Site-controlled quantum-wire photonic-crystal microcavity laser is experimentally demonstrated using optical pumping. The single-mode lasing and threshold are established based on the transient laser response, linewidth narrowing, and the details of the non-linear power input-output charateristics. Average-power threshold as low as similar to 240 nW (absorbed power) and spontaneous emission coupling coefficient beta similar to 0.3 are derived. (C) 2009 Optical Society of America