Author(s): Rundong Yuan, Wojciech J. Jankowski, Ka Shen, and Robert-Jan Slager Magnons with momentum-dependent chirality are a key signature of altermagnets. We identify bicircular light as a smoking-gun optical probe for chiral altermagnetic magnons, selectively targeting their quantum geometry induced by an alternation of magnonic chirality. We show that in $d$-wave altermag… [Phys. Rev. Lett. 137, 106901] Published Tue Sep 01, 2026