A clever glass trick fixes the decade-old photonic crystal laser problem

Engineers at the University of Illinois Urbana-Champaign (UIUC) have solved a decade-old challenge in photonic-crystal surface-emitting lasers (PCSELs) by replacing the traditionally used fragile air holes in the photonic crystal layer with embedded silicon dioxide, a solid dielectric material. This innovation prevents the collapse of the photonic crystal structure during semiconductor regrowth, a problem that previously hindered PCSEL development. Despite silicon dioxide being amorphous and difficult for semiconductor growth, the team successfully grew semiconductor layers laterally around the dielectric and merged them via coalescence, enabling the first demonstration of a room-temperature, eye-safe, photopumped PCSEL. This breakthrough creates a more stable, precise, and scalable PCSEL technology capable of producing high-brightness, narrow, circular laser beams suitable for applications such as LiDAR, optical communication, autonomous vehicle sensors, and defense systems. The use of solid dielectric material also simplifies fabrication and enhances device durability. However, the current design requires