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.
Danqing Wang is a fifth-year PhD candidate in Applied Physics of Northwestern University (USA), co-advised by Prof. Teri W. Odom and Prof. George C. Schatz. She received her B.S. degree in Physics in 2013 at Nanjing University, China. Her research focuses on structural engineering of plasmonic cavities for nanolasing and their light-matter interactions with different gain media. Danqing has received several fellowships and awards including the International Institute for Nanotechnology (IIN) Outstanding Research Award.