Pump-Probe Laser Photolytic Fragmentation Fluorescence Spectrometry of Isomeric Alkenes

1994 ◽  
Vol 48 (5) ◽  
pp. 616-619 ◽  
Author(s):  
Bobby J. Stanton ◽  
E. T. Monroe ◽  
E. L. Wehry
Keyword(s):  
Fluorescence Intensity ◽  
Laser Fluence ◽  
Laser Wavelength ◽  
Fluorescence Spectrometry ◽  
Probe Laser ◽  
Intermediate Species ◽  
Pump Probe ◽  
Laser Pump ◽  
Photolysis Laser ◽  
Spectral Patterns

The two-laser “pump-probe” photolytic fragmentation fluorescence spectrometry of three octenes and two nonenes is described. Probe-laser-induced C2 fluorescence (Deslandres-d'Azambuja system, C1II g→ A1II u) is detected. The relative C2 fluorescence intensity and spectral patterns exhibited by each alkene are strongly dependent on the probe-laser wavelength. The dependence of the fragment fluorescence intensity on the probe-laser fluence implies that the “probe” laser induces photofragmentation of intermediate species produced by the “photolysis” laser.

A Simultaneous Phase Shift Interferometry Used to Pulse Laser Pump-Probe Approach

2011 ◽  
Vol 346 ◽  
pp. 670-674 ◽  
Author(s):  
Hai Ying Song ◽  
Xue Peng He ◽  
Shi Bing Liu ◽  
Tao Chen
Keyword(s):  
Time Delay ◽  
Phase Shift ◽  
Pulse Laser ◽  
Laser Wavelength ◽  
Interference Channels ◽  
Phase Lag ◽  
Pump Probe ◽  
Laser Pump ◽  
Light Interference ◽  
Theoretical Results

A simultaneous phase shift interferometry was proposed to determine the time delay accurately in the pulse laser pump-probe detecting. The relevant optical system formed by four light interference channels was designed and optimized based on Jones theory. The light intensity distribution of interference pattern associated with the phase lag from these four light interference channels was derived by Jones matrix. The possible errors that exist in the applications were calculated. The theoretical results show that the minimum resolution of the time delay can be achieved to attosecond level for 800nm laser wavelength.

Selective detection in pump-probe laser photolytic-fragmentation fluorescence spectrometry of nitriles, amines, and alkenes

1992 ◽  
Vol 64 (3) ◽  
pp. 268-274 ◽  
Author(s):  
Sang C. Lee ◽  
Bobby J. Stanton ◽  
Brent A. Eldridge ◽  
E. L. Wehry
Keyword(s):  
Fluorescence Spectrometry ◽  
Probe Laser ◽  
Selective Detection ◽  
Pump Probe

electromagnetic field at the particl e has to be computed numerically. An example of such a computation using a program based on [49] is given in Fig. 4. But not only doe s the Mie theory describe an enhancement of the laser intensity in the particles' near field, it also predicts that for certain values of the size parameter nd/X (d denoting the particle diameter, À the laser wavelength) the enhancement should be particularly efficient, resulting in a resonant intensity enhancement, the so-called "Mie-resonances". 3.2.2. Near-field induced substrate damage When inspecting contaminated samples by scanning electron microscopy (SEM) or atomic force microscopy (AFM ) after DLC using ns laser pulses, the consequences of the field enhancement process became obvious: all over the cleaned areas w e found substrate damages localized exactly at the former particle positions [35, 37-39]. These damages manifested as melting pools or even holes in the surface, typical examples can be seen in Fig. 5. The consequences for the laser cleaning process are obvious. The intensity enhancement reduces the maximum laser fluence that can be applied in the process. Usually in laser cleaning studies [19, 31 ] the laser fluence corresponding to the melting threshold of a bare surface is taken as the damage threshold fluence. Our experiments show clearly that this is an inadequate definition. Instead one must take into account the enhanced laser fluence underneath the particles, as it will be discussed in Section 4. Fro m the obtained AFM images we were able to analyse in detail the surface profile at the damaged sites. Here we found that for high field enhancement factors the silicon substrate was not only molten , but that some material was even ablated (see Sec. 4). The momentum transfer to the particles during the ablation process significantly contributes to the cleanin g process and hence local substrate ablation

2003 ◽  
pp. 327-330
Keyword(s):  
Laser Fluence ◽  
Near Field ◽  
Particle Diameter ◽  
Surface Profile ◽  
Field Enhancement ◽  
Damage Threshold ◽  
Laser Pulses ◽  
Laser Wavelength ◽  
Laser Cleaning ◽  
Intensity Enhancement

Electron emission from films of Ag and Au nanoparticles excited by a femtosecond pump-probe laser

2008 ◽  
Vol 77 (19) ◽  
Author(s):  
A. Gloskovskii ◽  
D. A. Valdaitsev ◽  
M. Cinchetti ◽  
S. A. Nepijko ◽  
J. Lange ◽  
...  
Keyword(s):  
Electron Emission ◽  
Au Nanoparticles ◽  
Probe Laser ◽  
Pump Probe

Dynamics of Ultrafast Laser Induced Damage in Single Crystal Ni-based Superalloy During Machining

2006 ◽  
Vol 980 ◽  
Author(s):  
Joel P. McDonald ◽  
Shuwei Ma ◽  
John A. Nees ◽  
Tresa M. Pollock ◽  
Steven M. Yalisove
Keyword(s):  
Shock Wave ◽  
Laser Fluence ◽  
Ultrafast Laser ◽  
Laser Exposure ◽  
Mechanical Shock ◽  
Incident Laser ◽  
Machining Time ◽  
Time Resolved ◽  
Pump Probe ◽  
Laser Induced Damage

AbstractPump-probe imaging of femtosecond pulsed laser ablation was performed to investigate the mechanical shock induced on an intermetallic superalloy CMSX-4 during femtosecond laser machining. Time resolved shadowgraphic images were collected of the shock wave produced in the air above the target following laser exposure (0-10.3 nanoseconds). The dimensions of the shock wave were measured as a function of delay time and laser fluence (1.27 J/cm2 - 62.8 J/cm2). Time-resolved shadowgraphic images of the ablation event will be presented, and the corresponding damage morphology as a function of incident laser fluence will be discussed.

Laser Pump‐Probe Fiber‐Optic Technique for Characterization of Near‐Surface Layers of Solids: Development and Application Prospects for Studying Semiconductors and Weyl Semimetals

2020 ◽  
Vol 532 (8) ◽  
pp. 1900586
Author(s):  
Alexander A. Starostin ◽  
Victor V. Shangin ◽  
Alexander T. Lonchakov ◽  
Artem N. Kotov ◽  
Semyon B. Bobin
Keyword(s):  
Fiber Optic ◽  
Surface Layers ◽  
Pump Probe ◽  
Near Surface ◽  
Laser Pump ◽  
Weyl Semimetals ◽  
Application Prospects
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