Audrey (Ellerbee) Bowden
Assistant Professor of Electrical Engineering
Bio
Our lab seeks to develop and deploy novel tools for optical imaging and sensing at the microscale and nanoscale. Our work finds applications both in the clinic and for basic science research; we also have particular interest in the development of low-cost, portable technologies suited for use in poorly resourced environments.
Academic Appointments
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Assistant Professor, Electrical Engineering
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Member, Bio-X
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Member, Child Health Research Institute
Honors & Awards
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Golden Torch Award, National Society of Black Engineers (2013)
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Arthur H. Guenther Congressional Fellow, Arthur H. Guenther Congressional Fellowship Program (2013)
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Diversity Postdoctoral Fellowship, Ford Foundation (2013)
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Hellman Faculty Scholar, Hellman Fellowship Program (2013)
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Young Investigator Award, Air Force (2013)
Professional Education
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PhD, Duke University, Biomedical Engineering
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BS, Princeton University, Electrical Engineering
2015-16 Courses
- Biophotonics: Light in Biology
EE 230 (Aut) - Biophotonics: Light in Medicine and Biology
EE 331 (Win) - Introduction to Photonics
EE 134 (Spr) -
Independent Studies (5)
- Special Studies and Reports in Electrical Engineering
EE 191 (Aut, Win, Spr) - Special Studies and Reports in Electrical Engineering
EE 391 (Aut, Win, Spr, Sum) - Special Studies and Reports in Electrical Engineering (WIM)
EE 191W (Aut, Win, Spr) - Special Studies or Projects in Electrical Engineering
EE 190 (Aut, Win, Spr) - Special Studies or Projects in Electrical Engineering
EE 390 (Aut, Win, Spr, Sum)
- Special Studies and Reports in Electrical Engineering
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Prior Year Courses
2014-15 Courses
- Biophotonics: Light in Biology
EE 230 (Aut) - Biophotonics: Light in Medicine and Biology
EE 331 (Win) - Introduction to Photonics
EE 134 (Spr)
2013-14 Courses
- Biophotonics: Light in Medicine and Biology
EE 331 (Win) - Introduction to Photonics
EE 134 (Spr) - Modern Optics
EE 236A (Aut)
2012-13 Courses
- Biophotonics: Light in Medicine and Biology
EE 331 (Win) - Introduction to Photonics
EE 134 (Spr) - Modern Optics
EE 268 (Aut)
- Biophotonics: Light in Biology
All Publications
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Label-free characterization of vitrification-induced morphology changes in single-cell embryos with full-field optical coherence tomography.
Journal of biomedical optics
2015; 20 (9): 96004-?
View details for DOI 10.1117/1.JBO.20.9.096004
View details for PubMedID 26334977
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Fabrication of healthy and disease-mimicking retinal phantoms with tapered foveal pits for optical coherence tomography.
Journal of biomedical optics
2015; 20 (8): 85004-?
View details for DOI 10.1117/1.JBO.20.8.085004
View details for PubMedID 26287985
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Rapid scanning catheterscope for expanded forward-view volumetric imaging with optical coherence tomography
OPTICS LETTERS
2015; 40 (13): 3165-3168
Abstract
We demonstrate a novel catheterscope, based on scanning fiber endoscopy, for volumetric imaging with optical coherence tomography (OCT), which possesses a high resonance frequency (>2 kHz) and a small outer diameter (OD) (1.07 mm). Our design is the fastest volumetric-scanning, forward-viewing catheterscope for OCT, and the scanning package has the smallest OD of any such OCT package published to date. Using a proof-of-operation catheterscope with commercial lenses, we demonstrate high-quality in vivo and ex vivo volumetric imaging and extend the 1.1 mm diameter field of view more than 200-fold by mosaicking. Due to its small OD, short rigid tip length, and fast scan rate, this scope is the leading candidate design to enable early detection and staging of bladder cancer during flexible white light cystoscopy.
View details for DOI 10.1364/OL.40.003165
View details for Web of Science ID 000357486800059
View details for PubMedID 26125393
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Polarization-sensitive interleaved optical coherence tomography
OPTICS EXPRESS
2015; 23 (10): 13693-13703
Abstract
We introduce a new strategy for single-mode fiber based polarization-sensitive (PS-) optical coherence tomography (OCT) using orthogonally polarized optical frequency combs (OFC) in the sample arm. The two OFCs are tuned to be interleaved in the spectral domain, permitting simultaneous measurement of both polarization states from the same spatial region C close to the location of zero pathlength delay. The two polarization states of the beam in the sample arm are demultiplexed by interpolation after performing wavelength stabilization via a two-mirror calibration method. The system uses Jones matrix methods to measure quantitatively the round-trip phase retardation B-scans in the sample. A glass plate and quarter-wave plate were measured to validate the accuracy of the birefringence measurement. Further, we demonstrated the potential of this system for biomedical applications by measurement of chicken breast muscle.
View details for DOI 10.1364/OE.23.013693
View details for Web of Science ID 000354706800116
View details for PubMedID 26074618
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Optical separation of heterogeneous size distributions of microparticles on silicon nitride strip waveguides
OPTICS EXPRESS
2015; 23 (7): 8855-8866
Abstract
We demonstrate two complementary optical separation techniques of dielectric particles on the surface of silicon nitride waveguides. Glass particles ranging from 2 μm to 10 μm in diameter are separated at guided powers below 40 mW. The effects of optical, viscous, and frictional forces on the particles are modeled and experimentally shown to enable separation. Particle interactions are investigated and shown to decrease measured particle velocity without interfering with the overall particle separation distribution. The demonstrated separation techniques have the potential to be integrated with microfluidic structures for cell sorting.
View details for DOI 10.1364/OE.23.008855
View details for Web of Science ID 000352290000088
View details for PubMedID 25968723
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Noninvasive in vivo imaging reveals differences between tectorial membrane and basilar membrane traveling waves in the mouse cochlea
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2015; 112 (10): 3128-3133
Abstract
Sound is encoded within the auditory portion of the inner ear, the cochlea, after propagating down its length as a traveling wave. For over half a century, vibratory measurements to study cochlear traveling waves have been made using invasive approaches such as laser Doppler vibrometry. Although these studies have provided critical information regarding the nonlinear processes within the living cochlea that increase the amplitude of vibration and sharpen frequency tuning, the data have typically been limited to point measurements of basilar membrane vibration. In addition, opening the cochlea may alter its function and affect the findings. Here we describe volumetric optical coherence tomography vibrometry, a technique that overcomes these limitations by providing depth-resolved displacement measurements at 200 kHz inside a 3D volume of tissue with picometer sensitivity. We studied the mouse cochlea by imaging noninvasively through the surrounding bone to measure sound-induced vibrations of the sensory structures in vivo, and report, to our knowledge, the first measures of tectorial membrane vibration within the unopened cochlea. We found that the tectorial membrane sustains traveling wave propagation. Compared with basilar membrane traveling waves, tectorial membrane traveling waves have larger dynamic ranges, sharper frequency tuning, and apically shifted positions of peak vibration. These findings explain discrepancies between previously published basilar membrane vibration and auditory nerve single unit data. Because the tectorial membrane directly overlies the inner hair cell stereociliary bundles, these data provide the most accurate characterization of the stimulus shaping the afferent auditory response available to date.
View details for DOI 10.1073/pnas.1500038112
View details for Web of Science ID 000350646500059
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Label-free and non-contact optical biosensing of glucose with quantum dots.
Biosensors & bioelectronics
2015; 64: 30-35
Abstract
We present a label-free, optical sensor for biomedical applications based on changes in the visible photoluminescence (PL) of quantum dots in a thin polymer film. Using glucose as the target molecule, the screening of UV excitation due to pre-absorption by the product of an enzymatic assay leads to quenching of the PL of quantum dots (QDs) in a non-contact scheme. The irradiance changes in QD PL indicate quantitatively the level of glucose present. The non-contact nature of the assay prevents surface degradation of the QDs, which yields an efficient, waste-free, cost-effective, portable, and sustainable biosensor with attractive market features. The limit of detection of the demonstrated biosensor is ~3.5 µm, which is competitive with existing contact-based bioassays. In addition, the biosensor operates over the entire clinically relevant range of glucose concentrations of biological fluids including urine and whole blood. The comparable results achieved across a range of cost-affordable detectors, including a spectrophotometer, portable spectrometer, and iPhone camera, suggest that label-free and visible quantification of glucose with QD films can be applied to low-cost, point-of-care biomedical sensing as well as scientific applications in the laboratory for characterizing glucose or other analytes.
View details for DOI 10.1016/j.bios.2014.08.035
View details for PubMedID 25189097
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Fabrication of Anatomically Tapered Foveal Pits in Retinal Phantoms for Optical Coherence Tomography
DESIGN AND PERFORMANCE VALIDATION OF PHANTOMS USED IN CONJUNCTION WITH OPTICAL MEASUREMENT OF TISSUE VII
2015; 9325
View details for DOI 10.1117/12.2079730
View details for Web of Science ID 000353883600003
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Perspectives of the optical coherence tomography community on code and data sharing
OPTICAL COHERENCE TOMOGRAPHY AND COHERENCE DOMAIN OPTICAL METHODS IN BIOMEDICINE XIX
2015; 9312
View details for DOI 10.1117/12.2082412
View details for Web of Science ID 000353885800019
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Single-shot speckle noise reduction by interleaved optical coherence tomography
JOURNAL OF BIOMEDICAL OPTICS
2014; 19 (12)
Abstract
Speckle noise is one of the dominant factors that degrade image quality in optical coherence tomography (OCT). Here, we propose a new strategy, interleaved OCT (iOCT), for spatial compounding and angular compounding. We demonstrate the efficiency of compounding with iOCT to restrain speckle noise without compromising imaging speed in phantoms and tissue samples.
View details for DOI 10.1117/1.JBO.19.12.120501
View details for Web of Science ID 000347442600001
View details for PubMedID 25486093
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Automated identification of basal cell carcinoma by polarization-sensitive optical coherence tomography
BIOMEDICAL OPTICS EXPRESS
2014; 5 (10): 3717-3729
View details for DOI 10.1364/BOE.5.003717
View details for Web of Science ID 000343135200036
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Automated identification of basal cell carcinoma by polarization-sensitive optical coherence tomography.
Biomedical optics express
2014; 5 (10): 3717-3729
Abstract
We report an automated classifier to detect the presence of basal cell carcinoma in images of mouse skin tissue samples acquired by polarization-sensitive optical coherence tomography (PS-OCT). The sensitivity and specificity of the classifier based on combined information of the scattering intensity and birefringence properties of the samples are significantly higher than when intensity or birefringence information are used alone. The combined information offers a sensitivity of 94.4% and specificity of 92.5%, compared to 78.2% and 82.2% for intensity-only information and 85.5% and 87.9% for birefringence-only information. These results demonstrate that analysis of the combination of complementary optical information obtained by PS-OCT has great potential for accurate skin cancer diagnosis.
View details for DOI 10.1364/BOE.5.003717
View details for PubMedID 25360384
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Quantitative measurements of strain and birefringence with common-path polarization-sensitive optical coherence tomography
OPTICS LETTERS
2014; 39 (19): 5507-5510
View details for DOI 10.1364/OL.39.005507
View details for Web of Science ID 000343906400010
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Scalable multiplexing for parallel imaging with interleaved optical coherence tomography
BIOMEDICAL OPTICS EXPRESS
2014; 5 (9): 3192-3203
View details for DOI 10.1364/BOE.5.003192
View details for Web of Science ID 000341650900028
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Scalable multiplexing for parallel imaging with interleaved optical coherence tomography.
Biomedical optics express
2014; 5 (9): 3192-3203
Abstract
We demonstrate highly parallel imaging with interleaved optical coherence tomography (iOCT) using an in-house-fabricated, air-spaced virtually-imaged phased array (VIPA). The air-spaced VIPA performs spectral encoding of the interferograms from multiple lateral points within a single sweep of the source and allows us to tune and balance several imaging parameters: number of multiplexed points, ranging depth, and sensitivity. In addition to a thorough discussion of the parameters and operating principles of the VIPA, we experimentally demonstrate the effect of different VIPA designs on the multiplexing potential of iOCT. Using a 200-kHz light source, we achieve an effective A-scan rate of 3.2-MHz by multiplexing 16 lateral points onto a single wavelength sweep. The improved sensitivity of this system is demonstrated for 3D imaging of biological samples such as a human finger and a fruit fly.
View details for DOI 10.1364/BOE.5.003192
View details for PubMedID 25401031
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Automated Mosaicing of Feature-Poor Optical Coherence Tomography Volumes With an Integrated White Light Imaging System
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING
2014; 61 (7): 2141-2153
View details for DOI 10.1109/TBME.2014.2316535
View details for Web of Science ID 000337808200023
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Three-dimensional, distendable bladder phantom for optical coherence tomography and white light cystoscopy.
Journal of biomedical optics
2014; 19 (3): 36009-?
Abstract
ABSTRACT. We describe a combination of fabrication techniques and a general process to construct a three-dimensional (3-D) phantom that mimics the size, macroscale structure, microscale surface topology, subsurface microstructure, optical properties, and functional characteristics of a cancerous bladder. The phantom also includes features that are recognizable in white light (i.e., the visual appearance of blood vessels), making it suitable to emulate the bladder for emerging white light+optical coherence tomography (OCT) cystoscopies and other endoscopic procedures of large, irregularly shaped organs. The fabrication process has broad applicability and can be generalized to OCT phantoms for other tissue types or phantoms for other imaging modalities. To this end, we also enumerate the nuances of applying known fabrication techniques (e.g., spin coating) to contexts (e.g., nonplanar, 3-D shapes) that are essential to establish their generalizability and limitations. We anticipate that this phantom will be immediately useful to evaluate innovative OCT systems and software being developed for longitudinal bladder surveillance and early cancer detection.
View details for DOI 10.1117/1.JBO.19.3.036009
View details for PubMedID 24623158
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Three-dimensional, distendable bladder phantom for optical coherence tomography and white light cystoscopy
JOURNAL OF BIOMEDICAL OPTICS
2014; 19 (3)
View details for DOI 10.1117/1.JBO.19.3.036009
View details for Web of Science ID 000338333400022
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Multilayered disease-mimicking bladder phantom with realistic surface topology for optical coherence tomography
DESIGN AND PERFORMANCE VALIDATION OF PHANTOMS USED IN CONJUNCTION WITH OPTICAL MEASUREMENT OF TISSUE VI
2014; 8945
View details for DOI 10.1117/12.2036402
View details for Web of Science ID 000334097200012
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Volumetric mosaicing for optical coherence tomography for large area bladder wall visualization
PHOTONIC THERAPEUTICS AND DIAGNOSTICS X
2014; 8926
View details for DOI 10.1117/12.2036325
View details for Web of Science ID 000337574500033
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Evaluation of fingerprint deformation using optical coherence tomography
OPTICAL ELASTOGRAPHY AND TISSUE BIOMECHANICS
2014; 8946
View details for DOI 10.1117/12.2038694
View details for Web of Science ID 000334343200009
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Telemedicine plus OCT: toward design of optimized algorithms for high-quality compressed images
DESIGN AND QUALITY FOR BIOMEDICAL TECHNOLOGIES VII
2014; 8936
View details for DOI 10.1117/12.2038530
View details for Web of Science ID 000334099600005
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Assessment of imaging parameters correlated with the effects of cryopreservation on embryo development
OPTICAL METHODS IN DEVELOPMENTAL BIOLOGY II
2014; 8953
View details for DOI 10.1117/12.2040487
View details for Web of Science ID 000336049000006
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Label-free assay for the detection of glucose mediated by the effects of narrowband absorption on quantum dot photoluminescence
FRONTIERS IN BIOLOGICAL DETECTION: FROM NANOSENSORS TO SYSTEMS VI
2014; 8933
View details for DOI 10.1117/12.2039963
View details for Web of Science ID 000336738600007
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Interleaved optical coherence tomography
OPTICS EXPRESS
2013; 21 (22): 26542-26556
Abstract
We present a novel and cost-effective technique--interleaved optical coherence tomography (iOCT)--to enhance the imaging speed of swept source OCT systems by acquiring data from multiple lateral positions simultaneously during a single wavelength sweep, using a single detector and a virtually imaged phase array (VIPA) as a multi-band demultiplexer. This technique uses spectral encoding to convert coherence length into higher imaging speed; the speed enhancement factor is independent of the source speed or center wavelength, and the effective A-scan rate scales linearly with sweep speed. The optical configuration requires only a change in the sample arm of a traditional OCT system and preserves the axial resolution and fall-off characteristic of a traditional SS-OCT using the same light source. Using 10 kHz, 20 kHz and 100 kHz sources we provide a first demonstration of image speed enhancement factors of up to 12, 6 and 10, respectively, which yield effective A-scan rates of 120 kHz, 120 kHz and 1 MHz for B-scan imaging, with a sensitivity of up to 82.5 dB. We also show that iOCT can image faster dynamics than traditional OCT B-scan imaging and is capable of 3D biological imaging. The iOCT concept suggests a new route to high-speed OCT imaging for laser developers: that is, by focusing on improving the coherence length and linewidth of existing and emerging sources. Hence, iOCT is a nice complement to ongoing research and commercial efforts to enable faster imaging through development of lasers with faster sweep rates, and offers new hope for existing sources with slow sweep rates and potential for enhancement of coherence length to compete with faster sources to achieve high-speed OCT.
View details for DOI 10.1364/OE.21.026542
View details for Web of Science ID 000327007800111
View details for PubMedID 24216876
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Air Force test chart-like phantom for measuring axial and lateral resolution in optical coherence tomography
DESIGN AND PERFORMANCE VALIDATION OF PHANTOMS USED IN CONJUNCTION WITH OPTICAL MEASUREMENT OF TISSUE V
2013; 8583
View details for DOI 10.1117/12.2003189
View details for Web of Science ID 000322903900006
- High-resolution spectrometer: solution to the axial resolution and imaging depth tradeoff of SD-OCT 2013
- Full-field Optical Coherence Tomography of Early Embryonic Development 2013
- Combined Polarization Sensitive OCT (PS-OCT) and Raman Spectroscopy (RS) for Label-free Assessment of Molecular and Structural Abnormalities for Point-of-Care Skin Cancer Diagnostics 2013
- Non-contact, label-free 3D imaging of developing embryos 2013
- Full-field Optical Coherence Tomography of Early Embryonic Development 2013
- Enhanced Speed in Swept-Source OCT with a Multi-band Demultiplexer 2013
- Co-registration of OCT volumes for 3D bladder mosaicing 2013
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The magnitude of lift forces acting on drops and bubbles in liquids flowing inside microchannels
LAB ON A CHIP
2013; 13 (3): 365-376
Abstract
Hydrodynamic lift forces offer a convenient way to manipulate particles in microfluidic applications, but there is little quantitative information on how non-inertial lift mechanisms act and compete with each other in the confined space of microfluidic channels. This paper reports measurements of lift forces on nearly spherical drops and bubbles, with diameters from one quarter to one half of the width of the channel, flowing in microfluidic channels, under flow conditions characterized by particle capillary numbers Ca(P) = 0.0003-0.3 and particle Reynolds numbers Re(P) = 0.0001-0.1. For Ca(P) < 0.01 and Re(P) < 0.01 the measured lift forces were much larger than predictions of deformation-induced and inertial lift forces found in the literature, probably due to physicochemical hydrodynamic effects at the interface of drops and bubbles, such as the presence of surfactants. The measured forces could be fit with good accuracy using an empirical formula given herein. The empirical formula describes the power-law dependence of the lift force on hydrodynamic parameters (velocity and viscosity of the carrier phase; sizes of channel and drop or bubble), and includes a numerical lift coefficient that depends on the fluids used. The empirical formula using an average lift coefficient of ~500 predicted, within one order of magnitude, all lift force measurements in channels with cross-sectional dimensions below 1 mm.
View details for DOI 10.1039/c2lc41035d
View details for Web of Science ID 000312947300007
View details for PubMedID 23212283
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High-resolution spectrometer: solution to the axial resolution and ranging depth trade-off of SD-OCT
ADVANCED BIOMEDICAL AND CLINICAL DIAGNOSTIC SYSTEMS XI
2013; 8572
View details for DOI 10.1117/12.2003865
View details for Web of Science ID 000337082600009
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Single-shot interpixel shifting for optical coherence tomography by oblique incidence spectroscopy
OPTICAL COHERENCE TOMOGRAPHY AND COHERENCE DOMAIN OPTICAL METHODS IN BIOMEDICINE XVII
2013; 8571
View details for DOI 10.1117/12.2007197
View details for Web of Science ID 000322744300009
- Interleaved Optical Coherence Tomography Opt. Exp 2013; 22 (21): 26542-26556
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Variable-sized bar targets for characterizing three-dimensional resolution in OCT
BIOMEDICAL OPTICS EXPRESS
2012; 3 (9): 2317-2325
Abstract
Resolution is an important figure of merit for imaging systems. We designed, fabricated and tested an optical phantom that mimics the simplicity of an Air Force Test Chart but can characterize both the axial and lateral resolution of optical coherence tomography systems. The phantom is simple to fabricate, simple to use and functions in versatile environments.
View details for Web of Science ID 000308861100032
View details for PubMedID 23024923
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Design considerations for polarization-sensitive optical coherence tomography with a single input polarization state
BIOMEDICAL OPTICS EXPRESS
2012; 3 (9): 2273-2287
Abstract
Using a generalized design for a polarization-sensitive optical coherence tomography (PS-OCT) system with a single input polarization state (SIPS), we prove the existence of an infinitely large design space over which it is possible to develop simple PS-OCT systems that yield closed form expressions for birefringence. Through simulation and experiment, we validate this analysis by demonstrating new configurations for PS-OCT systems, and present guidelines for the general design of such systems in light of their inherent inaccuracies. After accounting for systemic errors, alternative designs exhibit similar performance on average to the traditional SIPS PS-OCT system. This analysis could be extended to systems with multiple input polarization states and could usher in a new generation of PS-OCT systems optimally designed to probe specific birefringent samples with high accuracy.
View details for Web of Science ID 000308861100028
View details for PubMedID 23024919
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The effects of reduced bit depth on optical coherence tomography phase data
OPTICS EXPRESS
2012; 20 (14): 15654-15668
Abstract
Past studies of the effects of bit depth on OCT magnitude data concluded that 8 bits of digitizer resolution provided nearly the same image quality as a 14-bit digitizer. However, such studies did not assess the effects of bit depth on the accuracy of phase data. In this work, we show that the effects of bit depth on phase data and magnitude data can differ significantly. This finding has an important impact on the design of phase-resolved OCT systems, such as those measuring motion and the birefringence of samples, particularly as one begins to consider the tradeoff between bit depth and digitizer speed.
View details for Web of Science ID 000306176100100
View details for PubMedID 22772258
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The Effects of Different Gold Standards on the Accuracy of Optical Coherence Tomography
IMAGING, MANIPULATION, AND ANALYSIS OF BIOMOLECULES, CELLS, AND TISSUES X
2012; 8225
View details for DOI 10.1117/12.909328
View details for Web of Science ID 000302555800015
- Measuring Performance of Different Compression Algorithms for Fourier Domain OCT Data 2012
- High-Resolution Spectrometer for Spectral-Domain Optical Coherence Tomography 2012
- Extend Imaging Depth in Spectral-domain Optical Coherence Tomography by Oblique Incidence 2012
- New Design Options for Polarization-Sensitive Optical Coherence Tomography 2012
- Extend Imaging Depth in Spectral-domain Optical Coherence Tomography by Oblique Incidence 2012
- Effects of Reduced Bit-Depth on Phase Data in Common-Path Optical Coherence Tomography 2012
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Analysis of the Effects of Different Resampling Techniques for Optical Coherence Tomography
THREE-DIMENSIONAL AND MULTIDIMENSIONAL MICROSCOPY: IMAGE ACQUISITION AND PROCESSING XIX
2012; 8227
View details for DOI 10.1117/12.909268
View details for Web of Science ID 000302561200018
- Considerations for Polarization-sensitive optical coherence tomography design 2012
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Sheathless hydrodynamic positioning of buoyant drops and bubbles inside microchannels
PHYSICAL REVIEW E
2011; 84 (3)
Abstract
Particles, bubbles, and drops carried by a fluid in a confined environment such as a pipe can be subjected to hydrodynamic lift forces, i.e., forces that are perpendicular to the direction of the flow. We investigated the positioning effect of lift forces acting on buoyant drops and bubbles suspended in a carrier fluid and flowing in a horizontal microchannel. We report experiments on drops of water in fluorocarbon liquid, and on bubbles of nitrogen in hydrocarbon liquid and silicone oil, inside microchannels with widths on the order of 0.1-1 mm. Despite their buoyancy, drops and bubbles could travel without contacting with the walls of channels; the most important parameters for reaching this flow regime in our experiments were the viscosity and the velocity of the carrier fluid, and the sizes of drops and bubbles. The dependencies of the transverse position of drops and bubbles on these parameters were investigated. At steady state, the trajectories of drops and bubbles approached the center of the channel for drops and bubbles almost as large as the channel, carried by rapidly flowing viscous liquids; among our experiments, these flow conditions were characterized by larger capillary numbers and smaller Reynolds numbers. Analytical models of lift forces developed for the flow of drops much smaller than the width of the channel failed to predict their transverse position, while computational fluid dynamic simulations of the experiments agreed better with the experimental measurements. The degrees of success of these predictions indicate the importance of confinement on generating strong hydrodynamic lift forces. We conclude that, inside microfluidic channels, it is possible to support and position buoyant drops and bubbles simply by flowing a single-stream (i.e., "sheathless") carrier liquid that has appropriate velocity and hydrodynamic properties.
View details for DOI 10.1103/PhysRevE.84.036302
View details for Web of Science ID 000294945500005
View details for PubMedID 22060487
- A Spectral Encoding-Based Approach to Real-time Volumetric Imaging with Optical Coherence Tomography 2011
- Towards Polarization-Sensitive OCT for Non-Invasive Blood Glucose Monitoring 2011
- Optical Coherence Tomography: Paradoxical Problem Solving 2011
- Optical Coherence Tomography: Advancing Technology, Impacting Disease 2011
- Using magnetic levitation for three-dimentional self assembly Adv. Mat. 2011; 36 (23): 4134-4140
- Templated three-dimensional self-assembly using magnetic levitation Soft Matter 2011; 19 (7): 9113-9118
- Bubbles navigating through networks of microchannels Lab Chip 2011; 23 (8): 3970-3978
- Towards Polarization-Sensitive OCT for Non-Invasive Blood Glucose Monitoring 2011
- Flows of Bubbles in Microfluidic Networks 2011
- Using magnetic levitation for meso-scale self-assembly 2010
- Quantifying colorimetric assays in paper-based microfluidic devices by measuring the transmission of light through paper 2009
- Programmable Self-Assembly of Complex Shapes in Three Dimensions 2009
- Infochemistry: Encoding information as optical pulses using droplets in a microfluidic device J. Am. Chem. Soc. 2009; 34 (131): 12420-12429
- Quantifying colorimetric assays in paper-based microfluidic devices by measuring the transmission of light through paper Anal. Chem. 2009; 20 (81): 8447-8452
- Extension of Spectral Domain Phase Microscopy to Three-Dimensional Nanoscale Displacement Mapping in Cardiomyocytes 2008
- Spectral domain phase microscopy for local measurements of cytoskeletal rheology in cells J. Biomed. Opt. 2007; 4 (12): 044008
- Investigating nanoscale cellular dynamics with cross-sectional spectral domain phase microscopy Opt. Exp. 2007; 13 (15): 8115-8124
- Phase retrieval in low-coherence interference microscopy Opt. Lett. 2007; 4 (32): 388-390
- Examining Cardiomyocyte Development with Spectral Domain Phase Microscopy 2007
- Full-field swept-source phase microscopy 2006
- High Speed Spectral Domain Phase Microscopy for Quantitative Cell Surface and Cytoplasmic Flow Measurements 2006
- High Speed Multidimensional Spectral Domain Phase Microscopy 2006
- Doppler flow imaging of cytoplasmic flow using spectral domain phase microscopy J. Biomed. Opt. 2006; 11: 024014
- Spectral-domain phase microscopy Opt. Lett. 2005; 30: 1162-1164
- Spectral domain phase microscopy: a new tool for measuring cellular dynamics and cytoplasmic flow 2005
- Characterizing Cellular Contractility and Cytoplasmic Flow Using Spectral Domain Phase Microscopy 2005
- Spectral domain phase microscopy: a new tool for investigating nanoscale and cellular dynamics 2005
- Spectral domain phase microscopy 2004
- Exploring heart cell dynamics using spectral domain phase microscopy 2004
- Spectral domain phase microscopy 2004
- Temperature and Fish Immunology: Assumptions, Truths, and New Data 1997