title: Ultrasmall Mode Volumes in Plasmonic Cavities of Nanoparticle-On-Mirror Structures.
abstract: The mode volume and Purcell factor are two important parameters to assess the performance of optical nanocavities. Achieving small mode volumes and high Purcell factors for nanocavity structures while simplifying their fabrication has been a major task to realize high-performance and large-scale photonic devices and systems. Different optical resonators based on nanoparticle-on-mirror (NPoM) structures are systematically analyzed, which are easy to fabricate and flexible to use. Direct comparison of these optical resonators is made through finite-difference time-domain (FDTD) simulations. The achievement of ultrasmall mode volumes below 10-7(λ/n)3 based on the NPoM structure through FDTD simulations is demonstrated by rationally selecting the structural parameters. Such NPoM structures provide a decent Purcell factor on the order of 107, which can effectively enhance spontaneous emission and facilitate a number of photonic applications. The simulation results are confirmed by dark field scattering and second-harmonic generation measurements. This work is scientifically important and offers practical guidelines for the design of optical resonators for state-of-the-art optical and photonic devices.
authors: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
authors: Shengxi
authors: S
authors: Huang
authors: Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
authors: Tian
authors: T
authors: Ming
authors: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
authors: Yuxuan
authors: Y
authors: Lin
authors: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
authors: Xi
authors: X
authors: Ling
authors: Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
authors: Qifeng
authors: Q
authors: Ruan
authors: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
authors: Tomás
authors: T
authors: Palacios
authors: Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
authors: Jianfang
authors: J
authors: Wang
authors: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. millie@mgm.mit.edu.|Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. millie@mgm.mit.edu.
authors: Mildred
authors: M
authors: Dresselhaus
authors: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. jingkong@mit.edu.
authors: Jing
authors: J
authors: Kong
keywords: dark field scattering; field enhancement; finite-difference time-domain simulation; scattering cross-section; second-harmonic generation, nanocavities