Speaker
Robert Keith Kirkwood
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/I5.015.pdf
The Advent of Non-linear Optical Components Made From Plasmas
R. K. Kirkwood, D. Turnbull*, T. Chapman, S. Wilks, M. Rosen, R. London, L. Pickworth,
A. Colaitis, W. Dunlop, P. Poole, J. Moody, D. Strozzi, P. Michel, L. Divol, O. Landen, B.
MacGowan, B. Van Wonterghem, K. Fournier, and B. Blue
Lawrence Livermore National Laboratory, P.O. Box 808 Livermore Ca. USA
*also at Laboratory of Laser Energetics, 250 E. River Rd, Rochester, NY USA
When the worldwide program in Inertial Confinement Fusion (ICF) pushed forward to build
MJ scale lasers it was recognized that the stimulated scattering processes that occur when
individual laser beams interact with a small scale plasma, would also allow beams to interact
with each other and exchange significant energy and power with the increased scale length
expected in the target plasmas produced by these lasers [1]. As a result NIF and other
lasers now provide the capability to adjust the wavelengths of the individual beams to control
the seeding of Stimulated Brillouin Scattering of one beam by another via the process of
Cross Beam Energy Transfer (CBET) [1]. From the outset of indirect drive experiments on
NIF, CBET controlled by wavelength tuning was shown to be effective in redistributing large
fractions of the incident power between the cones of beams, which improved implosion
symmetry and performance in important cases [1,2]. As a result many lasers now exist with
wavelength tuning to control CBET as does a wide range of data to validate CBET models.
These capabilities are presently being rapidly employed to produce optical devices made of
plasma using CBET interactions for many applications [3,4]. The most recent
demonstration is a plasma-based optic that combines the energy and fluence of many laser
beams into a single bright beam, thus creating a new technique for designing future high
energy density physics experiments. The technique has shown for the first time that a
plasma can combine beams to produce a single beam that emerges from the target with
energy and fluence beyond that of any of the input beams for delivery to another
experimental target. In an initial demonstration, multiple beams of the National Ignition
Facility (NIF) laser have been combined in a plasma to produce a directed pulse of light with
4 + 1 kJ of energy in its 1 ns duration which is 3.6 times the energy and 3.2 times the fluence
of any of the incident beams during that period and is NIFs brightest 1ns duration beam of
UV light [4]. Work performed at Lawrence Livermore National Lab., Contract DE-AC52-07NA27344.
[1] R. K. Kirkwood et al Plasma Phys. Control. Fusion 55, 103001 (2013).
[2] O. Hurricane et al Nature 506, 343–348 (2014). [3] D. Turnbull, et al, Phys. Rev. Lett. 116, 205001 (2016).
[4] R. K. Kirkwood et al Nature Physics online: 2 Oct. 2017, and Nature Physics, 14, 80, January (2018).
