Novel non-plasmonic nanolasers empowered by topology and interference effects

Abstract

Historically, nanophotonics deals with a control of light at the nanoscale being closely connected with the rapid advances in plasmonics – the physics of surface plasmon polaritons supported by metal–dielectric interfaces. Properly engineered nanostructures allow the subwavelength propagation of light and its strong confinement in nanowaveguides and nanocavities, making possible the field enhancement and lasing. Spaser was suggested as a special type of nanolaser with a very small footprint that can be modulated quickly thus becoming a good candidate for on-chip optical data processing. However, recent developments in the physics of high-index dielectric nanoparticles and resonant dielectric metasurfaces allowed to advance the field of nanophotonics and introduce novel nonplasmonic nanostructures and nanolasers empowered by topology and interference effects. Here we present first some examples of experimentally realized spasers, and then discuss the recent developments in the cutting-edge high-index dielectric nanostructures employed for nonplasmonic nanolasers based on Mie resonances, anapole states, bound states in the continuum, and the physics of topological phases.

Lasing Action from Quasi‐Propagating Modes

“…By demonstrating lasing across different wavelength ranges and directions, we also distinguish quasi‐propagating modes from accidental bound‐states‐in‐the‐continuum that support feedback only at specific wavevectors along the high‐symmetry directions. [ 59,60 ]…”

“…By demonstrating lasing across different wavelength ranges and directions, we also distinguish quasi-propagating modes from accidental boundstates-in-the-continuum that support feedback only at specific wavevectors along the high-symmetry directions. [59,60] To extend quasi-propagating lasing to include coupling between the higher (±1,±1) diffraction orders, we integrated CsPbBr 3 NC with Al NP square lattices with a larger periodicity (a 0 = 350 nm). In this scenario, because the mode cones intersect past the Γ point and approach the X point, quasi-propagating modes have energies that are between Γ and X.…”

Lattice Resonances of Nanohole Arrays for Quantum Enhanced Sensing

“…Notice that other symmetry breaking mechanisms, such as the use of two holes with different diameters, have been investigated in the past for nanohole arrays perforated in a silicon film [48]. Besides this, there are many more available mechanisms that have been proposed and investigated to reduce radiative losses, including the use of bound states in the continuum, anapole modes, and topological phases [49,50]. This opens the possibility for the design of more complicated geometries that could produce even narrower resonances.…”

Experimental Demonstration of Dark‐State Metasurface Laser with Controllable Radiative Coupling

“…In our experiments, to simplify the fabrication, we chose to implement the dark mode on a dielectric thin film as a bound standing wave guided mode and we used metallic wires to pin the E‐field and achieve discrete sets of resonant modes. Alternatively, we could have used typical plasmonic components, such as split‐ring‐resonators, [ 33 ] cut wire pairs, [ 34 ] or metallic nanodisks [ 24 ] to implement the dark surface state; that is the concept applies equally well to both fully dielectric [ 35 ] or plasmonic lasers. [ 36 ] Note that, our system is not plasmonic per se, that is lasing does not take place into a plasmonic mode; the metasurface does involve metallic parts as a means for quantizing the dark state, however the field has nodes on the metal grating and is concentrated in the dielectric film in between the metallic wires.…”