Phase distortion ratio: alternative to group delay dispersion for analysis and optimization of dispersion...

We present a new approach for designing dispersion-engineered optics based on a simple unitless spectral quantity we call the phase distortion ratio (PDR). In contrast to minimizing the group delay dispersion (GDD) deviation from the ideal, minimizing the PDR is optimal in the sense that it minimizes the fraction of pulse energy lost to phase distortions. As an example, a mirror system optimized via PDR is empirically found to result in significantly better compression of single-cycle pulses than a system designed in terms of GDD. In the context of coupling pulse trains to cavities, minimizing the PDR of the cavity is shown to maximize throughput.