检索结果-内蒙古大学图书馆

Design of compact surface-emitting nanolasers based on topological guided-mode resonance

OPTICS LETTERS 2025年第4期50卷 1069-1072页

作者： Qian, Linyong Zhang, Jiahua Wang, Kangni Jiangsu Normal Univ Sch Phys & Elect Engn Xuzhou 221116 Peoples R China

We numerically design a compact nanolaser based on a topological guided-mode resonance (GMR) structure. It consists of a topological junction formed by two GMR gratings, which induces a leaky Jackiw-Rebbi (JR) edge state that confines in-plane light within a small mode volume. Using the finite-difference time-domain (FDTD) method to simulate active optical responses, we show that surface-emitting lasing is achieved with a threshold of 4.5 mu J/cm2 within a cavity length of approximately 2.0 mu m. In addition, by replacing the junction with an array of equally spaced ridges in a critical phase, the edge mode transitions into a bulk mode. This modification allows for controllable cavity sizes of 4.9, 7.8, and 10.7 mu m, with corresponding thresholds of 6.0, 8.4, and 9.0 mu J/cm2, achieved by using 5, 10, and 15 cycles of critical state grating. The topological GMR holds promise for compact coherent sources. (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.

关键词： Bragg reflectors finite-difference time-domain method Laser arrays Q factor Refractive index Waveguide modes

来源：评论

学校读者我要写书评

暂无评论

High-efficiency reflective terahertz cross-polarization converter with broadband and wide-angle response

引用

APPLIED OPTICS 2024年第12期63卷 3212-3218页

作者： Yang, Jun Li, Kaiwen Zha, Xiaojie Zhang, Guozhen Xi, Hongzhu Deng, Guangsheng Li, Ying Yin, Zhiping Hefei Univ Technol Acad Photoelect Technol Natl Engn Lab Special Display Technol Hefei 230009 Peoples R China Hefei Univ Technol Sch Instrument Sci & Optoelect Engn Anhui Prov Key Lab Measuring Theory & Precis Instr Hefei 230009 Peoples R China Anhui Huadong Photoelect Technol Res Inst Co Ltd Wuhu 241002 Peoples R China

In this paper, a broadband terahertz metasurface dedicated to cross-polarization conversion was designed, fabricated, and assessed. The metasurface, comprising two nested double-split rings, features an inherent insensitivity to the angle of incidence. Simulations reveal that the converter achieves a > 99% polarization conversion efficiency across the 90-140 GHz range. Moreover, it maintains a > 90% polarization conversion ratio (PCR), even at a 50 degrees incidence angle. The sample, featuring 50 x 70 arrays, was fabricated, and the relevant experimental results align closely with the simulated outcomes. The metasurface characteristics can markedly enhance the performance of cross-polarization converters operating in the terahertz range. (c) 2024 Optica Publishing Group

关键词： Circular polarization Faraday effect finite-difference time-domain method Nondestructive testing Optical activity Wave propagation

来源：评论

学校读者我要写书评

暂无评论

Ultra-high Q-factor quasi-BIC BaTiO3 metasurface for electro-optic modulation

引用

OPTICS EXPRESS 2024年第11期32卷 20268-20278页

作者： Shen, Xiaokang Tian, Haiyi Li, Jiahao Wu, Yunkai Wang, Xu Guizhou Univ Coll Big Data & Informat Engn Guiyang 550025 Peoples R China Minist Educ Key Lab Adv Mfg Technol Guiyang 550025 Guizhou Peoples R China

Metasurfaces play a crucial role in trapping electromagnetic waves with specific wavelengths, serving as a significant platform for enhancing light-matter interactions. In all kinds of dynamic modulation metasurfaces, electro-optic modulation metasurfaces have attracted much attention due to its advantages of fast, stable and high efficiency. In order to respond to the extremely weak refractive index change of the electro-optical effect of the materials, the metasurfaces are required to support optical signals with high Q values. The quasi-bound state in the continuum (Q-BIC) is often used to enhance the light-field modulation capability of metasurfaces and to improve the modulation sensitivity of electro-optic modulators due to its ability to generate high Q-factor resonances. However, the design of an electro-optic modulation metasurface that facilitates the application of voltage and achieves modulation efficiency of nearly 100% is still in urgent need of development. In this study, single-crystal BTO metasurfaces are modeled using finite-difference time-domain method, and the structural symmetry is broken to introduce a Q-BIC resonance to generate a high Q-factor optical signal of 2.45 x 104 for high-depth electro-optic modulation. By simulating an applied electric field of 143 V/mm on the metasurface, a slight refractive index change of BTO of 8 x 10-4 was produced, leading to an electro-optical intensity modulation depth of 100%. Furthermore, the nanostructure of the metasurface was carefully designed to facilitate nano-fabrication and voltage application, and it is ideal for the development of low-power, CMOS-compatible, and miniaturized electro-optic modulation devices. Although the results of this study are based on simulations, they provide a crucial theoretical basis and guidance for the realization of efficient and realistic design of dynamic metasurfaces.

关键词： finite-difference time-domain method Modulation techniques Optical signals Phase modulation Refractive index Signal processing

来源：评论

学校读者我要写书评

暂无评论

Sub-area design of a reflective metasurface for Bessel beam generation to mitigate the impact of feed occlusion

引用

APPLIED OPTICS 2024年第25期63卷 6537-6543页

作者： Hao, Honggang Zhang, Ting Yin, Dan He, Jinfeng Chongqing Univ Posts & Telecommun Sch Optoelect Engn Chongqing Peoples R China

This paper introduces a sub-area metasurface designed to mitigate the effects of feed occlusion when generating Bessel beams on reflective metasurfaces. This unit incorporates an anisotropic structure with distinct phase responses tailored for two orthogonal linearly polarized (LP) electromagnetic (EM) waves. The energy loss of the Bessel beam, situated behind the feed source, generated by the outer ring, is minimized through the superposition of the inward traveling waves and strategic partitioning of the array area. Furthermore, the principle of electric field superposition is employed to focus on the inner ring. The simulated results demonstrate that at 9 GHz, the metasurface produces a bifocal effect with focusing efficiencies of 60.1% and 64.3%, in conjunction with a Bessel beam exhibiting a diffraction-free region of 799 mm. For x polarization, the full width at half-maximum (FWHM) of the post-feed Bessel beam is 49.83 mm (1.49 1). In contrast, under y polarization, the FWHM of the Bessel beam with an off-axis angle of 30 degrees is 47.63 mm (1.43 1). The simulated results suggest that the proposed metasurface has promising applications in point-to-multipoint or same-path multi-target wireless power transmission (WPT) systems. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.

关键词： Beam steering Dispersion finite-difference time-domain method Metasurfaces Phase compensation Polarization

来源：评论

学校读者我要写书评

暂无评论

Estimating Thickness of Defects at Rock-Concrete Lining Interface by Ground-Penetrating Radar

引用

JOURNAL OF MINING SCIENCE 2024年第2期60卷 265-277页

作者： Denisova, E. V. Sokolov, K. O. Khmelinin, A. P. Konurin, A. I. Orlov, D. V. Russian Acad Sci Chinakal Inst Min Siberian Branch Novosibirsk 630091 Russia Russian Acad Sci Siberian Branch Chersky Inst Min North Yakutsk 677980 Russia

Ground-penetrating radar is used to study defects in the form of internal layers in concrete structures. It is found that modulus of deflection coefficient of GPR signals changes as function of the layer thickness and electromagnetic properties of the material filling the layer (sand, wet sand or air). The experimental and numerical research used the method of peak-to-peak amplitude ratio, which enabled determining the Fresnel coefficients for the upper and lower boundaries of a layer. The minimal layer thickness recorded by GPR was 2 mm.

关键词： Concrete lining internal rock mass finite-difference time-domain method electromagnetic properties ground-penetrating radar

来源：评论

学校读者我要写书评

暂无评论

Fourier coupled modal method for parallel modal analysis of photonic structures

引用

OPTICS EXPRESS 2024年第27期32卷 48645-48655页

作者： Lee, Jonghyun Choi, Myeonggyu Jeong, Sehyeon Park, Shin-woong Kim, Hwi Korea Univ Dept Elect & Informat Engn Coll Sci & Technol Sejong Campus2511 Sejong Ro Sejong 30019 South Korea Korea Univ Ctr Adv Photovolta Mat CAPM Sejong Campus2511 Sejong Ro Sejong 30019 South Korea

We present the Fourier coupled modal method (FCMM) as a solution for large-scale photonic structure analysis, emphasizing its inherent parallelism, facilitated by spatial partitioning and Fourier modal field computation. The parallelism of the FCMM is achieved by integrating the coupled mode theory (CMT) within the Fourier modal method (FMM). The proposed numerical framework of the FCMM is detailed and validated through a comparative study with the conventional FMM. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

关键词： Coupled mode theory Energy transfer finite element method finite-difference time-domain method Photonic devices Total internal reflection

来源：评论

学校读者我要写书评

暂无评论

Integrated device for polarization-independent electro-optic modulation using a splitter-rotator structure

引用

APPLIED OPTICS 2024年第27期63卷 7087-7095页

作者： Pan, Wanle Chen, Heming Hu, Yuchen Nanjing Univ Posts & Telecommun Coll Elect & Opt Engn Nanjing 210023 Peoples R China Nanjing Univ Posts & Telecommun Bell Honors Sch Nanjing 210023 Peoples R China

An integrated device for polarization-independent electro-optic (EO) modulation based on photonic crystal is proposed. It primarily consists of three components: a polarization splitter-rotator (PSR), a combiner, and a graphene EO modulator. In the PSR, the TE0 modes and TM0 modes achieve polarization splitting and mode conversion. Subsequently, the two TE0 modes pass through the combiner to merge into a single beam. Finally, the TE0 modes enter the modulator for EO modulation. The performance parameters of the integrated device are computed and analyzed using the three-dimensional finite-difference time-domain method. The results reveal that the integrated device achieves a polarization extinction ratio of 23 dB, an insertion loss of 0.3 dB, and an extinction ratio of 21.1 dB. The modulator has a driving voltage of 3.56 V and a modulation speed of 33 GHz. The integrated device is well-suited for application in large-capacity optical communication systems. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.

关键词： Coupled mode theory finite-difference time-domain method Mode conversion Photonic crystals Plasmon waveguides Wavelength division multiplexing

来源：评论

学校读者我要写书评

暂无评论

Optical properties of particle dispersed coatings with gradient distribution

引用

APPLIED OPTICS 2024年第3期63卷 681-691页

作者： Zhai, Jinan Zhang, Shangyu Zheng, Chong Liu, Linhua Shandong Univ Sch Energy & Power Engn Jinan 250061 Shandong Peoples R China Shandong Univ Inst Frontier & Interdisciplinary Sci Opt & Thermal Radiat Res Ctr Qingdao 266237 Shandong Peoples R China Sci & Technol Opt Radiat Lab Beijing 100854 Peoples R China

Particle dispersed coatings with gradient distributions, resulting from either gravity or artificial control, are frequently encountered in practical applications. However, most current studies investigating the optical properties of coatings use the uniform model (uniform single layer assumption), overlooking the gradient distribution effects. Given the pervasiveness of gradient distributions and the widespread use of the uniform model, it is imperative to evaluate applicability conditions of the uniform model in practical applications. In this work, we comprehensively investigate the quantitative performance of the uniform model in predicting the infrared optical properties of coatings with gradient distributions of particle volume fraction using the superposition T -matrix method. The results show that the gradient distribution of particle volume fraction has a limited impact on the emissivity properties of TiO2-PDMS coatings in the midwavelength-infrared (MWIR) and long -wavelength -infrared (LWIR) bands, which validates the uniform model for the gradient coatings with weakly scattering dielectric particles. However, the uniform model can yield significant inaccuracies in estimating the emissivity properties of Al-PDMS coatings with gradient distributions in the MWIR and LWIR bands. To accurately estimate the emissivity of such gradient coatings with the scattering metallic particles, meticulous modeling of the particle volume fraction distribution is essential. (c) 2024 Optica Publishing Group

关键词： Effective medium theory Effective refractive index finite element method finite-difference time-domain method Optical coatings Optical properties

来源：评论

学校读者我要写书评

暂无评论

Efficient method for modeling large-scale arrays of optical nanoresonators based on the coupling theory of quasinormal mode

引用

OPTICS EXPRESS 2024年第5期32卷 7171-7184页

作者： Tao, Qiyong Su, Yuhang Tao, Can Zhong, Ying Liu, Haitao Nankai Univ Inst Modern Opt Coll Elect Informat & Opt Engn Tianjin 300350 Peoples R China Tianjin Key Lab Microscale Opt Informat Sci & Tech Tianjin 300350 Peoples R China Nankai Univ Sch Phys MOE Key Lab Weak Light Nonlinear Photon Tianjin 300457 Peoples R China Nankai Univ TEDA Appl Phys Inst Tianjin 300457 Peoples R China Tianjin Univ State Key Lab Precis Measurement Technol & Instrum Tianjin 300072 Peoples R China

We propose an efficient method for calculating the electromagnetic field of a largescale array of optical nanoresonators based on the coupling theory of quasinormal mode (QNM). In this method, two approaches of the scattered-field reconstruction and stationary-phase-principle calculated plane-wave expansion are developed to obtain the regularized QNM (RQNM) in different regions. This accurate and efficient calculation of RQNM resolves the far-field divergence issue of QNMs in the QNM-coupling theory, thus enabling a rapid computation of the electromagnetic field of a large-scale array of optical nanoresonators, which is a challenging task for full-wave numerical methods. Using this method, we consider the numerical example of the radiation problem of a single point source in a large-scale periodic array of optical nanoantennas. In comparison to full-wave numerical methods, this method significantly reduces the computation time by 1 similar to 2 orders of magnitude while maintaining accuracy. The high computational efficiency and physical intuitiveness of the method enables to clarify the impact of array size (exceeding 50 x 50 wavelengths), period and field-coupling range (far beyond the tight-binding approximation) on the optical response. The proposed method and results can provide an efficient tool and guidance for the design of large-scale arrays of optical nanoresonators.

关键词： Field enhancement finite-difference time-domain method Light matter interactions Optical antennas Optical fields Optical force

来源：评论

学校读者我要写书评

暂无评论

Polarization-independent tetramer metastructure with multi-Fano resonances governed by quasi-bound states in the continuum

引用

OPTICS EXPRESS 2024年第18期32卷 31905-31919页

作者： Pang, Jielong Fang, Wenjing Fan, Xinye Chen, Qingtao Guo, Haoyu Wang, Tingting Wei, Xin Bai, Chenglin Kumar, Santosh Liaocheng Univ Sch Phys Sci & Informat Engn Liaocheng 252000 Peoples R China Shandong Prov Key Lab Opt Commun Sci & Technol Liaocheng 252000 Peoples R China Liaocheng Key Lab Ind Internet Res & Applicat Liaocheng 252000 Peoples R China Chinese Acad Sci Inst Semicond Beijing 100083 Peoples R China Polytech Montreal Polygrames Res Ctr Dept Elect Engn Montreal PQ H3T 1J4 Canada Koneru Lakshmaiah Educ Fdn Ctr Excellence Nanotechnol Dept Elect & Commun Engn Vaddeswaram 522302 Andhra Pradesh India

We propose what we believe to be a novel metastructure consisting of silicon nanoblock tetramer clusters and investigated theoretically and experimentally how to enhance surface sensing capabilities with polarization-independent properties through bound states in the continuum (BICs). By introducing square defects, three quasi-BIC modes are excited at the wavelengths of 1013.29 nm, 1109.57 nm, and 1310.73 nm with a modulation depth up to 100% and a Q-factor of 16618, while achieving a sensitivity of 256 nm/RIU and a figure of merit of 2519.7 RIU-1. - 1 . Utilizing the finite-difference method in the time domain (FDTD), we have analyzed the electromagnetic near-field distributions, polarization properties, and robustness corresponding to resonance dips at different wavelengths. Our results reveal that the distinct electromagnetic near-field distributions excited by the quasi-BIC modes are characterized by the strong field confinement within the silica nanoblock tetramer clusters. The modes are primarily governed by magnetic quadrupole (MQ) resonance and toroidal dipole (TD) moment. Additionally, the polarization-independent properties of the metastructure are demonstrated to ensure that they can effectively respond to the incident light regardless of its polarization state, while the robustness is investigated to show the stability and reliability by shifting square defects. Moreover, the transmission spectra of the metastructure is experimentally verified by immersing the sample into CaCl2 2 solutions in different concentrations. This work plays a pivotal role in creating further novel and high-performance optical metastructures while demonstrating the potential applications of quasi-BIC modes in precision sensing in the future. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

关键词： Effective refractive index Field enhancement finite-difference time-domain method Photonic crystals Scanning electron microscopy Subwavelength gratings

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：