▎ 摘　　要

NOVELTY - Doped graphene quantum dot, which generates second harmonic non-linear optical signal under excitation light, and the wavelength of its emission peak is half of the wavelength of the excitation light, is claimed. USE - The quantum dot is useful in the field of biomedical optical imaging (claimed). ADVANTAGE - The quantum dot has high imaging precision; generates second harmonic light; exhibits good biocompatibility; and allows long-term, continuous, extremely fast and sensitive detection. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing the quantum dots, comprising adding reactant to reaction solvent and mixing, performing an ice bath ultrasound, producing a homogeneous mixed solution, transferring to the reactor, synthesizing by solvothermal method, centrifuging, taking the supernatant containing doped graphene quantum dots, dialyzing, and drying.