Department of Electronic Engineering Shanghai Jiao Tong University Shanghai 200240 China;
Department of Electronic Engineering Shanghai Jiao Tong University Shanghai 200240 China;
National Key Laboratory of Science and Technology on Micro/Nano Fabrication Shanghai Jiao Tong University Shanghai 200240 China;
Department of Electronic Engineering Shanghai Jiao Tong University Shanghai 200240 China;
orbital angular momentum(OAM); Fabry-Perot(F-P)cavity; divergence; partially reflecting surface(PRS);