Fig. 1

Design of the nanoplatelet nanolaser. a Absorption cross-section (blue) and photoluminescence (red) spectra of CdSe core / CdS shell nanoplatelets in solution. The inset shows a transmission-electron-microscope image of nanoplatelets, and the schematic below is an illustration of the nanoplatelet structure. Scale bar is 20 nm. b Scanning electron microscope image of a Silicon nitride photonic-crystal nanobeam cavity before deposition of the nanoplatelets. c Calculated electric-field intensity profile (|E|²) of the fundamental mode in the cavity. Scale bars in both b and c are 500 nm. d Experimental setup. M: mirror, BS: beam spliter, PBS: polarizing beam spliter, HWP: half-wave plate, OL: objective lens, HPF: high-pass filter (cut-off at 600 nm), PH: pin hole as spatial fiter, SPCM: single photon counting module