Ultra-compact InP nanowire photonic crystal surface emitting lasers H. Wagner*, N. Jayawardana*, M. Larson*, C. Tu*, W. Wong**, H. Tan**, C. Jagadish**,

Growing internet traffic and rising data-center energy demands are increasing the need for high-performance, energy-efficient integrated circuits. One promising approach is the integration of silicon-on-insulator electronics with photonic components. Photonic crystal surface-emitting lasers (PCSELs) are strong candidates for compact, coherent on-chip light sources in emerging photonic integrated circuits. Recently, we demonstrated optically pumped lasing from InP nanowire (NW) PCSELs grown by selective area epitaxy on InP substrates [1, 2]. This bottom up approach yields NWs with atomically smooth facets, reducing non-radiative recombination and scattering losses. Here, we present lasing from InP NW hetero-PCSELs composed of a small inner lasing array surrounded by a non-lasing photonic crystal region, as well as from ultra-compact NW PCSELs with array side lengths of only a few micrometers. Hetero-PCSELs with inner arrays smaller than the pump-beam focus show reduced threshold power and threshold gain compared to large-area devices. This improvement arises from enhanced reflection at the interface between the inner PCSEL and the surrounding array, where the lasing energy lies within the outer array’s photonic bandgap. In ultra-compact PCSELs, the threshold gain reduction is attributed to an improved back reflection of the laser emission at the photonic crystal array-to-air boundary. 12:45-13:45 Mittagspause 13:45-14:30 Nachwuchspreis