NASA Scientific and Technical Aerospace Reports

20040073556 Florida State Univ., Tallahassee, FL
Laser Induced Desorption Time of Flight Mass Spectrometer Analysis of Adsorbed Contaminants on Vacuum
Ultraviolet Lithography Optic Materials
Allen, Susan D.; Feb. 2004; 104 pp.; In English; Original contains color illustrations
Contract(s)/Grant(s): F33615-00-1-1727; Proj-ARPS
Report No.(s): AD-A422349; AFRL-SN-WP-TR-2004-1054; No Copyright; Avail: CASI; A06, Hardcopy
Adsorbed surface contaminants on optical elements absorb light energy in an optical lithography system and, if left
unclean, will result in reduced wafer yield. In order to nondestructively analyze the surface adsorbate of different CaF2
samples, a laser induced desorption-Time of Flight Mass Spectrometer (LID-TOFMS) technique was developed. The main
object of this technique is to investigate the surface composition of adsorbed contaminants as a function of position on the
sample. An Er:YAG laser at 2.94 micrometers was used as the light source to induce desorption. Electron impact ionization
was used to obtain ionization of desorbed molecules. The detection of ionized species was accomplished by TOFMS operated
in Angular Reflectron (AREF) mode to obtain better resolution. The data reported here can be used in semiconductor industries
either to modify conventional processing or to design a new efficient laser cleaning process for optical elements.
DTIC
Adsorption; Contaminants; Desorption; Detection; Far Ultraviolet Radiation; Lasers; Lithography; Mass Spectrometers;
Optical Measurement; Time of Flight Spectrometers
20040073559 Naval Postgraduate School, Monterey, CA
Multiple Beam Directors for Naval Free Electron Laser Weapons
Mitchell, Ethan D.; Mar. 2004; 82 pp.; In English; Original contains color illustrations
Report No.(s): AD-A422357; No Copyright; Avail: CASI; A05, Hardcopy
The Free Electron Laser has the potential to become a revolutionary weapon system. Deep magazines, low cost- per-shot,
pinpoint accuracy, and speed of light delivery give this developing weapon system significant advantages over conventional
systems. One limiting factor in high energy laser implementation is then%al blooming, a lensing effect which is caused by the
quick heating of the atmosphere, so that the laser beam does not focus on the desired spot, thereby degrading the effectiveness
of the laser on target. The use of multiple beam directors focusing on a target from a single platform% may mitigate then%al
blooming by allowing half of the laser’s energy to travel through a given volume of air, so that they only overlap very near
the target. Less energy traveling through a given volume of space means less heating, and therefore lessens the effects of
then%al blooming. Also, simulations of FEL’s were conducted modifying parameters such as the number of undulator periods,
electron beam focus, the normalized Rayleigh length, and mirror output coupling, in order to determine optimum design
parameters. New parameters for the next proposed FEL were simulated to examine the effect of mirror tilt on laser power and
extraction as well.
DTIC
Free Electron Lasers; Laser Weapons
20040074138 National Defense Univ., Washington, DC
Defense Horizons. Number 18, October 2002. High- Energy Lasers: Technical, Operational, and Policy Issues
Zimet, Elihu; Oct. 2002; 9 pp.; In English; Original contains color illustrations
Report No.(s): AD-A422467; No Copyright; Avail: CASI; A02, Hardcopy
No abstract available
High Power Lasers; Horizon; Policies
20040074140 National Defense Univ., Washington, DC
Defense Horizons. Number 12, April 2002. The Airborne Laser From Theory to Reality: An Insider’s Account
Mark, Hans; Apr. 2002; 7 pp.; In English; Original contains color illustrations
Report No.(s): AD-A422471; No Copyright; Avail: CASI; A02, Hardcopy
No abstract available
Airborne Lasers; Horizon; Laser Weapons
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