Schimpf Damian N, Seise Enrico, Limpert Jens, Tünnermann Andreas
Institute of Applied Physics, Friedrich Schiller University Jena, Albert-Einstein-Str. 15,D-07745 Jena, Germany.
Opt Express. 2008 Jul 7;16(14):10664-74. doi: 10.1364/oe.16.010664.
A detrimental pulse distortion mechanism inherent to nonlinear chirped-pulse amplification systems is revealed and analyzed. When seeding the nonlinear amplification stage with pulses possessing weak side-pulses, the Kerr-nonlinearity causes a transfer of energy from the main pulse to side pulses. The resulting decrease in pulse contrast is determined by the accumulated nonlinear phase-shift (i.e., the B-integral) and the initial pulse-contrast. The energy transfer can be described by Bessel-functions. Thus, applications relying on a high pulse-contrast demand a low B-integral of the amplification system and a master-oscillator that exhibits an excellent pulse-contrast. In particular, nonlinear fiber CPA-systems operated at B-integrals far beyond pi have to be revised in this context.
