Nanoparticle-on-mirror pairs: building blocks for remote spectroscopies

Area of Science:

• Plasmonics
• Nanophotonics
• Spectroscopy

Background:

• Surface-enhanced spectroscopies (SERS, SEF) offer high sensitivity for nano-entity investigation.
• Plasmonic nanogaps enable single-molecule detection but risk sample damage from local laser excitation.
• Remote spectroscopy avoids direct laser exposure, mitigating background noise and sample degradation.

Purpose of the Study:

• To develop a novel remote spectroscopy approach using nanoparticle-on-mirror (NPoM) pairs.
• To establish a figure of merit for evaluating remote spectroscopy performance.
• To demonstrate the efficacy of NPoM pairs for remote surface-enhanced Raman scattering (SERS) and fluorescence (SEF).

Main Methods:

• Constructed "NPoM pairs" comprising two identical NPoMs with matched resonances.
• Designed NPoMs to function as separate receiving and transmitting antennas for remote signal transfer.
• Defined a figure of merit quantifying signal receiving, transport, and transmission efficiencies.

Main Results:

• NPoM pairs successfully enabled remote SERS and SEF measurements.
• The developed figure of merit provides a quantitative evaluation of remote spectroscopy systems.
• Demonstrated the dual capability of NPoM pairs for both local and remote optical signal access.

Conclusions:

• NPoM pairs are effective building blocks for advanced remote spectroscopy.
• This approach overcomes limitations of direct laser excitation in sensitive molecular detection.
• The technology holds promise for applications in biomedicine, including early diagnosis and monitoring.