Reviews|43 Article(s)
Reviews
Dynamically responsive photonic metal–organic frameworks
He-Qi Zheng, Lin Zhang, Yuanjing Cui, and Guodong Qian
Different from single and static photonic materials, dynamically responsive materials possess numerous advantages, such as being multifunctional, dynamically responsive, and able to provide multiple channels within spatially limited platforms, thus exhibiting great potential for application in the color-on-demand areas, including imaging, optical displays, anticounterfeiting, and encoding. Photonic functional metal–organic frameworks (MOFs), with highly designable framework structures and varieties of optical functional building units, possess broad research and application prospects in the field of photonics, which make it possible to design a promising platform with multifunctional and integrated photonic performance. In this review, beyond the preparation strategies of stimuli-responsive photonic MOFs, we also summarize the stimuli-responsive photonic MOFs regarding several most representative types of external stimuli (such as light, gas, pressure, and polarization). As shown, external stimulation endows the stimuli-responsive photonic MOFs with intriguing regulatable photonic properties: intensive and tunable emission, multiphoton-excitable luminescence, nonlinear optical, circularly polarized luminescence, lasing, etc. Furthermore, their advanced representative applications, such as information encryption and anticounterfeiting display, biological imaging, chemosensing, and others, are also reviewed. The challenges are proposed and the prospects are addressed.
Advanced Photonics
  • Publication Date: Sep. 06, 2023
  • Vol. 5, Issue 5, 054001 (2023)
Torsion pendulum driven by the angular momentum of light: Beth’s legacy continues
Etienne Brasselet
The optical angular momentum is ubiquitous to the science of light, especially whenever the polarization state and the spatial distribution of the phase are involved, which are most often associated with the spin and orbital parts of the total angular momentum, respectively. Notably, the independent introduction of these two contributions to the total optical angular momentum was accompanied by suggestions regarding the possible detection of their mechanical effects using a torsion pendulum. Today, the classical and quantum mechanical aspects of spin and orbital angular momentum of light and their mutual coupling remain active research topics offering exciting perspectives for photonic technologies. Our brief historical overview shows how the torsion pendulum has accompanied scientific advances on mechanical effects based on the angular degrees of freedom of light since Beth’s pioneering contribution published in 1935.
Advanced Photonics
  • Publication Date: Jun. 30, 2023
  • Vol. 5, Issue 3, 034003 (2023)
Advances in lithium niobate thin-film lasers and amplifiers: a review
Qiang Luo, Fang Bo, Yongfa Kong, Guoquan Zhang, and Jingjun Xu
Lithium niobate (LN) thin film has received much attention as an integrated photonic platform, due to its rich and great photoelectric characteristics, based on which various functional photonic devices, such as electro-optic modulators and nonlinear wavelength converters, have been demonstrated with impressive performance. As an important part of the integrated photonic system, the long-awaited laser and amplifier on the LN thin-film platform have made a series of breakthroughs and important progress recently. In this review paper, the research progress of lasers and amplifiers realized on lithium niobate thin film platforms is reviewed comprehensively. Specifically, the research progress on optically pumped lasers and amplifiers based on rare-earth ions doping of LN thin films is introduced. Some important parameters and existing limitations of the current development are discussed. In addition, the implementation scheme and research progress of electrically pumped lasers and amplifiers on LN thin-film platforms are summarized. The advantages and disadvantages of optically and electrically pumped LN thin film light sources are analyzed. Finally, the applications of LN thin film lasers and amplifiers and other on-chip functional devices are envisaged.
Advanced Photonics
  • Publication Date: May. 30, 2023
  • Vol. 5, Issue 3, 034002 (2023)
Metasurface-enabled augmented reality display: a review
Zeyang Liu, Danyan Wang, Hao Gao, Moxin Li, Huixian Zhou, and Cheng Zhang
Augmented reality (AR) display, which superimposes virtual images on ambient scene, can visually blend the physical world and the digital world and thus opens a new vista for human–machine interaction. AR display is considered as one of the next-generation display technologies and has been drawing huge attention from both academia and industry. Current AR display systems operate based on a combination of various refractive, reflective, and diffractive optical elements, such as lenses, prisms, mirrors, and gratings. Constrained by the underlying physical mechanisms, these conventional elements only provide limited light-field modulation capability and suffer from issues such as bulky volume and considerable dispersion, resulting in large size, severe chromatic aberration, and narrow field of view of the composed AR display system. Recent years have witnessed the emerging of a new type of optical elements—metasurfaces, which are planar arrays of subwavelength electromagnetic structures that feature an ultracompact footprint and flexible light-field modulation capability, and are widely believed to be an enabling tool for overcoming the limitations faced by current AR displays. Here, we aim to provide a comprehensive review on the recent development of metasurface-enabled AR display technology. We first familiarize readers with the fundamentals of AR display, covering its basic working principle, existing conventional-optics-based solutions, as well as the associated pros and cons. We then introduce the concept of optical metasurfaces, emphasizing typical operating mechanisms, and representative phase modulation methods. We elaborate on three kinds of metasurface devices, namely, metalenses, metacouplers, and metaholograms, which have empowered different forms of AR displays. Their physical principles, device designs, and the performance improvement of the associated AR displays are explained in details. In the end, we discuss the existing challenges of metasurface optics for AR display applications and provide our perspective on future research endeavors.
Advanced Photonics
  • Publication Date: May. 15, 2023
  • Vol. 5, Issue 3, 034001 (2023)
Integrated-resonant metadevices: a review|On the Cover
Jin Yao, Rong Lin, Mu Ku Chen, and Din Ping Tsai
Integrated-resonant units (IRUs), associating various meta-atoms, resonant modes, and functionalities into one supercell, have been promising candidates for tailoring composite and multifunctional electromagnetic responses with additional degrees of freedom. Integrated-resonant metadevices can overcome many bottlenecks in conventional optical devices, such as broadband achromatism, efficiency enhancement, response selectivity, and continuous tunability, offering great potential for performant and versatile application scenarios. We focus on the recent progress of integrated-resonant metadevices. Starting from the design principle of IRUs, a variety of IRU-based characteristics and subsequent practical applications, including achromatic imaging, light-field sensing, polarization detection, orbital angular momentum generation, metaholography, nanoprinting, color routing, and nonlinear generation, are introduced. Existing challenges in this field and opinions on future research directions are also provided.
Advanced Photonics
  • Publication Date: Feb. 22, 2023
  • Vol. 5, Issue 2, 024001 (2023)
Computation at the speed of light: metamaterials for all-optical calculations and neural networks
Trevon Badloe, Seokho Lee, and Junsuk Rho
The explosion in the amount of information that is being processed is prompting the need for new computing systems beyond existing electronic computers. Photonic computing is emerging as an attractive alternative due to performing calculations at the speed of light, the change for massive parallelism, and also extremely low energy consumption. We review the physical implementation of basic optical calculations, such as differentiation and integration, using metamaterials, and introduce the realization of all-optical artificial neural networks. We start with concise introductions of the mathematical principles behind such optical computation methods and present the advantages, current problems that need to be overcome, and the potential future directions in the field. We expect that our review will be useful for both novice and experienced researchers in the field of all-optical computing platforms using metamaterials.
Advanced Photonics
  • Publication Date: Dec. 21, 2022
  • Vol. 4, Issue 6, 064002 (2022)
Silicon nitride-based Kerr frequency combs and applications in metrology
Zhaoyang Sun, Yang Li, Benfeng Bai, Zhendong Zhu, and Hongbo Sun
Kerr frequency combs have been attracting significant interest due to their rich physics and broad applications in metrology, microwave photonics, and telecommunications. In this review, we first introduce the fundamental physics, master equations, simulation methods, and dynamic process of Kerr frequency combs. We then analyze the most promising material platform for realizing Kerr frequency combs—silicon nitride on insulator (SNOI) in comparison with other material platforms. Moreover, we discuss the fabrication methods, process optimization as well as tuning and measurement schemes of SNOI-based Kerr frequency combs. Furthermore, we highlight several emerging applications of Kerr frequency combs in metrology, including spectroscopy, ranging, and timing. Finally, we summarize this review and envision the future development of chip-scale Kerr frequency combs from the viewpoint of theory, material platforms, and tuning methods.
Advanced Photonics
  • Publication Date: Nov. 14, 2022
  • Vol. 4, Issue 6, 064001 (2022)
Silicon-based optoelectronics for general-purpose matrix computation: a review
Pengfei Xu, and Zhiping Zhou
Conventional electronic processors, which are the mainstream and almost invincible hardware for computation, are approaching their limits in both computational power and energy efficiency, especially in large-scale matrix computation. By combining electronic, photonic, and optoelectronic devices and circuits together, silicon-based optoelectronic matrix computation has been demonstrating great capabilities and feasibilities. Matrix computation is one of the few general-purpose computations that have the potential to exceed the computation performance of digital logic circuits in energy efficiency, computational power, and latency. Moreover, electronic processors also suffer from the tremendous energy consumption of the digital transceiver circuits during high-capacity data interconnections. We review the recent progress in photonic matrix computation, including matrix-vector multiplication, convolution, and multiply–accumulate operations in artificial neural networks, quantum information processing, combinatorial optimization, and compressed sensing, with particular attention paid to energy consumption. We also summarize the advantages of silicon-based optoelectronic matrix computation in data interconnections and photonic-electronic integration over conventional optical computing processors. Looking toward the future of silicon-based optoelectronic matrix computations, we believe that silicon-based optoelectronics is a promising and comprehensive platform for disruptively improving general-purpose matrix computation performance in the post-Moore’s law era.
Advanced Photonics
  • Publication Date: Jul. 06, 2022
  • Vol. 4, Issue 4, 044001 (2022)
Advances in lithium niobate photonics: development status and perspectives|Article Video , On the Cover
Guanyu Chen, Nanxi Li, Jun Da Ng, Hong-Lin Lin, Yanyan Zhou, Yuan Hsing Fu, Lennon Yao Ting Lee, Yu Yu, Ai-Qun Liu, and Aaron J. Danner
Lithium niobate (LN) has experienced significant developments during past decades due to its versatile properties, especially its large electro-optic (EO) coefficient. For example, bulk LN-based modulators with high speeds and a superior linearity are widely used in typical fiber-optic communication systems. However, with ever-increasing demands for signal transmission capacity, the high power and large size of bulk LN-based devices pose great challenges, especially when one of its counterparts, integrated silicon photonics, has experienced dramatic developments in recent decades. Not long ago, high-quality thin-film LN on insulator (LNOI) became commercially available, which has paved the way for integrated LN photonics and opened a hot research area of LN photonics devices. LNOI allows a large refractive index contrast, thus light can be confined within a more compact structure. Together with other properties of LN, such as nonlinear/acousto-optic/pyroelectric effects, various kinds of high-performance integrated LN devices can be demonstrated. A comprehensive summary of advances in LN photonics is provided. As LN photonics has experienced several decades of development, our review includes some of the typical bulk LN devices as well as recently developed thin film LN devices. In this way, readers may be inspired by a complete picture of the evolution of this technology. We first introduce the basic material properties of LN and several key processing technologies for fabricating photonics devices. After that, various kinds of functional devices based on different effects are summarized. Finally, we give a short summary and perspective of LN photonics. We hope this review can give readers more insight into recent advances in LN photonics and contribute to the further development of LN related research.
Advanced Photonics
  • Publication Date: Jun. 08, 2022
  • Vol. 4, Issue 3, 034003 (2022)