Collapse and revivals in a two-photon absorption process

1987 ◽  
Vol 4 (2) ◽  
pp. 177 ◽  
Author(s):  
P. Alsing ◽  
M. S. Zubairy
Keyword(s):  
Photon Absorption ◽  
Absorption Process ◽  
Two Photon Absorption ◽  
Two Photon

scholarly journals Photolysis of SiH4 by the Third Harmonic of a Nd:YAG Laser at 355 NM

1996 ◽  
Vol 16 (4) ◽  
pp. 245-253
Author(s):  
K. Sentrayan ◽  
E. Haque ◽  
A. Michael ◽  
V. S. Kushawaha
Keyword(s):  
Laser Energy ◽  
Emission Spectra ◽  
Photon Absorption ◽  
Absorption Process ◽  
Third Harmonic ◽  
Two Photon Absorption ◽  
Two Photon ◽  
The Third ◽  
Atomic Lines ◽  
White Deposit

The photolysis of silane (SiH4) was carried out using the third harmonic of a Nd: YAG laser at 355 nm, at a fixed SiH4 pressure of 350 Torr, varying the laser energy fluence in the range of 30–300 Jcm-2. The emission spectra indicates that the photofragments formed are SiH2, SiH, Si, H2, and H. The (A1B1-X1A1) transitions at 552.7 nm, 525.3 nm, 505.6 nm, and 484.7 nm of SiH2 are due to a two photon absorption process. The (A2Δ-X2π) transitions of SiH at 425.9 nm, 418 nm, 414.2 nm, 412.8 nm and 395.6 nm are due to a three photon absorption process. The brownish white deposit on the cell windows indicates the presence of amorphous silicon (a:Si-H). The two atomic lines of Si(4s1P0→ 3p21D2) at 288.1 nm, and (4s3Pj→ 3P3Pj) at 251.6 nm are observed. The atomic Si transitions are due to a three photon absorption. We observed seven transitions due to molecular hydrogen at wavelengths 577.5 nm, 565.5 nm, 534.4 nm, 542.5 nm, 471 nm, 461.7 nm, and 455.4 nm. These bands are due to a four photon absorption proc6ss. In addition to the molecular bands we also observed hydrogen atomic lines Hβ, Hγ and Hδ.

scholarly journals Determination of 4H-SiC Ionization Rates Using OBIC Based on Two-Photon Absorption

2016 ◽  
Vol 858 ◽  
pp. 245-248 ◽  
Author(s):  
Hassan Hamad ◽  
Christophe Raynaud ◽  
Pascal Bevilacqua ◽  
Sigo Scharnholz ◽  
Bertrand Vergne ◽  
...  
Keyword(s):  
Single Photon ◽  
Green Laser ◽  
Photon Absorption ◽  
Absorption Process ◽  
Field Range ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Avalanche Diodes ◽  
Single Photon Absorption ◽  
Ionization Rates

Optical Beam Induced Current (OBIC) measurements are performed on 4H-SiC avalanche diodes with a very thin and a highly doped active region. A pulsed green laser, with a wavelength of 532 nm, illuminates a reverse biased diode leading to generate electron-hole pairs in the space charge region. Comparison between the 4H-SiC bandgap and the incident photon energy shows that single photon absorption process can be neglected and two-photon absorption process dominates in this case. Ionization rates are then extracted from multiplication curve in a high electric field range (3 to 5 MV.cm–1). Results are in good agreement with previous ones obtained on the same diodes using single photon absorption process.

Ruthenium(II)-nitrosyl polypyridinyl Complexes: from NO/ON Isomerization to NO delivery

2015 ◽  
Vol 1767 ◽  
pp. 65-74
Author(s):  
Pascal G. Lacroix ◽  
Isabelle Malfant
Keyword(s):  
Solid State ◽  
Photon Absorption ◽  
High Yield ◽  
Absorption Process ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Ruthenium Nitrosyl ◽  
Nlo Response ◽  
No Release ◽  
Computational Strategy

ABSTRACTRuthenium-nitrosyl (RuII(NO)) complexes are stable in the dark, but exhibit a unique photoreactivity which can lead either to a solid state isomerization from RuII(NO) to RuII(ON), or to a nitric oxide (NO·) release in solution. From our recent discovery of a high yield of isomerization (> 92%) in [RuII(py)4Cl(NO)](PF6)2, we have developed a computational strategy aimed at designing switchable nonlinear optical (NLO) material with high contrast (large difference in the on / off NLO response) in the solid state. Our synthetic targets are terpyridine based RuII chromophores in which various substituents can be introduced to adjust the NLO response which, at best, should be vanishing in the off state. Alternatively, these complexes can undergo a photo-induced NO· release in solution, a possibility which becomes increasingly appealing in relation to the discovery of the numerous biological roles of NO·, in the context of the emergence of the photodynamic therapy. A promising fluorene-terpyridine RuII(NO) complex was investigated, which could find an additional interest in relation to its capability for releasing NO· by a two-photon absorption process.

LASER INDUCED THERMAL LENS EFFECT IN RHODAMINE B — SIGNATURE OF RESONANT TWO PHOTON ABSORPTION

1995 ◽  
Vol 09 (22) ◽  
pp. 1471-1477 ◽  
Author(s):  
C. V. BINDHU ◽  
S. S. HARILAL ◽  
RIJU C. ISSAC ◽  
GEETHA K. VARIER ◽  
V. P. N. NAMPOORI ◽  
...  
Keyword(s):  
Rhodamine B ◽  
Laser Power ◽  
Photon Absorption ◽  
Thermal Lensing ◽  
Absorption Process ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Photon Process ◽  
Thermal Lens Effect ◽  
Made In

Measurement of thermal lensing signal as a function of laser power made in Rhodamine B solutions in methanol give clear evidence of two photon absorption process within certain concentration ranges when 488 nm Ar + laser beam is used as the pump source. Only one photon process is found to occur when 514 nm and 476 nm beams are used as the pump.

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