Continuous-wave room-temperature lasing from Bloch surface plasmon polaritons

Plasmonic nanolasers promise to miniaturize coherent light sources beyond the diffraction limit, bridging the gap between electronics and photonics. However, realizing practical room-temperature, continuous-wave (CW) operation remains limited by the fundamental trade-off between mode confinement and ohmic losses. Here, we report a room-temperature, tunable CW plasmonic laser driven by delocalized hybrid Bloch surface plasmon polaritons on a continuous silver plasmonic lattice with a gentle periodic surface potential. This architecture yields highly directional, six-fold symmetric lasing with ultralow thresholds of \(\:\sim\:\)11.7 mW/cm ² , a value comparable to terrestrial solar irradiance. The device efficiency is sufficiently high to sustain coherent lasing even under incoherent pumping by a standard light-emitting diode. Furthermore, intrinsic momentum-energy locking couples the lasing wavelength deterministically to the emission angle, enabling continuous tunability over a 70 nm bandwidth. Our architecture overcomes the dissipative bottlenecks hindering the field, providing a versatile platform for programmable sources in integrated nano-photonics.