Coherent Axion Production through Laser Crystal Interaction

We investigate the interaction between an optical laser and an ionic crystal and reveal coherent emission of axions through phase-match between laser and axion fields. Such emission is further enhanced by stacking thin crystal layers of half-wavelength thickness. Based on these findings, we propose a novel method for generating and detecting axions in terrestrial experiments, achieving up to a two-order-of-magnitude increase in transition probability compared to light-shining-through-wall (LSW) experiments with the same interaction region size. For an experimental length of 10 meters, this setup could lower the exclusion limit to $g_{a\gamma \gamma }\gtrsim 1.32\times {10}^{-11}{\text{GeV}}^{-1}$ with currently available laser technologies.