Thresholdless Nanoscale Lasers

M. Khajavikhan
University of Minnesota, US

Keywords: Nano, lasers

Summary:

Nanolasers with sub-wavelength dimensions that require miniscule pump power to reach lasing threshold will have numerous applications in many areas of science and technology. It is now well known that metals, by strongly confining the optical field, can provide a previously unavailable route to sub-wavelength laser cavities. However, at optical frequencies metals suffer from high dissipation losses which can potentially result in prohibitively high lasing threshold, making the metallic sub-wavelength nanolasers technologically unusable. In this presentation, we introduce nanoscale coaxial cavities as a new family of plasmonic nanolasers that provide a scalable solution for overcoming the high threshold pump power by employing the cavity quantum electro-dynamic effects. In particular, with these nano-coaxial cavities, we demonstrated room-temperature continuous-wave lasing action in the smallest cavities to date at telecom wavelengths. In addition, by utilizing the unique properties of the coaxial cavities, which may have a single non-degenerate mode, we demonstrated thresholdless lasing operation at cryogenic temperatures.