Interaction between metal nanotip and substrate under terahertz wave radiation

Abstract

In this paper, the interaction between a gold nanotip and a silver substrate under the terahertz (THz) wave radiation is simulated by a finite difference time domain method and theoretically analyzed from the quasi-static charges model. Results from simulations and theoretical analysis show that with the increase in the distance between the nanotip and the substrate, the maximum electric field intensity on the substrate prominently decreases. With the increase in radius of the nanotip, diameter of the focused THz spot almost linearly increases and the intensity of THz spot also has a slight increase. These results are in agreement with the physical principles of the tip-enhanced near-field optical microscopy (TENOM), which indicates the TENOM technique is also suitable for the THz frequency range.

Keywords:

• terahertz
• nanotip
• substrate
• near-field optical microscopy
• quasi-static charge
• finite difference time domain

Additional information

Funding

This work was supported by national 973 program [No. 2015CB755401] of China; application development project of Chongqing, China [No. cstc2013yykfC00007]; fundamental & advanced research project of Chongqing, China [No. cstc2013jcyjC00001]; scientific equipment research project of Chinese Academy of Sciences (Name: Development of THz imaging spectrometer for biomacromolecules).