The critical role of headcap and plasmonic near-field enhancement in mushroom-shaped Au nanorod

- Optical properties of the mushroom-shaped nanorods are analyzed.
- Great tunability in the NIR region has been obtained.
- Field amplification up to four orders of magnitude can be obtained.
- More field hot spots can be obtained with modified rod end.
- Open a path to tune the optical response of nanorods instead of just changing the aspect ratio.