Size Scaling of Photonic Crystal Surface Emitting Lasers on Silicon Substrates

We report here the lateral cavity size scaling and confinement effects on the lasing performance in defect-free photonic crystal surface-emitting lasers (PCSEL) on silicon substrates. Hybrid PCSELs with different lateral cavity sizes and different lateral confinement geometries have been fabricated using transfer printing technology and controlled selective etching. The measured lasing properties show a strong dependence on the lateral cavity size below 100 μm. In particular, the finite lateral dimension significantly affects the laser threshold and side mode suppression ratio (SMSR) of the PCSEL devices. On the other hand, by controlling the lateral confinement using vertical etching, a reduction of the laser threshold is observed. The experimental results agree well with theoretical predictions. The work presented here can lead to ultra-compact PCSELs for on-chip integration with excellent energy efficiency.