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11 pages, 3003 KiB

Open AccessCommunication

Deep Learning Enables Optofluidic Zoom System with Large Zoom Ratio and High Imaging Resolution

by Jiancheng Xu, Fenglin Kuang, Shubin Liu and Lei Li

Sensors 2023, 23(6), 3204; https://doi.org/10.3390/s23063204 - 17 Mar 2023

Cited by 5 | Viewed by 2360

Due to the relatively low optical power of a liquid lens, it is usually difficult to achieve a large zoom ratio and a high-resolution image simultaneously in an optofluidic zoom imaging system. We propose an electronically controlled optofluidic zoom imaging system combined with [...] Read more.

Due to the relatively low optical power of a liquid lens, it is usually difficult to achieve a large zoom ratio and a high-resolution image simultaneously in an optofluidic zoom imaging system. We propose an electronically controlled optofluidic zoom imaging system combined with deep learning, which achieves a large continuous zoom change and a high-resolution image. The zoom system consists of an optofluidic zoom objective and an image-processing module. The proposed zoom system can achieve a large tunable focal length range from 4.0 mm to 31.3 mm. In the focal length range of 9.4 mm to 18.8 mm, the system can dynamically correct the aberrations by six electrowetting liquid lenses to ensure the image quality. In the focal length range of 4.0–9.4 mm and 18.8–31.3 mm, the optical power of a liquid lens is mainly used to enlarge the zoom ratio, and deep learning enables the proposed zoom system with improved image quality. The zoom ratio of the system reaches 7.8×, and the maximum field of view of the system can reach ~29°. The proposed zoom system has potential applications in camera, telescope and so on. Full article

(This article belongs to the Special Issue Recent Advances in Optical Imaging and 3D Display Technologies)

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19 pages, 9461 KiB

Open AccessReview

Electrically Tunable Lenses for Imaging and Light Manipulation

by Lijun Chen, Shijie Liang, Zhenshi Chen, Xifa Liang and Qingming Chen

Micromachines 2023, 14(2), 319; https://doi.org/10.3390/mi14020319 - 26 Jan 2023

Cited by 8 | Viewed by 3475

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Micro/Nano-Structure Based Optoelectronics and Photonics Devices)

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14 pages, 5752 KiB

Open AccessArticle

Design and Fabrication of a Tunable Optofluidic Microlens Driven by an Encircled Thermo-Pneumatic Actuator

by Wei Zhang, Heng Li, Yongchao Zou, Pengpeng Zhao and Zeren Li

Micromachines 2022, 13(8), 1189; https://doi.org/10.3390/mi13081189 - 28 Jul 2022

Cited by 5 | Viewed by 2463

Abstract

This paper presents the design, simulation, fabrication, assembly, and testing of a miniature thermo-pneumatic optofluidic lens. The device comprises two separate zones for air heating and fluid pressing on a flexible membrane. A buried three-dimensional spiral microchannel connects the two zones without pumps [...] Read more.

This paper presents the design, simulation, fabrication, assembly, and testing of a miniature thermo-pneumatic optofluidic lens. The device comprises two separate zones for air heating and fluid pressing on a flexible membrane. A buried three-dimensional spiral microchannel connects the two zones without pumps or valves. The three-dimensional microfluidic structure is realized using a high-resolution three-dimensional printing technique. Multi-physics finite element simulations are introduced to assess the optimized air chamber design and the low-temperature gradient of the optical liquid. The tunable lens can be operated using a direct-current power supply. The temperature change with time is measured using an infrared thermal imager. The focal length ranges from 5 to 23 mm under a maximum voltage of 6 V. Because of the small size and robust actuation scheme, the device can potentially be integrated into miniature micro-optics devices for the fine-tuning of focal lengths. Full article

(This article belongs to the Special Issue Optical Sensing and Devices)

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22 pages, 7201 KiB

Open AccessReview

Microscopic Imaging Methods for Organ-on-a-Chip Platforms

by Bailey C. Buchanan and Jeong-Yeol Yoon

Micromachines 2022, 13(2), 328; https://doi.org/10.3390/mi13020328 - 19 Feb 2022

Cited by 26 | Viewed by 5371

Abstract

Microscopic imaging is essential and the most popular method for in situ monitoring and evaluating the outcome of various organ-on-a-chip (OOC) platforms, including the number and morphology of mammalian cells, gene expression, protein secretions, etc. This review presents an overview of how various [...] Read more.

Microscopic imaging is essential and the most popular method for in situ monitoring and evaluating the outcome of various organ-on-a-chip (OOC) platforms, including the number and morphology of mammalian cells, gene expression, protein secretions, etc. This review presents an overview of how various imaging methods can be used to image organ-on-a-chip platforms, including transillumination imaging (including brightfield, phase-contrast, and holographic optofluidic imaging), fluorescence imaging (including confocal fluorescence and light-sheet fluorescence imaging), and smartphone-based imaging (including microscope attachment-based, quantitative phase, and lens-free imaging). While various microscopic imaging methods have been demonstrated for conventional microfluidic devices, a relatively small number of microscopic imaging methods have been demonstrated for OOC platforms. Some methods have rarely been used to image OOCs. Specific requirements for imaging OOCs will be discussed in comparison to the conventional microfluidic devices and future directions will be introduced in this review. Full article

(This article belongs to the Special Issue Microfluidic Tools for Advancing Cancer Research)

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13 pages, 5609 KiB

Open AccessFeature PaperArticle

Lorentz Force Actuated Tunable-Focus Liquid Lens

by Kari L. Van Grinsven, Alireza Ousati Ashtiani and Hongrui Jiang

Micromachines 2019, 10(10), 714; https://doi.org/10.3390/mi10100714 - 22 Oct 2019

Cited by 4 | Viewed by 4262

Abstract

Tunable-focus liquid lenses provide focal length tuning for optical systems, e.g., cameras, where physical movement of rigid lenses are not an option or not preferable. In this work we present a magnetically actuated liquid lens utilizing the Lorentz force to vary the focal [...] Read more.

Tunable-focus liquid lenses provide focal length tuning for optical systems, e.g., cameras, where physical movement of rigid lenses are not an option or not preferable. In this work we present a magnetically actuated liquid lens utilizing the Lorentz force to vary the focal length as the current through the system is varied. The resulting lens can operate as both a diverging and a converging lens depending on the direction of current applied and has a large range of focal lengths, from −305 mm to –111 mm and from 272 mm to 146 mm. We also characterized the aberrations of the lens during the actuation with a Shack–Hartmann wavefront sensor, and utilized the lens for imaging, during which we measured a resolution of 7.13 lp/mm. Full article

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16 pages, 3138 KiB

Open AccessReview

Optofluidic Tunable Lenses for In-Plane Light Manipulation

by Qingming Chen, Tenghao Li, Zhaohui Li, Jinlin Long and Xuming Zhang

Micromachines 2018, 9(3), 97; https://doi.org/10.3390/mi9030097 - 26 Feb 2018

Cited by 25 | Viewed by 6901

Abstract

Optofluidics incorporates optics and microfluidics together to construct novel devices for microsystems, providing flexible reconfigurability and high compatibility. Among many novel devices, a prominent one is the in-plane optofluidic lens. It manipulates the light in the plane of the substrate, upon which the [...] Read more.

Optofluidics incorporates optics and microfluidics together to construct novel devices for microsystems, providing flexible reconfigurability and high compatibility. Among many novel devices, a prominent one is the in-plane optofluidic lens. It manipulates the light in the plane of the substrate, upon which the liquid sample is held. Benefiting from the compatibility, the in-plane optofluidic lenses can be incorporated into a single chip without complicated manual alignment and promises high integration density. In term of the tunability, the in-plane liquid lenses can be either tuned by adjusting the fluidic interface using numerous microfluidic techniques, or by modulating the refractive index of the liquid using temperature, electric field and concentration. In this paper, the in-plane liquid lenses will be reviewed in the aspects of operation mechanisms and recent development. In addition, their applications in lab-on-a-chip systems are also discussed. Full article

(This article belongs to the Special Issue Advances in Optofluidics)

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24 pages, 3367 KiB

Open AccessFeature PaperReview

Recent Developments in Optofluidic Lens Technology

by Kartikeya Mishra, Dirk Van den Ende and Frieder Mugele

Micromachines 2016, 7(6), 102; https://doi.org/10.3390/mi7060102 - 10 Jun 2016

Cited by 72 | Viewed by 17254

Abstract

Optofluidics is a rapidly growing versatile branch of adaptive optics including a wide variety of applications such as tunable beam shaping tools, mirrors, apertures, and lenses. In this review, we focus on recent developments in optofluidic lenses, which arguably forms the most important [...] Read more.

Optofluidics is a rapidly growing versatile branch of adaptive optics including a wide variety of applications such as tunable beam shaping tools, mirrors, apertures, and lenses. In this review, we focus on recent developments in optofluidic lenses, which arguably forms the most important part of optofluidics devices. We report first on a number of general characteristics and characterization methods for optofluidics lenses and their optical performance, including aberrations and their description in terms of Zernike polynomials. Subsequently, we discuss examples of actuation methods separately for spherical optofluidic lenses and for more recent tunable aspherical lenses. Advantages and disadvantages of various actuation schemes are presented, focusing in particular on electrowetting-driven lenses and pressure-driven liquid lenses that are covered by elastomeric sheets. We discuss in particular the opportunities for detailed aberration control by using either finely controlled electric fields or specifically designed elastomeric lenses. Full article

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15 pages, 11155 KiB

Open AccessArticle

An Optofluidic Lens Array Microchip for High Resolution Stereo Microscopy

by Mayurachat Ning Gulari, Anurag Tripathi, Mostafa Ghannad-Rezaie and Nikos Chronis

Micromachines 2014, 5(3), 607-621; https://doi.org/10.3390/mi5030607 - 28 Aug 2014

Cited by 10 | Viewed by 11375

Abstract

We report the development of an add-on, chip-based, optical module—termed the Microfluidic-based Oil-immersion Lenses (μOIL) chip—which transforms any stereo microscope into a high-resolution, large field of view imaging platform. The μOIL chip consists of an array of ball mini-lenses that are assembled onto [...] Read more.

We report the development of an add-on, chip-based, optical module—termed the Microfluidic-based Oil-immersion Lenses (μOIL) chip—which transforms any stereo microscope into a high-resolution, large field of view imaging platform. The μOIL chip consists of an array of ball mini-lenses that are assembled onto a microfluidic silicon chip. The mini-lenses are made out of high refractive index material (sapphire) and they are half immersed in oil. Those two key features enable submicron resolution and a maximum numerical aperture of ~1.2. The μOIL chip is reusable and easy to operate as it can be placed directly on top of any biological sample. It improves the resolution of a stereo microscope by an order of magnitude without compromising the field of view; therefore, we believe it could become a versatile tool for use in various research studies and clinical applications. Full article

(This article belongs to the Special Issue Microlenses)

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