1 W Single‐Mode Large‐Area Edge‐Emitting Laser via Non‐Hermitian Spatial Mode Filtering

We experimentally demonstrate that non‐Hermitian spatial mode filtering enables single‐mode operation in an electrically pumped, large‐area edge‐emitting laser diode that would otherwise support multiple transverse modes. The resulting device achieves 1 W output power while maintaining near‐diffraction‐limited beam quality. The proposed design extends our previous quasi‐parity‐time‐symmetric (q‐PTS) architecture by implementing a symmetric, two‐sided filter array, which strengthens discrimination against higher‐order modes while preserving the integrity and gain of the fundamental mode. The device exhibits near‐ and far‐field emission profiles with exceptional beam quality, as confirmed by M 2 1.2, and meets the 1 W single‐mode benchmark for optical pumping, sensing, and optical links. This work bridges theoretical advances in non‐Hermitian photonics with scalable, fabrication‐compatible strategies for high‐brightness semiconductor lasers.