excellent narrow beam divergence [7] make them highly promising for light detection and ranging [8] and optical sensing applications. Conventionally, top-down nanofabrication processes are used for fabricating PhC surface-emitting lasers (PCSELs) as well as emerging topological cavity surface-emitting lasers. [9][10][11][12] Over the last few years, selective area, catalyst-free growth of nanowires has progressed rapidly, providing a unique platform for ultracompact bottom-up PhC lasers. [13][14][15][16] In comparison to top-down etched PhC cavities, the vertical and atomically flat sidewall surface and the ability to form in situ passivation layers in nanowire growth minimize scattering and propagation losses and thereby preserve high radiative recombination efficiency. By breaking or relaxing the constraints from materials lattice mismatch, combining dissimilar materials into 3D axial and core-shell structures with strong quantum confinement and direct epitaxial integration on technologically important substrates such as silicon-on-insulator (SOI) chips also become possible. Optically pumped lasing from a lift-off 2D GaAs/InGaAs/GaAs nanowire arrays was realized emitting at wavelengths between 960 and 989 nm. [17] Near vertical surface emission around 850 nm from an InP nanowire PhC structure on InP substrate was recently reported, exhibiting pulse lasing at room temperature as well as continuous-wave lasing at 77 K with an output power of 470 µW. [18] Electrically pumped surface-emitting laser diodes using bottom-up PhC cavities have so far only been achieved by InGaN/AlGaN nanowires [1] and remain one of the biggest challenges in III-As/P based nanowires. For practical integration of nanowire lasers with silicon photonic integrated circuits and silicon electronics, direct growth of nanowire lasers on silicon operating in the relevant telecom spectral bandwidth (1.3-1.55 µm) is crucial. To date, this has been developed using either bandgap tunable InGaAs nanowire-based 1D or 2D PhC arrays [15,[19][20][21] or straincompensated InGaAs/(In,Al)GaAs multiquantum-well nanowires. [22] Despite impressive waveguide-coupled lasing at room temperature and low-threshold characteristics that have been demonstrated, a surface-emitting telecom wavelength nanowire PhC laser, which could be of great interest for optical sensing applications, has not been reported yet.Photonic crystals can be used to achieve high-performance surface-emitting lasers and enable novel photonic topological insulator devices. In this work, a GaAs/InGaAs heterojunction nanowire platform by selective area metalorganic vapor phase epitaxy for such applications is demonstrated. The nanowires are arranged into deformed honeycomb lattices on silicon-on-insulator substrate to exploit the quadrupolar photonic band-edge mode. Coreshell and axial heterostructures are formed with their crystalline properties studied by scanning transmission electron microscopy. Room-temperature, single mode lasing from both stretched and compressed honeycomb lattices within th...

We report a semiconductor laser based on optical cavities formed by topologically distinct honeycomb lattice photonic crystals. Topological lasers, fabricated on SOI wafers by using a selective area epitaxy method, can have edge modes and bulk modes under optical pumping.