Department of Physics;
The Hong Kong University of Science and Technology;
Hong Kong 999077;
China;
State Key Laboratory of Surface Physics;
Key Laboratory of Micro-and Nano-Photonic Structures(Ministry of Education);
and Department of Physics;
Fudan University;
Shanghai 200433;
China;
Collaborative Innovation Center of Advanced Microstructures;
Nanjing University;
Nanjing 210093;
China;
photonic crystal; polarization field; polarization singularity;