Video-Rate Scanning Two-Photon Excitation Fluorescence Microscopy

1998 ◽  
Vol 4 (S2) ◽  
pp. 424-425
Author(s):  
G.Y. Fan ◽  
H. Fujisaki ◽  
R.-K. Tsay ◽  
R.Y. Tsien ◽  
Mark H. Ellisman
Keyword(s):  
Laser Beam ◽  
Group Velocity Dispersion ◽  
Laser System ◽  
Average Power ◽  
Laser Pulses ◽  
Green Laser ◽  
Two Photon ◽  
Photon Excitation ◽  
Schematic Layout ◽  
Two Photon Excitation

A video-rate scanning two-photon excitation microscope (TPEM) has been successfully constructed and tested. The TPEM, based on a Nikon RCM-8000, incorporates a femtosecond pulsed laser, a pre-chirper, and a non-confocal detection box for ratio imaging. Fig. 1 shows the schematic layout of the main components of the instrument, each of which is briefly discussed below.Laser System: A Tsunami Ti: Sapphire laser (from Spectra-Physics) is optically pumped by a 5 W green laser (Millennia from Spectra-Physics) and is capable of generating 100 fs pulses at a repetition rate of 82 MHz and an average power of 0.8 W. The output wavelength is tunable from 690 to 1050 nm with three optical sets, each covering part of the spectrum with some overlapping.Pre-chirper: After leaving the Tsunami, the laser beam enters an optic unit known as a pre-chirper which pre-chirps laser pulses to compensate for the group velocity dispersion which will result when the laser beam goes through the microscope optics.

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.

scholarly journals Multifarious control of two-photon excitation of multiple fluorophores achieved by phase modulation of ultra-broadband laser pulses

2009 ◽  
Vol 17 (16) ◽  
pp. 13737 ◽  
Author(s):  
Keisuke Isobe ◽  
Akira Suda ◽  
Masahiro Tanaka ◽  
Fumihiko Kannari ◽  
Hiroyuki Kawano ◽  
...  
Keyword(s):  
Phase Modulation ◽  
Laser Pulses ◽  
Two Photon ◽  
Photon Excitation ◽  
Broadband Laser ◽  
Two Photon Excitation

scholarly journals Исследование мощности люминесценции экситонов и примесно-дефектных центров, возбуждаемых с помощью двухфотонного поглощения

2020 ◽  
Vol 54 (1) ◽  
pp. 48
Author(s):  
А.А. Гладилин ◽  
В.П. Данилов ◽  
Н.Н. Ильичев ◽  
В.П. Калинушкин ◽  
М.И. Студеникин ◽  
...  
Keyword(s):  
Radiation Power ◽  
Average Power ◽  
Electronic System ◽  
Quadratic Character ◽  
Degree Of Contamination ◽  
Two Photon ◽  
Defect Centers ◽  
Photon Excitation ◽  
Impurity Defect ◽  
Two Photon Excitation

In the present work, using as an example ZnSe: Fe2+ single crystals, it was experimentally and theoretically studied the effect of the average power of femtosecond laser radiation on the average luminescence power of excitons and impurity-defect centers upon two-photon excitation of the electronic system of a crystal. It has been experimentally shown that the average luminescence power of crystal excitons in the studied range of excitation powers is proportional to 4 degrees of the average excitation radiation power. The average luminescence power of impurity-defect centers has a quadratic character. A theory is constructed that explains the experimentally observed dependencies. It is noted that the nature of the dependence of the crystal luminescence on the pump power during two-photon excitation can be used to estimate the degree of contamination of the crystal by impurity-defect centers.

scholarly journals Two-Color Two-Photon Excitation Using Femtosecond Laser Pulses

2008 ◽  
Vol 112 (18) ◽  
pp. 5768-5773 ◽  
Author(s):  
Stefan Quentmeier ◽  
Stefan Denicke ◽  
Jan-Eric Ehlers ◽  
Raluca A. Niesner ◽  
Karl-Heinz Gericke
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Two Photon ◽  
Photon Excitation ◽  
Two Photon Excitation

scholarly journals Two-photon controlled sol–gel condensation for the microfabrication of silica based microstructures. The role of photoacids and photobases

RSC Advances ◽  
2017 ◽  
Vol 7 (74) ◽  
pp. 46615-46620 ◽  
Author(s):  
J. Kustra ◽  
E. Martin ◽  
D. Chateau ◽  
F. Lerouge ◽  
C. Monnereau ◽  
...  
Keyword(s):  
Laser Beam ◽  
Focal Point ◽  
Sol Gel ◽  
Ph Changes ◽  
Two Photon ◽  
Photon Excitation ◽  
Sol Gel Process ◽  
And Control ◽  
Two Photon Excitation

Two-photon excitation of photobases is used to induce pH changes and control the condensation step of the sol–gel process at the focal point of a laser beam in a confocal configuration.

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