Observation of time-domain modulation of free-electron-laser pulses by multipeaked electron-energy spectrum.
We present the experimental demonstration of a new scheme for the generation of ultrashort pulse trains based on free-electron-laser (FEL) emission from a multipeaked electron energy distribution. Two electron beamlets with energy difference larger than the FEL parameter ρ have been generated by illuminating the cathode with two ps-spaced laser pulses, followed by a rotation of the longitudinal phase space by velocity bunching in the linac. The resulting self-amplified spontaneous emission FEL radiation, measured through frequency-resolved optical gating diagnostics, reveals a double-peaked spectrum and a temporally modulated pulse structure.
INFN-Milano and Università di Milano, Via Celoria, 16 20133 Milano, Italy.
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V
Petrillo
M P
MP
Anania
M
M
Artioli
A
A
Bacci
M
M
Bellaveglia
E
E
Chiadroni
A
A
Cianchi
F
F
Ciocci
G
G
Dattoli
D
D
Di Giovenale
G
G
Di Pirro
M
M
Ferrario
G
G
Gatti
L
L
Giannessi
A
A
Mostacci
P
P
Musumeci
A
A
Petralia
R
R
Pompili
M
M
Quattromini
J V
JV
Rau
C
C
Ronsivalle
A R
AR
Rossi
E
E
Sabia
C
C
Vaccarezza
F
F
Villa