Calculation of simultaneous absorption of two gases reacting with the absorbent

1976 ◽  
Vol 41 (5) ◽  
pp. 1302-1309
Author(s):  
V. Rod ◽  
F. Kaštánek
Author(s):  
David W. Piston ◽  
Brian D. Bennett ◽  
Robert G. Summers

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.


Author(s):  
David W. Piston

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.


1982 ◽  
Vol 15 (5) ◽  
pp. 362-367 ◽  
Author(s):  
MUTSUO AOKI ◽  
HIROYUKI TANAKA ◽  
HIROSHI KOMIYAMA ◽  
HAKUAI INOUE

1993 ◽  
Vol 71 (7-8) ◽  
pp. 326-333 ◽  
Author(s):  
B. Wallbank ◽  
J. K. Holmes ◽  
A. Weingartshofer

We report experimental differential cross sections for inelastic scattering of electrons from helium atoms in the presence of an intense (~108 W cm−2) carbon dioxide laser. The cross sections for excitation of the 21P state of helium with the simultaneous absorption or emission of one laser quantum were measured over the incident electron energy range of 36–70 eV and scattering angles of 13–31°.


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