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 ring FEL.