FEL physics: optical properties
I have four projects going on for now.
The first is measurment of the temporal structure of a
SASE FEL. The experiment showed that the SASE FEL is a chaotic light in nature
and the temporal dynamics can be well described by stochastic processes.
The measurement uses the FROG technique, some and the FEL output is green
light from the LEUTL. Some of the FROG trace are very pretty but with phase
and intensity chaotically distributed, as shown below.
The emission is fundamentally the same as the street light and the start
light you see in this Vangouh's painting. Or, in another word, the measurement
reals the general properties of the light sources we see every day.
Here is some of the papers we published on this experiment: Appl
Phys B 80, 31 (2005) (rapid communication), Phys
Rev Lett 91, 243602 (2003),
Phys Rev Lett 89, 234801 (2002).
The second project is to measure the grow of the spatial
coherence of such FEL output, the plan
is to use uniform radom array. Some initial test has been finished, and the
ecperiment has been panned out. An initial
test with uniform array has also been accomplished on the Duke storage