Magnetic on-off switching of a plasmonic laser

Abstract

The nanoscale mode volumes of surface plasmon polaritons have enabled\nplasmonic lasers and condensates with ultrafast operation. Most plasmonic\nlasers are based on noble metals, rendering the optical mode structure inert to\nexternal fields. Here, we demonstrate active magnetic-field control over lasing\nin a periodic array of Co/Pt multilayer nanodots immersed in an IR-140 dye\nsolution. We exploit the magnetic nature of the nanoparticles combined with\nmode tailoring to control the lasing action. Under circularly polarized\nexcitation, angle-resolved photoluminescence measurements reveal a transition\nbetween lasing action and non-lasing emission as the nanodot magnetization is\nreversed. Our results introduce magnetization as a means of externally\ncontrolling plasmonic nanolasers, complementary to the modulation by\nexcitation, gain medium, or substrate. Further, the results show how effects of\nmagnetization on light that are inherently weak can be observed in the lasing\nregime, inspiring studies of topological photonics.\n