Cascaded Energy Transfer for Efficient Broad‐Band Pumping of High‐Quality, Micro‐Lasers

Micro-ring lasers that exhibit a quality factor (Q) larger than 5.2 × 106 with a direct-illumination, non-resonant pump are demonstrated (a,b). The micro-rings are coated with three organic dyes forming a cascaded energy-transfer (c,d), which reduces material-losses by a factor larger than 104 (e), transforming incoherent light to coherent light with high quantum-efficiency. The operating principle is general and can enable fully integrated on-chip, high-Q micro-lasers.