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AhmedAl-BayatiPhDDissertation.pdf (1.72 MB)

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Design and Analysis of Optical Directional Coupler and Long-range Surface Plasmon Biosensors with Applications

Al-Bayati, Ahmed Mohammed
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1659270842515831

Abstract Details

2022, Doctor of Philosophy, University of Toledo, Physics.
In this thesis we consider two different types of all-optical sensors which may be used to determine a biological sample’s composition by accurately measuring its refractive index (RI). In particular, we present and discuss the design of a novel planar geometry directional coupler which may be tuned to maximize its sensitivity over a given range of values of the sample’s refractive index (RI). We also discuss the design of a long-range surface plasmon sensor whose parameters may also be tuned to maximize sensitivity for a given range of values of RI. We then present theoretical calculations of the sensitivity of each device for several different ranges of RI corresponding to different biological samples. Our results indicate that while the directional coupler device appears to have somewhat greater sensitivity, the surface plasmon device has the advantage of linear behavior for a given RI range of interest. However, in both cases we find that - in the case of a homogeneous sample - the proposed devices can be designed to accurately measure a refractive index change on the order of 10−5 - 10−4 refractive index units. This thesis is organized as follows. In Chapter 1, we briefly review the use of optical devices as biosensors. In Chapter 2 we develop the basic theory of propagation in a waveguide and its applications to the propagation of surface plasmons. In Chapter 3 we discuss the basic theory and allowed modes of a directional coupler and derive an expression for the coupling length of a symmetric directional coupler. In Chapter 4, we discuss the details of our directional coupler design and also present results - obtained via numerical simulations carried out using BeamProp software - for the device sensitivity for several different cases. In Chapter 5 we discuss the design of our surface plasmon device and also present theoretical expressions for the dependence of the reflectance on the sample RI. We then present results for the sensitivity of this device for several different cases. Finally, in Chapter 6 we summarize our results and discuss possible future work.
Jacques Amar (Committee Chair)
Robert Deck (Committee Member)
Arunan Nadarajah (Committee Member)
Aniruddha Ray (Committee Member)
Richard Irving (Committee Member)
42 p.
Optics; Physics
Biosensor, Optical directional coupler, Long-range surface plasmon, Refractive index

Recommended Citations

Citations

  • Al-Bayati, A. M. (2022). Design and Analysis of Optical Directional Coupler and Long-range Surface Plasmon Biosensors with Applications [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1659270842515831

    APA Style (7th edition)

  • Al-Bayati, Ahmed. Design and Analysis of Optical Directional Coupler and Long-range Surface Plasmon Biosensors with Applications. 2022. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1659270842515831.

    MLA Style (8th edition)

  • Al-Bayati, Ahmed. "Design and Analysis of Optical Directional Coupler and Long-range Surface Plasmon Biosensors with Applications." Doctoral dissertation, University of Toledo, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1659270842515831

    Chicago Manual of Style (17th edition)

toledo1659270842515831
142
© 2022, all rights reserved.
This open access ETD is published by University of Toledo and OhioLINK.