Plasmon rulers: The optical angstrometers

• Published in: Laser focus world Vol. 50; no. 9; p. 60
• Main Author: Hill, Ryan T
• Format: Magazine Article
• Language: English
• Published: Tulsa Endeavor Business Media 01-09-2014
• Subjects: Broadband; Devices; Electric fields; Illumination; Metrology; Nanoparticles; Nanostructure; Optics; Plasmons; Reporting; Scientific apparatus & instruments; Scientific imaging
• ISSN: 1043-8092

Plasmon rulers are a fascinating class of metrology devices because of their exquisite, atomic-bond-length sensitivity to distance and their transduction of signal as a simple spectroscopic measurement. They are composed of plasmon resonant nanoparticles (NP), and hence report distance information from a very localized, nanoscale environment--be it a biologically relevant, aqueous sample reporting structural dynamics of molecules or a molecularly thin surface coating. While their development into robust metrology tools is not without challenges, evolving nanofabrication techniques suggest that plasmon rulers can function as optical "angstrometers". The optical signal from a plasmon ruler arises from a localized surface plasmon resonance (LSPR) from metallic NPs. This LSPR is produced when broadband illumination of plasmon resonant NPs with sub-wavelength dimensions causes the free electrons on the NP surfaces to oscillate in response to the oscillating electric field of the incident light. Here, Hill discusses the advantages of NP LSPRs.