Tunable and large plasmonic field enhancement in core-shell heterodimer/trimer

ABSTRACT

Heterodimer/trimer are two/three closely adjacent nanoparticles dissimilar in shape or size, and represent a simple nanoscale geometry which gives rise to a remarkably rich set of properties. The core-shell nanostructure has advantages of tunability and stability over a similar homogeneous particle. We theoretically demonstrate tunable and significant field enhancement in both heterodimer and heterotrimer systems using core-shell geometry with a metal shell and dielectric core and compared our results with core-shell homodimer and homotrimer. The analytical modeling is based on the Rayleigh theory for small particles and Foldy–Lax multi-scattering theory for multiple particles. It is shown that the E-field can be enhanced in core-shell dimer/trimer due to the plasmonic resonance in the metal shell, which can be easily tunable by changing the core-shell ratio, composition of the core and shell, relative size and distance between the particles, and wavelength of the incident light. We report significant maximum field intensity enhancement near the particles. Moreover, this tunable nanostructures with high field intensity can be useful as potential bio-sensing applications.

KEYWORDS:

• Heterotrimer
• tunability
• core-shell NPs
• plasmonic resonance
• Foldy–Lax theory
• Rayleigh theory

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Funding for this research was provided by the Center for Advanced Surface Engineering, under the National Science Foundation [grant number IIA-1457888] and the Arkansas EPSCoR Program, ASSET III.

Notes on contributors

Mohammad Habibur Rahaman

Mohammad Habibur Rahaman is a graduate student, pursuing his Doctor of Philosophy at the University of Maryland College Park. He completed his BS in Electrical and Electronic Engineering at the Bangladesh University of Engineering and Technology, 2013 and MS in electrical engineering at Arkansas State University. He is the author of 4 journal papers and 6 conference papers. His research interests are in the areas of electromagnetics, photonics, and quantum photonics.

Tamal Sarkar

Tamal Sarkar received his MS in Electrical Engineering from Arkansas State University, USA in 2019. He completed his BS in Electrical and Electrical Engineering from Rajshahi University of Engineering and Technology, Bangladesh in 2013. He is currently working as a postgraduate researcher at Arkansas State University. He has authored two journal articles and six conference papers. His research interest encompasses the areas of electromagnetics and photonics.

Brandon A. Kemp

Brandon A. Kemp is a Verbeth & Henry E. Coe Professor of Engineering at Arkansas State University. He is an NSF CAREER award winner and an Arkansas Research Alliance fellow. He received his BS degree from Arkansas State University, an MS degree in electrical engineering from the University of Missouri-Rolla, and his Ph.D. in electrical engineering from Massachusetts Institute of Technology. He is the author of more than 30 journals and eight patents.