It was performed a Time of Flight (TOF) study for the plume produced by laser ablation of cooper by 355 nm, 23 ns
duration laser pulses, in vacuum. The plume sensor was made of a piezoelectric PVDF film associated with a pair of
electrodes. By varying the electrodes polarization we evaluated the fraction of neutral atoms, which ranged from 8 to
30 % of the plume. By adjusting a TOF function to the PVDF electric signal we obtained the center of mass velocity and
the translational temperature. It was observed that product vCM × Tz remains constant with the electrodes potential and
that the accelerating potential to which the plume is submitted has practical limits.
It is presented a new method that allows real-time measurement of the laser beam quality from a single lateral image of a
beam propagating in a scattering medium. The development of this method involved studies of an adequate scattering
medium and the design of an image acquisition optical system. Comparing with traditional methods, this new method is
faster and less exhaustive, providing multiple beam diameters measurements with the same (or even better) accuracy
from a unique image in real time. For a single mode HeNe laser beam, it was obtained the value M2 = 1.1 ± 0.1.
The pulse parameters of a Cu-HyBrID laser were measured in a large range of discharge conditions. It was shown that the laser efficiency is determined by an adequate pre-pulse electron density. Almost constant laser average power and efficiency can be obtained in very different pulse repetition rates provided other discharge parameters were adjusted in order to maintain the optimal pre-pulse electron density. We observed that the pulse width depends mainly on the HBr concentration while the pulse energy is mainly dependent on the absolute HBr pressure and repetition rate.
In this work we present the results of CVD-diamond processing using a copper vapor laser. With a self filtering unstable resonator the laser produces an average power of 9 watts in a 3.5 times limited diffraction beam at a 10 KHz repetition rate. The laser beam is focused on the diamond surface using a lens with a 150 mm focal distance producing a spot size of 70 microns. The laser intensity achieves 2 GW/cm2 on the focus. Electronic microscopy of the processed samples showed clean cut and drill with the whole diameter coincident to the laser beam spot size. Since diamond has a very high thermal diffusivity the temperature rise due to the average power would not be enough to promote evaporation, thus it was concluded that the diamond processing is only die to the laser peak power. Diamond burr with 1.0 mm diameter were cut with the same apparatus at a linear velocity of 200 mm/hour showing a clear and shape cut.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.