Surface emitting laser diodes with enhanced higher order spatial modes and/or filamentation

A method for inducing uniform filament formation in large-area SEL comprising:

• a light generation layer for generating light in response to light passing therethrough;
• mirror means disposed on opposite faces of said light generation layer for reflecting light generated in said light generation layer toward said light generation layer such that said reflected light adds coherently to said light generated in said light generation layer;
• and
• a reflective electrode deposited on a face of said mirror means, remote from said light generation layer,
• said method comprising a step of providing plural localized imperfection regions in said mirror means, each imperfection region causing light interacting therewith to be attenuated or shifted in phase relative to light that does not interact with said imperfection region to induce filamentation adjacent thereto, wherein said step of providing plural localized regions includes a step of forming localized regions of different refractive index in said mirror means and, wherein:
• said mirror means includes plural layers disposed substantially parallel to said light generation layer, and additionally includes a phase correcting layer remote from the light generation layer, and wherein, the localized regions of different refractive index are formed in the phase correcting layer.