Pixelated vertical-cavity surface-emitting laser arrays from colloidal quantum dot films

Pixelated arrays of vertical-cavity surface-emitting lasers from colloidal quantum dot thin films have been demonstrated. CdSe/ZnCdS core/shell structured colloidal quantum dots have been used as laser gain medium. 10 pairs of alternating layers between GaN and nanoporous GaN consisted highly reflective distributed Bragg reflectors, exhibiting more than 99% of reflectivity in the spectral range of 600 nm–650 nm. Close-packed colloidal quantum dot solid thin films were sandwiched between the two GaN/nanoporous GaN distributed Bragg reflectors to achieve well-defined lasing outputs under pulsed optical excitation with the lasing threshold as low as 11.0 μJ/cm². The resulting CQD-VCSEL devices exhibited a lasing output power of 1.5 μW and a conversion efficiency of 11.4%. Finally, a two-axis scanning micro-mirror was used to complete the 25 (5 by 5) pixelated laser arrays system.