Greatly enhanced continuous-wave terahertz emission by nano-electrodes in a photoconductive photomixer (Retracted Article) - Tanoto,H; Teng,JH; Wu,QY; Sun,M; Chen,ZN; Maier,SA; Wang,B; Chum,CC; Si,GY; Danner,AJ; Chua,SJ (NATURE PHOTONICS, 2012)