Microscopic study on lasing characteristics of the UVSOR storage ring free electron laser

Conference · Sun Dec 31 04:00:00 EST 1995

DOI:https://doi.org/10.1016/0168-9002(96)00103-9· OSTI ID:238610

Hama, H ^[1]; Yamazaki, J; Kinoshita, T ^[2]

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1. Institute for Molecular Science, Okazaki (Japan)
2. Institute for Molecular Science, Okazaki (Japan); and others

Characteristics of storage ring free electron laser (SRFEL) at a short wavelength region (UV and visible) has been studied at the UVSOR facility, Institute for Molecular Science. We have measured the laser power evolution by using a biplanar photodiode, and the micro-macro temporal structure of both the laser and the electron bunch with a dualsweep streak camera. The saturated energy of the laser micropulse in the gain-switching (Q-switching) mode has been measured as a function of the ring current. We have not observed a limitation of the output power yet within the beam current can be stored. We have analyzed the saturated micropulse energy based on a model of gain reduction due to the bunch-heating. The bunch-heating process seems to be very complicate. We derived time dependent gain variations from the shape of macropulse and the bunch length. Those two gain variations are almost consistent with each other but slightly different in detail. The gain may be not only simply reduced by the energy spread but also affected by the phase space rotation due to synchrotron oscillation of the electron bunch. As reported in previous issue, the lasing macropulse consists of a couple of micropulses that are simultaneously evolved. From high resolution two-dimensional spectra taken by the dual-sweep streak camera, we noticed considerable internal substructures of the laser micropulse in both the time distribution and the spectral shape. There are a couple of peaks separated with almost same distance in a optical bunch. Such substructure does not seem to result from statistical fluctuations of laser seeds. Although the origin of the substructure of macropulse is not dear at the present, we are going to discuss about SRFEL properties.

• Research Organization: Brookhaven National Lab., Upton, NY (United States)
• OSTI ID: 238610
• Report Number(s): BNL--61982-Absts.; CONF-9508156--Absts.; ON: DE96002729
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
43 PARTICLE ACCELERATORS
BEAM BUNCHING
EVALUATION
FREE ELECTRON LASERS
GAIN
PHOTODIODES
STORAGE RINGS