In this work, we present an experimental investigation for welding Nylon: Bi-Oriented Polyamide (BOPA) thin films
using a CO2 waveguide laser in a pulsed configuration. The material used in this study is Nylon 6, all set in square sheet
thin films samples of 100 cm2 with 15 μm thickness. Our optical setup is based on deliver the laser beam all the way
through the work piece using X-Y scanning mirrors mounted on galvo-like motors and an f-theta lens with 15 cm focal
length and 50 μm focal spot sizes. The fluence (laser energy) is controlled by a pulse signal generator having the
possibility to change the pulse repetition rate (PRR) and the pulse width (PW) of the laser beam. Our results show the
best weld seam for scanning speeds of 20mm/s and the pulsed laser beam with 2 KHz PRR and 80 μs for the PW time.
The scanning speed and trajectory for the welding process are all controlled by a computer in which one can modify the
weld parameters. The irradiance at the focal point is set to 1.146 MW/cm2 while the average optical power was set to
22.5W. Our experimental parameters are previously modeled by using COMSOL Multiphysics software were the laser
heat source is modeled on the selected material. This model is based on the heat transfer partial differential equation and
solved by finite elements procedure. Model results show a perfect agreement with the experiments. Finally, the quality
of the welded seam is studied by means of sealed tight and share force critical mechanical test.
Optical properties of ultrathin aluminum quantum wells deposited on glass (SiO2) and crystalline silicon (a-Si) are studied at room temperature in the infrared region at 9.201 micrometers wavelength within two thicknesses range: d approximately 5 to 35 angstroms and 36 to 112 angstroms. All our thickness dependence reflectivity measurements were made by tuning a CO2 laser to 9.201 micrometers for p-polarization and an angle of incidence of 7 degree(s). Our main contribution here is the reveled fine oscillatory behavior on a gradually increasing reflectivity spectra. These fine oscillation structure can be attributed to quantum size effects.
In this paper we present the experimental results of the study of silver thin films using a photoacoustic spectroscopic system. The experimental setup incorporates a pulsed N2 pumped dye laser, a mechanical chopped ion argon and He- Ne lasers as tunable ligth sources to scan the sample over a wide wavelength range. With the laser as the light source, it is possible to obtain a signal to noise ratio that is better than the obtained by means of a coupled monochromator with a white light source in the experiments. The sample setup is a conventional Kretschmann-Reather' configuration with a rigth angle prism oil matched with the substrate on which it is evaporated the Ag thin film with thickness of 300A and 500A. By using the photoacoustic technique, we expect to have a lower intensity in the photoacoustic signal associated with the surface plasmon (SP) resonance, due to the probability of radiative decay of the plasmon. In our experiments we found that the frecuency of the chopped ligth, obtained for the SP signal detection was 4Hz, and it could be increased up to 60Hz as the maximum frecuency where we still have a signal; this differ with the results of other authors. We also present the behavior of the dispersion curve for Ag thin films, which it depends on the wavelength and the incidence angle scans. Finally, we compare the photoacoustic data plots with the Attenuated Total Reflection (ATR) for the samples.
NON-SPIE: Laser Fundamentals
This course descrives the fundamental theory of laser systems. It is intended to professionals in industry