Article
Optics
Yayan Huang, Rui Zhao, Wenhao Miao, Dan Liang, Zhiqiang Liu, Xian Wei, Zhongcheng Liang
Summary: This paper proposes a tunable zoom bifocal liquid lens based on selective wettability. The lens consists of immiscible internal and external droplets that can change their curvatures by applying different voltages, resulting in continuous movement of the long and short focal points. Experimental results demonstrate the feasibility and practicability of this concept.
Article
Optics
Jingyu Mo, Xuefeng Chang, Duoji Renqing, Jinpeng Zhang, Longxing Liao, Shanming Luo
Summary: This study presents a novel type of concave lens array on an aspheric convex substrate (CLAACs) composed of an aspheric substrate and a spherical concave subeye array. A method for designing, fabricating, and characterizing the CLAACs is proposed. The results demonstrate the feasibility and effectiveness of this method for designing and fabricating lens arrays with complex discontinuous surfaces.
Article
Materials Science, Multidisciplinary
Vinay Kumar, Fabrizio Gota, Julien Neyret, Ngei Katumo, Aditya Chauhan, Stephan Dottermusch, Bryce S. Richards, Ian A. Howard
Summary: A phosphor-particle-loaded microlens array on a polymer substrate provides an unclonable anticounterfeiting label design. The random coincidences of light focused by a microlens with a phosphor microparticle create a random pattern of bright emission points. The authentication of these labels using a single smartphone is possible through the smartphone flashlight and camera, with >99% confidence in matching test and reference images and a 1 cm tolerance for smartphone positioning accuracy.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Optics
Souptik Mukherjee, Zheng-Nan Yuan, Zhi-Bo Sun, An-Ran Li, Chen-Bing Kang, Hoi-Sing Kwok, Abhishek K. Srivastava
Summary: The article introduces a switchable lens device combining a fast FLC-based polarization rotation unit and a passive LC lens, allowing rapid access to multiple focal points, making it a convenient device for VR applications.
Article
Materials Science, Multidisciplinary
Yueqi Zhai, Jiaqi Niu, Jingquan Liu, Bin Yang
Summary: A large-scale artificial compound eye with a wide field of view and high sensitivity was fabricated using a low-cost strategy. The collaboration of the compound eye and CMOS sensor enables capturing multiple images of human organs. This micro-based imaging system has significant potential in medical applications and drone navigation.
OPTICAL MATERIALS EXPRESS
(2021)
Article
Optics
Yang Shu, Wenchen Zhou, Zhixiong Zhou, Allen Y. Yi
Summary: In this study, a rapid non-isothermal imprinting process for Fresnel lens arrays was proposed, which can be carried out at room temperature to greatly reduce thermal cycle time and energy consumption. The process allows for production of high-quality microlenses with a high precision surface finish.
Article
Physics, Applied
Mo Zohrabi, Wei Yang Lim, Samuel Gilinsky, Victor M. Bright, Juliet T. Gopinath
Summary: We present a method using an array of electrowetting prisms for wavefront aberration correction. The combination of a fixed high fill factor microlens array and an adaptive electrowetting prism array with lower fill factor is utilized in correcting wavefront aberration. The design and simulation of this aberration correction mechanism are described. Our results demonstrate a significant improvement in the Strehl ratio, leading to diffraction limited performance. The compact and effective design of our approach could be implemented in various applications requiring aberration correction, including microscopy and consumer electronics.
APPLIED PHYSICS LETTERS
(2023)
Article
Optics
Hanheng Du, Waisze Yip, Zhiwei Zhu, Sandy To
Summary: A novel two-degree-of-freedom vibration generator (2DOF-VG) is designed for generating optical microstructure arrays, and a detailed multi-physics finite element method is proposed to simulate its working performance accurately. The numerical simulation algorithm successfully predicts the surface topography of microstructure arrays, and two unique microstructure arrays are fabricated, demonstrating the feasibility and flexibility of the 2DOF-VG.
Article
Chemistry, Multidisciplinary
Jose Carlos Mejia, Miho Aizawa, Kyohei Hisano, Kohsuke Matsumoto, Sayuri Hashimoto, Shoichi Kubo, Atsushi Shishido
Summary: This study proposes a novel approach for fabricating a microlens array with a tunable surface topographical structure and focal length. The microlens array is manufactured through the photoinduced molecular reorientation of nematic liquid crystals (LCs) stabilized by a polymer network. The fabricated microlens array has a specific mountain-shaped topographical structure due to the accumulation of polymers and LC molecules. The surface topographical structure and the focal length of the microlens array can be reversibly tuned under heat treatment.
APPLIED SCIENCES-BASEL
(2022)
Article
Nanoscience & Nanotechnology
Houchao Zhang, Tianyu Qi, Xiaoyang Zhu, Longjian Zhou, Zhenghao Li, Yuan-Fang Zhang, Wenchao Yang, Jianjun Yang, Zilong Peng, Guangming Zhang, Fei Wang, Pengfei Guo, Hongbo Lan
Summary: The study introduces a method for efficiently manufacturing CMLAs with a high fill-factor using electric-field-driven microscale 3D printing of PDMS. By adjusting printing parameters, the profile and fill-factor of CMLAs can be controlled to enhance their optical performance. The results show good morphology and optical properties of the prepared CMLAs, suggesting a potential cost-effective route for manufacturing large-area CMLAs.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Rui Chen, Yifan Shao, Yi Zhou, Yongdi Dang, Hongguang Dong, Sen Zhang, Yubo Wang, Jian Chen, Bing-Feng Ju, Yungui Ma
Summary: In this study, a semisolid micromechanical beam steering system based on micrometa-lens arrays (MMLAs) is demonstrated. It is operated by manipulating the probe beam over two sets of decentered MMLAs potentially driven by high-speed piezo-electric motors. The system optimizes overall technical parameters with small f-numbers, well-corrected aberration, and easy lateral reproduction of micrometa-lenses. As a proof-of-concept, the device achieves diffraction-limited resolution within a large field of view of 30 degrees X 30 degrees and shows potential in light detection and ranging applications.
Article
Optics
Zenghui Ge, Zhiying Liu, Yunhan Huang, Zhiyang Lv
Summary: This paper analyzes the impact of the microlens array (MLA) scanning system on the detection distance and imaging resolution. A design method for the initial configuration of the MLA system is proposed based on the principle of minimum spherical aberration. The findings of this paper can be beneficial for the design and evaluation of MLA systems.
Article
Optics
Rong-Ying Yuan, Xiao-Li Ma, Fan Chu, Guang-Xu Wang, Min-Yang He, Chao Liu, Qiong-Hua Wang
Summary: This paper proposes an optofluidic lenticular lens array (OLLA) for a switchable 2D/3D display. By filling different mediums, it can achieve 2D and 3D displays respectively, and experiments confirm high-resolution display on smartphones.
Article
Optics
Hui Li, Yancheng He, Yi Yu, Yuntao Wu, Shuiping Zhang, Yanduo Zhang
Summary: This study demonstrates a light field display system utilizing a combination of a liquid crystal microlens array and a polymer dispersed liquid crystal film. By adopting a depolarization algorithm, high-resolution intermediate 3D images are generated using the microlens array without polarization effects. The polymer dispersed liquid crystal film efficiently modulates the reconstructed 3D images, resulting in full-parallax images with a wide field of view.
Article
Physics, Multidisciplinary
Dongwei Li, Weiming Wang, Song Gao, Yuanmei Gao, Yangjian Cai, Zuoqiang Hao, Zengrun Wen
Summary: In this study, it was demonstrated experimentally and theoretically that the moiré distributed dual-microlens array can generate optical fields with better healing ability compared to a single microlens array. The self-healing degree of the optical field was found to be significantly affected by both the interval distance and the relative angle of the dual-microlens arrays. The research provides a simple and effective method to generate self-healing optical wave fields with potential applications in optical communication, assisted imaging technology, and intense laser physics.
NEW JOURNAL OF PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
Pan Kyu Choi, Yong-Bok Lee, Suhyun Kim, Tae-Soo Kim, Jun-Bo Yoon
Summary: A non-volatile mechanical memory device with CMOS-level operation voltage and low contact resistance is proposed utilizing electro-thermal actuation and exploiting stiction. The device successfully performed 200 repeated cycles of write and erase operations, achieved a contact resistance of 17 omega, and retained both ON and OFF states for over 10^6 seconds without power.
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
(2022)
Article
Nanoscience & Nanotechnology
Hyeonhee Roh, Young Jun Yoon, Jin Soo Park, Dong-Hyun Kang, Seung Min Kwak, Byung Chul Lee, Maesoon Im
Summary: This study presents a novel and simple method to fabricate high-density silicon microneedle arrays with varying heights and cross-sectional shapes depending on photomask designs. The fabrication process involves photolithography and two subsequent deep reactive ion etching (DRIE) steps, allowing for the creation of high-aspect ratio microneedles on silicon wafers. Insertion tests showed low force requirements for the microneedle arrays to penetrate the dura mater of a mouse brain, demonstrating the feasibility of drug delivery applications.
NANO-MICRO LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Min-Seung Jo, Ki-Hoon Kim, Kwang-Wook Choi, Jae-Shin Lee, Jae-Young Yoo, Sung-Ho Kim, Heejeong Jin, Min-Ho Seo, Jun-Bo Yoon
Summary: A phase-transition-inhibited Pd nanowire H-2 sensor is proposed, which can detect high concentrations of H-2 with high linearity and sensitivity. By optimizing the nanowire dimensions and using a special fabrication method, the sensor achieves high stability and accuracy, enabling real-time detection of H-2 leakage.
Review
Neurosciences
Jaya Dilip Badadhe, Hyeonhee Roh, Byung Chul Lee, Jae Hun Kim, Maesoon Im
Summary: Globally, there are over 2.2 billion visually impaired individuals, and ultrasound stimulation can serve as a non-invasive alternative approach to restore vision. Recent studies have demonstrated that ultrasound stimulation can successfully modulate retinal/brain neuronal activities without causing any damage to nerve cells. The superior penetration depth and high spatial resolution of focused ultrasound can open new avenues in neuromodulation research.
FRONTIERS IN CELLULAR NEUROSCIENCE
(2022)
Review
Neurosciences
Sein Kim, Hyeonhee Roh, Maesoon Im
Summary: This article discusses the importance of neural information for high-quality artificial vision, and introduces methods for calculating information transmission rates and modeling artificial retinal neural networks.
FRONTIERS IN CELLULAR NEUROSCIENCE
(2022)
Article
Engineering, Biomedical
Hyeonhee Roh, Yanjinsuren Otgondemberel, Maesoon Im
Summary: This study systematically explored network-mediated responses that arise from various short pulses in both normal and degenerate retinas. The results showed that short pulses elicited strong network-mediated responses in both healthy and degenerate retinas. The response of ON RGCs was highly dependent on the current amplitude, while the response of OFF RGCs was more influenced by the number of stimuli.
JOURNAL OF NEURAL ENGINEERING
(2022)
Article
Multidisciplinary Sciences
Yong-Bok Lee, Min-Ho Kang, Pan-Kyu Choi, Su-Hyun Kim, Tae-Soo Kim, So-Young Lee, Jun-Bo Yoon
Summary: With the rapid growth of the semiconductor industry, radiation hardness has become essential for memory devices. However, implementing radiation-hardened semiconductor memory devices requires various technologies and incurs significant energy overhead. Therefore, there is a growing demand for energy-efficient and intrinsically radiation-hard memory devices. Here, we present a nanoelectromechanical non-volatile memory (NEM-NVM) with ultra-low energy consumption and radiation hardness. The NEM-NVM can be programmed with an ultra-low energy of 2.83 fJ bit(-1) and retains its superb characteristics even after 1 Mrad irradiation.
NATURE COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Hyogeun Shin, Gun-Wook Yoon, Woongsun Choi, Donghwan Lee, Hoyun Choi, Deok Su Jo, Nakwon Choi, Jun-Bo Yoon, Il-Joo Cho
Summary: Miniaturized fluorescence imaging systems have great potential in the biomedical field, overcoming limitations of conventional microscopes. However, existing miniaturized systems face physical limitations for multicolor fluorescence imaging due to the need for multiple filters in a small structure. This study presents a miniaturized multicolor fluorescence imaging system integrated with a single polydimethylsiloxane (PDMS) light-guide plate (LGP) that allows for multicolor imaging without multiple filters. The system was demonstrated to successfully observe green- and red-labeled cells in an incubator, showing its usability in the biomedical field for various applications requiring multicolor fluorescence imaging.
NPJ FLEXIBLE ELECTRONICS
(2023)
Article
Pharmacology & Pharmacy
Jun Hong Park, Seunghyun Lee, Hoyoon Jeon, Jung Hoon Kim, Da Jung Kim, Maesoon Im, Byung Chul Lee
Summary: Target-specific drug release is essential for enhancing chemotherapeutic efficacy. This study proposes a convex acoustic lens-attached US (CALUS) as a simple and efficient alternative to focused ultrasound for drug delivery system (DDS) application. CALUS effectively focuses ultrasound and optimizes acoustic parameters to achieve microbubble destruction and enhance the therapeutic effects of an antitumor drug. In a melanoma mouse model, CALUS exhibited superior tumor growth inhibition, indicating its potential as a treatment approach.
INTERNATIONAL JOURNAL OF PHARMACEUTICS
(2023)
Article
Chemistry, Multidisciplinary
Sung-Ho Kim, Min-Seung Jo, Kwang-Wook Choi, Jae-Young Yoo, Beom-Jun Kim, Jae-Soon Yang, Myung-Kun Chung, Tae-Soo Kim, Jun-Bo Yoon
Summary: A method for developing efficient gas sensors using an ultrathin insulation layer and a unique serpentine architecture is proposed, which can effectively improve the energy efficiency of the sensors while maintaining mechanical durability and long lifespan.
Article
Nanoscience & Nanotechnology
Hyunsun Song, Hyeonhee Roh, Jae Young Kim, Byung Chul Lee, Bright Walker, Maesoon Im
Summary: The use of organic photovoltaic materials in retinal implants allows for artificial vision restoration without the need for external connections, showing higher efficiency compared to previously used materials, especially when blended with other non-fullerene acceptors.
MICRO AND NANO SYSTEMS LETTERS
(2023)
Article
Engineering, Biomedical
Yunseo Son, Zhijie Charles Chen, Hyeonhee Roh, Byung Chul Lee, Maesoon Im
Summary: This study used the finite element method to simulate the electric fields generated by three different designs of 3D microelectrodes in a retina model with a stratified conductivity profile. The results showed that a pillar electrode with an insulating wall generated a stronger and more confined electric field, which is preferred for high-resolution retinal prostheses. Additionally, the insertion depth of the electrode was found to significantly affect the magnitude and shape of the potential distribution.
IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING
(2023)
Article
Engineering, Biomedical
Yanjinsuren Otgondemberel, Hyeonhee Roh, Shelley Fried, Maesoon Im
Summary: The study characterized the electrically-evoked network-mediated responses of ON-OFF direction-selective (DS) RGCs in rabbit and mouse retinas for the first time. Different species showed strong negative correlations between spike counts of electric responses and direction selective indices, with some distinct differences between DS cells. Proper animal model selection is crucial in prosthetic researches as species-dependent retinal circuits may result in different electric response features.
IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING
(2021)
Meeting Abstract
Ophthalmology
Yanjinsuren Otgondemberel, Hyeonhee Roh, Shelley Fried, Maesoon Im
INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE
(2021)
Meeting Abstract
Ophthalmology
Hyeonhee Roh, Eunju Kim, Soo Min Chung, Joon Ho Kang, Taegon Kim, Maesoon Im
INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE
(2021)
