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Gilinsky SD, Jung DN, Futia GL, Zohrabi M, Welton TA, Supekar OD, Gibson EA, Restrepo D, Bright VM, Gopinath JT. Tunable liquid lens for three-photon excitation microscopy. BIOMEDICAL OPTICS EXPRESS 2024; 15:3285-3300. [PMID: 38855666 PMCID: PMC11161341 DOI: 10.1364/boe.516956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 03/28/2024] [Accepted: 04/06/2024] [Indexed: 06/11/2024]
Abstract
We demonstrate a novel electrowetting liquid combination using a room temperature ionic liquid (RTIL) and a nonpolar liquid, 1-phenyl-1-cyclohexene (PCH) suitable for focus-tunable 3-photon microscopy. We show that both liquids have over 90% transmission at 1300 nm over a 1.1 mm pathlength and an index of refraction contrast of 0.123. A lens using these liquids can be tuned from a contact angle of 133 to 48° with applied voltages of 0 and 60 V, respectively. Finally, a three-photon imaging system including an RTIL electrowetting lens was used to image a mouse brain slice. Axial scans taken with an electrowetting lens show excellent agreement with images acquired using a mechanically scanned objective.
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Affiliation(s)
- Samuel D. Gilinsky
- Department of Electrical, Computer, and Energy Engineering, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Diane N. Jung
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Greg L. Futia
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Mo Zohrabi
- Department of Electrical, Computer, and Energy Engineering, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Tarah A. Welton
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Omkar D. Supekar
- Department of Electrical, Computer, and Energy Engineering, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Emily A. Gibson
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Diego Restrepo
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Victor M. Bright
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Juliet T. Gopinath
- Department of Electrical, Computer, and Energy Engineering, University of Colorado Boulder, Boulder, Colorado 80309, USA
- Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309, USA
- Materials Science and Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, USA
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2
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Gilinsky SD, Zohrabi M, Lim WY, Supekar OD, Bright VM, Gopinath JT. Fabrication and characterization of a two-dimensional individually addressable electrowetting microlens array. OPTICS EXPRESS 2023; 31:30550-30561. [PMID: 37710595 PMCID: PMC10544957 DOI: 10.1364/oe.497992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 08/08/2023] [Accepted: 08/11/2023] [Indexed: 09/16/2023]
Abstract
We demonstrate a two-dimensional, individually tunable electrowetting microlens array fabricated using standard microfabrication techniques. Each lens in our array has a large range of focal tunability from -1.7 mm to -∞ in the diverging regime, which we verify experimentally from 0 to 75 V for a device coated in Parylene C. Additionally, each lens can be actuated to within 1% of their steady-state value within 1.5 ms. To justify the use of our device in a phase-sensitive optical system, we measure the wavefront of a beam passing through the center of a single lens in our device over the actuation range and show that these devices have a surface quality comparable to static microlens arrays. The large range of tunability, fast response time, and excellent surface quality of these devices open the door to potential applications in compact optical imaging systems, transmissive wavefront shaping, and beam steering.
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Affiliation(s)
- Samuel D. Gilinsky
- Department of Electrical, Computer and Energy Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Mo Zohrabi
- Department of Electrical, Computer and Energy Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Wei Yang Lim
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Omkar D. Supekar
- Department of Electrical, Computer and Energy Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Victor M. Bright
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Juliet T. Gopinath
- Department of Electrical, Computer and Energy Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
- Department of Physics, University of Colorado Boulder, Boulder, CO 80309, USA
- Materials Science and Engineering Program, University of Colorado Boulder, Boulder, CO 80309, USA
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3
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Duan Z, Wang L, Li Z, Fu J, Fu S, Chen B, Chen Y, Zhao Y. Dynamic performance of a membrane-based variable focus lens with a large aperture. APPLIED OPTICS 2023; 62:4609-4617. [PMID: 37707158 DOI: 10.1364/ao.486278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/26/2023] [Indexed: 09/15/2023]
Abstract
Dynamic performance is one of the most important characteristics of a variable focus lens. However, there are few studies investigating the dynamic response of a membrane-based variable focus lens. In this paper, we present a mathematical model to describe spring-damping phenomena in theory. The first order natural frequencies with different scales were confirmed via finite element analysis. We also built a dynamic response experiment platform with changeable optical apertures, which was driven by a high-speed piezo stack actuator. A photodiode module was placed behind the lens to measure the variation of light luminance as the lens changed, and a laser displacement sensor was used to measure the deformation of the membrane. A series of data was collected with different optical apertures (20 mm, 30 mm, 50 mm) and different pre-stretching ratios (200%, 300%) under different driving frequencies (from 5 Hz to 25 Hz in every 5 Hz step). The experimental results were consistent with the mathematical model, which showed that the first order natural frequency increased as the aperture decreased or the membrane stiffness increased. This frequency-dependent characteristic of the variable focus lens provides a basis for further research on its dynamic performance.
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4
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Miscles EJ, Lim WY, Supekar OD, Zohrabi M, Gopinath JT, Bright VM. Axisymmetrical resonance modes in an electrowetting optical lens. APPLIED PHYSICS LETTERS 2023; 122:201106. [PMID: 37214761 PMCID: PMC10195114 DOI: 10.1063/5.0141787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 04/29/2023] [Indexed: 05/24/2023]
Abstract
Electrowetting-based adaptive optics are of great interest for applications ranging from confocal microscopy to LIDAR, but the impact of low-frequency mechanical vibration on these devices remains to be studied. We present a simple theoretical model for predicting the resonance modes induced on the liquid interface in conjunction with a numerical simulation. We experimentally confirm the resonance frequencies by contact angle modulation. They are found to be in excellent agreement with the roots of the zero-order Bessel functions of the first kind. Next, we experimentally verify that external axial vibration of an electrowetting lens filled with density mismatched liquids (Δρ = 250 kg/m3) will exhibit observable Bessel modes on the liquid-liquid interface. An electrowetting lens filled with density matched liquids (Δρ = 4 kg/m3) is robust to external axial vibration and is shown to be useful in mitigating the effect of vibrations in an optical system.
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Affiliation(s)
- Eduardo J. Miscles
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | - Wei Yang Lim
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | | | - Mo Zohrabi
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | | | - Victor M. Bright
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA
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5
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Zohrabi M, Lim WY, Gilinsky S, Bright VM, Gopinath JT. Adaptive aberration correction using an electrowetting array. APPLIED PHYSICS LETTERS 2023; 122:081102. [PMID: 36846091 PMCID: PMC9946697 DOI: 10.1063/5.0133473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 02/04/2023] [Indexed: 05/10/2023]
Abstract
We demonstrate a method that permits wavefront aberration correction using an array of electrowetting prisms. A fixed high fill factor microlens array followed by a lower fill factor adaptive electrowetting prism array is used to correct wavefront aberration. The design and simulation of such aberration correction mechanism is described. Our results show significant improvement to the Strehl ratio by using our aberration correction scheme which results in diffraction limited performance. Compactness and effectiveness of our design can be implemented in many applications that require aberration correction, such as microscopy and consumer electronics.
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Affiliation(s)
- Mo Zohrabi
- Department of Electrical, Computer and Energy Engineering, University of Colorado, Boulder, Colorado 80309, USA
- Author to whom correspondence should be addressed:
| | - Wei Yang Lim
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | - Samuel Gilinsky
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | - Victor M. Bright
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA
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6
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Chen L, Liang S, Chen Z, Liang X, Chen Q. Electrically Tunable Lenses for Imaging and Light Manipulation. MICROMACHINES 2023; 14:319. [PMID: 36838021 PMCID: PMC9964308 DOI: 10.3390/mi14020319] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/18/2023] [Accepted: 01/21/2023] [Indexed: 06/18/2023]
Abstract
Optofluidics seamlessly combines optics and microfluidics together to construct novel devices for microsystems, providing flexible reconfigurability and high compatibility. By taking advantage of mature electronic fabrication techniques and flexible regulation of microfluidics, electrically actuated optofluidics has achieved fantastic optical functions. Generally, the optical function is achieved by electrically modulating the interfaces or movements of microdroplets inside a small chamber. The high refractive index difference (~0.5) at the interfaces between liquid/air or liquid/liquid makes unprecedented optical tunability a reality. They are suitable for optical imaging devices, such as microscope and portable electronic. This paper will review the working principle and recent development of electrical optofluidic devices by electrowetting and dielectrophoresis, including optical lens/microscope, beam steering and in-plane light manipulation. Some methods to improve the lens performance are reviewed. In addition, the applications of electrical microfluidics are also discussed. In order to stimulate the development of electrically controlled liquid lens, two novel designs derived from electrowetting and dielectrophoresis are introduced in this paper.
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Affiliation(s)
- Lijun Chen
- School of Microelectronics Science and Technology, Sun Yat-sen University, Zhuhai 519082, China
| | - Shijie Liang
- School of Microelectronics Science and Technology, Sun Yat-sen University, Zhuhai 519082, China
| | - Zhenshi Chen
- School of Electronic Information, Huzhou College, Huzhou 313000, China
| | - Xifa Liang
- School of Microelectronics Science and Technology, Sun Yat-sen University, Zhuhai 519082, China
| | - Qingming Chen
- School of Microelectronics Science and Technology, Sun Yat-sen University, Zhuhai 519082, China
- Guangdong Provincial Key Laboratory of Optoelectronic Information Processing Chips and Systems, Sun Yat-sen University, Guangzhou 511400, China
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7
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Flores Figueroa MA, Manchon B, Maillard M. Two-liquid wetting and phase electrowetting as a probe for surface chemistry of hydrophobic materials. Phys Chem Chem Phys 2022; 24:23323-23328. [PMID: 36165394 DOI: 10.1039/d2cp03288k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two-liquid contact angle measurement and electrowetting under low frequency are two measurement methods extremely sensitive to surface polarity and charge density. The theory underlying these two methods are described and have been applied to hydrophobic coatings. By combining these two methods, we successfully demonstrated the variations of the surface properties of polymer-based hydrophobic coatings when exposed to different chemical environments (pH modification or molecular grafting) with real-time phase electrowetting measurements.
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Affiliation(s)
- Manuel A Flores Figueroa
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Univ Lyon, Université Claude Bernard Lyon 1, F-69622 Villeurbanne, France.
| | - Benoît Manchon
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Univ Lyon, Université Claude Bernard Lyon 1, F-69622 Villeurbanne, France.
| | - Mathieu Maillard
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Univ Lyon, Université Claude Bernard Lyon 1, F-69622 Villeurbanne, France.
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8
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Lim WY, Zohrabi M, Zhu J, Soco TU, Carmon T, Gopinath JT, Bright VM. Spectrally tunable liquid resonator based on electrowetting. OPTICS EXPRESS 2022; 30:18949-18965. [PMID: 36221684 DOI: 10.1364/oe.455536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/22/2022] [Indexed: 06/16/2023]
Abstract
We present a tunable on-chip liquid resonator in conjunction with a tapered fiber coupling scheme. The resonator consists of a glycerol droplet submerged within an immiscible liquid bath, which mitigates the effects of environmental fluctuations. The platform is fabricated using standard semiconductor techniques, which enable the future integration of photonic components for an on-chip liquid resonator device. The liquid resonator maintains its high Q-factor on chip (105) due to surface tension forming an atomically smooth liquid-liquid interface. Higher Q-factor resonance modes experienced linewidth broadening due to the random excitation of thermal capillary vibrations. Spectral tuning is demonstrated using the electrowetting effect, increasing the surface's wettability and an expansion in the droplet diameter. A maximum spectral tuning of 1.44 nm ± 5 pm is observed by applying 35 V. The tuning range is twice the free spectral range (FSR) of 0.679 nm measured at a pumping wavelength range of 770-775 nm. A 2D axisymmetric finite-element simulation shows resonance modes in good agreement with experimentally measured spectra and with predicted tuning speeds of 20 nm/s.
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9
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Chen L, Ghilardi M, Busfield JJC, Carpi F. Electrically Tunable Lenses: A Review. Front Robot AI 2021; 8:678046. [PMID: 34179110 PMCID: PMC8220069 DOI: 10.3389/frobt.2021.678046] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/24/2021] [Indexed: 11/13/2022] Open
Abstract
Optical lenses with electrically controllable focal length are of growing interest, in order to reduce the complexity, size, weight, response time and power consumption of conventional focusing/zooming systems, based on glass lenses displaced by motors. They might become especially relevant for diverse robotic and machine vision-based devices, including cameras not only for portable consumer electronics (e.g. smart phones) and advanced optical instrumentation (e.g. microscopes, endoscopes, etc.), but also for emerging applications like small/micro-payload drones and wearable virtual/augmented-reality systems. This paper reviews the most widely studied strategies to obtain such varifocal “smart lenses”, which can electrically be tuned, either directly or via electro-mechanical or electro-thermal coupling. Only technologies that ensure controllable focusing of multi-chromatic light, with spatial continuity (i.e. continuous tunability) in wavefronts and focal lengths, as required for visible-range imaging, are considered. Both encapsulated fluid-based lenses and fully elastomeric lenses are reviewed, ranging from proof-of-concept prototypes to commercially available products. They are classified according to the focus-changing principles of operation, and they are described and compared in terms of advantages and drawbacks. This systematic overview should help to stimulate further developments in the field.
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Affiliation(s)
- Leihao Chen
- School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom.,Department of Industrial Engineering, University of Florence, Florence, Italy
| | - Michele Ghilardi
- School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - James J C Busfield
- School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - Federico Carpi
- Department of Industrial Engineering, University of Florence, Florence, Italy
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10
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Zhao P, Li Y, Zappe H. Accelerated electrowetting-based tunable fluidic lenses. OPTICS EXPRESS 2021; 29:15733-15746. [PMID: 33985269 DOI: 10.1364/oe.423460] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 04/02/2021] [Indexed: 06/12/2023]
Abstract
One of the limitations in the application of electrowetting-based tunable fluidic lenses is their slow response time. We consider here two approaches for enhancing the response speed of tunable fluidic lenses: optimization of the properties of the fluids employed and modification of the time-dependent actuation voltages. Using a tubular optofluidic configuration, it is shown through simulations how one may take advantage of the interplay between liquid viscosities and surface tension to reduce the actuation time. In addition, by careful designing the actuation pulses, the response speed of both overdamped and underdamped systems may be increased by over an order of magnitude, leading to response times of several ten milliseconds. These performance improvements may significantly enhance the applicability of tunable optofluidic-based components and systems.
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11
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Onaka J, Iwase T, Fukui M, Koyama D, Matsukawa M. Ultrasound liquid crystal lens with enlarged aperture using traveling waves. OPTICS LETTERS 2021; 46:1169-1172. [PMID: 33649684 DOI: 10.1364/ol.414295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 02/01/2021] [Indexed: 06/12/2023]
Abstract
A new type of ultrasonically controlled concave liquid crystal lens based on traveling waves (TWs) with a divided electrode structure and an appropriate driving scheme is proposed in this Letter. The lens uses an annular piezoelectric ceramic divided into four parts for four-phase driving and consists of a liquid crystal layer in a sandwich structure between two circular glass substrates. The lens configuration was simulated by finite element analysis using the Ansys software. Here we discuss the use of TWs to expand the lens aperture and clarify the lens' optical characteristics using a Shack-Hartmann wavefront sensor. The effective lens aperture using TWs was 4.4 mm, and the focal length was 3.8 m.
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12
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Ivanova N. Biomimetic optics: liquid-based optical elements imitating the eye functionality. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190442. [PMID: 32008449 PMCID: PMC7015283 DOI: 10.1098/rsta.2019.0442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/22/2019] [Indexed: 06/10/2023]
Abstract
The optical systems mimicking the eye functions are of great importance in various applications including consumer electronics, medical equipment, machine vision systems and robotics. This optics offers advantages over traditional optical technologies such as the superior adaptation to changing conditions and the comprehensive range of functional characteristics at miniature sizes. This paper presents a review on the recent progress in the development of human eye-inspired optical systems. Liquid-based and elastomer-based tunable optical elements are discussed with the focus on the actuation mechanism, optical performance and the possibility of integration into artificial eye systems. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 3)'.
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Yi Z, Huang Z, Lai S, He W, Wang L, Chi F, Zhang C, Shui L, Zhou G. Driving Waveform Design of Electrowetting Displays Based on an Exponential Function for a Stable Grayscale and a Short Driving Time. MICROMACHINES 2020; 11:mi11030313. [PMID: 32188157 PMCID: PMC7142935 DOI: 10.3390/mi11030313] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 03/09/2020] [Accepted: 03/12/2020] [Indexed: 11/29/2022]
Abstract
The traditional driving waveform of the electrowetting display (EWD) has many disadvantages, such as the large oscillation of the target grayscale aperture ratio and a long time for achieving grayscale. Therefore, a driving waveform based on the exponential function was proposed in this study. First, the maximum driving voltage value of 30 V was obtained by testing the hysteresis curve of the EWD pixel unit. Secondly, the influence of the time constant on the driving waveform was analyzed, and the optimal time constant of the exponential function was designed by testing the performance of the aperture ratio. Lastly, an EWD panel was used to test the driving effect of the exponential-function-driving waveform. The experimental results showed that a stable grayscale and a short driving time could be realized when the appropriate time constant value was designed for driving EWDs. The aperture ratio oscillation range of the gray scale could be reduced within 0.95%, and the driving time of a stable grayscale was reduced by 30% compared with the traditional driving waveform.
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Affiliation(s)
- Zichuan Yi
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (Z.Y.); (F.C.); (C.Z.); (L.S.)
| | - Zhenyu Huang
- Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (W.H.); (L.W.); (G.Z.)
- Shenzhen Guohua Optoelectronics Tech. Co., Ltd., Shenzhen 518110, China;
- Correspondence: ; Tel.: +86-0755-2941-5855
| | - Shufa Lai
- Shenzhen Guohua Optoelectronics Tech. Co., Ltd., Shenzhen 518110, China;
| | - Wenyao He
- Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (W.H.); (L.W.); (G.Z.)
| | - Li Wang
- Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (W.H.); (L.W.); (G.Z.)
- Shenzhen Guohua Optoelectronics Tech. Co., Ltd., Shenzhen 518110, China;
| | - Feng Chi
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (Z.Y.); (F.C.); (C.Z.); (L.S.)
| | - Chongfu Zhang
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (Z.Y.); (F.C.); (C.Z.); (L.S.)
| | - Lingling Shui
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (Z.Y.); (F.C.); (C.Z.); (L.S.)
- Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (W.H.); (L.W.); (G.Z.)
| | - Guofu Zhou
- Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (W.H.); (L.W.); (G.Z.)
- Shenzhen Guohua Optoelectronics Tech. Co., Ltd., Shenzhen 518110, China;
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14
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Zohrabi M, Yang Lim W, Bright VM, Gopinath JT. High extinction ratio, low insertion loss, optical switch based on an electrowetting prism. OPTICS EXPRESS 2020; 28:5991-6001. [PMID: 32225857 PMCID: PMC7347523 DOI: 10.1364/oe.381565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
An optical switch based on an electrowetting prism coupled to a multimode fiber has demonstrated a large extinction ratio with speeds up to 300 Hz. Electrowetting prisms provide a transmissive, low power, and compact alternative to conventional free-space optical switches, with no moving parts. The electrowetting prism performs beam steering of ±3° with an extinction ratio of 47 dB between the ON and OFF states and has been experimentally demonstrated at scanning frequencies of 100-300 Hz. The optical design is modeled in Zemax to account for secondary rays created at each surface interface (without scattering). Simulations predict 50 dB of extinction, in good agreement with experiment.
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Affiliation(s)
- Mo Zohrabi
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | - Wei Yang Lim
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | - Victor M. Bright
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | - Juliet T. Gopinath
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
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15
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Liu C, Wang D, Wang QH. Holographic display system with adjustable viewing angle based on multi-focus optofluidic lens. OPTICS EXPRESS 2019; 27:18210-18221. [PMID: 31252768 DOI: 10.1364/oe.27.018210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 05/29/2019] [Indexed: 06/09/2023]
Abstract
In this paper, a holographic display system with adjustable viewing angle is proposed. The system consists of a collimated beam, a spatial light modulator (SLM), a multi-focus optofluidic (MFO) lens and an aperture. The MFO lens with high focal power is produced and it consists of two substrates, one multilayer substrate and two chambers. When the liquids are pulled in/out from the channels, the curvature of the liquid-liquid interface changes due to the surface tension and adsorption between the liquids and the multilayer substrate. The relationship between the parameters of the MFO lens and the holographic display viewing angle is revealed for the first time. Based on the theoretical analysis, the mechanisms of the high focal power and mechanical stability of the proposed MFO lens are also clarified. The experiments show that the focal power of the proposed MFO lens can be varied from -20 D (m-1) to 4 D (m-1), respectively. By using the MFO lens, the viewing angle of the holographic display system can be adjusted without moving any components mechanically. Meanwhile the setup of the system is greatly simplified. The experimental results verify the feasibility of the system, and it is expected to bring new ideas to the holographic display with large viewing angle.
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16
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Ruiz-Gutiérrez É, Ledesma-Aguilar R. Lattice-Boltzmann Simulations of Electrowetting Phenomena. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:4849-4859. [PMID: 30869524 DOI: 10.1021/acs.langmuir.9b00098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
When a voltage difference is applied between a conducting liquid and a conducting (solid) electrode, the liquid is observed to spread on the solid. This phenomenon, generally referred to as electrowetting, underpins a number of interfacial phenomena of interest in applications that range from droplet microfluidics to optics. Here, we present a lattice-Boltzmann method that can simulate the coupled hydrodynamics and electrostatics equations of motion of a two-phase fluid as a means to model the electrowetting phenomena. Our method has the advantage of modeling the electrostatic fields within the lattice-Boltzmann algorithm itself, eliminating the need for a hybrid method. We validate our method by reproducing the static equilibrium configuration of a droplet subject to an applied voltage and show that the apparent contact angle of the drop depends on the voltage following the Young-Lippmann equation up to contact angles of ≈50°. At higher voltages, we observe a saturation of the contact angle caused by the competition between electric and capillary stresses, similar to previous experimental observations. We also study the stability of a dielectric film trapped between a conducting fluid and a solid electrode and find a good agreement with analytical predictions based on lubrication theory. Finally, we investigate the film dynamics at long times and report observations of film breakup and entrapment similar to previously reported experimental results.
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Affiliation(s)
- Élfego Ruiz-Gutiérrez
- Smart Materials and Surfaces Laboratory , Northumbria University , Ellison Building, Ellison Place , Newcastle upon Tyne NE1 8ST , U.K
| | - Rodrigo Ledesma-Aguilar
- Smart Materials and Surfaces Laboratory , Northumbria University , Ellison Building, Ellison Place , Newcastle upon Tyne NE1 8ST , U.K
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17
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Zohrabi M, Lim WY, Cormack RH, Supekar OD, Bright VM, Gopinath JT. Lidar system with nonmechanical electrowetting-based wide-angle beam steering. OPTICS EXPRESS 2019; 27:4404-4415. [PMID: 30876059 PMCID: PMC6410924 DOI: 10.1364/oe.27.004404] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 01/07/2019] [Accepted: 01/07/2019] [Indexed: 05/27/2023]
Abstract
A light detection and ranging (lidar) system with ±90° of steering based on an adaptive electrowetting-based prism for nonmechanical beam steering has been demonstrated. Electrowetting-based prisms provide a transmissive, low power, and compact alternative to conventional adaptive optics as a nonmechanical beam scanner. The electrowetting prism has a steering range of ±7.8°. We demonstrate a method to amplify the scan angle to ±90° and perform a one-dimensional scan in a lidar system.
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Affiliation(s)
- Mo Zohrabi
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309,
USA
| | - Wei Yang Lim
- Department of Mechanical Engineering, University of Colorado Boulder, Colorado 80309,
USA
| | - Robert H. Cormack
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309,
USA
| | - Omkar D. Supekar
- Department of Mechanical Engineering, University of Colorado Boulder, Colorado 80309,
USA
| | - Victor M. Bright
- Department of Mechanical Engineering, University of Colorado Boulder, Colorado 80309,
USA
| | - Juliet T. Gopinath
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309,
USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309,
USA
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18
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Lim WY, Supekar OD, Zohrabi M, Gopinath JT, Bright VM. Liquid Combination with High Refractive Index Contrast and Fast Scanning Speeds for Electrowetting Adaptive Optics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:14511-14518. [PMID: 30411903 DOI: 10.1021/acs.langmuir.8b02849] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Electrowetting adaptive optical devices are versatile, with applications ranging from microscopy to remote sensing. The choice of liquids in these devices governs its tuning range, temporal response, and wavelength of operation. We characterized a liquid system, consisting of 1-phenyl-1-cyclohexene and deionized water, using both lens and prism devices. The liquids have a large contact angle tuning range, from 173 to 60°. Measured maximum scanning angle was realized at ±13.7° in a two-electrode prism, with simulation predictions of ±18.2°. The liquid's switching time to reach 90° contact angle from rest, in a 4 mm diameter device, was measured at 100 ms. Steady-state scanning with a two-electrode prism showed linear and consistent scan angles of ±4.8° for a 20 V differential between the two electrodes, whereas beam scanning using the liquid system achieved ±1.74° at 500 Hz for a voltage differential of 80 V.
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19
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Dong B, Tang B, Groenewold J, Li H, Zhou R, Henzen AV, Zhou G. Failure modes analysis of electrofluidic display under thermal ageing. ROYAL SOCIETY OPEN SCIENCE 2018; 5:181121. [PMID: 30564404 PMCID: PMC6281906 DOI: 10.1098/rsos.181121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/30/2018] [Indexed: 06/09/2023]
Abstract
Dielectric failure as well as optical switching failure in electrofluidic display (EFD) are still a bottleneck for sufficient device lifetime. In this study, a dielectric redundancy-designed multilayer insulator of ParyleneC/AF1600X was applied in an EFD device. The reliability performance was systematically studied by tracking the applied voltage-dependent leakage current and capacitance changes (I-V and C-V curves) with thermal ageing time. The multilayer insulator shows a more stable performance in leakage current compared to a single-layer insulator. The failure modes during operation underlying the single-layer and the multilayer dielectric appear to be different as exemplified by microscopic images. The single-layer AFX shows significant detachment. In addition, by quantitatively analysing the C-V curves with ageing time, we find that for the single AFX device, the dominant failure mode is 'no-opening' of the pixels. For the multilayer device, the dominant failure mode is 'no-closing' of the pixels. This study provides tools for distinguishing the basic failure modes of an EFD device and demonstrates a quantitative method for evaluating the reliability performance of the device under thermal ageing.
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Affiliation(s)
- Baoqin Dong
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology and Institute of Electronic Paper Displays, SouthChinaAcademy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
| | - Biao Tang
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology and Institute of Electronic Paper Displays, SouthChinaAcademy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
| | - Jan Groenewold
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology and Institute of Electronic Paper Displays, SouthChinaAcademy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
- Van ‘t Hoff Laboratory for Physical and Colloid Chemistry, Debye Research Institute, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Hui Li
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology and Institute of Electronic Paper Displays, SouthChinaAcademy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
| | - Rui Zhou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology and Institute of Electronic Paper Displays, SouthChinaAcademy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
| | - Alexander Victor Henzen
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology and Institute of Electronic Paper Displays, SouthChinaAcademy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
| | - Guofu Zhou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology and Institute of Electronic Paper Displays, SouthChinaAcademy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
- Shenzhen Guohua Optoelectronics Tech. Co. Ltd, Shenzhen 518110, People's Republic of China
- Academy of Shenzhen Guohua Optoelectronics, Shenzhen 518110, People's Republic of China
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20
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Three dimensional two-photon brain imaging in freely moving mice using a miniature fiber coupled microscope with active axial-scanning. Sci Rep 2018; 8:8108. [PMID: 29802371 PMCID: PMC5970169 DOI: 10.1038/s41598-018-26326-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 05/09/2018] [Indexed: 02/06/2023] Open
Abstract
We present a miniature head mounted two-photon fiber-coupled microscope (2P-FCM) for neuronal imaging with active axial focusing enabled using a miniature electrowetting lens. We show three-dimensional two-photon imaging of neuronal structure and record neuronal activity from GCaMP6s fluorescence from multiple focal planes in a freely-moving mouse. Two-color simultaneous imaging of GFP and tdTomato fluorescence is also demonstrated. Additionally, dynamic control of the axial scanning of the electrowetting lens allows tilting of the focal plane enabling neurons in multiple depths to be imaged in a single plane. Two-photon imaging allows increased penetration depth in tissue yielding a working distance of 450 μm with an additional 180 μm of active axial focusing. The objective NA is 0.45 with a lateral resolution of 1.8 μm, an axial resolution of 10 μm, and a field-of-view of 240 μm diameter. The 2P-FCM has a weight of only ~2.5 g and is capable of repeatable and stable head-attachment. The 2P-FCM with dynamic axial scanning provides a new capability to record from functionally distinct neuronal layers, opening new opportunities in neuroscience research.
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21
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Zohrabi M, Cormack RH, Mccullough C, Supekar OD, Gibson EA, Bright VM, Gopinath JT. Numerical analysis of wavefront aberration correction using multielectrode electrowetting-based devices. OPTICS EXPRESS 2017; 25:31451-31461. [PMID: 29245820 PMCID: PMC5941994 DOI: 10.1364/oe.25.031451] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 11/15/2017] [Accepted: 11/16/2017] [Indexed: 05/25/2023]
Abstract
We present numerical simulations of multielectrode electrowetting devices used in a novel optical design to correct wavefront aberration. Our optical system consists of two multielectrode devices, preceded by a single fixed lens. The multielectrode elements function as adaptive optical devices that can be used to correct aberrations inherent in many imaging setups, biological samples, and the atmosphere. We are able to accurately simulate the liquid-liquid interface shape using computational fluid dynamics. Ray tracing analysis of these surfaces shows clear evidence of aberration correction. To demonstrate the strength of our design, we studied three different input aberrations mixtures that include astigmatism, coma, trefoil, and additional higher order aberration terms, with amplitudes as large as one wave at 633 nm.
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Affiliation(s)
- Mo Zohrabi
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, CO 80309,
USA
| | - Robert H. Cormack
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, CO 80309,
USA
| | - Connor Mccullough
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO 80045,
USA
| | - Omkar D. Supekar
- Department of Mechanical Engineering, University of Colorado Boulder, CO 80309,
USA
| | - Emily A. Gibson
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO 80045,
USA
| | - Victor M. Bright
- Department of Mechanical Engineering, University of Colorado Boulder, CO 80309,
USA
| | - Juliet T. Gopinath
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, CO 80309,
USA
- Department of Physics, University of Colorado, Boulder, CO 80309,
USA
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22
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Supekar OD, Ozbay BN, Zohrabi M, Nystrom PD, Futia GL, Restrepo D, Gibson EA, Gopinath JT, Bright VM. Two-photon laser scanning microscopy with electrowetting-based prism scanning. BIOMEDICAL OPTICS EXPRESS 2017; 8:5412-5426. [PMID: 29296477 PMCID: PMC5745092 DOI: 10.1364/boe.8.005412] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 10/31/2017] [Accepted: 11/02/2017] [Indexed: 05/24/2023]
Abstract
Laser scanners are an integral part of high resolution biomedical imaging systems such as confocal or 2-photon excitation (2PE) microscopes. In this work, we demonstrate the utility of electrowetting on dielectric (EWOD) prisms as a lateral laser-scanning element integrated in a conventional 2PE microscope. To the best of our knowledge, this is the first such demonstration for EWOD prisms. EWOD devices provide a transmissive, low power consuming, and compact alternative to conventional adaptive optics, and hence this technology has tremendous potential. We demonstrate 2PE microscope imaging of cultured mouse hippocampal neurons with a FOV of 130 × 130 μm2 using EWOD prism scanning. In addition, we show simulations of the optical system with the EWOD prism, to evaluate the effect of propagating a Gaussian beam through the EWOD prism on the imaging quality. Based on the simulation results a beam size of 0.91 mm full width half max was chosen to conduct the imaging experiments, resulting in a numerical aperture of 0.17 of the imaging system.
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Affiliation(s)
- Omkar D. Supekar
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309, USA
| | - Baris N. Ozbay
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Mo Zohrabi
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, CO, 80309, USA
| | - Philip D. Nystrom
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309, USA
| | - Gregory L. Futia
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Diego Restrepo
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Emily A. Gibson
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Juliet T. Gopinath
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, CO, 80309, USA
- Department of Physics, University of Colorado, Boulder, CO 80309-0390, USA
| | - Victor M. Bright
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309, USA
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