Vacuum-ultraviolet stimulated emission from two-photon-excited molecular hydrogen

1983 ◽  
Vol 28 (2) ◽  
pp. 795-801 ◽  
Author(s):  
H. Pummer ◽  
H. Egger ◽  
T. S. Luk ◽  
T. Srinivasan ◽  
C. K. Rhodes
Keyword(s):  
Molecular Hydrogen ◽  
Vacuum Ultraviolet ◽  
Stimulated Emission ◽  
Two Photon

scholarly journals Progresses on the Use of Two-Photon Absorption Laser Induced Fluorescence (TALIF) Diagnostics for Measuring Absolute Atomic Densities in Plasmas and Flames

Plasma ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 145-171
Author(s):  
Kristaq Gazeli ◽  
Guillaume Lombardi ◽  
Xavier Aubert ◽  
Corinne Y. Duluard ◽  
Swaminathan Prasanna ◽  
...  
Keyword(s):  
Optical Transition ◽  
Thin Film Deposition ◽  
Laser Induced Fluorescence ◽  
Film Deposition ◽  
Stimulated Emission ◽  
Photon Absorption ◽  
Collisional Quenching ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Wide Range

Recent developments in plasma science and technology have opened new areas of research both for fundamental purposes (e.g., description of key physical phenomena involved in laboratory plasmas) and novel applications (material synthesis, microelectronics, thin film deposition, biomedicine, environment, flow control, to name a few). With the increasing availability of advanced optical diagnostics (fast framing imaging, gas flow visualization, emission/absorption spectroscopy, etc.), a better understanding of the physicochemical processes taking place in different electrical discharges has been achieved. In this direction, the implementation of fast (ns) and ultrafast (ps and fs) lasers has been essential for the precise determination of the electron density and temperature, the axial and radial gradients of electric fields, the gas temperature, and the absolute density of ground-state reactive atoms and molecules in non-equilibrium plasmas. For those species, the use of laser-based spectroscopy has led to their in situ quantification with high temporal and spatial resolution, with excellent sensitivity. The present review is dedicated to the advances of two-photon absorption laser induced fluorescence (TALIF) techniques for the measurement of reactive species densities (particularly atoms such as N, H and O) in a wide range of pressures in plasmas and flames. The requirements for the appropriate implementation of TALIF techniques as well as their fundamental principles are presented based on representative published works. The limitations on the density determination imposed by different factors are also discussed. These may refer to the increasing pressure of the probed medium (leading to a significant collisional quenching of excited states), and other issues originating in the high instantaneous power density of the lasers used (such as photodissociation, amplified stimulated emission, and photoionization, resulting to the saturation of the optical transition of interest).

Stimulated emission effects in excitonic molecule luminescence of CuCl under resonant two-photon excitation

1977 ◽  
Vol 24 (12) ◽  
pp. 845-848 ◽  
Author(s):  
Masahiro Ojima ◽  
Yasuo Oka ◽  
Takashi Kushida ◽  
Shigeo Shionoya
Keyword(s):  
Stimulated Emission ◽  
Two Photon ◽  
Photon Excitation ◽  
Two Photon Excitation

Interactions of picosecond laser pulses with organic molecules I. Two-photon fluorescence quenching and singlet states excitation in Rhodamine dyes

1972 ◽  
Vol 328 (1572) ◽  
pp. 97-121 ◽  
Keyword(s):  
Rhodamine 6G ◽  
Second Harmonic ◽  
Random Phase ◽  
Stimulated Emission ◽  
Photon Absorption ◽  
Picosecond Pulses ◽  
Two Photon ◽  
Singlet States ◽  
Two Photon Fluorescence ◽  
Photon Fluorescence

Intensity dependent quenching and reversal of the two-photon fluorescence patterns in Rhodamine 6G and DPA, of picosecond pulses from a mode-locked ruby laser have been investigated by measurements of the two-photon fluorescence efficiencies of these dyes. While for Rhodamine 6G there was a marked departure from the square law dependence at high laser intensities, the experimental curve for DPA showed no evidence of quenching. When excited by a mode-locked neodymium: glass laser Rhodamine 6G fluorescence was not quenched at fluxes as high as 5 x 10 30 photons cm -2 s -1 but in Rhodamine B quenching appeared at a laser flux of 3 x 10 27 photons cm -2 s -1 . These quenching results and measurements of the absorption of pulses by Rhodamine 6G, previously excited by second harmonic pulses, are explained by the effects of single photon absorption and stimulated emission from the S 1 and S 2 excited singlet states. A square pulse approximation has been employed to solve the general rate equations and the fitting of the calculated curves to the experimental results gave values for the stimulated emission and absorption cross-sections of the S 1 and S 2 states of Rhodamine 6G and for the relaxation time (~ 2 ps) between the vibrational manifolds of these excited states. Taking into account random phase and amplitude fluctuations of the picosecond pulses, time and space averaged two-photon fluorescence profiles, using these values of the dye parameters, showed quenching and reversal of the patterns for the laser pulse intensities at which these effects were experimentally observed. The possibilities of frequency tunable pulses, of transform-limited durations, from mode-locked dye lasers employed with an electro-optical streak camera of time-resolution equal to that of the pulse durations (~ 2 ps) for time-resolved excited state molecular spectroscopy are briefly considered.

scholarly journals Time-resolved stimulated emission depletion and energy transfer dynamics in two-photon excited EGFP

2018 ◽  
Vol 148 (13) ◽  
pp. 134312 ◽  
Author(s):  
T. A. Masters ◽  
N. A. Robinson ◽  
R. J. Marsh ◽  
T. S. Blacker ◽  
D. A. Armoogum ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Stimulated Emission ◽  
Time Resolved ◽  
Two Photon ◽  
Stimulated Emission Depletion
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