title: Photoacoustic measurement of refractive index of dye solutions and myoglobin for biosensing applications.
abstract: Current methods of determining the refractive index of chemicals and materials, such as ellipsometry and reflectometry, are limited by their inability to analyze highly absorbing or highly transparent materials, as well as the required prior knowledge of the sample thickness and estimated refractive index. Here, we present a method of determining the refractive index of solutions using the photoacoustic effect. We show that a photoacoustic refractometer can analyze highly absorbing dye samples to within 0.006 refractive index units of a handheld optical refractometer. Further, we use myoglobin, an early non-invasive biomarker for malignant hyperthermia, as a proof of concept that this technique is applicable for use as a medical diagnostic. Comparison of the speed, cost, simplicity, and accuracy of the techniques shows that this photoacoustic method is well-suited for optically complex systems.
authors.affiliation: 242 Christopher S. Bond Life Sciences Center, University of Missouri-Columbia, 1201 E. Rollins Rd. Columbia, Missouri 65211, USA.
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Goldschmidt
authors.forename: Smit
authors.initials: S
authors.lastname: Mehta
authors.forename: Jeff
authors.initials: J
authors.lastname: Mosley
authors.forename: Chris
authors.initials: C
authors.lastname: Walter
authors.forename: Paul J D
authors.initials: PJ
authors.lastname: Whiteside
authors.forename: Heather K
authors.initials: HK
authors.lastname: Hunt
authors.forename: John A
authors.initials: JA
authors.lastname: Viator
keywords: (170.1470) Blood or tissue constituent monitoring; (170.1610) Clinical applications; (240.0240) Optics at surfaces; (240.2130) Ellipsometry and polarimetry; (240.6490) Spectroscopy, surface; (240.7040) Tunneling