Anomalous phase matching through inter sub-cycle interference

TL;DR

This paper uncovers a novel dispersion condition where phase and group velocity mismatches synergize to enable efficient nonlinear optical frequency conversion, demonstrated through high-harmonic-generation simulations.

Contribution

It introduces a new dispersion condition that allows efficient frequency conversion by leveraging inter sub-cycle interference, challenging traditional phase matching limitations.

Findings

Identifies a unique dispersion condition for efficient conversion

Demonstrates the effect through numerical simulations of high-harmonic-generation

Suggests broader implications for nonlinear optics applications

Abstract

Providing efficient nonlinear optical frequency conversion is essential for numerous applications. Fundamentally, dispersion limits the efficiency of such processes through mismatch of the phase velocities and the group velocities of the involved optical waves. We reveal a dispersion condition at which, surprisingly, phase and group velocity mismatch act together to provide efficient optical frequency conversion. We demonstrate this condition numerically for the process of high-harmonic-generation. This finding could be valuable to the theory and practice of nonlinear optical frequency conversion in general.