Article
Engineering, Electrical & Electronic
Jingquan Xu, Kexin Chen, Yingying Qu, Chen Liu, Songnian Fu, Deming Liu
Summary: This article presents a novel double gratings configuration based on LCOS optical filter, which achieves higher spectral resolution by enlarging and accumulating dispersion. With this configuration, a spectral resolution of 1.63 GHz is achieved, almost tenfold enhancement compared to traditional single grating configuration.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Rui Yuan, Yuan Liu, Qinggui Tan, Jinman Ge, Peng Chen, Qi Guo, Wei Hu
Summary: An all-liquid-crystal device that enables fast orbital angular momentum encoding and optical vortex beam steering is proposed and demonstrated. It combines a cascaded spin-determined beam deflector and an optical vortex generator. The rapid switching is achieved through the rapid in-plane optical axis rotation of ferroelectric liquid crystal half-wave plates, while the q-plate and meta-q-plate made by photopatterned liquid crystal polymer ensure efficient and high-quality orbital angular momentum encoding. By programming binary signals, electrical optical vortex deflection and 32 different orbital angular momentum encoding can be achieved in less than 70 microseconds with an efficiency over 85%. This device provides a practical strategy for fast optical vortex steering and orbital angular momentum encoding, and has potential applications in vortex LiDAR, multitarget communications, and orbital angular momentum multiplexed optical telecoms.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2022)
Article
Multidisciplinary Sciences
Ryohei Hokari, Kyohei Takakuwa, Hirohisa Kato, Akitaka Yamamoto, Yusuke Yamaguchi, Kazuma Kurihara
Summary: This study presents a low-reflective wire-grid polariser (WGP) sheet for the visible light region, with nanowires made of sintered silver nanoparticle ink using a nanoprinting process. The sheet has high degree of polarization and low reflectance, and can achieve mass production through a special nanoprinting process.
SCIENTIFIC REPORTS
(2021)
Review
Crystallography
Shiyuan Zhang, Wan Chen, Yang Yu, Qidong Wang, Quanquan Mu, Shixiao Li, Jin Chen
Summary: Recent research has shown that diverse twisting structures can be used to design liquid crystal polarization gratings and lenses with high diffraction efficiency, broad bandwidth, wide view, and large diffraction angle. By phase compensation, multi-layer twisting structures have been found to present a broader bandwidth and wider view angle, while Bragg twisting structures can achieve a large diffraction angle with high efficiency. Potential research directions on novel twisting structures were discussed based on theoretical analysis in the review.
Article
Energy & Fuels
Amid Ranjkesh, Yeongyu Choi, Jae-Won Huh, Seung-Won Oh, Tae-Hoon Yoon
Summary: A flexible cholesteric liquid crystal (CLC) polymer reflector is proposed in this study to selectively control the reflection of infrared (IR) light, effectively lowering indoor temperature. The fabricated IR reflector demonstrates thinness, high mechanical stability, flexibility, durability, resistance to solvents and acids, high transparency, and low haze in visible light. This innovative approach shows promise for applications in anti-IR devices, energy-saving windows for cars, and modern building facades.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2021)
Article
Chemistry, Multidisciplinary
Moritsugu Sakamoto, Tomoki Yayama, Kohei Noda, Tomoyuki Sasaki, Nobuhiro Kawatsuki, Hiroshi Ono
Summary: This study presents an optical system for efficient characterization of optical vortices with arbitrary states of polarization. By combining a straight-line polarization grating and parabolic-line polarization gratings, the system can accurately characterize the topological charge of incident optical vortices regardless of their polarization states.
APPLIED SCIENCES-BASEL
(2022)
Article
Materials Science, Multidisciplinary
Zongcheng Miao, Xianliang Chen, Yutong Zhang, Dong Wang, Lei Wang
Summary: A flexible bistable cholesteric liquid crystal film with polymer spacer columns for displays was prepared by stepwise UV light polymerization, which showed better electro-optical performance and spacing stability.
ACS APPLIED POLYMER MATERIALS
(2022)
Review
Crystallography
Tiegang Lin, Jin Xie, Yingjie Zhou, Yaqin Zhou, Yide Yuan, Fan Fan, Shuangchun Wen
Summary: This review paper discusses the physical principles, exposure methods, fabrication process, and promising applications of the liquid crystal circular polarization gratings, which have high diffraction efficiency and polarization selectivity characteristics.
Article
Optics
Migle Stebryte, Inge Nys, Jeroen Beeckman, Kristiaan Neyts
Summary: Flat optics based on chiral liquid crystal (CLC) can be achieved using holographic polarization recording with the help of a photoalignment technique to vary the orientation of the optical axis in a thin CLC layer. This study discusses the use of CLC diffractive lenses in a spectrometer, combining the functionalities of mirrors and a linear grating into a single holographic CLC component. Circularly polarized light can be efficiently reflected and projected by the CLC component, offering the opportunity for device integration.
Article
Physics, Multidisciplinary
T. Smolenski, K. Watanabe, T. Taniguchi, M. Kroner, A. Imamoglu
Summary: In this study, we investigate the relaxation dynamics of a strongly correlated electron system in a gate-tunable MoSe2 monolayer exposed to a strong magnetic field. We find that the relaxation and light-induced depolarization rates exhibit different behaviors at different Landau level filling factors. Our findings reveal the potential of spin-valley dynamics in probing the effects of disorder and strong interactions.
PHYSICAL REVIEW LETTERS
(2022)
Article
Polymer Science
Mark J. Moran, Olena Ouskova, Katherine M. Gerosa, Anna Tabirian, Nelson Tabiryan, Nicholas P. Godman, Michael E. McConney, Jonathan Slagle, Timothy J. Bunning
Summary: The directed self-assembly of liquid crystal polymers has superior optical properties compared to conventional isotropic optical materials. However, the exploration of reflective liquid crystalline polymeric films has been limited due to production challenges. In this study, we investigate stacked polymer cholesteric liquid crystal thin films as a means to generate reflective diffractive optics for circularly polarized light. We present three different exemplar cases to demonstrate the potential of these unique thin polymer films.
Article
Optics
Yourong Liu, Tong Shen, Biao Kang, Shaoxing Li, Zengrong Zheng, Huaqing Lv, Jihong Zheng
Summary: This paper investigates the effects of using a composite photopolymer system and a photoinitiator on the optical properties of a volume phase holographic grating. The study shows that the performance of the hologram can be improved under specific conditions, and demonstrates the high-density data recording capability of the photopolymer.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Multidisciplinary Sciences
Pravinraj Selvaraj, Sheng-Le Wang, Tsung-Yi Hou, Cheng-Kai Liu, Ko-Ting Cheng
Summary: This study demonstrates the use of reflective phase-only spatial light modulator (RLC-SLM) to achieve white light focusing and color separation with high diffraction efficiency in the visible range. These recent advances open up new possibilities for adaptive camera systems, microscopes, holograms, and portable and wearable devices.
SCIENTIFIC REPORTS
(2023)
Article
Engineering, Electrical & Electronic
Ali Momeni, Hamid Rajabalipanah, Mahdi Rahmanzadeh, Ali Abdolali, Karim Achouri, Viktar S. Asadchy, Romain Fleury
Summary: Analog computing, utilizing reciprocal metasurfaces with cross-polarization exciting normal polarizabilities, demonstrates a flexible design and successful implementation of asymmetric optical transfer functions for on-axis reflective optical signal processing. By providing dual computing channels under orthogonal polarizations, this approach offers a promising method for ultrafast image processing and analog computation. The comprehensive theoretical discussion and detailed design of an all-dielectric optical metasurface highlights the potential of this method in facilitating experimental setup and achieving desired surface polarizabilities.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Yuan Li, Yang Shen, Jiajun Tian, Qi Fu, Yong Yao
Summary: A novel multi-wavelength erbium-doped fiber laser with wavelength switchable capabilities is demonstrated based on PDL modulation and cascaded FBGs as wavelength comb filters. The PDL modulation balances the total loss and lasing gain, allowing for the creation of multiple lasing lines by adjusting PDLs in different wavelengths. The experiment successfully verifies the switching operation for single to four-wavelength laser outputs by adjusting the polarization controllers.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Zhiyong Yang, En-Lin Hsiang, Yizhou Qian, Shin-Tson Wu
Summary: The performance of a 15.6-inch mLCD and an OLED panel were evaluated and compared. The mLCD exhibited advantages in peak brightness, color volume, and power consumption compared to OLED. The study also adopted a new color measurement method recommended by ICDM and proposed a novel strategy for measuring the point spread function.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Electrical & Electronic
Zhenyi Luo, Yuqiang Ding, Yi Rao, Shin-Tson Wu
Summary: The pancake lens structure offers a compact solution for near-eye displays, but the use of a half mirror results in a significant optical loss. The proposed folded optical structure, using polarization-selective cholesteric liquid crystal reflectors, doubles the efficiency and optical path length to balance the tradeoff between form factor and efficiency. Simulation results match well with experiments. Two display configurations are established to evaluate the imaging performances of the proposed pancake lens structure.
JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY
(2023)
Article
Engineering, Electrical & Electronic
Yizhou Qian, Zhiyong Yang, Yu-Hsin Huang, Kuan-Heng Lin, Shin-Tson Wu
Summary: The RGB nanowire light-emitting diode (LED) structures were optimized using a 3D dipole cloud model to achieve a narrower radiation pattern, reduced angular color shift, and higher optical efficiency. Compared to micro-LEDs, which have externally quantum efficiency depending on mesa size, the RGB nanowire LEDs are more efficient for chip sizes below 20, 80, and 10 μm, respectively. Therefore, nanowire LEDs show promise for augmented reality and virtual reality displays that require high-resolution density and efficient directional light emission.
JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY
(2023)
Article
Engineering, Electrical & Electronic
Yannanqi Li, John Semmen, Qian Yang, Shin-Tson Wu
Summary: A new electrically driven polymer-stabilized polarization volume grating (PVG) has been developed, with the diffraction efficiency modulated by a vertical electric field. By doping a small amount of liquid crystal monomer into the host cholesteric liquid crystal, a stabilized polymer network is formed, allowing for reversible unwinding. The fabricated device exhibits submillisecond response time, a large range of diffraction efficiency modulation, and clear see-through capability. Demonstrations of potential applications show suppressed rainbow effect, enhanced light efficiency, and expanded field of view for a waveguide-based augmented reality display. The unique properties and benefits of switchable PVGs could revolutionize near-eye display research, particularly in novel optical systems for augmented reality waveguide displays.
JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY
(2023)
Article
Engineering, Electrical & Electronic
En-Lin Hsiang, Zhiyong Yang, Shin-Tson Wu
Summary: Virtual reality (VR) devices use imaging optics to magnify microdisplay images, providing an immersive viewing experience. Microdisplays need high-resolution density and dynamic range to meet human vision system requirements. However, increasing resolution and dynamic range can reduce optical efficiency and complicate microdisplay panel fabrication. This paper analyzes image degradation in VR devices caused by both imaging optics and microdisplay, finding that imaging optics significantly impact microdisplay requirements, such as contrast ratio, local dimming zones, and resolution density. These findings help prevent excessive microdisplay design in pancake lens-based VR headsets.
JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY
(2023)
Article
Engineering, Electrical & Electronic
Yuqiang Ding, Yannanqi Li, Qian Yang, Shin-Tson Wu
Summary: This paper proposes a single full-color waveguide AR display based on reflective polarization volume gratings (PVGs) to improve stability and wearing comfort. By analyzing the optical system, we optimize a three-layer PVG as an in-coupler and derive the field of view limit. With a single-layer, thin PVG as an out-coupler, we achieve a relatively uniform exit pupil of 8 mm at the horizontal pupil expansion direction.
JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY
(2023)
Editorial Material
Optics
En-Lin Hsiang, Shin-Tson Wu
Summary: Compared to conventional bulky spectropolarimeters, computational spectropolarimeters reconstruct light-field information in a compact form factor, enabling new applications. A tunable liquid crystal metasurface can modulate the phase and spectral information of light, paving the way for developing compact and low-cost spectropolarimetric imaging devices with widespread applications.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Zhiyong Yang, Yizhou Qian, Junyu Zou, Chia-Lun Lee, Chih-Lung Lin, Shin-Tson Wu
Summary: To achieve high resolution and low power consumption in virtual reality applications, field sequential color (FSC) is used to triple the resolution density and optical efficiency of LCDs. By evaluating the physical properties of a high birefringence nematic LC mixture, a fringe-field switching (FFS) LCD was designed to exhibit fast response time for FSC operation. The FSC LCD also demonstrated wide color gamut and superior color uniformity.
APPLIED SCIENCES-BASEL
(2023)
Article
Optics
Zhenyi Luo, Yannanqi Li, John Semmen, Yi Rao, Shin-Tson Wu
Summary: This study demonstrates an achromatic diffractive liquid-crystal device to overcome the chromatic aberration issue. The proposed device consists of three stacked diffractive liquid crystal optical elements with specific spectral response and polarization selectivity. Simulation and experimental results show significant improvement in imaging performance. This technology has potential applications in virtual reality and mixed reality fields.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Crystallography
Yizhou Qian, Zhiyong Yang, En-Lin Hsiang, Qian Yang, Kevin Nilsen, Yu-Hsin Huang, Kuan-Heng Lin, Shin-Tson Wu
Summary: Vehicle displays are becoming increasingly integrated into our daily lives, requiring high-resolution density and sufficient brightness to combat intense ambient light. Infotainment displays demand over 800 nit brightness to display images clearly under direct sunlight, while head-up displays need to strike a delicate balance between resolution density, brightness, transparency, and image quality.
Article
Optics
Chien-Chung Lin, Yuh-Renn Wu, Hao-Chung Kuo, Matthew S. Wong, Steven P. Denbaars, Shuji Nakamura, Ayush Pandey, Zetian Mi, Pengfei Tian, Kazuhiro Ohkawa, Daisuke Iida, Tao Wang, Yuefei Cai, Jie Bai, Zhiyong Yang, Yizhou Qian, Shin-Tson Wu, Jung Han, Chen Chen, Zhaojun Liu, Byung-Ryool Hyun, Jae-Hyun Kim, Bongkyun Jang, Hyeon-Don Kim, Hak-Joo Lee, Ying-Tsang Liu, Yu-Hung Lai, Yun-Li Li, Wanqing Meng, Haoliang Shen, Bin Liu, Xinran Wang, Kai-ling Liang, Cheng-Jhih Luo, Yen-Hsiang Fang
Summary: Micro light-emitting diode (micro-LED) is expected to play a significant role in future smart displays, offering advantages in various applications. The article focuses on the current status, challenges, and potential advances in micro-LED technology, highlighting the importance of epitaxy innovation and quantum scale structures. Peripheral components and technologies, such as microchip transfer and repair, heterogeneous integration, and novel 2D materials, are also discussed. The potential of micro-LED displays in augmented reality (AR) and the efforts to address existing problems are emphasized.
JOURNAL OF PHYSICS-PHOTONICS
(2023)
Article
Optics
Jianghao Xiong, Haizheng Zhong, Dewen Cheng, Shin-Tson Wu, Yongtian Wang
Summary: This study demonstrates a polarization hologram with full DoF for local manipulation of optical structure, based on emerging self-assembled photo-aligned liquid crystal technology. The ability to record arbitrary wavefront and perform local liquid crystal adjustment is achieved through freeform surface exposure and inkjet printing, respectively, resulting in a full-color retinal scanning display without color crosstalk.
Review
Optics
Yuqian Ding, Qian Yang, Yannanqi Li, Zhiyong Yang, Zhengyang Wang, Haowen Liang, Shin-Tson Wu
Summary: This review paper focuses on the perspectives and challenges of optical waveguide combiners for augmented reality (AR) displays. It introduces the basic device structures and operation principles of different AR architectures, and delves into different waveguide combiners, including geometric and diffractive waveguide combiners. Commonly used in-couplers and out-couplers are discussed, and their properties are analyzed in detail. The paper also explores recent advances in waveguide combiner design and modeling, and discusses the bottlenecks and future development trends in waveguide combiner technologies.
Article
Crystallography
Yuge Huang, Shin-Tson Wu
Summary: The Mini-LED backlit LCD exhibits premium display performance, including motion blur reduction, high dynamic range, and suppression of the halo effect.
LIQUID CRYSTALS TODAY
(2023)
Article
Materials Science, Multidisciplinary
Junyu Zou, Lingshan Li, Shin-Tson Wu
Summary: Maxwellian-view structure has several advantages in augmented reality (AR) displays, including high efficiency, always-in-focus, and a simple optical structure. However, its small eyebox has been a bottleneck. Many efforts have been made to enlarge the eyebox, but the importance of gaze matching has been neglected. This study demonstrates a gaze-matching Maxwellian-view AR system with an enlarged eyebox.
ADVANCED PHOTONICS RESEARCH
(2022)