Fig. 1. Surface detection of transferred graphene. (a) Dark-field microscopy; (b) SEM

Fig. 2. Schematic of optical path of SPP microscopic imaging

Fig. 3. Principle of graphene detection by SPP. (a) Schematic of SPP excited by Kretschmann configuration; (b) change of reflectance introduced by refractive index of graphene at interface; (c) change of SPP field distribution on interface induced by defects (dot: defect; straight line: incident SPP; dashed line: scattered SPP)

Fig. 4. SPP imaging of different graphene edges and propagation direction of SPP is shown as arrow

Fig. 5. Internal imaging of graphene and propagation direction of SPP is shown as arrow. (a) SPP imaging; (b) SEM imaging

Fig. 6. Imaging of wrinkles and break on edge of transferred graphene and propagation direction of SPP is shown as arrow. (a) SPP imaging; (b) SEM imaging

Fig. 7. Imaging of impurity nanoparticles on transferred graphene and propagation direction of SPP is shown as arrow. (a) SPP imaging; (b) SEM imaging

Fig. 8. Imaging of other impurities on transferred graphene and propagation direction of SPP is shown as arrow. (a) SPP imaging; (b) SEM imaging