FEL2012 - List of Authors (Fry, A.R.)

Paper

Title

Page

Laser Phase Errors in Seeded FELs

17

D.F. Ratner, A.R. Fry, G.V. Stupakov, W.E. White
SLAC, Menlo Park, California, USA

Harmonic seeding is a promising method for producing transform-limited FEL pulses in the soft x-ray region. While harmonic multiplication schemes extend seeding to shorter wavelengths, they also amplify the spectral phase errors of the initial seed laser, degrading the final pulse quality and decreasing longitudinal coherence. Here we consider the effect of seed laser phase errors on longitudinal coherence for high gain harmonic generation and echo-enabled harmonic generation. We develop simulations to confirm analytical results for the case of linearly chirped seed lasers, and extend the results for arbitrary seed laser envelope and phase.

Slides MOOCI01 [2.534 MB]

THOAI01

Strategies for achieving sub-10fs timing in large-scale FELs

R.B. Wilcox, J.M. Byrd, L.R. Doolittle, G. Huang
LBNL, Berkeley, California, USA
J.C. Frisch, A.R. Fry
SLAC, Menlo Park, California, USA

Funding: This work was supported by the U.S. Department of Energy under contract DE-AC02-05CH11231.
Current and planned X-ray FELs produce pulses with sub-10fs duration, requiring comparable timing stability to enable pump/probe experiments. We describe methods of achieving stability on this time scale, for FEL facilities hundreds of meters long. Our approach is based on CW and amplitude modulated optical signals delivered over fiber to pulsed lasers. A comprehensive design approach includes control of modelocked laser oscillators, amplifiers, propagation paths, arrival time diagnostics and finally cross-correlation between pump and probe signals at the experiment. Design options depend on global FEL parameters such as repetition rate. We show that current laser technology is capable of supporting performance at the few-femtosecond level using these techniques. High precision is achieved by leveraging recently developed, frequency stable spectroscopic lasers and optical clocks, as well as the mature field of fiber interferometry. Current experimental results using pulsed and CW lasers are described.

Slides THOAI01 [4.507 MB]

Paper	Title	Page
MOOCI01	Laser Phase Errors in Seeded FELs	17
	D.F. Ratner, A.R. Fry, G.V. Stupakov, W.E. White SLAC, Menlo Park, California, USA
	Harmonic seeding is a promising method for producing transform-limited FEL pulses in the soft x-ray region. While harmonic multiplication schemes extend seeding to shorter wavelengths, they also amplify the spectral phase errors of the initial seed laser, degrading the final pulse quality and decreasing longitudinal coherence. Here we consider the effect of seed laser phase errors on longitudinal coherence for high gain harmonic generation and echo-enabled harmonic generation. We develop simulations to confirm analytical results for the case of linearly chirped seed lasers, and extend the results for arbitrary seed laser envelope and phase.
	Slides MOOCI01 [2.534 MB]

THOAI01	Strategies for achieving sub-10fs timing in large-scale FELs
	R.B. Wilcox, J.M. Byrd, L.R. Doolittle, G. Huang LBNL, Berkeley, California, USA J.C. Frisch, A.R. Fry SLAC, Menlo Park, California, USA
	Funding: This work was supported by the U.S. Department of Energy under contract DE-AC02-05CH11231. Current and planned X-ray FELs produce pulses with sub-10fs duration, requiring comparable timing stability to enable pump/probe experiments. We describe methods of achieving stability on this time scale, for FEL facilities hundreds of meters long. Our approach is based on CW and amplitude modulated optical signals delivered over fiber to pulsed lasers. A comprehensive design approach includes control of modelocked laser oscillators, amplifiers, propagation paths, arrival time diagnostics and finally cross-correlation between pump and probe signals at the experiment. Design options depend on global FEL parameters such as repetition rate. We show that current laser technology is capable of supporting performance at the few-femtosecond level using these techniques. High precision is achieved by leveraging recently developed, frequency stable spectroscopic lasers and optical clocks, as well as the mature field of fiber interferometry. Current experimental results using pulsed and CW lasers are described.
	Slides THOAI01 [4.507 MB]