Demonstration of laser-frequency upshift by electron-density modulations in a plasma wakefield.
In a plasma wake wave generated by a high power laser, modulations of the electron density take the shape of paraboloidal dense shells, moving almost at the speed of light. A counterpropagating laser pulse is partially reflected from the shells, acting as relativistic flying mirrors, producing a time-compressed frequency-multiplied pulse due to the double Doppler effect. The counterpropagating laser pulse reflection from the plasma wake wave accompanied by its frequency multiplication (with a factor from 50 to 114) was detected in our experiment.
Kando
M
M
Advanced Photon Research Center, JAEA, 8-1 Umemidai, Kizugawa, Kyoto 619-0215, Japan.
Fukuda
Y
Y
Pirozhkov
A S
AS
Ma
J
J
Daito
I
I
Chen
L-M
LM
Esirkepov
T Zh
TZh
Ogura
K
K
Homma
T
T
Hayashi
Y
Y
Kotaki
H
H
Sagisaka
A
A
Mori
M
M
Koga
J K
JK
Daido
H
H
Bulanov
S V
SV
Kimura
T
T
Kato
Y
Y
Tajima
T
T