Nonlinear laser focusing using a conical guide and generation of energetic ions.
Using conventional methods, a laser pulse can be focused down to around 6-8 microm, but further reduction of the spot size has proven to be difficult. Here it is shown by particle-in-cell simulation that with a hollow cone an intense laser pulse can be reduced to a tiny, highly localized, spot of around 1 microm radius, accompanied by much enhanced light intensity. The pulse shaping and focusing effect is due to a nonlinear laser-plasma interaction on the inner surface of the cone. When a thin foil is attached to the tip of the cone, the cone-focused light pulse compresses and accelerates the ions in its path and can punch through the thin target, creating highly localized energetic ion bunches of high density.
Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088, China.
Lihua
L
Cao
Wei
W
Yu
M Y
MY
Yu
Han
H
Xu
X T
XT
He
Yuqiu
Y
Gu
Zhanjun
Z
Liu
Jinghong
J
Li
Chunyang
C
Zheng