Article
Engineering, Electrical & Electronic
Takemasa Tamanuki, Hiroyuki Ito, Toshihiko Baba
Summary: This study focuses on an optical beam scanning device utilizing photonic crystal slow-light waveguides and switch trees, operated through thermo-optic tuning at a fixed wavelength. With a custom prism lens for beam collimation, the device achieved two-dimensional scanning with a small divergence angle and low power consumption.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Jianwei Chen, Ran Hao, Ibrahim Nasidi, Huangjie Zhang, Xilan Wang, Shangzhong Jin
Summary: In this study, an ultrafast solution based on a tandem classification regression neural network is proposed to solve the design difficulties of photonic crystal waveguides (PCWs) and realize instant prediction of PCW's performances. The network achieves high accuracy with a coefficient of determination of 0.99. Furthermore, the reverse-designed neural network enables the determination of PCW parameters according to desired optical properties. The results could pave the way for future deep learning-based photonic device design towards high-performances.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2023)
Article
Optics
Luis Torrijos-Moran, Amadeu Griol, Jaime Garcia-Ruperez
Summary: Researchers have demonstrated slow light bimodal interferometric behavior in an integrated single-channel one-dimensional photonic crystal for the first time. This structure supports two electromagnetic modes with a large group velocity difference, resulting in over a 20-fold reduction in higher-order mode group velocity compared to other conventional interferometers. The proposed bimodal photonic crystal interferometer shows significant performance improvement in creating an ultra-compact optical modulator and a highly sensitive photonic sensor.
LIGHT-SCIENCE & APPLICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Omid Jafari, Wei Shi, Sophie LaRochelle
Summary: "The paper explores the efficiency-speed tradeoff in slow-light silicon photonic modulators, presenting comprehensive models and comparing them to experiments. It also examines design strategies to reduce V-pi of conventional MZMs, finding that the slow-light effect offers the best overall performance among different approaches."
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2021)
Review
Engineering, Electrical & Electronic
Anuj Singhal, Igor Paprotny
Summary: This review article discusses the properties and applications of photonic crystals, with a focus on slow-light phenomenon and enhanced sensing for gases and liquids. It also discusses the challenges in fabrication and highlights the importance of high-sensitivity detectors for ubiquitous monitoring.
IEEE SENSORS JOURNAL
(2022)
Article
Optics
Kazuhiro Kuruma, Hironobu Yoshimi, Yasutomo Ota, Ryota Katsumi, Masahiro Kakuda, Yasuhiko Arakawa, Satoshi Iwamoto
Summary: This study reports single-photon sources using single quantum dots embedded in topological slow light waveguides based on valley photonic crystals. The experiment demonstrates Purcell-enhanced single-photon emission in a topological slow light mode with a group index over 20, showing robust propagation even under sharp bends.
LASER & PHOTONICS REVIEWS
(2022)
Article
Optics
Chirag Murendranath Patil, Guillermo Arregui, Morten Mechlenborg, Xiaoyan Zhou, Hadiseh Alaeian, Pedro David Garcia, Soren Stobbe
Summary: We report optical transmission measurements on suspended silicon photonic-crystal waveguides with a glide symmetry and slow light. The chiral light-matter interaction is strongly enhanced by this combination, but the interplay between slow light and backscattering has not been experimentally investigated in such waveguides. Photonic-crystal resonators consisting of glide-symmetric waveguides terminated by reflectors were built, and transmission measurements and evanescent coupling were used to map out the dispersion relation. The results show excellent agreement with theory and reveal the potential of these waveguides for applications in slow-light devices and chiral quantum optics.
Article
Engineering, Electrical & Electronic
Stephen R. Anderson, Amir Begovic, Z. Rena Huang
Summary: An integrated RF-photonic link using a slow-light enhanced silicon electro-optic modulator, a single mode Si optical waveguide, and a silicon-germanium photodetector was fabricated. By optimizing the parameters of the Si Mach-Zehnder modulator, high SFDR and modulation efficiency were achieved in the slow-light region.
IEEE PHOTONICS JOURNAL
(2022)
Article
Optics
Keisuke Hirotani, Ryo Shiratori, Toshihiko Baba
Summary: Machine learning was used to model the photonic bands of SiO2-dadded Si lattice-shifted photonic crystal waveguides, leading to the discovery of a structure that can generate low-dispersion slow light with a group index of approximately 20 in the full C-band at telecom wavelengths. The transition structure between this waveguide and a Si-channel waveguide was designed using an evolutional optimization, resulting in a C-band average loss of 0.116 dB/transition. These results suggest the potential for further enhancing the versatility of slow light.
Article
Engineering, Electrical & Electronic
Luis Torrijos-Moran, Antoine Brimont, Amadeu Griol, Pablo Sanchis, Jaime Garcia-Ruperez
Summary: A highly compact optical switch based on slow-light-enhanced bimodal interferometry in one-dimensional silicon photonic crystals is proposed and demonstrated, showing high efficiency operation with low power consumption. The device engineering highly dispersive and broadband bimodal regions for high-performance operation by exploiting the different symmetry of the modes.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Optics
Hironobu Yoshimi, Takuto Yamaguchi, Ryota Katsumi, Yasutomo Ota, Yasuhiko Arakawa, Satoshi Iwamoto
Summary: Experimental demonstration of topological slow light waveguides in valley photonic crystals, showing more efficient waveguiding in the topological mode compared to the non-topological mode.
Article
Engineering, Electrical & Electronic
Alexander Chen, Amir Begovic, Stephen Anderson, Zhaoran Rena Huang
Summary: Si photonic foundry fabricated cascaded and continuous spiral shaped silicon nitride waveguides with Bragg grating structures to achieve on-chip true-time delay line. Time-domain measurement method was used to characterize the delay time, and the highest group index extracted from cascaded SiN grating waveguides is 19.7, while the continuous spiral SiN grating waveguide produces a delay time of 3.78 ns.
IEEE PHOTONICS JOURNAL
(2022)
Article
Optics
Shushu Shi, Shan Xiao, Jingnan Yang, Shulun Li, Xin Xie, Jianchen Dang, Longlong Yang, Danjie Dai, Bowen Fu, Sai Yan, Yu Yuan, Rui Zhu, Bei-Bei Li, Zhanchun Zuo, Can Wang, Haiqiao Ni, Zhichuan Niu, Kuijuan Jin, Qihuang Gong, Xiulai Xu
Summary: We report the slow-light enhanced spin-resolved in-plane emission from a single quantum dot (QD) in a photonic crystal waveguide (PCW). The slow light dispersions in PCWs are designed to match the emission wavelengths of single QDs. The resonance between two spin states emitted from a single QD and a slow light mode of a waveguide is investigated under a magnetic field with Faraday configuration. Strongly polarized photon emission enhanced by a slow light mode shows great potential to attain controllable spin-resolved photon sources for integrated optical quantum networks on chip.
Article
Optics
Xiaobin Li, Zhi-yuan Li, Wenyao Liang
Summary: The proposed research presents a tunable topological slow-light state in a photonic crystal waveguide using a unified magnetic field. The waveguide offers a compact structure, high maneuverability, and strong immunity to defects.
Article
Chemistry, Physical
Siew Yee Lim, Carina Hedrich, Lin Jiang, Cheryl Suwen Law, Manohar Chirumamilla, Andrew D. Abell, Robert H. Blick, Robert Zierold, Abel Santos
Summary: Spectrally tunable nanoporous anodic alumina distributed Bragg reflectors (NAA-DBRs) modified with titanium dioxide (TiO2) coatings were used as optoelectronic platforms to utilize slow light for photocatalysis. The performance of the photocatalysts is influenced by the spectral position of the photonic stop band (PSB) and thickness of the semiconductor, with optimal performance achieved when the red edge of the PSB is close to the red or blue boundary of the absorbance band of methylene blue (MB).
Article
Optics
Fengwen Kang, Yongping Du, Ze Yang, Philippe Boutinaud, Martijn Wubs, Jie Xu, Haiyan Ou, Dongzhe Li, Kaibo Zheng, Abebe T. Tarekegne, Guohuan Sun, Xuhui Xu, Sanshui Xiao
Summary: In this study, CsPbBr3:Ln(3+) nanocrystals grown into glass were successfully designed and fabricated using an in situ nanocrystallization method. It was found that substitution of Pb2+ sites with Ln(3+) ions led to a blueshift of emission position. The nanocrystals exhibited excellent photoluminescent properties and showed good stability in various environments. Additionally, the emission intensity could be controlled through heat-cooling experiments and laser irradiation. Furthermore, a white light-emitting prototype was achieved by combining the CsPbBr3 nanocrystals with other phosphors.
LASER & PHOTONICS REVIEWS
(2023)
Article
Chemistry, Multidisciplinary
Sergii Morozov, Stefano Vezzoli, Alina Myslovska, Alessio Di Giacomo, N. Asger Mortensen, Iwan Moreels, Riccardo Sapienza
Summary: Giant shell CdSe/CdS quantum dots exhibit high brightness and flexibility, with near-unity quantum yield and suppressed blinking. However, their single photon purity is reduced due to efficient multiexcitonic emission. In this study, we observed a significant blueshift in the photoluminescence biexciton spectrum of pure-phase wurtzite quantum dots. By using spectral filtering, we achieved a 2.3 times reduction in biexciton quantum yield while preserving 60% of the exciton single photon emission, leading to an improvement in purity from g2(0)=0.07±0.01 to g2(0)=0.03±0.01. Furthermore, at higher pump fluence, the spectral purification was even more effective, resulting in up to a 6.6 times reduction in g2(0) by suppressing higher order excitons and shell states with larger blueshifts.
Article
Materials Science, Multidisciplinary
Jie Xu, Yamei Luo, Sanshui Xiao, Fengwen Kang, Kosmas L. Tsakmakidis
Summary: This study proposes an all-optical digital logical system based on unidirectional modes in the microwave regime, which can achieve continuous broadband operation for basic logic gates. Utilizing the concept of negative logic, the system exhibits low-loss, broadband, and robust characteristics, and has the potential for multi-input and/or multi-output logical functionalities, making it promising for parallel computation. The numerical simulations and theoretical analyses support the feasibility of this system.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Hengkang Li, Bo Wu, Weiyu Tong, Jianji Dong, Xinliang Zhang
Summary: Nonlinear activation functions are crucial for optical neural networks (ONNs) to achieve more various functions. However, the current nonlinear functions suffer from some dilemma, including high power consumption, high loss, and limited bandwidth. Here, we propose and demonstrate an all-optical implementation of a nonlinear activation function based on germanium silicon hybrid integration. The principle lies in the intrinsic absorption and the carrier-induced refractive index change of germanium in C -band. It has a large operating bandwidth and a response frequency of 70 MHz, with a loss of 4.28 dB and a threshold power of 5.1 mW. Adopting it to the MNIST handwriting data set classification, it shows an improvement in accuracy from 91.6% to 96.8%. This proves that our scheme has great potential for advanced ONN applications.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Yaoxin Liu, Lars Sogaard Rishoj, Michael Galili, Quentin Saudan, Yunhong Ding, Leif Katsuo Oxenlowe, Toshio Morioka
Summary: We designed and fabricated a silicon photonic orbital angular momentum (OAM) multiplexer (MUX) chip for simultaneous wavelength-division multiplexing (WDM) and OAM mode-division multiplexing (MDM) in optical fiber communication systems. Using this chip, we successfully demonstrated simultaneous 3 OAM MDM transmission and OAM MDM/WDM transmission in an 800-m OAM ring-core fiber. The achieved bit error rates (BERs) were below the 7% forward error correction (FEC) limit using 10 Gbit/s on-off keying (OOK) signals.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Optics
Jueming Bao, Zhaorong Fu, Tanumoy Pramanik, Jun Mao, Yulin Chi, Yingkang Cao, Chonghao Zhai, Yifei Mao, Tianxiang Dai, Xiaojiong Chen, Xinyu Jia, Leshi Zhao, Yun Zheng, Bo Tang, Zhihua Li, Jun Luo, Wenwu Wang, Yan Yang, Yingying Peng, Dajian Liu, Daoxin Dai, Qiongyi He, Alif Laila Muthali, Leif K. Oxenlowe, Caterina Vigliar, Stefano Paesani, Huili Hou, Raffaele Santagati, Joshua W. Silverstone, Anthony Laing, Mark G. Thompson, Jeremy L. O'Brien, Yunhong Ding, Qihuang Gong, Jianwei Wang
Summary: Researchers have successfully manufactured a quantum photonic device based on graph theory, which can be used to perform complex quantum computing tasks with high design flexibility and scalability.
Article
Nanoscience & Nanotechnology
Rui Chen, Yi Zheng, Xingyu Huang, Qiaoling Lin, Chaochao Ye, Meng Xiong, Martijn Wubs, Yungui Ma, Minhao Pu, Sanshui Xiao
Summary: Obtaining bound states in the continuum (BICs) in photonic crystals allows for resonances with high quality factors for lasing and nonlinear applications. We design photonic-crystal BIC cavities encircled by the photonic bandgap of lateral heterostructures to confine the mode profile and suppress side leakage. Multiple bulk quantized modes are observed in both simulation and experiment, with resonance peaks depending on the illuminating position explained by mode profile distribution analysis and numerical simulations. Our findings have potential applications in mode selectivity for BIC devices and manipulation of lasing modes or radiation patterns in photonic-crystal surface-emitting lasers or nonlinear optics.
BEILSTEIN JOURNAL OF NANOTECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Alvaro Rodriguez Echarri, Fadil Iyikanat, Sergejs Boroviks, N. Asger Mortensen, Joel D. Cox, F. Javier Garcia de Abajo
Summary: The promising applications of photonics rely on the fabrication of high-quality metal thin films with controlled thickness in the range of a few nanometers. These materials exhibit highly nonlinear response to optical fields due to ultrafast electron dynamics. However, the understanding of this phenomenon on such small length scales is limited. In this study, a new mechanism controlling the nonlinear optical response of thin metallic films is revealed, which is dominated by ultrafast electronic heat transport when the film thickness is sufficiently small. By experimentally and theoretically studying electronic transport in these materials, the researchers explained the observed temporal evolution of photoluminescence in two-pulse correlation measurements. They found that ultrafast thermal dynamics plays a crucial role in determining the strength and time-dependent characteristics of the nonlinear photoluminescence signal. Their findings provide new insights into the nonlinear optical response of nanoscale materials and offer possibilities for controlling and utilizing hot carrier distributions in metallic films.
Article
Chemistry, Multidisciplinary
Yuxin Lei, Qiaoling Lin, Sanshui Xiao, Juntao Li, Hanlin Fang
Summary: This work demonstrates the generation of deep defect states in MoTe2 fewlayers via a heating process, enabling light emission in the telecommunication O-band for quantum light emission. Optical measurements reveal localized excitons and strong interaction among defects. Furthermore, the optical emission of defects depends on the thickness of the host materials. These findings offer a new route for tailoring the optical properties of two-dimensional materials in optoelectronic applications.
Article
Engineering, Electrical & Electronic
Ali Cem, Siqi Yan, Yunhong Ding, Darko Zibar, Francesco Da Ros
Summary: Photonic integrated circuits are advancing optical neural networks, which could potentially outperform electronic counterparts in speed and energy efficiency due to the suitability of optical signals for matrix multiplication. However, programming photonic chips for accurate optical matrix multiplication remains challenging.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Moritz Fischer, Ali Sajid, Jake Iles-Smith, Alexander Hoetger, Denys I. Miakota, Mark K. Svendsen, Christoph Kastl, Stela Canulescu, Sanshui Xiao, Martijn Wubs, Kristian S. Thygesen, Alexander W. Holleitner, Nicolas Stenger
Summary: By combining theory and experiments, we have identified three carbon-based defects as the microscopic origin of luminescent centers in hBN. We have also developed a method to calculate photoluminescence excitation (PLE) maps, which accurately describe the vibronic structure of the optical transition and the phonon-assisted excitation mechanism.
Article
Nanoscience & Nanotechnology
Saskia Fiedler, Sergii Morozov, Danylo Komisar, Evgeny A. A. Ekimov, Liudmila F. F. Kulikova, Valery A. A. Davydov, Viatcheslav N. N. Agafonov, Shailesh Kumar, Christian Wolff, Sergey I. I. Bozhevolnyi, N. Asger Mortensen
Summary: Impurity-vacancy centers in diamond provide a class of robust photon sources with versatile quantum properties. The ensembles of color centers have tunable photon-emission statistics and their emission properties can be controlled by different types of excitation. Electron-beam excitation can synchronize the emitters' excitation and control the second-order correlation function g(2)(0), as confirmed by experimental results in this letter. Such a photon source based on an ensemble of few color centers in a diamond crystal offers a highly tunable platform for room temperature informational technologies.
Article
Optics
Christos Tserkezis, Christian Wolff, Fedor A. Shuklin, Francesco Todisco, Mikkel H. Eriksen, P. A. D. Goncalves, N. Asger Mortensen
Summary: We propose an efficient approach for actively controlling the Rabi oscillations in nanophotonic emitter-cavity analogs based on the presence of an element with optical gain. Inspired by recent developments in parity-time (PT)-symmetry photonics, we show that nano-or microcavities where intrinsic losses are partially or fully compensated by an externally controllable amount of gain offer unique capabilities for manipulating the dynamics of extended (collective) excitonic emitter systems. Furthermore, we show that there is a specific gain value that leads to an exceptional point, where both the emitter and cavity occupation oscillate practically in phase, with occupation numbers that can significantly exceed unity.
Article
Materials Science, Multidisciplinary
Gino Wegner, Dan-Nha Huynh, N. Asger Mortensen, Francesco Intravaia, Kurt Busch
Summary: The paper discusses the impact of an extended model proposed by Halevi on the nonlocal response of plasmonic materials and nanostructures. It reevaluates the Mie scattering coefficients for a cylinder and corresponding plasmon-polariton resonances within this framework. The analysis reveals a nonlocal, collisional, and size-dependent damping term that affects the resonances in the extinction spectrum. The implementation of the Halevi model in the time domain is particularly important for efficient and accurate modeling of nanogap structures and other nanoscale features in nanoplasmonics applications.
Review
Engineering, Electrical & Electronic
Huaqing Qiu, Yong Liu, Xiansong Meng, Xiaowei Guan, Yunhong Ding, Hao Hu
Summary: This paper proposes and demonstrates two energy-efficient optical phase shifters that achieve a well-balanced performance in terms of power consumption, insertion loss, modulation speed, and footprint. The proposed round-spiral phase shifter is robust in fabrication and suitable for large-scale photonic integrated circuits.
FRONTIERS OF OPTOELECTRONICS
(2023)
