Fig. 1. Preparation process of SiO2@Au core-capped nanoparticles

Fig. 2. Relationship between incident light polarization direction and different SiO2@Au nanoparticles. (a)(b) Core-capped structure; (c)(d) core-shell structure

Fig. 3. Calculation results related to optical properties. (a) Core-capped structure, polarization direction parallel to symmetry axis; (b) core-capped structure, polarization direction perpendicular to symmetry axis; (c) core-shell structure, polarization direction parallel to symmetry axis; (d) core-shell structure, polarization direction perpendicular to symmetry axis

Fig. 4. Variance of absorption spectrum of single SiO2@Au core-capped nanoparticle with polarization direction

Fig. 5. Electric field distributions. (a) x-y cross section, polarization direction parallel to symmetry axis of core-capped nanoparticles; (b) x-y cross section, polarization direction perpendicular to symmetry axis of core-capped nanoparticles; (c) y-z cross section, polarization direction parallel to symmetry axis of core-shell nanoparticles; (d) x-y cross section, polarization direction perpendicular to symmetry axis of core-shell nanoparticles

Fig. 6. Variance of absorption spectra of nanoparticles with gold shell thickness (a) Single SiO2@Au core-capped structure; (b) single SiO2@Au core-shell structure

Fig. 7. Variance of absorption spectra of nanoparticles with core-shell ratio. (a) Single SiO2@Au core-capped structure; (b) single SiO2@Au core-shell structure

Fig. 8. Variance of absorption spectra of nanoparticles with core diameter. (a) Single SiO2@Au core-capped structure; (b) single SiO2@Au core-shell structure

Fig. 9. Variance of absorption spectra of core-capped nanoparticles with gold shell surface coverage

Fig. 10. TEM images of SiO2@Au core-capped nanoparticles and distribution of gold shell thickness. (a) Various morphologies; (b) enlargement of single particle; (c) distribution histogram of gold shell thickness

Fig. 11. UV-visible absorption spectra of SiO2@Au core-capped nanoparticles