Low-threshold topological nanolasers based on the second-order corner state

Abstract

Topological lasers are immune to imperfections and disorder. They have been recently demonstrated based on many kinds of robust edge states, which are mostly at the microscale. The realization of 2D on-chip topological nanolasers with a small footprint, a low threshold and high energy efficiency has yet to be explored. Here, we report the first experimental demonstration of a topological nanolaser with high performance in a 2D photonic crystal slab. A topological nanocavity is formed utilizing the Wannier-type 0D corner state. Lasing behaviour with a low threshold of approximately 1 µW and a high spontaneous emission coupling factor of 0.25 is observed with quantum dots as the active material. Such performance is much better than that of topological edge lasers and comparable to that of conventional photonic crystal nanolasers. Our experimental demonstration of a low-threshold topological nanolaser will be of great significance to the development of topological nanophotonic circuitry for the manipulation of photons in classical and quantum regimes.

Multipolar lasing modes from topological corner states

“…Very recently, lasing in a single corner has been reported for similar nanopatterned structures 35,36 . Those corner lasers, however, operate at low temperatures 35 or do not show the unique properties of multipolar lasing in coupled corner modes with different field profiles and Q factors 35,36 . In this work, we have conclusively demonstrated the stable multipole corner modes with antinode intensities at two or four corners as a result of coupling between the corners.…”

Highlighting photonics: looking into the next decade

“…Since then, several groups followed with a variety of configurations for realizing topological insulator lasers, e.g., a topological quantum cascade laser with valley edge modes [102] (Fig. 2b), a topological bulk laser based on band-inversion-induced reflection [103], a topological nanolasers based on second-order corner states [104], a topological insulator laser with next-nearest-neighbor coupling [105], and a Dirac-vortex topological cavity promising for large-area single-mode lasing [106]. Finally, we note the very recent experiments on a topological vertical cavity surface emitting laser [107].…”

Multiband Photonic Topological Valley‐Hall Edge Modes and Second‐Order Corner States in Square Lattices

“…As an example, the 2D second‐order topological insulators generate zero‐dimensional corner states as well as 1D edge states immune to the structural defects, enabling robust photonic nanocavities [ 43 ] and nanolasers. [ 44 ]…”

“…As an example, the 2D second-order topological insulators generate zero-dimensional corner states as well as 1D edge states immune to the structural defects, enabling robust photonic nanocavities [43] and nanolasers. [44] In photonic practices, one needs multiband edge and corner states, in particular for nonlinear topological photo nics which frequently requires operating over wide spectral ranges. Up to date, multiband edge states [45,46] in photonic topological systems and their applications for nonlinear optical frequency conversion [36] have been reported, while multiband corner states have still not been investigated.…”