Limitations on the fidelity of 100-fs pulses produced by chirped-pulse amplification

We have developed a system for continuously variable independent tuning of the higher order frequency dependent phase of ultrashort laser pulses. This technique relies on geometric aberrations that arise from adjustments to the relative alignment of the elements of an air spaced doublet lens in systems such as a diffraction grating stretcher in which the spectral components of the optical pulses are spatially dispersed. Modeling results are compared to experimental measurements for a non optimized pulse stretcher/compressor combination showing the higher order phase aberrations that limit the performance of a chirped pulse amplification system. Numerical results are presented indicating these higher order phase terms can be compensated by a properly adjusted air spaced doublet design within the pulse stretcher.