ◽  
Photon Excitation ◽  
Higher Excited States ◽  
Two Photon Excitation

scholarly journals Room-Temperature Fluorescence Imaging and Spectroscopy of Single Molecules by Two-Photon Excitation.

1998 ◽  
Vol 102 (25) ◽  
pp. 4948-4948
Author(s):  
Erik J. Sánchez ◽  
Lukas Novotny ◽  
Gary R. Holtom ◽  
X. Sunney Xie
Keyword(s):  
Fluorescence Imaging ◽  
Room Temperature ◽  
Single Molecules ◽  
Two Photon ◽  
Photon Excitation ◽  
Imaging And Spectroscopy ◽  
Two Photon Excitation

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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