Structural Engineering in Plasmon Nanolasers

Miniaturized lasers enable applications in on-chip optical communication, medical imaging, and nanoscale optical displays. Compared to traditional lasers, plasmonic nanolasers can break the diffraction limit and support ultrasmall mode volumes, but unwanted multi-modal nanolasing exhibits both uncontrolled mode spacing and output behavior. Single band-edge states can trap slow light and function as high-quality optical feedback for microscale lasers to nanolasers. However, access to more than a single band-edge mode has not been possible because of limited cavity designs. My talk will focus on plasmonic superlattices—finite-arrays of nanoparticles grouped into microscale arrays—to support multiple band-edge modes capable of multi-modal nanolasing at programmed emission wavelengths and with large mode spacings. Different lasing modes showed distinct input-output light-light behavior and ultrafast decay dynamics tailored by nanoparticle size. Moreover, symmetry-broken superlattices exhibited switchable nanolasing between a single mode and multiple modes. Coherent nanoscale light sources with multiple tunable, on-demand optical modes can enable multiplexing for on-chip photonic devices.