Niu, NanWoolf, Alexander JWang, DanqingZhu, TongtongQuan, QiminOliver, RachelHu, Evelyn2016-07-212015Niu, Nan, Alexander Woolf, Danqing Wang, Tongtong Zhu, Qimin Quan, Rachel A. Oliver, and Evelyn L. Hu. 2015. “Ultra-Low Threshold Gallium Nitride Photonic Crystal Nanobeam Laser.” Applied Physics Letters 106 (23) (June 8): 231104. Portico. doi:10.1063/1.4922211.0003-6951http://nrs.harvard.edu/urn-3:HUL.InstRepos:27727028We report exceptionally low thresholds (9.1 μJ/cm2) for room temperature lasing at ∼450 nm in optically pumped Gallium Nitride (GaN) nanobeam cavity structures. The nanobeam cavity geometry provides high theoretical Q (>100 000) with small modal volume, leading to a high spontaneous emission factor, β = 0.94. The active layer materials are Indium Gallium Nitride (InGaN) fragmented quantum wells (fQWs), a critical factor in achieving the low thresholds, which are an order-of-magnitude lower than obtainable with continuous QW active layers. We suggest that the extra confinement of photo-generated carriers for fQWs (compared to QWs) is responsible for the excellent performance.en-USJournal Article2016-07-2110.1063/1.4922211