**Angular-Resolved Optical Characteristics and Threshold Gain Analysis of GaN-Based 2-D Photonics Crystal Surface Emitting Lasers**

Shih-Wei Chen1,2, Tien-Chang Lu1, Ting-Chun Liu1, Peng-Hsiang Weng1, Hao-Chung Kuo1 and Shing-Chung Wang1 *1Department of Photonic and Institute of Electro-Optical Engineering National Chiao Tung University, Hsinchu 2Green Energy & Environment Research Labs Industrial Technology Research Institute, Hsinchu Taiwan, R.O.C.* 
