Nonlinear photodissociation of molecular iodine

1978 ◽  
Vol 56 (2) ◽  
pp. 183-190 ◽  
Author(s):  
C. Tai ◽  
F. W. Dalby
Keyword(s):  
Laser Power ◽  
Radiative Decay ◽  
Pulsed Laser ◽  
Molecular Iodine ◽  
Laser Wavelength ◽  
Two Photon ◽  
A Cell ◽  
Photoionization Spectrum ◽  
Atomic Iodine ◽  
Pulsed Laser Beam

Strong ultraviolet fluorescence originating from the radiative decay of the atomic iodine levels (3P2)6s[2]3/2 at 56092.88 cm−1 and (3P2)6s[2]5/2 at 54 633.46 cm−1 was observed when a pulsed laser beam was focused in a cell containing iodine vapour. The fluorescence intensity varied quasi-continously when the laser wavelength was scanned from 3950 to 4500 Å. Over 40 resonances at the frequency of one-photon transitions originating from the same two atomic iodine levels were observed in the fluorescence spectrum as well as in the photoionization spectrum. The intensity of both the fluorescence and the photoionization was found to vary quadratically with the laser power. The excited iodine atoms are formed by a coherent two-photon transition in molecular iodine followed by saturated photodissociation.

scholarly journals Authentication and Testing of Banknotes Using Laser Multiphoton Electron Extraction Spectroscopy (MEES)

2021 ◽  
Vol 11 (21) ◽  
pp. 10465
Author(s):  
Danny Fisher ◽  
Valery Bulatov ◽  
Israel Schechter
Keyword(s):  
Laser Beam ◽  
Pulsed Laser ◽  
Laser Wavelength ◽  
Clear Distinction ◽  
Electron Extraction ◽  
Pulsed Laser Beam

In laser multiphoton electron extraction spectroscopy (MEES), the photo-charges extracted from a surface by a pulsed laser beam are recorded as a function of laser wavelength. We report the first application of this spectroscopy to banknotes. Various banknotes from different countries, authentic and counterfeit, have been tested. The results indicate that MEES spectra are both informative (many peaks) and reproducible. The spectra allow for clear distinction between authentic and counterfeit banknotes. Actually, MEES provides a unique fingerprint of the banknotes, so that distinction between various forgery methods (printer used) is also possible.

Picosecond Single-Photon and Femtosecond Two-Photon Pulsed Laser Stimulation for IC Characterization and Failure Analysis

2009 ◽  
Author(s):  
V. Pouget ◽  
E. Faraud ◽  
K. Shao ◽  
S. Jonathas ◽  
D. Horain ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Single Photon ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Laser Stimulation ◽  
Two Photon ◽  
Resolution Improvement ◽  
Ultrashort Laser

Abstract This paper presents the use of pulsed laser stimulation with picosecond and femtosecond laser pulses. We first discuss the resolution improvement that can be expected when using ultrashort laser pulses. Two case studies are then presented to illustrate the possibilities of the pulsed laser photoelectric stimulation in picosecond single-photon and femtosecond two-photon modes.

Two-photon-excited fluorescence from silicate glass containing tantalum ions pumped by a near-infrared femtosecond pulsed laser

2006 ◽  
Vol 31 (19) ◽  
pp. 2867 ◽  
Author(s):  
Xiangeng Meng ◽  
Katsuhisa Tanaka ◽  
Shunsuke Murai ◽  
Koji Fujita ◽  
Kiyotaka Miura ◽  
...  
Keyword(s):  
Silicate Glass ◽  
Near Infrared ◽  
Pulsed Laser ◽  
Two Photon ◽  
Femtosecond Pulsed Laser

Quasi-one-dimensional thermal deformation and displacement of the surface of a solid in a pulsed laser beam

1997 ◽  
Vol 39 (12) ◽  
pp. 1985-1988
Author(s):  
S. V. Vintsents ◽  
S. G. Dmitriev ◽  
K. I. Spiridonov
Keyword(s):  
Laser Beam ◽  
Thermal Deformation ◽  
Pulsed Laser ◽  
One Dimensional ◽  
Pulsed Laser Beam

Formation of Sic, Si3N4 and SiO2 by High-Dose Ion Implantation and Laser Annealing

1980 ◽  
Vol 1 ◽  
Author(s):  
S.W. Chiang ◽  
Y.S. Liu ◽  
R.F. Reihl
Keyword(s):  
Ion Implantation ◽  
Polycrystalline Silicon ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
High Dose ◽  
Pulsed Laser Annealing ◽  
Transmission Electron ◽  
A Cell ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

ABSTRACTHigh-dose ion implantation (1017 ions-cm−2) of C+, N+, and O+ at 50 KeV into silicon followed by pulsed laser annealing at 1.06 μm was studied. Formation of SiC, Si3N4, and SiO2 has been observed and investigated using Transmission Electron Microscopy (TEM) and Differential Fourier-Transform Infrared (FT-IR) Spectroscopy. Furthermore, in N+-implanted and laser-annealed silicon samples, we have observed a cell-like structure which has been identified to be spheroidal polycrystalline silicon formed by the rapid laser irradiation.

Acoustic Field-Assisted Two-Photon Polymerization Process

2021 ◽  
Vol 143 (10) ◽  
Author(s):  
Ketki M. Lichade ◽  
Yayue Pan
Keyword(s):  
Polymer Composite ◽  
Acoustic Field ◽  
Laser Power ◽  
Liquid Droplet ◽  
Three Dimensional ◽  
Polymerization Process ◽  
Photothermal Effect ◽  
Full Potential ◽  
Two Photon ◽  
Two Photon Polymerization

Abstract This study successfully integrates acoustic patterning with the Two-Photon Polymerization (TPP) process for printing nanoparticle–polymer composite microstructures with spatially varied nanoparticle compositions. Currently, the TPP process is gaining increasing attention within the engineering community for the direct manufacturing of complex three-dimensional (3D) microstructures. Yet the full potential of TPP manufactured microstructures is limited by the materials used. This study aims to create and demonstrate a novel acoustic field-assisted TPP (A-TPP) process, which can instantaneously pattern and assemble nanoparticles in a liquid droplet, and fabricate anisotropic nanoparticle–polymer composites with spatially controlled particle–polymer material compositions. It was found that the biggest challenge in integrating acoustic particle patterning with the TPP process is that nanoparticles move upon laser irradiation due to the photothermal effect, and hence, the acoustic assembly is distorted during the photopolymerization process. To cure acoustic assembly of nanoparticles in the resin through TPP with the desired nanoparticle patterns, the laser power needs to be carefully tuned so that it is adequate for curing while low enough to prevent the photothermal effect. To address this challenge, this study investigated the threshold laser power for polymerization of TPP resin (Pthr) and photothermal instability of the nanoparticle (Pthp). Patterned nanoparticle–polymer composite microstructures were fabricated using the novel A-TPP process. Experimental results validated the feasibility of the developed acoustic field-assisted TPP process on printing anisotropic composites with spatially controlled material compositions.

Sign in / Sign up

Export Citation Format

Share Document