Fig. 3.

Electric field enhancement (contours of ‖E‖²) for disk dimers composed of identical Au disks with different thicknesses and gap distances. In columns 1–5, the disk thicknesses are 40, 80, 120, 160, and 200 nm, respectively. In rows 1–5, the gap distances are 5, 10, 15, 30, and 80 nm, respectively. Contours vary from 0 (blue) to 50 (red) times the incident field intensity. The number in the lower right corner of each image is ‖E‖² relative to the isolated particle result.