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Using the Gouy phase shift to estimate gas vesicle concentrations in salmonella (Conference Presentation)

Nadeau, Jay L. and Bedrossian, Manuel and Farhadi, Arash and Ho, Gabrielle and Shapiro, Mikhail (2019) Using the Gouy phase shift to estimate gas vesicle concentrations in salmonella (Conference Presentation). In: Quantitative Phase Imaging V. Proceedings of SPIE. No.10887. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 1088706. ISBN 9781510624160.

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As light, or any other wave, converges into focus, the apparent wavelength of the wave increases as the phase velocity surpasses the speed of propagation in that medium. For a Gaussian beam, this causes a phase change Δϕ equal to ±π. This phenomenon, named the Gouy phase shift, can be observed when a plane wave is refracted by a lens and caused to come into focus. The location where this phase shift occurs in the axial direction is the focal length of the lens. Many biological structures are curved and thus can be modeled as lenslets. Bacterial cells have a radius of curvature that can be readily determined from high resolution images. A plane wave passing through them would be refracted and converge at some point after interacting with the bacterium. Altering the refractive index of the cells will change the effective focal length of the lenslet and thus the location of the Gouy phase shift. We have previously shown that purified gas vesicles (GVs) can be transfected into bacterial cells, altering the refractive index in large areas of the cell. In this work, we use off-axis digital holographic microscopy to measure the effect of GVs on the index of refraction of Salmonella cells and relate this to changes in the Gouy phase shift. By observing the location of this phase shift relative to the location of the bacterium, the GV concentration within the cell can be estimated, highlighting the potential of GVs as a quantitative contrast agent for QPI.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Nadeau, Jay L.0000-0001-5258-0076
Farhadi, Arash0000-0001-9137-8559
Ho, Gabrielle0000-0002-8511-5549
Shapiro, Mikhail0000-0002-0291-4215
Additional Information:© 2019 Society of Photo-Optical Instrumentation Engineers (SPIE).
Series Name:Proceedings of SPIE
Issue or Number:10887
Record Number:CaltechAUTHORS:20190822-134051942
Persistent URL:
Official Citation:Jay L. Nadeau, Manuel Bedrossian, Arash Farhadi, Gabrielle Ho, and Mikhail Shapiro "Using the Gouy phase shift to estimate gas vesicle concentrations in salmonella (Conference Presentation)", Proc. SPIE 10887, Quantitative Phase Imaging V, 1088706 (4 March 2019);
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:98120
Deposited By: George Porter
Deposited On:22 Aug 2019 21:53
Last Modified:16 Nov 2021 17:36

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