High Harmonic Interferometry Based on ZnO Microwire Pair

High harmonic generation (HHG) provides an experimental method for producing attosecond pulses and probing electron dynamics. Precise dipole phase measurement, critical for tailoring harmonic emission phase and identifying HHG mechanism, remains challenging in traditional two-beam far-field interferometry when applied to solid materials. In this study, we present a novel interferometric approach that utilizes a single laser beam to simultaneously excite two ZnO microwires (MWs), thereby generating coherent high-harmonic sources that form interference fringes in the far-field region. By exploiting the diameter-dependent field enhancement effect in MWs, the measured intensity-dependent fringe shift reveals that the intraband current mechanism dominates the below-bandgap harmonic, and the interband polarization mechanism dominates the above-bandgap harmonic. This study offers a robust method for measuring the dipole phase of solid-state HHG and inspires intensity-modulated high-harmonic applications in coherent imaging and microdevice design.