Pub Date : 2024-09-09DOI: 10.1515/nanoph-2024-0295
Seokjin Hong, Jinhyeong Yoon, Junhyeong Kim, Berkay Neseli, Jae-Yong Kim, Hyo-Hoon Park, Hamza Kurt
Once light is coupled to a photonic chip, its efficient distribution in terms of power splitting throughout silicon photonic circuits is very crucial. We present two types of 1 × 4 power splitters with different splitting ratios of 1:1:1:1 and 2:1:1:2. Various taper configurations were compared and analyzed to find the suitable configuration for the power splitter, and among them, parabolic tapers were chosen. The design parameters of the power splitter were determined by means of solving inverse design problems via incorporating particle swarm optimization that allows for overcoming the limitation of the intuition-based brute-force approach. The front and rear portions of the power splitters were optimized sequentially to alleviate local minima issues. The proposed power splitters have a compact footprint of 12.32 × 5 μm2 and can be fabricated through a CMOS-compatible fabrication process. Two-stage power splitter trees were measured to enhance reliability in an experiment. As a result, the power splitter with a splitting ratio of 1:1:1:1 exhibited an experimentally measured insertion loss below 0.61 dB and an imbalance below 1.01 dB within the bandwidth of 1,518–1,565 nm. Also, the power splitter with a splitting ratio of 2:1:1:2 showed an insertion loss below 0.52 dB and a targeted imbalance below 1.15 dB within the bandwidth of 1,526–1,570 nm. Such inverse-designed power splitters can be an essential part of many large-scale photonic circuits including optical phased arrays, programmable photonics, and photonic computing chips.
{"title":"Inverse-designed taper configuration for the enhancement of integrated 1 × 4 silicon photonic power splitters","authors":"Seokjin Hong, Jinhyeong Yoon, Junhyeong Kim, Berkay Neseli, Jae-Yong Kim, Hyo-Hoon Park, Hamza Kurt","doi":"10.1515/nanoph-2024-0295","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0295","url":null,"abstract":"Once light is coupled to a photonic chip, its efficient distribution in terms of power splitting throughout silicon photonic circuits is very crucial. We present two types of 1 × 4 power splitters with different splitting ratios of 1:1:1:1 and 2:1:1:2. Various taper configurations were compared and analyzed to find the suitable configuration for the power splitter, and among them, parabolic tapers were chosen. The design parameters of the power splitter were determined by means of solving inverse design problems via incorporating particle swarm optimization that allows for overcoming the limitation of the intuition-based brute-force approach. The front and rear portions of the power splitters were optimized sequentially to alleviate local minima issues. The proposed power splitters have a compact footprint of 12.32 × 5 μm<jats:sup>2</jats:sup> and can be fabricated through a CMOS-compatible fabrication process. Two-stage power splitter trees were measured to enhance reliability in an experiment. As a result, the power splitter with a splitting ratio of 1:1:1:1 exhibited an experimentally measured insertion loss below 0.61 dB and an imbalance below 1.01 dB within the bandwidth of 1,518–1,565 nm. Also, the power splitter with a splitting ratio of 2:1:1:2 showed an insertion loss below 0.52 dB and a targeted imbalance below 1.15 dB within the bandwidth of 1,526–1,570 nm. Such inverse-designed power splitters can be an essential part of many large-scale photonic circuits including optical phased arrays, programmable photonics, and photonic computing chips.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"4 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-09DOI: 10.1515/nanoph-2024-0298
Canran Zhang, Yijing Xu, Hui Tao, Pan Wang, Yunkang Cui, Qilong Wang
Optical interconnects, leveraging surface plasmon modes, are revolutionizing high-performance computing and AI, overcoming the limitations of electrical interconnects in speed, energy efficiency, and miniaturization. These nanoscale photonic circuits integrate on-chip light manipulation and signal conversion, marking significant advancements in optoelectronics and data processing efficiency. Here, we present a novel plasmonic interconnect circuit, by introducing refractive index matching layer, the device supports both pure SPP and different hybrid modes, allowing selective excitation and transmission based on light wavelength and polarization, followed by photocurrent conversion. We optimized the coupling gratings to fine-tune transmission modes around specific near-infrared wavelengths for effective electrical detection. Simulation results align with experimental data, confirming the device’s ability to detect complex optical modes. This advancement broadens the applications of plasmonic interconnects in high-speed, compact optoelectronic and sensor technologies, enabling more versatile nanoscale optical signal processing and transmission.
{"title":"On chip control and detection of complex SPP and waveguide modes based on plasmonic interconnect circuits","authors":"Canran Zhang, Yijing Xu, Hui Tao, Pan Wang, Yunkang Cui, Qilong Wang","doi":"10.1515/nanoph-2024-0298","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0298","url":null,"abstract":"Optical interconnects, leveraging surface plasmon modes, are revolutionizing high-performance computing and AI, overcoming the limitations of electrical interconnects in speed, energy efficiency, and miniaturization. These nanoscale photonic circuits integrate on-chip light manipulation and signal conversion, marking significant advancements in optoelectronics and data processing efficiency. Here, we present a novel plasmonic interconnect circuit, by introducing refractive index matching layer, the device supports both pure SPP and different hybrid modes, allowing selective excitation and transmission based on light wavelength and polarization, followed by photocurrent conversion. We optimized the coupling gratings to fine-tune transmission modes around specific near-infrared wavelengths for effective electrical detection. Simulation results align with experimental data, confirming the device’s ability to detect complex optical modes. This advancement broadens the applications of plasmonic interconnects in high-speed, compact optoelectronic and sensor technologies, enabling more versatile nanoscale optical signal processing and transmission.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"22 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-09DOI: 10.1515/nanoph-2024-0213
Jacob LaMountain, Amogh Raju, Daniel Wasserman, Viktor A. Podolskiy
Photonic funnels, microscale conical waveguides that have been recently realized in the mid-IR spectral range with the help of an all-semiconductor designer metal material platform, are promising devices for efficient coupling of light between the nanoscales and macroscales. Previous analyses of photonic funnels have focused on structures with highly conductive claddings. Here, we analyze the performance of funnels with and without cladding, as a function of material properties, operating wavelength, and geometry. We demonstrate that bare (cladding-free) funnels enable orders-of-magnitude higher enhancement of local intensity than their clad counterparts, with virtually no loss of confinement, and relate this phenomenon to anomalous reflection of light at the anisotropic material–air interface. Intensity enhancement of the order of 25, with confinement of light to wavelength/20 scale, is demonstrated. Efficient extraction of light from nanoscale areas is predicted.
{"title":"Anomalous reflection for highly efficient subwavelength light concentration and extraction with photonic funnels","authors":"Jacob LaMountain, Amogh Raju, Daniel Wasserman, Viktor A. Podolskiy","doi":"10.1515/nanoph-2024-0213","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0213","url":null,"abstract":"Photonic funnels, microscale conical waveguides that have been recently realized in the mid-IR spectral range with the help of an all-semiconductor designer metal material platform, are promising devices for efficient coupling of light between the nanoscales and macroscales. Previous analyses of photonic funnels have focused on structures with highly conductive claddings. Here, we analyze the performance of funnels with and without cladding, as a function of material properties, operating wavelength, and geometry. We demonstrate that bare (cladding-free) funnels enable orders-of-magnitude higher enhancement of local intensity than their clad counterparts, with virtually no loss of confinement, and relate this phenomenon to anomalous reflection of light at the anisotropic material–air interface. Intensity enhancement of the order of 25, with confinement of light to wavelength/20 scale, is demonstrated. Efficient extraction of light from nanoscale areas is predicted.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"148 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-07DOI: 10.1515/nanoph-2024-0320
Xiaolin Yi, Dongyue Sun, Weike Zhao, Hanwen Li, Long Zhang, Yaocheng Shi, Daoxin Dai
Efficient coupling between optical fibers and on-chip photonic waveguides has long been a crucial issue for photonic chips used in various applications. Edge couplers (ECs) based on an inverse taper have seen widespread utilization due to their intrinsic broadband operation. However, it still remains a big challenge to realize polarization-insensitive low-loss ECs working at the O-band (1,260–1,360 nm), mainly due to the strong polarization dependence of the mode coupling/conversion and the difficulty to fabricate the taper tip with an ultra-small feature size. In this paper, a high-efficiency and polarization-insensitive O-band EC is proposed and demonstrated with great advantages that is fully compatible with the current 130-nm-node fabrication processes. By introducing an asymmetric bi-level dual-core mode converter, the fundamental mode confined in the thick core is evanescently coupled to that in the thin core, which has an expanded mode size matched well with the fiber and works well for both TE/TM-polarizations. Particularly, no bi-level junction in the propagation direction is introduced between the thick and thin waveguide sections, thereby breaking the critical limitation of ultra-small feature sizes. The calculated coupling loss is 0.44–0.56/0.48–0.61 dB across the O-band, while achieving 1-dB bandwidths exceeding 340/230 nm for the TE/TM-polarization modes. For the fabricated ECs, the peak coupling loss is ∼0.82 dB with a polarization dependent loss of ∼0.31 dB at the O-band when coupled to a fiber with a mode field diameter of 4 μm. It is expected that this coupling scheme promisingly provides a general solution even for other material platforms, e.g., lithium niobate, silicon nitride and so on.
光纤与片上光子波导之间的高效耦合一直是各种应用中光子芯片的关键问题。基于反锥形的边缘耦合器（EC）因其固有的宽带工作特性而得到广泛应用。然而，在 O 波段（1,260-1,360 nm）实现对偏振不敏感的低损耗边缘耦合器仍然是一个巨大的挑战，这主要是由于模式耦合/转换具有很强的偏振依赖性，而且很难制造出具有超小特征尺寸的锥形尖端。本文提出并演示了一种高效且对偏振不敏感的 O 波段电子镇流器，它具有与当前 130 纳米节点制造工艺完全兼容的巨大优势。通过引入非对称双电平双核模式转换器，限制在厚纤芯中的基模被逐渐耦合到薄纤芯中的基模，从而扩大了与光纤相匹配的模式尺寸，并在 TE/TM 两种偏振情况下都能正常工作。特别是，厚波导和薄波导之间在传播方向上没有引入双电平结，从而打破了超小特征尺寸的关键限制。计算得出的 O 波段耦合损耗为 0.44-0.56/0.48-0.61 dB，而 TE/TM 偏振模式的 1-dB 带宽超过 340/230 nm。对于所制造的 EC，当与模式场直径为 4 μm 的光纤耦合时，O 波段的峰值耦合损耗为 ∼0.82 dB，偏振相关损耗为 ∼0.31 dB。这种耦合方案有望为其他材料平台（如铌酸锂、氮化硅等）提供通用解决方案。
{"title":"Asymmetric bi-level dual-core mode converter for high-efficiency and polarization-insensitive O-band fiber-chip edge coupling: breaking the critical size limitation","authors":"Xiaolin Yi, Dongyue Sun, Weike Zhao, Hanwen Li, Long Zhang, Yaocheng Shi, Daoxin Dai","doi":"10.1515/nanoph-2024-0320","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0320","url":null,"abstract":"Efficient coupling between optical fibers and on-chip photonic waveguides has long been a crucial issue for photonic chips used in various applications. Edge couplers (ECs) based on an inverse taper have seen widespread utilization due to their intrinsic broadband operation. However, it still remains a big challenge to realize polarization-insensitive low-loss ECs working at the O-band (1,260–1,360 nm), mainly due to the strong polarization dependence of the mode coupling/conversion and the difficulty to fabricate the taper tip with an ultra-small feature size. In this paper, a high-efficiency and polarization-insensitive O-band EC is proposed and demonstrated with great advantages that is fully compatible with the current 130-nm-node fabrication processes. By introducing an asymmetric bi-level dual-core mode converter, the fundamental mode confined in the thick core is evanescently coupled to that in the thin core, which has an expanded mode size matched well with the fiber and works well for both TE/TM-polarizations. Particularly, no bi-level junction in the propagation direction is introduced between the thick and thin waveguide sections, thereby breaking the critical limitation of ultra-small feature sizes. The calculated coupling loss is 0.44–0.56/0.48–0.61 dB across the O-band, while achieving 1-dB bandwidths exceeding 340/230 nm for the TE/TM-polarization modes. For the fabricated ECs, the peak coupling loss is ∼0.82 dB with a polarization dependent loss of ∼0.31 dB at the O-band when coupled to a fiber with a mode field diameter of 4 μm. It is expected that this coupling scheme promisingly provides a general solution even for other material platforms, e.g., lithium niobate, silicon nitride and so on.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"48 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142152416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-05DOI: 10.1515/nanoph-2024-0338
Yu Zhao, Huijiao Wang, Tian Huang, Zhiqiang Guan, Zile Li, Lei Yu, Shaohua Yu, Guoxing Zheng
Advancements in computer science have propelled society into an era of data explosion, marked by a critical need for enhanced data transmission capacity, particularly in the realm of space-division multiplexing and demultiplexing devices for fiber communications. However, recently developed mode demultiplexers primarily focus on mode divisions within one dimension rather than multiple dimensions (i.e., intensity distributions and polarization states), which significantly limits their applicability in space-division multiplexing communications. In this context, we introduce a neural network-assisted meta-router to recognize intensity distributions and polarization states of optical fiber modes, achieved through a single layer of metasurface optimized via neural network techniques. Specifically, a four-mode meta-router is theoretically designed and experimentally characterized, which enables four modes, comprising two spatial modes with two polarization states, independently divided into distinct spatial regions, and successfully recognized by positions of corresponding spatial regions. Our framework provides a paradigm for fiber mode demultiplexing apparatus characterized by application compatibility, transmission capacity, and function scalability with ultra-simple design and ultra-compact device. Merging metasurfaces, neural network and mode routing, this proposed framework paves a practical pathway towards intelligent metasurface-aided optical interconnection, including applications such as fiber communication, object recognition and classification, as well as information display, processing, and encryption.
{"title":"Neural network-assisted meta-router for fiber mode and polarization demultiplexing","authors":"Yu Zhao, Huijiao Wang, Tian Huang, Zhiqiang Guan, Zile Li, Lei Yu, Shaohua Yu, Guoxing Zheng","doi":"10.1515/nanoph-2024-0338","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0338","url":null,"abstract":"Advancements in computer science have propelled society into an era of data explosion, marked by a critical need for enhanced data transmission capacity, particularly in the realm of space-division multiplexing and demultiplexing devices for fiber communications. However, recently developed mode demultiplexers primarily focus on mode divisions within one dimension rather than multiple dimensions (i.e., intensity distributions and polarization states), which significantly limits their applicability in space-division multiplexing communications. In this context, we introduce a neural network-assisted meta-router to recognize intensity distributions and polarization states of optical fiber modes, achieved through a single layer of metasurface optimized via neural network techniques. Specifically, a four-mode meta-router is theoretically designed and experimentally characterized, which enables four modes, comprising two spatial modes with two polarization states, independently divided into distinct spatial regions, and successfully recognized by positions of corresponding spatial regions. Our framework provides a paradigm for fiber mode demultiplexing apparatus characterized by application compatibility, transmission capacity, and function scalability with ultra-simple design and ultra-compact device. Merging metasurfaces, neural network and mode routing, this proposed framework paves a practical pathway towards intelligent metasurface-aided optical interconnection, including applications such as fiber communication, object recognition and classification, as well as information display, processing, and encryption.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"1 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142142619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-05DOI: 10.1515/nanoph-2024-0344
Yuzhong Ou, Yan Chen, Fei Zhang, Mingbo Pu, Mengna Jiang, Mingfeng Xu, Yinghui Guo, Chaolong Feng, Ping Gao, Xiangang Luo
Asymmetric spin–orbit interaction (ASOI) breaks the limitations in conjugate symmetry of traditional geometric phase metasurfaces, bringing new opportunities for various applications such as spin-decoupled holography, imaging, and complex light field manipulation. Since anisotropy is a requirement for spin–orbit interactions, existing ASOI mainly relies on meta-atom with C1 and C2 symmetries, which usually suffer from an efficiency decrease caused by the propagation phase control through the structural size. Here, we demonstrate for the first time that ASOI can be realized in meta-atoms with rotational symmetry ≥3 by combining the generalized geometric phase with the propagation phase. Utilizing an all-metallic configuration, the average diffraction efficiency of the spin-decoupled beam deflector based on C3 meta-atoms reaches ∼84 % in the wavelength range of 9.3–10.6 μm, which is much higher than that of the commonly used C2 meta-atoms with the same period and height. This is because the anisotropy of the C3 metasurface originates from the lattice coupling effect, which is relatively insensitive to the propagation phase control through the meta-atom size. A spin-decoupled beam deflector and hologram meta-device were experimentally demonstrated and performed well over a broadband wavelength range. This work opens a new route for ASOI, which is significant for realizing high-efficiency and broadband spin-decoupled meta-devices.
{"title":"High-efficiency and broadband asymmetric spin–orbit interaction based on high-order composite phase modulation","authors":"Yuzhong Ou, Yan Chen, Fei Zhang, Mingbo Pu, Mengna Jiang, Mingfeng Xu, Yinghui Guo, Chaolong Feng, Ping Gao, Xiangang Luo","doi":"10.1515/nanoph-2024-0344","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0344","url":null,"abstract":"Asymmetric spin–orbit interaction (ASOI) breaks the limitations in conjugate symmetry of traditional geometric phase metasurfaces, bringing new opportunities for various applications such as spin-decoupled holography, imaging, and complex light field manipulation. Since anisotropy is a requirement for spin–orbit interactions, existing ASOI mainly relies on meta-atom with C1 and C2 symmetries, which usually suffer from an efficiency decrease caused by the propagation phase control through the structural size. Here, we demonstrate for the first time that ASOI can be realized in meta-atoms with rotational symmetry ≥3 by combining the generalized geometric phase with the propagation phase. Utilizing an all-metallic configuration, the average diffraction efficiency of the spin-decoupled beam deflector based on C3 meta-atoms reaches ∼84 % in the wavelength range of 9.3–10.6 μm, which is much higher than that of the commonly used C2 meta-atoms with the same period and height. This is because the anisotropy of the C3 metasurface originates from the lattice coupling effect, which is relatively insensitive to the propagation phase control through the meta-atom size. A spin-decoupled beam deflector and hologram meta-device were experimentally demonstrated and performed well over a broadband wavelength range. This work opens a new route for ASOI, which is significant for realizing high-efficiency and broadband spin-decoupled meta-devices.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"102 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142142626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-04DOI: 10.1515/nanoph-2024-0240
Eduardo Granados, Miguel Martinez-Calderon, Baptiste Groussin, Jean Philippe Colombier, Ibon Santiago
The prospect of employing nanophotonic methods for controlling photon–electron interactions has ignited substantial interest within the particle accelerator community. Silicon-based integrated dielectric laser acceleration (DLA) has emerged as a viable option by leveraging localized photonic effects to emit, accelerate, and measure electron bunches using exclusively light. Here, using highly regular nanopatterning over large areas while preserving the crystalline structure of silicon is imperative to enhance the efficiency and yield of photon-electron effects. While several established fabrication techniques may be used to produce the required silicon nanostructures, alternative techniques are beneficial to enhance scalability, simplicity and cost-efficiency. In this study, we demonstrate the nano-synthesis of silicon structures over arbitrarily large areas utilizing exclusively deep ultraviolet (DUV) ultrafast laser excitation. This approach delivers highly concentrated electromagnetic energy to the material, thus producing nanostructures with features well beyond the diffraction limit. At the core of our demonstration is the production of silicon laser-induced surface structures with an exceptionally high aspect-ratio -reaching a height of more than 100 nm- for a nanostructure periodicity of 250 nm. This result is attained by exploiting a positive feedback effect on the locally enhanced laser electric field as the surface morphology dynamically emerges, in combination with the material properties at DUV wavelengths. We also observe strong nanopattern hybridization yielding intricate 2D structural features as the onset of amorphization takes place at high laser pulse fluence. This technique offers a simple, yet efficient and attractive approach to produce highly uniform and high aspect ratio silicon nanostructures in the 200–300 nm range.
{"title":"Highly uniform silicon nanopatterning with deep-ultraviolet femtosecond pulses","authors":"Eduardo Granados, Miguel Martinez-Calderon, Baptiste Groussin, Jean Philippe Colombier, Ibon Santiago","doi":"10.1515/nanoph-2024-0240","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0240","url":null,"abstract":"The prospect of employing nanophotonic methods for controlling photon–electron interactions has ignited substantial interest within the particle accelerator community. Silicon-based integrated dielectric laser acceleration (DLA) has emerged as a viable option by leveraging localized photonic effects to emit, accelerate, and measure electron bunches using exclusively light. Here, using highly regular nanopatterning over large areas while preserving the crystalline structure of silicon is imperative to enhance the efficiency and yield of photon-electron effects. While several established fabrication techniques may be used to produce the required silicon nanostructures, alternative techniques are beneficial to enhance scalability, simplicity and cost-efficiency. In this study, we demonstrate the nano-synthesis of silicon structures over arbitrarily large areas utilizing exclusively deep ultraviolet (DUV) ultrafast laser excitation. This approach delivers highly concentrated electromagnetic energy to the material, thus producing nanostructures with features well beyond the diffraction limit. At the core of our demonstration is the production of silicon laser-induced surface structures with an exceptionally high aspect-ratio -reaching a height of more than 100 nm- for a nanostructure periodicity of 250 nm. This result is attained by exploiting a positive feedback effect on the locally enhanced laser electric field as the surface morphology dynamically emerges, in combination with the material properties at DUV wavelengths. We also observe strong nanopattern hybridization yielding intricate 2D structural features as the onset of amorphization takes place at high laser pulse fluence. This technique offers a simple, yet efficient and attractive approach to produce highly uniform and high aspect ratio silicon nanostructures in the 200–300 nm range.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"101 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142138105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Owing to its topological properties and band collapse, Floquet helical photonic lattices have gained increasing attention as a purely classical setting to realize the optical analogues of a wide variety of quantum phenomena. We demonstrate both theoretically and numerically that light propagation in an appropriately designed helical superlattice can exhibit spatial photonic Zitterbewegung effect, i.e., a quiver spatial oscillatory motion of the beam center of mass around its mean trajectory, in both one- and two-dimensional cases. The lattice spacing determines the effective coupling strength between adjacent helical waveguides, and further drastically not only affects the oscillation amplitude and frequency, but also invert their direction of drift when the effective coupling strength is tuned from positive to negative. Complete arrest and inversion of the drift direction of Zitterbewegung effect are reported.
{"title":"Optical Zitterbewegung effect in arrays of helical waveguides","authors":"Kaiyun Zhan, Qixuan Chen, Qian Zhang, Tingjun Zhao, Hanqiang Qin, Haolong He, Guangting Yao","doi":"10.1515/nanoph-2024-0329","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0329","url":null,"abstract":"Owing to its topological properties and band collapse, Floquet helical photonic lattices have gained increasing attention as a purely classical setting to realize the optical analogues of a wide variety of quantum phenomena. We demonstrate both theoretically and numerically that light propagation in an appropriately designed helical superlattice can exhibit spatial photonic Zitterbewegung effect, i.e., a quiver spatial oscillatory motion of the beam center of mass around its mean trajectory, in both one- and two-dimensional cases. The lattice spacing determines the effective coupling strength between adjacent helical waveguides, and further drastically not only affects the oscillation amplitude and frequency, but also invert their direction of drift when the effective coupling strength is tuned from positive to negative. Complete arrest and inversion of the drift direction of Zitterbewegung effect are reported.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"8 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142138106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-29DOI: 10.1515/nanoph-2024-0301
Junpeng Liao, Dongmei Huang, Yegang Lu, Yan Li, Ye Tian
Mode converters (MCs) play an essential role in mode-division multiplexing (MDM) systems. Numerous schemes have been developed on the silicon-on-insulator (SOI) platform, yet most of them focus solely on the conversion of fundamental mode to one or two specific higher-order modes. In this study, we introduce a hybrid shape optimization (HSO) method that combines particle swarm optimization (PSO) with adjoint methods to optimize the shape of the S-bend waveguide, facilitating the design of arbitrary-order MCs featuring compactness and high performance. Our approach was validated by designing a series of 13 μm-long MCs, enabling efficient conversion between various TE modes, ranging from TE0 to TE3. These devices can be fabricated in a single lithography step and exhibit robust fabrication tolerances. Experiment results indicate that these converters achieve low insertion losses under 1 dB and crosstalks below −15 dB across bandwidths of 80 nm (TE0–TE1), 62 nm (TE0–TE2), 70 nm (TE0–TE3), 80 nm (TE1–TE2), 55 nm (TE1–TE3), and 75 nm (TE2–TE3). This advancement paves the way for flexible mode conversion, significantly enhancing the versatility of on-chip MDM technologies.
模式转换器（MC）在模分复用（MDM）系统中发挥着至关重要的作用。在绝缘体上硅（SOI）平台上已开发出许多方案，但其中大多数方案仅侧重于将基本模式转换为一个或两个特定的高阶模式。在本研究中，我们介绍了一种混合形状优化（HSO）方法，该方法将粒子群优化（PSO）与辅助方法相结合，以优化 S 形弯曲波导的形状，从而促进具有紧凑性和高性能特点的任意阶 MC 的设计。我们的方法通过设计一系列 13 μm 长的 MC 得到了验证，这些 MC 能够在 TE0 到 TE3 的各种 TE 模式之间实现高效转换。这些器件只需一个光刻步骤就能制作完成，并表现出良好的制作公差。实验结果表明，这些转换器在 80 nm（TE0-TE1）、62 nm（TE0-TE2）、70 nm（TE0-TE3）、80 nm（TE1-TE2）、55 nm（TE1-TE3）和 75 nm（TE2-TE3）的带宽范围内实现了低于 1 dB 的低插入损耗和低于 -15 dB 的串扰。这一进步为灵活的模式转换铺平了道路，大大提高了片上 MDM 技术的通用性。
{"title":"Low-loss and compact arbitrary-order silicon mode converter based on hybrid shape optimization","authors":"Junpeng Liao, Dongmei Huang, Yegang Lu, Yan Li, Ye Tian","doi":"10.1515/nanoph-2024-0301","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0301","url":null,"abstract":"Mode converters (MCs) play an essential role in mode-division multiplexing (MDM) systems. Numerous schemes have been developed on the silicon-on-insulator (SOI) platform, yet most of them focus solely on the conversion of fundamental mode to one or two specific higher-order modes. In this study, we introduce a hybrid shape optimization (HSO) method that combines particle swarm optimization (PSO) with adjoint methods to optimize the shape of the S-bend waveguide, facilitating the design of arbitrary-order MCs featuring compactness and high performance. Our approach was validated by designing a series of 13 μm-long MCs, enabling efficient conversion between various TE modes, ranging from TE<jats:sub>0</jats:sub> to TE<jats:sub>3</jats:sub>. These devices can be fabricated in a single lithography step and exhibit robust fabrication tolerances. Experiment results indicate that these converters achieve low insertion losses under 1 dB and crosstalks below −15 dB across bandwidths of 80 nm (TE<jats:sub>0</jats:sub>–TE<jats:sub>1</jats:sub>), 62 nm (TE<jats:sub>0</jats:sub>–TE<jats:sub>2</jats:sub>), 70 nm (TE<jats:sub>0</jats:sub>–TE<jats:sub>3</jats:sub>), 80 nm (TE<jats:sub>1</jats:sub>–TE<jats:sub>2</jats:sub>), 55 nm (TE<jats:sub>1</jats:sub>–TE<jats:sub>3</jats:sub>), and 75 nm (TE<jats:sub>2</jats:sub>–TE<jats:sub>3</jats:sub>). This advancement paves the way for flexible mode conversion, significantly enhancing the versatility of on-chip MDM technologies.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"146 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142100987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-28DOI: 10.1515/nanoph-2024-0169
Domenico Genchi, Francesca Dodici, Tiziana Cesca, Giovanni Mattei
The design of optical materials in nonlinear devices represents a fundamental step for their optimization and miniaturization, that would significantly contribute to the progress of advanced nanophotonics and quantum technologies. In this work, the effect of geometry and composition of multilayer hyperbolic metamaterials on their third-order nonlinear optical properties, i.e. the optical Kerr effect, is investigated. One figure of merit is provided to be used as a predictive tool to design and best exploit the local intensity enhancement in low-loss metamaterials to be used for various applications in nonlinear nanophotonics.
{"title":"Design of optical Kerr effect in multilayer hyperbolic metamaterials","authors":"Domenico Genchi, Francesca Dodici, Tiziana Cesca, Giovanni Mattei","doi":"10.1515/nanoph-2024-0169","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0169","url":null,"abstract":"The design of optical materials in nonlinear devices represents a fundamental step for their optimization and miniaturization, that would significantly contribute to the progress of advanced nanophotonics and quantum technologies. In this work, the effect of geometry and composition of multilayer hyperbolic metamaterials on their third-order nonlinear optical properties, i.e. the optical Kerr effect, is investigated. One figure of merit is provided to be used as a predictive tool to design and best exploit the local intensity enhancement in low-loss metamaterials to be used for various applications in nonlinear nanophotonics.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"2014 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142089914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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