[Paper Review] Mapping the radiative and non-radiative local density of states in the near-field of a gold nanoantenna

Da Cao, A. Cazé+7 more|arXiv (Cornell University)|Jan 13, 2014

Plasmonic and Surface Plasmon Research3 citations

TL;DR

This paper introduces a method to quantitatively map both radiative and non-radiative decay rates of fluorescent emitters in the near-field of a gold nanoantenna by simultaneously measuring fluorescence intensity and decay rate, using the reciprocity theorem and validated against exact numerical simulations with strong quantitative agreement.

ABSTRACT

We present a novel method for mapping the radiative and non-radiative decay rate of a fluorescent emitter in the near-field of a nanostructured sample. The approach is based on the simultaneous mapping of the fluorescence intensity and decay rate and on the rigorous application of the reciprocity theorem. Data analysis is based on an analytical calculation which is detailed in the paper. Experimental data are compared with exact numerical simulations and we show a good quantitative agreement between theory and experiment, which proves the validity of the method.

Motivation & Objective

• To develop a quantitative method for mapping both radiative and non-radiative decay rates of fluorescent emitters in the near-field of nanostructures.
• To overcome limitations in existing techniques that cannot separately quantify radiative and non-radiative contributions to emission decay.
• To establish a rigorous experimental framework based on the reciprocity theorem for accurate near-field decay rate measurements.
• To validate the method through direct comparison with exact numerical simulations.

Proposed method

• Simultaneously maps fluorescence intensity and decay rate of emitters positioned in the near-field of a gold nanoantenna.
• Applies the reciprocity theorem to relate the measured decay rate to the local density of states (LDOS), separating radiative and non-radiative components.
• Uses analytical calculations derived from the reciprocity theorem to extract radiative and non-radiative LDOS from experimental data.
• Performs rigorous data analysis by comparing experimental maps with exact numerical simulations of the nanoantenna's electromagnetic response.
• Employs precise nanoscale positioning of fluorescent emitters to ensure accurate near-field sampling.
• Validates the method by demonstrating quantitative agreement between experimental measurements and full-wave simulations.

Experimental results

Research questions

• RQ1 Can the radiative and non-radiative components of the local density of states be quantitatively mapped in the near-field of a nanoantenna?
• RQ2 How accurately can the reciprocity theorem be applied to extract decay rate contributions from experimental fluorescence intensity and lifetime measurements?
• RQ3 To what extent does the experimental method agree with exact numerical simulations of the nanoantenna's electromagnetic environment?
• RQ4 Can the method distinguish between radiative and non-radiative decay pathways at the nanoscale in a plasmonic structure?

Key findings

• The method successfully maps both radiative and non-radiative decay rates with high spatial resolution in the near-field of a gold nanoantenna.
• A strong quantitative agreement is observed between experimental measurements and exact numerical simulations, confirming the validity of the approach.
• The application of the reciprocity theorem enables accurate separation of radiative and non-radiative contributions to the local density of states.
• The technique provides a reliable experimental framework for probing the full LDOS in plasmonic nanostructures, including both radiative and non-radiative decay pathways.