Photonic-Crystal Surface Emitting Lasers (PCSELS) in the Near-Infrared (NIR)

STTR topic DON27TZ02-NV015 (U.S. Department of Defense – Navy), Phase I and II. Open to U.S. small businesses; STTR projects partner with a U.S. research institution. Opens: December 2, 2026. Closes: January 6, 2027. The Navy seeks innovations in PCSELs that combine novel in-plane photonic crystal designs with out-of-plane epitaxial and gain structures to overcome the limitations of current approaches and produce the next generation of semiconductor laser technologies. Current PCSEL architectures face power-scaling limitations as device aperture increases because the mode margin between the desired fundamental mode and competing higher-order modes decreases, making stable, single-mode, diffraction operations increasingly difficult at higher powers. Capabilities that enable single mode, high power density, combinable lasers in the one-micron regime are the focus for any near-term transition. Concepts that maximize laser device area above previous limits, either by increasing the number of photons generated per unit area or increasing conversion efficiency, are potential options. Other potential approaches include reducing optical, electrical, and other losses – either with single devices, or through multi-device combinations. For example, stacking multiple gain regions vertically and horizontally, a successful technique used in vertical-cavity surface-emitting lasers ( VCSELs) arrays, may limit current PCSEL designs because of interactions between n++/p++ tunnel junctions in gain layers introducing unwanted absorption. Means to correct this issue through material modification might offer counteracting but beneficial additional total gain from a single device – especially when combined in the far field. Similarly, adding optical features as part of the photonic crystal to extend single-mode operation, especially those with higher conductivity material might reduce thermal distortions and lead to better performance even at the potential limits of vertical heat…