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
Recommended Citation
Otto, Lauren M.; Mohr, Daniel A.; Johnson, Timothy W.; Oh, Sang Hyun; and Lindquist, Nathan C., "Polarization interferometry for real-time spectroscopic plasmonic sensing" (2015). Physics and Engineering Faculty Publications. 20.
https://spark.bethel.edu/physics-faculty/20