Photonic neuromorphic computing has emerged as a promising avenue toward building a high-speed, low-latency, and energy-efficient non-von-Neumann computing system. Photonic spiking neural network (PSNN) exploits brain-like spatiotemporal processing to realize high-performance neuromorphic computing. Linear weighting and nonlinear spiking activation are two fundamental functions of a SNN. However, the nonlinear computation of PSNN remains a significant challenge. Therefore, this perspective focuses on the nonlinear computation of photonic spiking neurons, including numerical simulation, device fabrication, and experimental demonstration. Different photonic spiking neurons are considered, such as vertical-cavity surface-emitting lasers, distributed feedback (DFB) lasers, Fabry–Pérot (FP) lasers, or semiconductor lasers embedded with saturable absorbers (SAs) (e.g., FP-SA and DFB-SA). PSNN architectures, including fully connected and convolutional structures, are developed, and supervised and unsupervised learning algorithms that take into account optical constraints are introduced to accomplish specific applications. This work covers devices, architectures, learning algorithms, and applications for photonic and optoelectronic neuromorphic computing and provides our perspective on the challenges and prospects of photonic neuromorphic computing based on semiconductor lasers.
{"title":"Semiconductor lasers for photonic neuromorphic computing and photonic spiking neural networks: A perspective","authors":"Shuiying Xiang, Yanan Han, Shuang Gao, Ziwei Song, Yahui Zhang, Dianzhuang Zheng, Chengyang Yu, Xingxing Guo, XinTao Zeng, Zhiquan Huang, Yue Hao","doi":"10.1063/5.0217968","DOIUrl":"https://doi.org/10.1063/5.0217968","url":null,"abstract":"Photonic neuromorphic computing has emerged as a promising avenue toward building a high-speed, low-latency, and energy-efficient non-von-Neumann computing system. Photonic spiking neural network (PSNN) exploits brain-like spatiotemporal processing to realize high-performance neuromorphic computing. Linear weighting and nonlinear spiking activation are two fundamental functions of a SNN. However, the nonlinear computation of PSNN remains a significant challenge. Therefore, this perspective focuses on the nonlinear computation of photonic spiking neurons, including numerical simulation, device fabrication, and experimental demonstration. Different photonic spiking neurons are considered, such as vertical-cavity surface-emitting lasers, distributed feedback (DFB) lasers, Fabry–Pérot (FP) lasers, or semiconductor lasers embedded with saturable absorbers (SAs) (e.g., FP-SA and DFB-SA). PSNN architectures, including fully connected and convolutional structures, are developed, and supervised and unsupervised learning algorithms that take into account optical constraints are introduced to accomplish specific applications. This work covers devices, architectures, learning algorithms, and applications for photonic and optoelectronic neuromorphic computing and provides our perspective on the challenges and prospects of photonic neuromorphic computing based on semiconductor lasers.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"35 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141778525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Chhabindra Gautam, Mingsen Pan, Subhashree Seth, Thomas J. Rotter, Ming Zhou, Bradley J. Thompson, Ricky Gibson, Shanhui Fan, Ganesh Balakrishnan, Weidong Zhou
As a new type of semiconductor laser, photonic crystal surface-emitting lasers (PCSELs) feature large-area single-mode surface emission with high power and high beam quality. The unique features of single-mode lasing over a large area active region are implemented by the in-plane optical feedback from two-dimensional (2D) photonic crystal cavities. In larger PCSEL cavities, the lasing gain threshold becomes similar for the fundamental and high-order modes, which degrades single-mode operation. Here, we investigate the impact of carrier injection on PCSEL modes by controlling the injection area and the gain mode interaction. Optical and electrical simulations are carried out to calculate the gain mode overlapping factor for different p electrode designs. We fabricated 250 × 250 µm2 photonic crystal cavities with different p electrode sizes for injection area control. The PCSEL device characterization results show that devices with an electrode size to cavity side length ratio of 0.6 have the maximum slope efficiency and a lower lasing threshold with a single lobe beam profile. Such selective carrier injection can also provide gain-guided resonance in the PCSEL cavities and enhance optical gain in the fundamental mode while suppressing gain in the high-order modes.
作为一种新型半导体激光器，光子晶体表面发射激光器（PCSEL）具有大面积单模表面发射、高功率和高光束质量的特点。通过二维（2D）光子晶体腔的面内光反馈，实现了大面积有源区单模激光的独特功能。在较大的 PCSEL 腔中，基模和高阶模的激光增益阈值变得相似，从而降低了单模工作性能。在此，我们通过控制注入区域和增益模式相互作用，研究载流子注入对 PCSEL 模式的影响。我们进行了光学和电学模拟，以计算不同 p 电极设计的增益模式重叠系数。我们制作了 250 × 250 µm2 的光子晶体腔，采用不同尺寸的 p 电极来控制注入面积。PCSEL 器件的表征结果表明，电极尺寸与腔体边长比为 0.6 的器件具有最高的斜率效率和较低的激光阈值，并具有单叶光束轮廓。这种选择性载流子注入还能在 PCSEL 腔中产生增益导向共振，并在抑制高阶模式增益的同时提高基阶模式的光学增益。
{"title":"Mode distribution impact on photonic crystal surface emitting laser performance","authors":"Chhabindra Gautam, Mingsen Pan, Subhashree Seth, Thomas J. Rotter, Ming Zhou, Bradley J. Thompson, Ricky Gibson, Shanhui Fan, Ganesh Balakrishnan, Weidong Zhou","doi":"10.1063/5.0199361","DOIUrl":"https://doi.org/10.1063/5.0199361","url":null,"abstract":"As a new type of semiconductor laser, photonic crystal surface-emitting lasers (PCSELs) feature large-area single-mode surface emission with high power and high beam quality. The unique features of single-mode lasing over a large area active region are implemented by the in-plane optical feedback from two-dimensional (2D) photonic crystal cavities. In larger PCSEL cavities, the lasing gain threshold becomes similar for the fundamental and high-order modes, which degrades single-mode operation. Here, we investigate the impact of carrier injection on PCSEL modes by controlling the injection area and the gain mode interaction. Optical and electrical simulations are carried out to calculate the gain mode overlapping factor for different p electrode designs. We fabricated 250 × 250 µm2 photonic crystal cavities with different p electrode sizes for injection area control. The PCSEL device characterization results show that devices with an electrode size to cavity side length ratio of 0.6 have the maximum slope efficiency and a lower lasing threshold with a single lobe beam profile. Such selective carrier injection can also provide gain-guided resonance in the PCSEL cavities and enhance optical gain in the fundamental mode while suppressing gain in the high-order modes.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"16 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141738812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Ultrasound-induced optical clearing microscopy (US-OCM) addresses limited imaging depth in optical microscopy, caused by light scattering in biological tissues. It uses ultrasound-induced gas bubbles to better image biological samples. However, controlling the bubble location using only ultrasound is challenging. This study introduces a novel method, “optrasound,” combining optical and ultrasound energies for precise bubble control. It presents the ultrasound field and uses a focused laser to trigger bubble formation. Optrasound-induced deep microscopy improves light beam width by 3.39 times at a depth of 350 µm because the gas bubbles reduce light scattering. This technique can precisely localize a bubble cloud while matching the US-OCM performance.
{"title":"Gas bubbles induced by combined optical and ultrasound energies for high-resolution deep optical microscopy","authors":"Jinwoo Kim, Juhwan Kim, Haemin Kim, Jin Ho Chang","doi":"10.1063/5.0203205","DOIUrl":"https://doi.org/10.1063/5.0203205","url":null,"abstract":"Ultrasound-induced optical clearing microscopy (US-OCM) addresses limited imaging depth in optical microscopy, caused by light scattering in biological tissues. It uses ultrasound-induced gas bubbles to better image biological samples. However, controlling the bubble location using only ultrasound is challenging. This study introduces a novel method, “optrasound,” combining optical and ultrasound energies for precise bubble control. It presents the ultrasound field and uses a focused laser to trigger bubble formation. Optrasound-induced deep microscopy improves light beam width by 3.39 times at a depth of 350 µm because the gas bubbles reduce light scattering. This technique can precisely localize a bubble cloud while matching the US-OCM performance.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"78 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141738808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
In this paper, we introduce a quantum-secured single-pixel imaging technique designed to withstand spoofing attacks, wherein adversaries attempt to deceive imaging systems with fake signals. Unlike previous quantum-secured protocols that impose a threshold error rate limiting their operation, even with the existence of true signals, our approach not only identifies spoofing attacks but also facilitates the reconstruction of a true image. Our method involves the analysis of a specific mode correlation of a photon-pair, which is independent of the mode used for image construction, to check security. Through this analysis, we can identify both the targeted image region of the attack and the type of spoofing attack, enabling reconstruction of the true image. A proof-of-principle demonstration employing the polarization-correlation of a photon-pair is provided, showcasing successful image reconstruction even under the condition of spoofing signals that are 2000 times stronger than true signals. We expect our approach to be applied to quantum-secured signal processing, such as quantum target detection or ranging.
{"title":"True image construction in quantum-secured single-pixel imaging under spoofing attack","authors":"Jaesung Heo, Taek Jeong, Nam Hun Park, Yonggi Jo","doi":"10.1063/5.0209041","DOIUrl":"https://doi.org/10.1063/5.0209041","url":null,"abstract":"In this paper, we introduce a quantum-secured single-pixel imaging technique designed to withstand spoofing attacks, wherein adversaries attempt to deceive imaging systems with fake signals. Unlike previous quantum-secured protocols that impose a threshold error rate limiting their operation, even with the existence of true signals, our approach not only identifies spoofing attacks but also facilitates the reconstruction of a true image. Our method involves the analysis of a specific mode correlation of a photon-pair, which is independent of the mode used for image construction, to check security. Through this analysis, we can identify both the targeted image region of the attack and the type of spoofing attack, enabling reconstruction of the true image. A proof-of-principle demonstration employing the polarization-correlation of a photon-pair is provided, showcasing successful image reconstruction even under the condition of spoofing signals that are 2000 times stronger than true signals. We expect our approach to be applied to quantum-secured signal processing, such as quantum target detection or ranging.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"21 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141738807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Sebastian Müller, Kane Hill, Dominik Walter Vogt, Thomas A. Puppe, Yuriy Mayzlin, Rafal Wilk
We demonstrate the capabilities of a novel frequency-domain terahertz spectrometer based on a comb-locked frequency synthesizer, which provides absolute frequency calibration. The inherent stability and repeatability of the scans allow for the combination of fast data acquisition with an average time-limited signal-to-noise ratio. We demonstrate kilohertz level frequency resolution in terahertz precision spectroscopy of ultra-high quality whispering-gallery-mode resonators. Spectra covering multiple free spectral ranges (>36 GHz) with sub-20 kHz resolution are acquired in 5 s. We analyze the coupling behavior and temperature tuning of single resonances and, for the first time, observe minute red and blue shifts of different mode families. The experimental results are supported with finite element simulations.
{"title":"Ultra-high precision comb-locked terahertz frequency-domain spectroscopy of whispering-gallery modes","authors":"Sebastian Müller, Kane Hill, Dominik Walter Vogt, Thomas A. Puppe, Yuriy Mayzlin, Rafal Wilk","doi":"10.1063/5.0217898","DOIUrl":"https://doi.org/10.1063/5.0217898","url":null,"abstract":"We demonstrate the capabilities of a novel frequency-domain terahertz spectrometer based on a comb-locked frequency synthesizer, which provides absolute frequency calibration. The inherent stability and repeatability of the scans allow for the combination of fast data acquisition with an average time-limited signal-to-noise ratio. We demonstrate kilohertz level frequency resolution in terahertz precision spectroscopy of ultra-high quality whispering-gallery-mode resonators. Spectra covering multiple free spectral ranges (>36 GHz) with sub-20 kHz resolution are acquired in 5 s. We analyze the coupling behavior and temperature tuning of single resonances and, for the first time, observe minute red and blue shifts of different mode families. The experimental results are supported with finite element simulations.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"20 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141718514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
The cerebral lymphatic drainage plays an important role in the occurrence and development of central nervous system diseases. Recent studies have shown that cerebral lymphatic drainage is regulated by circadian rhythm and anesthesia state; however, the regulating mechanism is still unclear. In this study, we used the second near-infrared region in vivo imaging to explore the regulation of cerebral lymphatic drainage in mice at different states. At first, by injection of a tracer at different times, we confirmed that the drainage of the meningeal lymphatic system was the fastest at zeitgeber time 2, while the internal flow of the glymphatic system was the slowest. Under anesthesia with isoflurane, administration of dexmedetomidine, an anesthetic that inhibits norepinephrine (NE) release, enabled mice to enter the stage of non-rapid eye movement sleep, at which time the influx of the glymphatic system increased, the efflux of the meningeal lymphatic system decreased, and the clearance rate of the brain parenchyma decreased. However, following the exogenous NE supplement, mice quickly changed from a non-rapid eye movement stage into an awake state with the meningeal lymphatic drainage retrieval. The results showed whether the drainage of the glymphatic system and meningeal lymphatic vessels, or parenchymal clearance, has made rapid adjustments based on sleep status that is regulated by NE. This study reveals that the NE-regulated sleep–wake cycle is a powerful regulator of cerebral lymphatic drainage and provides a potential therapeutic target for related central nervous system diseases.
脑淋巴引流在中枢神经系统疾病的发生和发展中起着重要作用。近年来的研究表明，脑淋巴引流受昼夜节律和麻醉状态的调控，但其调控机制尚不清楚。在本研究中，我们利用第二近红外区域活体成像技术探讨了不同状态下小鼠脑淋巴引流的调控。首先，通过在不同时间注射示踪剂，我们证实脑膜淋巴系统的引流在zeitgeber时间2时最快，而甘淋巴系统的内流最慢。在异氟醚麻醉下，给小鼠注射右美托咪定（一种抑制去甲肾上腺素（NE）释放的麻醉剂）可使小鼠进入非快速眼动睡眠阶段，此时甘液系统的流入量增加，脑膜淋巴系统的流出量减少，脑实质的清除率降低。然而，在补充外源性 NE 后，小鼠很快从眼球非快速运动阶段转入清醒状态，脑膜淋巴引流恢复。研究结果表明，甘液系统和脑膜淋巴管的引流或实质清除是否会根据睡眠状态进行快速调整，这是受 NE 调节的。这项研究揭示了受 NE 调节的睡眠-觉醒周期是大脑淋巴引流的一个强有力的调节器，并为相关的中枢神经系统疾病提供了一个潜在的治疗靶点。
{"title":"Analysis of norepinephrine-regulated cerebral lymphatic drainage by the second near-infrared region in vivo imaging","authors":"Xi Li, Tianhao Yang, Zhongyang Zhang, Shengnan Wu, Zhen Yuan, Feifan Zhou","doi":"10.1063/5.0205571","DOIUrl":"https://doi.org/10.1063/5.0205571","url":null,"abstract":"The cerebral lymphatic drainage plays an important role in the occurrence and development of central nervous system diseases. Recent studies have shown that cerebral lymphatic drainage is regulated by circadian rhythm and anesthesia state; however, the regulating mechanism is still unclear. In this study, we used the second near-infrared region in vivo imaging to explore the regulation of cerebral lymphatic drainage in mice at different states. At first, by injection of a tracer at different times, we confirmed that the drainage of the meningeal lymphatic system was the fastest at zeitgeber time 2, while the internal flow of the glymphatic system was the slowest. Under anesthesia with isoflurane, administration of dexmedetomidine, an anesthetic that inhibits norepinephrine (NE) release, enabled mice to enter the stage of non-rapid eye movement sleep, at which time the influx of the glymphatic system increased, the efflux of the meningeal lymphatic system decreased, and the clearance rate of the brain parenchyma decreased. However, following the exogenous NE supplement, mice quickly changed from a non-rapid eye movement stage into an awake state with the meningeal lymphatic drainage retrieval. The results showed whether the drainage of the glymphatic system and meningeal lymphatic vessels, or parenchymal clearance, has made rapid adjustments based on sleep status that is regulated by NE. This study reveals that the NE-regulated sleep–wake cycle is a powerful regulator of cerebral lymphatic drainage and provides a potential therapeutic target for related central nervous system diseases.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"28 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141611022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
To realize nanoscale manufacturing based on laser direct writing technology, objective lenses with high numerical apertures immersed in water or oil are necessary. The use of liquid medium restricts its application in semiconductors. Achieving nanoscale features on silicon by laser direct writing in a low refractive index medium has been a challenge. In this work, a microsphere assisted femtosecond laser far-field induced dewetting approach is proposed. A reduction in the full-width at half-maximum of the focused light spot is realized by modulating tightly focused light through microspheres and achieving a minimum feature size of 9 nm on silicon in ambient air with energy smaller than the ablation threshold. Theoretical analysis and numerical simulation of laser processing are performed based on a two-temperature model. Furthermore, we explored the potential of femtosecond laser-induced dewetting in nanolithography and demonstrated its ability to achieve an arbitrary structure on silicon. Our work enables laser-based far-field sub-10-nm feature etching on a large-scale, providing a novel avenue for nanoscale silicon manufacturing.
{"title":"Femtosecond laser-induced dewetting of sub-10-nm nanostructures on silicon in ambient air","authors":"Hao Luo, Xiaoduo Wang, Yangdong Wen, Ye Qiu, Lianqing Liu, Haibo Yu","doi":"10.1063/5.0205219","DOIUrl":"https://doi.org/10.1063/5.0205219","url":null,"abstract":"To realize nanoscale manufacturing based on laser direct writing technology, objective lenses with high numerical apertures immersed in water or oil are necessary. The use of liquid medium restricts its application in semiconductors. Achieving nanoscale features on silicon by laser direct writing in a low refractive index medium has been a challenge. In this work, a microsphere assisted femtosecond laser far-field induced dewetting approach is proposed. A reduction in the full-width at half-maximum of the focused light spot is realized by modulating tightly focused light through microspheres and achieving a minimum feature size of 9 nm on silicon in ambient air with energy smaller than the ablation threshold. Theoretical analysis and numerical simulation of laser processing are performed based on a two-temperature model. Furthermore, we explored the potential of femtosecond laser-induced dewetting in nanolithography and demonstrated its ability to achieve an arbitrary structure on silicon. Our work enables laser-based far-field sub-10-nm feature etching on a large-scale, providing a novel avenue for nanoscale silicon manufacturing.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"46 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141586283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
We studied high-order harmonic generation (HHG) in graphene driven by either linearly or elliptically polarized mid-infrared (MIR) light, and we additionally applied terahertz (THz) pulses to modulate the electron distribution in graphene. The high-harmonic spectrum obtained using linearly polarized MIR light contains only odd-order harmonics. We found that the intensities of the fifth- and seventh-order harmonics are reduced by the modulation with the THz pulses. In addition, we found that the THz-induced reduction of the seventh-order harmonic driven by elliptically polarized MIR light (at ellipticity ε = 0.3) is larger than that of seventh-order harmonic driven by linearly polarized MIR light (ε = 0). The observed behavior can be reproduced by theoretical calculations that consider different electron temperatures (caused by the THz pulses). Furthermore, the observed stronger suppression of HHG driven by elliptically polarized light reveals the following: in the case of elliptically polarized light, the generation of harmonics via interband transitions to conduction-band states that are closer to the Dirac point is more important than in the case of linearly polarized light. In other words, the quantum pathways via interband transitions to low-energy states are the origin of the enhancement of HHG that can be achieved in graphene by using elliptically polarized light.
我们研究了线性偏振或椭圆偏振中红外光（MIR）驱动石墨烯产生的高次谐波（HHG），并额外应用太赫兹（THz）脉冲调制石墨烯中的电子分布。使用线性偏振中红外光获得的高次谐波频谱只包含奇阶谐波。我们发现，在太赫兹脉冲的调制下，五阶和七阶谐波的强度降低了。此外，我们还发现太赫兹对椭圆偏振 MIR 光（椭圆度 ε = 0.3 时）驱动的七阶谐波的抑制作用大于线性偏振 MIR 光（ε = 0）驱动的七阶谐波。理论计算考虑了不同的电子温度（由太赫兹脉冲引起），可以再现观察到的行为。此外，观察到的椭圆偏振光对 HHG 的更强抑制揭示了以下几点：与线性偏振光相比，在椭圆偏振光情况下，通过带间跃迁到更接近狄拉克点的导带态来产生谐波更为重要。换句话说，通过带间跃迁到低能态的量子途径是使用椭圆偏振光在石墨烯中增强 HHG 的起源。
{"title":"Hot electron effect in high-order harmonic generation from graphene driven by elliptically polarized light","authors":"Kotaro Nakagawa, Wenwen Mao, Shunsuke A. Sato, Hiroki Ago, Angel Rubio, Yoshihiko Kanemitsu, Hideki Hirori","doi":"10.1063/5.0212022","DOIUrl":"https://doi.org/10.1063/5.0212022","url":null,"abstract":"We studied high-order harmonic generation (HHG) in graphene driven by either linearly or elliptically polarized mid-infrared (MIR) light, and we additionally applied terahertz (THz) pulses to modulate the electron distribution in graphene. The high-harmonic spectrum obtained using linearly polarized MIR light contains only odd-order harmonics. We found that the intensities of the fifth- and seventh-order harmonics are reduced by the modulation with the THz pulses. In addition, we found that the THz-induced reduction of the seventh-order harmonic driven by elliptically polarized MIR light (at ellipticity ε = 0.3) is larger than that of seventh-order harmonic driven by linearly polarized MIR light (ε = 0). The observed behavior can be reproduced by theoretical calculations that consider different electron temperatures (caused by the THz pulses). Furthermore, the observed stronger suppression of HHG driven by elliptically polarized light reveals the following: in the case of elliptically polarized light, the generation of harmonics via interband transitions to conduction-band states that are closer to the Dirac point is more important than in the case of linearly polarized light. In other words, the quantum pathways via interband transitions to low-energy states are the origin of the enhancement of HHG that can be achieved in graphene by using elliptically polarized light.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"11 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141548276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Spectral routing techniques have attracted plenty of research attention for the past decades, as they enable light manipulation in both the frequency domain and the spatial domain, which is crucial for applications in on-chip spectroscopy, optical switching, and modern communications. Here, we demonstrate an ultra-compact asymmetric nanoplasmonic router for communication bands that routes O and C bands to opposite positions. The nanorouter consists of two uneven grooves that create bidirectional scattered optical fields, utilizing the interference between different optical modes inside the grooves. A broadband spectrum exceeding 100 nm and a maximum extinction ratio of 31 dB are achieved, providing new opportunities for nanophotonic color routing solutions and extensions to other areas such as imaging sensors and spectral measurements.
过去几十年来，光谱路由技术吸引了大量研究人员的关注，因为它们可以在频域和空间域对光进行操纵，这对于片上光谱学、光开关和现代通信中的应用至关重要。在这里，我们展示了一种用于通信波段的超紧凑非对称纳米光电路由器，它能将 O 波段和 C 波段路由到相反的位置。该纳米路由器由两个凹凸不平的凹槽组成，利用凹槽内不同光学模式之间的干涉，产生双向散射光场。实现了超过 100 nm 的宽带光谱和 31 dB 的最大消光比，为纳米光子色彩路由解决方案提供了新的机遇，并扩展到成像传感器和光谱测量等其他领域。
{"title":"Broadband color routing with a single element nanoantenna for communication bands","authors":"Xianghua Liu, Ang Li, Chenyang Liu, Nengyang Zhao, Jiahao Peng, Fengyuan Gan, Xinrui Lei, Ruxue Wang, Aimin Wu","doi":"10.1063/5.0206274","DOIUrl":"https://doi.org/10.1063/5.0206274","url":null,"abstract":"Spectral routing techniques have attracted plenty of research attention for the past decades, as they enable light manipulation in both the frequency domain and the spatial domain, which is crucial for applications in on-chip spectroscopy, optical switching, and modern communications. Here, we demonstrate an ultra-compact asymmetric nanoplasmonic router for communication bands that routes O and C bands to opposite positions. The nanorouter consists of two uneven grooves that create bidirectional scattered optical fields, utilizing the interference between different optical modes inside the grooves. A broadband spectrum exceeding 100 nm and a maximum extinction ratio of 31 dB are achieved, providing new opportunities for nanophotonic color routing solutions and extensions to other areas such as imaging sensors and spectral measurements.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"31 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141517026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
High quality (Q) factor toroidal dipole (TD) resonances have played an increasingly important role in enhancing light–matter interactions. Interestingly, TDs share a similar far-field distribution as the conventional electric/magnetic dipoles but have distinct near-field profiles from them. While most reported works focused on the electric TD, magnetic TDs (MTDs), particularly high-Q MTD, have not been fully explored yet. Here, we successfully realized a high-Q MTD by effectively harnessing the ultrahigh Q-factor guided mode resonances supported in an all-dielectric metasurface, that is, changing the interspacing between silicon nanobar dimers. Other salient properties include the stable resonance wavelength but a precisely tailored Q-factor by interspacing distance. A multipole decomposition analysis indicates that this mode is dominated by the MTD, where the electric fields are mainly confined within the dielectric nanostructures, while the induced magnetic dipole loops are connected head-to-tail. Finally, we experimentally demonstrated such high-Q MTD resonance by fabricating a series of silicon metasurfaces and measuring their transmission spectra. The MTD resonance is characterized by a sharp Fano resonance in the transmission spectrum. The maximum measured Q-factor is up to 5079. Our results provide useful guidance for realizing high-Q MTD and may find exciting applications in boosting light–matter interactions.
{"title":"High-Q magnetic toroidal dipole resonance in all-dielectric metasurfaces","authors":"Ying Zhang, Lulu Wang, Haoxuan He, Hong Duan, Jing Huang, Chenggui Gao, Shaojun You, Lujun Huang, Andrey E. Miroshnichenko, Chaobiao Zhou","doi":"10.1063/5.0208936","DOIUrl":"https://doi.org/10.1063/5.0208936","url":null,"abstract":"High quality (Q) factor toroidal dipole (TD) resonances have played an increasingly important role in enhancing light–matter interactions. Interestingly, TDs share a similar far-field distribution as the conventional electric/magnetic dipoles but have distinct near-field profiles from them. While most reported works focused on the electric TD, magnetic TDs (MTDs), particularly high-Q MTD, have not been fully explored yet. Here, we successfully realized a high-Q MTD by effectively harnessing the ultrahigh Q-factor guided mode resonances supported in an all-dielectric metasurface, that is, changing the interspacing between silicon nanobar dimers. Other salient properties include the stable resonance wavelength but a precisely tailored Q-factor by interspacing distance. A multipole decomposition analysis indicates that this mode is dominated by the MTD, where the electric fields are mainly confined within the dielectric nanostructures, while the induced magnetic dipole loops are connected head-to-tail. Finally, we experimentally demonstrated such high-Q MTD resonance by fabricating a series of silicon metasurfaces and measuring their transmission spectra. The MTD resonance is characterized by a sharp Fano resonance in the transmission spectrum. The maximum measured Q-factor is up to 5079. Our results provide useful guidance for realizing high-Q MTD and may find exciting applications in boosting light–matter interactions.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"44 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141517025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：