Issue 10 Volume 41 May 16, 2003

Self-organization of polymers to achieve nanoscale structures has been widely studied. Examples of such systems are
liquid crystalline polymers (1), block copolymers (2) and polymer-amphiphile complexes. They form nanostructures due to
repulsive and attractive forces within the system. Probably the most common self-organized polymers are diblock copolymers,
which consist of two polymer blocks A and B, which are covalently bonded to each other. Due to repulsive forces between
them, the material microphase separates to form nanostructures such as spherical, cylindrical and lamellar structures .
NTIS
Flow Characteristics; Nanostructure Growth; Nanostructure (Characteristics); Block Copolymers
20030037005 Lawrence Livermore National Lab., Livermore, CA
Advanced Techniques for Fourier Transform Wavefront Reconstruction
Poyneer, L. A.; Aug. 05, 2002; 18 pp.; In English
Report No.(s): DE2002-15002381; UCRL-JC-149568; No Copyright; Avail: Department of Energy Information Bridge
The performance of Fourier transform (FT) reconstructors in large adaptive optics systems with Shack-Hartmann sensors
and a deformable mirror is analyzed. FT methods, which are derived for point-based geometries, are adapted for use on the
continuous systems. Analysis and simulation show how to compensate for effects such as misalignment of the deformable
mirror and wavefront sensor gain. Further filtering methods to reduce noise and improve performance are presented. All these
modifications can be implemented at the filtering stage, preserving the speed of FT reconstruction. Simulation of a large
system shows how compensated FT methods can have equivalent or better performance to slower vector-matrix-multiply
reconstructions.
NTIS
Adaptive Optics; Fourier Transformation; Wave Front Reconstruction; Noise Reduction
20030037032 Lawrence Livermore National Lab., Livermore, CA
Filamentation and Forward Brillouin Scatter of Entire Smoothed and Aberrated Laser Beams
Still, C. H.; Berger, R. L.; Langdon, A. B.; Hinkel, D. E.; Suter, L. J.; Oct. 29, 1999; 42 pp.
Report No.(s): DE2002-790942; No Copyright; Avail: Department of Energy Information Bridge
Laser-plasma interactions are sensitive to both the fine-scale speckle and the larger scale envelope intensity of the beam.
For some time, simulations have been done on volumes taken from part of the laser beam cross-section, and the results from
multiple simulations extrapolated to predict the behavior of the entire beam. However, extrapolation could very well miss
effects of the larger scale structure on the fine-scale. The only definitive method is to simulate the entire beam. These very
large calculations have been infeasible until recently, but they are now possible on massively parallel computers. Whole beam
simulations show the dramatic difference in the propagation and break up of smoothed and aberrated beams.
NTIS
Laser Beams; Laser Plasma Interactions
20030037068 Argonne National Lab., IL
Spontaneous and Amplified Radiation at the Initial of a SASE FEL
Huang, Z.; Kim, K. J.; 2002; 8 pp.
Report No.(s): DE2002-805259; No Copyright; Avail: Department of Energy Information Bridge
At the initial stage of a self-amplified spontaneous emission (SASE) free-electron laser (FEL), spontaneous undulator
radiation in certain experimental configurations can dominate the amplified signal over an extended undulator distance. In this
paper we study both the spontaneous and the amplified radiation in the framework of the paraxial wave equation and determine
the transition from the dominance of spontaneous emission to exponential amplification. We compare theoretical expectations
with SASE simulation codes GINGER and GENESIS.
NTIS
Free Electron Lasers; Spontaneous Emission
20030037116 Lawrence Livermore National Lab., Livermore, CA
Reflectance, Optical Properties, and Stability of Molybdenum/Strontium and Molybenum/Yttrium Multilayer Mirrors
Kjornrattananwanich, B.; Sep. 01, 2002; In English
Report No.(s): DE2002-15002102; UCRL-LR-150541; No Copyright; Avail: National Technical Information Service (NTIS)
The motivation of this work is to develop high reflectance normal-incidence multilayer mirrors in the 8-12 nm wavelength
region for applications in astronomy and extreme ultraviolet lithography. To achieve this goal, Mo/Sr and Mo/Y multilayers
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