Hot‐Electron‐Assisted Femtosecond All‐Optical Modulation in Plasmonics
Abstract
The optical Kerr nonlinearity of plasmonic metals provides enticing prospects for developing reconfigurable and ultracompact all‐optical modulators. In nanostructured metals, the coherent coupling of light energy to plasmon resonances creates a nonequilibrium electron distribution at an elevated electron temperature that gives rise to significant Kerr optical nonlinearities. Although enhanced nonlinear responses of metals facilitate the realization of efficient modulation devices, the intrinsically slow relaxation dynamics of the photoexcited carriers, primarily governed by electron–phonon interactions, impedes ultrafast all‐optical modulation. Here, femtosecond (≈190 fs) all‐optical modulation in plasmonic systems via the activation of relaxation pathways for hot electrons at the interface of metals and electron acceptor materials, following an on‐resonance excitation of subradiant lattice plasmon modes, is demonstrated. Both the relaxation kinetics and the optical nonlinearity can be actively tuned by leveraging the spectral response of the plasmonic design in the linear regime. The findings offer an opportunity to exploit hot‐electron‐induced nonlinearities for design of self‐contained, ultrafast, and low‐power all‐optical modulators based on plasmonic platforms.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 15, 2018
- Source ID
- 10.1002/adma.201704915
Entities
People
- Ali Adibi
- Hossein Taghinejad
- Kyu‐tae Lee
- Mohammad Taghinejad
- Sean P Rodrigues
- Tianquan Lian
- Wenshan Cai
- Yawei Liu
- Zihao Xu
Organizations
- Air Force Office of Scientific Research
- Emory University
- Georgia Tech
- National Science Foundation
- Office of Naval Research
- United States Department of Energy