Abstract

There are many optical detection and sensing methods used today that provide powerful ways to diagnose, characterize, and study materials. For example, the measurement of spontaneous Raman scattering allows for remote detection and identification of chemicals. Many other optical techniques provide unique solutions to learn about biological, chemical, and even structural systems. However, when these systems exist in a highly scattering or turbid medium, the optical scattering effects reduce the effectiveness of these methods. In this article, we demonstrate a method to engineer the geometry of the optical interface of a turbid medium, thereby drastically enhancing the coupling efficiency of light into the material. This enhanced optical coupling means that light incident on the material will penetrate deeper into (and through) the medium. It also means that light thus injected into the material will have an enhanced interaction time with particles contained within the material. These results show that, by using the multiple scattering of light in a turbid medium, enhanced light-matter interaction can be achieved; this has a direct impact on spectroscopic methods such as Raman scattering and fluorescence detection in highly scattering regimes. Furthermore, the enhanced penetration depth achieved by this method will directly impact optical techniques that have previously been limited by the inability to deposit sufficient amounts of optical energy below or through highly scattering layers.

Department(s)

Physics

Comments

This research was supported in part by the National Science Foundation [Chemical, Bioengineering, Environmental, and Transport Systems Award 1250363, Division of Biological Infrastructure Award 1455671, Electrical, Communications, and Cyber Systems (ECCS) Award 1509268, and Grant ECCS-1509361], the Robert A. Welch Foundation (Grant A-1261), the Office of Naval Research (Grants N00014-16-1-3054 and N00014-13-1-0649), and the US Department of Defense (Grant FA9550-15-1-0517).

Keywords and Phrases

Enhanced transmittance; Optical coupling; Optical scattering; Spectroscopy; Turbid media

International Standard Serial Number (ISSN)

0027-8424; 1091-6490

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2017 National Academy of Sciences, All rights reserved.

Included in

Physics Commons

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