PT-Symmetric Magnon Lasing and Antilasing.

A mechanism for electrically tunable PT-symmetric magnonic lasing and antilasing is proposed along with a device consisting of a current-biased region in a magnetically ordered planar waveguide. Within the bias area, several heavy-metal wires carrying dc charge currents are periodically attached to the waveguide, generating spatially periodic spin-orbit torques that produce electrically modulated magnon gain and loss. We demonstrate that despite the nonlinear magnon dispersion, this decorated waveguide can emit a strong, single frequency magnon mode at the Bragg point (lasing) and also absorb at the same frequency phase-matched incoming coherent magnons (antilasing). In contrast to spin torque oscillators with multimode excitations driven solely by gain, the PT-symmetric gain-loss balance stabilizes a single magnon mode operation. The underlying physics is captured by an analytical model and validated with full material and device-specific numerical simulations. We further show that the magnonic laser absorber can be electrically tuned and implemented in ring geometries and for antiferromagnetic ordering. These results establish an experimentally realistic platform where a single element functions simultaneously as a magnon laser and absorber, opening opportunities for reconfigurable non-Hermitian magnonics and integrated magnon signal processing.