Title

Polarization interferometry for real-time spectroscopic plasmonic sensing

Document Type

Article

Abstract

We present quantitative, spectroscopic polarization interferometry phase measurements on plasmonic surfaces for sensing applications. By adding a liquid crystal variable wave plate in our beam path, we are able to measure phase shifts due to small refractive index changes on the sensor surface. By scanning in a quick sequence, our technique is extended to demonstrate real-time measurements. While this optical technique is applicable to different sensor geometries - e.g., nanoparticles, nanogratings, or nanoapertures - the plasmonic sensors we use here consist of an ultrasmooth gold layer with buried linear gratings. Using these devices and our phase measurement technique, we calculate a figure of merit that shows improvement over measuring only surface plasmon resonance shifts from a reflected intensity spectrum. To demonstrate the general-purpose versatility of our phase-resolved measurements, we also show numerical simulations with another common device architecture: periodic plasmonic slits. Since our technique inherently measures both the intensity and phase of the reflected or transmitted light simultaneously, quantitative sensor device characterization is possible. This journal is

Department(s)

Physics and Engineering

Publication Title

Nanoscale

Volume

7

Issue

9

First Page

4226

Last Page

4233

Publication Date

3-7-2015

DOI

10.1039/c4nr06586g

ISSN

20403364

E-ISSN

20403372

PubMed ID

25672889

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