Littrow diffraction devices are commonly used in the laser field (e.g., laser resonators and spectrometers), where system integration requires larger incidence angles and perfect broadband efficiency. Compared to traditional diffraction devices, which struggle to manipulate light paths under large-angle incidence, metasurfaces has the potential to enhance the broadband efficiency. Despite quasi three-dimensional metasurfaces effects, only perfect anomalous reflection under normal incidence at limited wavelengths was achieved due to energy flow mismatch in the broadband Littrow configuration. Here, we propose a supercell metasurface capable of regulating broadband non-local responses. The metasurface effectively suppresses non-local responses under Littrow mounting, while providing sufficient non-local responses through strong structural coupling effects when the incidence deviates from the Littrow mounting. A large-angle broadband Littrow diffraction metasurface in the mid-infrared spectrum (3.11 µm ∼ 3.52 µm) has been successfully realized, with 99 % efficiency at Littrow angle of 70°. Our results break through the bandwidth limitations of perfect diffraction, providing robust support for the practical applications of metasurfaces in Littrow diffraction devices.
{"title":"Broadband perfect Littrow diffraction metasurface under large-angle incidence","authors":"Jingyuan Zhu, Siliang Zhou, Tao He, Chao Feng, Zhanshan Wang, Siyu Dong, Xinbin Cheng","doi":"10.1515/nanoph-2024-0622","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0622","url":null,"abstract":"Littrow diffraction devices are commonly used in the laser field (e.g., laser resonators and spectrometers), where system integration requires larger incidence angles and perfect broadband efficiency. Compared to traditional diffraction devices, which struggle to manipulate light paths under large-angle incidence, metasurfaces has the potential to enhance the broadband efficiency. Despite quasi three-dimensional metasurfaces effects, only perfect anomalous reflection under normal incidence at limited wavelengths was achieved due to energy flow mismatch in the broadband Littrow configuration. Here, we propose a supercell metasurface capable of regulating broadband non-local responses. The metasurface effectively suppresses non-local responses under Littrow mounting, while providing sufficient non-local responses through strong structural coupling effects when the incidence deviates from the Littrow mounting. A large-angle broadband Littrow diffraction metasurface in the mid-infrared spectrum (3.11 µm ∼ 3.52 µm) has been successfully realized, with 99 % efficiency at Littrow angle of 70°. Our results break through the bandwidth limitations of perfect diffraction, providing robust support for the practical applications of metasurfaces in Littrow diffraction devices.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"21 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143371509","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 : 2025-02-08DOI: 10.1515/nanoph-2024-0593
Bahadır Utku Kesgin, Uğur Teğin
Optical computing has gained significant attention as a potential solution to the growing computational demands of machine learning, particularly for tasks requiring large-scale data processing and high energy efficiency. Optical systems offer promising alternatives to digital neural networks by exploiting light’s parallelism. This study explores a photonic neural network design using spatiotemporal chaos within graded-index multimode fibers to improve machine learning performance. Through numerical simulations and experiments, we show that chaotic light propagation in multimode fibers enhances data classification accuracy across domains, including biomedical imaging, fashion, and satellite geospatial analysis. This chaotic optical approach enables high-dimensional transformations, amplifying data separability and differentiation for greater accuracy. Fine-tuning parameters such as pulse peak power optimizes the reservoir’s chaotic properties, highlighting the need for careful calibration. These findings underscore the potential of chaos-based nonlinear photonic neural networks to advance optical computing in machine learning, paving the way for efficient, scalable architectures.
{"title":"Photonic neural networks at the edge of spatiotemporal chaos in multimode fibers","authors":"Bahadır Utku Kesgin, Uğur Teğin","doi":"10.1515/nanoph-2024-0593","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0593","url":null,"abstract":"Optical computing has gained significant attention as a potential solution to the growing computational demands of machine learning, particularly for tasks requiring large-scale data processing and high energy efficiency. Optical systems offer promising alternatives to digital neural networks by exploiting light’s parallelism. This study explores a photonic neural network design using spatiotemporal chaos within graded-index multimode fibers to improve machine learning performance. Through numerical simulations and experiments, we show that chaotic light propagation in multimode fibers enhances data classification accuracy across domains, including biomedical imaging, fashion, and satellite geospatial analysis. This chaotic optical approach enables high-dimensional transformations, amplifying data separability and differentiation for greater accuracy. Fine-tuning parameters such as pulse peak power optimizes the reservoir’s chaotic properties, highlighting the need for careful calibration. These findings underscore the potential of chaos-based nonlinear photonic neural networks to advance optical computing in machine learning, paving the way for efficient, scalable architectures.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"11 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143367399","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 : 2025-02-08DOI: 10.1515/nanoph-2024-0505
Jeong Min Shin, Sanmun Kim, Sergey G. Menabde, Sehong Park, In-Goo Lee, Injue Kim, Min Seok Jang
It has long been desired to enable global structural optimization of organic light-emitting diodes (OLEDs) for maximal light extraction. The most critical obstacles to achieving this goal are time-consuming optical simulations and discrepancies between simulation and experiment. In this work, by leveraging transfer learning, we demonstrate that fast and reliable prediction of OLED optical properties is possible with several times higher data efficiency compared to previously demonstrated surrogate solvers based on artificial neural networks. Once a neural network is trained for a base OLED structure, it can be transferred to predict the properties of modified structures with additional layers with a relatively small number of additional training samples. Moreover, we demonstrate that, with only a few tenths of experimental data sets, a neural network can be trained to accurately predict experimental measurements of OLEDs, which often differ from simulation results due to fabrication and measurement errors. This is enabled by transferring a pre-trained network, built with a large amount of simulated data, to a new network capable of correcting systematic errors in experiment. Our work proposes a practical approach to designing and optimizing OLED structures with a large number of design parameters to achieve high optical efficiency.
{"title":"Data-efficient prediction of OLED optical properties enabled by transfer learning","authors":"Jeong Min Shin, Sanmun Kim, Sergey G. Menabde, Sehong Park, In-Goo Lee, Injue Kim, Min Seok Jang","doi":"10.1515/nanoph-2024-0505","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0505","url":null,"abstract":"It has long been desired to enable global structural optimization of organic light-emitting diodes (OLEDs) for maximal light extraction. The most critical obstacles to achieving this goal are time-consuming optical simulations and discrepancies between simulation and experiment. In this work, by leveraging transfer learning, we demonstrate that fast and reliable prediction of OLED optical properties is possible with several times higher data efficiency compared to previously demonstrated surrogate solvers based on artificial neural networks. Once a neural network is trained for a base OLED structure, it can be transferred to predict the properties of modified structures with additional layers with a relatively small number of additional training samples. Moreover, we demonstrate that, with only a few tenths of experimental data sets, a neural network can be trained to accurately predict experimental measurements of OLEDs, which often differ from simulation results due to fabrication and measurement errors. This is enabled by transferring a pre-trained network, built with a large amount of simulated data, to a new network capable of correcting systematic errors in experiment. Our work proposes a practical approach to designing and optimizing OLED structures with a large number of design parameters to achieve high optical efficiency.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"21 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143367403","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 : 2025-02-08DOI: 10.1515/nanoph-2024-0559
Chenghong Lei, Dehong Hu
A new concept of electrochemically modulated single-molecule localization super-resolution imaging is developed. Applications of single-molecule localization super-resolution microscopy have been limited due to insufficient availability of qualified fluorophores with favorable low duty cycles. The key for the new concept is that the “On” state of a redox-active fluorophore with unfavorable high duty cycle could be driven to “Off” state by electrochemical potential modulation and thus become available for single-molecule localization imaging. The new concept was carried out using redox-active cresyl violet with unfavorable high duty cycle as a model fluorophore by synchronizing electrochemical potential scanning with a single-molecule localization microscope. The two cytoskeletal protein structures, the microtubules from porcine brain and the actins from rabbit muscle, were selected as the model target structures for the conceptual imaging in vitro. The super-resolution images of microtubules and actins were obtained from precise single-molecule localizations determined by modulating the On/Off states of single fluorophore molecules on the cytoskeletal proteins via electrochemical potential scanning. Importantly, this method could allow more fluorophores even with unfavorable photophysical properties to become available for a wider and more extensive application of single-molecule localization microscopy.
{"title":"Electrochemically modulated single-molecule localization microscopy for in vitro imaging cytoskeletal protein structures","authors":"Chenghong Lei, Dehong Hu","doi":"10.1515/nanoph-2024-0559","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0559","url":null,"abstract":"A new concept of electrochemically modulated single-molecule localization super-resolution imaging is developed. Applications of single-molecule localization super-resolution microscopy have been limited due to insufficient availability of qualified fluorophores with favorable low duty cycles. The key for the new concept is that the “On” state of a redox-active fluorophore with unfavorable high duty cycle could be driven to “Off” state by electrochemical potential modulation and thus become available for single-molecule localization imaging. The new concept was carried out using redox-active cresyl violet with unfavorable high duty cycle as a model fluorophore by synchronizing electrochemical potential scanning with a single-molecule localization microscope. The two cytoskeletal protein structures, the microtubules from porcine brain and the actins from rabbit muscle, were selected as the model target structures for the conceptual imaging <jats:italic>in vitro</jats:italic>. The super-resolution images of microtubules and actins were obtained from precise single-molecule localizations determined by modulating the On/Off states of single fluorophore molecules on the cytoskeletal proteins via electrochemical potential scanning. Importantly, this method could allow more fluorophores even with unfavorable photophysical properties to become available for a wider and more extensive application of single-molecule localization microscopy.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"29 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143371588","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 : 2025-02-08DOI: 10.1515/nanoph-2024-0626
Muhammad Ismail Khan, Tayyab Ali Khan, Moustafa Abdelbaky, Alex M. H. Wong
Circular dichroism – the spin-selective absorption of light – finds diverse applications in medicine, antennas and microwave devices. In this work, we propose and experimentally demonstrate an ultrathin electronically reconfigurable chiral metasurface which exploits the intrinsic symmetries of the meta-molecule to realize any spin absorption based on the handedness of the chirality chosen. We construct the left-chiral and right-chiral states by reconfiguring the meta-molecule into two enantiomeric states, which achieve strong circular dichroism exceeding 82 % at the design frequency of 9.5 GHz. The meta-molecule can be switched into a third (non-chiral) state which is isotropic and transparent. The achieved circular dichroism characteristics remain insensitive to incidence angles up to ±45°. The proposed reconfigurable chiral metasurface achieves left- and right- circular dichroism at the same frequency and with high efficiency, and is an attractive candidate for wide-ranging practical applications in imaging, wireless communication and medicine.
{"title":"Realizing electronically reconfigurable intrinsic chirality: from no absorption to maximal absorption of any desirable spin","authors":"Muhammad Ismail Khan, Tayyab Ali Khan, Moustafa Abdelbaky, Alex M. H. Wong","doi":"10.1515/nanoph-2024-0626","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0626","url":null,"abstract":"Circular dichroism – the spin-selective absorption of light – finds diverse applications in medicine, antennas and microwave devices. In this work, we propose and experimentally demonstrate an ultrathin electronically reconfigurable chiral metasurface which exploits the intrinsic symmetries of the meta-molecule to realize any spin absorption based on the handedness of the chirality chosen. We construct the left-chiral and right-chiral states by reconfiguring the meta-molecule into two enantiomeric states, which achieve strong circular dichroism exceeding 82 % at the design frequency of 9.5 GHz. The meta-molecule can be switched into a third (non-chiral) state which is isotropic and transparent. The achieved circular dichroism characteristics remain insensitive to incidence angles up to ±45°. The proposed reconfigurable chiral metasurface achieves left- and right- circular dichroism at the same frequency and with high efficiency, and is an attractive candidate for wide-ranging practical applications in imaging, wireless communication and medicine.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"84 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143367400","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 : 2025-02-07DOI: 10.1515/nanoph-2024-0641
Yue Huang, Rolando V. Aguilar, Stuart A. Trugman, Sang-Wook Cheong, Yuan Long, Min-Cheol Lee, Jian-Xin Zhu, Priscila F.S. Rosa, Rohit P. Prasankumar, Dmitry A. Yarotski, Abul Azad, Nicholas S. Sirica, Antoinette J. Taylor
Understanding and controlling the antiferromagnetic order in multiferroic materials on an ultrafast time scale is a long standing area of interest, due to their potential applications in spintronics and ultrafast magnetoelectric switching. We present an optical pump-terahertz (THz) probe study on multiferroic Eu0.75Y0.25MnO3. The optical pump predominantly excites the d-d transitions of the Mn3+ ions, and the temporal evolution of the pump-induced transient conductivity is measured with a subsequent THz pulse. Two distinct, temperature-dependent decay times are revealed. The shorter relaxation time corresponds to spin-lattice thermalization, while the longer one is ascribed to electron-hole recombination. A spin-selection rule in the relaxation process is proposed in the magnetic phase. Slight suppression of the electromagnons was observed after the optical pump pulse within the spin-lattice thermalization time scale. These observed fundamental magnetic processes can shed light on ultrafast control of magnetism and photoinduced phase transitions in multiferroics.
{"title":"Electrodynamics of photo-carriers in multiferroic Eu0.75Y0.25MnO3","authors":"Yue Huang, Rolando V. Aguilar, Stuart A. Trugman, Sang-Wook Cheong, Yuan Long, Min-Cheol Lee, Jian-Xin Zhu, Priscila F.S. Rosa, Rohit P. Prasankumar, Dmitry A. Yarotski, Abul Azad, Nicholas S. Sirica, Antoinette J. Taylor","doi":"10.1515/nanoph-2024-0641","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0641","url":null,"abstract":"Understanding and controlling the antiferromagnetic order in multiferroic materials on an ultrafast time scale is a long standing area of interest, due to their potential applications in spintronics and ultrafast magnetoelectric switching. We present an optical pump-terahertz (THz) probe study on multiferroic Eu<jats:sub>0.75</jats:sub>Y<jats:sub>0.25</jats:sub>MnO<jats:sub>3</jats:sub>. The optical pump predominantly excites the d-d transitions of the Mn<jats:sup>3+</jats:sup> ions, and the temporal evolution of the pump-induced transient conductivity is measured with a subsequent THz pulse. Two distinct, temperature-dependent decay times are revealed. The shorter relaxation time corresponds to spin-lattice thermalization, while the longer one is ascribed to electron-hole recombination. A spin-selection rule in the relaxation process is proposed in the magnetic phase. Slight suppression of the electromagnons was observed after the optical pump pulse within the spin-lattice thermalization time scale. These observed fundamental magnetic processes can shed light on ultrafast control of magnetism and photoinduced phase transitions in multiferroics.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"55 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143367402","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}
High resolution imaging represents a relentless pursuit within the field of optical system. Multi-frame super-resolution (SR) is an effective method for enhancing sampling density, while it heavily relies on sub-pixel scale displacement of a bulky camera. Based on the symmetric transformation of quadratic-phase metasurface, we propose scaled transverse translation (STT) utilizing planar optical elements (POEs) to facilitate sub-pixel sampling and remote super-resolution imaging. The STT module composed of a pair of planar optical elements with conjugated quadratic phase profile is fabricated and experimentally verified. By displacing POE within a millimeter-level range, we achieve sub-micron in imaging shift accuracy. Furthermore, the results of SR and SR enhanced Fourier ptychography imaging demonstrate significant compatibility and effectiveness of this module. The resolution improvement in FP imaging increases from 2× to 2.8× by sub-pixel sampling using this module. Moreover, defect reduction and contrast enhancement are obtained. With its advantages of light-weight, simple structure and ease of implementation, this method shows considerable potential for numerous imaging applications.
{"title":"Scaled transverse translation by planar optical elements for sub-pixel sampling and remote super-resolution imaging","authors":"Qi Zhang, Xin Xu, Yinghui Guo, Yuran Lu, Qiong He, Mingbo Pu, Xiaoyin Li, Mingfeng Xu, Fei Zhang, Xiangang Luo","doi":"10.1515/nanoph-2024-0600","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0600","url":null,"abstract":"High resolution imaging represents a relentless pursuit within the field of optical system. Multi-frame super-resolution (SR) is an effective method for enhancing sampling density, while it heavily relies on sub-pixel scale displacement of a bulky camera. Based on the symmetric transformation of quadratic-phase metasurface, we propose scaled transverse translation (STT) utilizing planar optical elements (POEs) to facilitate sub-pixel sampling and remote super-resolution imaging. The STT module composed of a pair of planar optical elements with conjugated quadratic phase profile is fabricated and experimentally verified. By displacing POE within a millimeter-level range, we achieve sub-micron in imaging shift accuracy. Furthermore, the results of SR and SR enhanced Fourier ptychography imaging demonstrate significant compatibility and effectiveness of this module. The resolution improvement in FP imaging increases from 2× to 2.8× by sub-pixel sampling using this module. Moreover, defect reduction and contrast enhancement are obtained. With its advantages of light-weight, simple structure and ease of implementation, this method shows considerable potential for numerous imaging applications.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"1 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143258451","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 : 2025-02-06DOI: 10.1515/nanoph-2024-0628
Young-Bin Kim, Jaehyeon Park, Jun-Young Kim, Seok-Beom Seo, Sun-Kyung Kim, Eungkyu Lee
The W-band is essential for applications like high-resolution imaging and advanced monitoring systems, but high-frequency signal attenuation leads to poor signal-to-noise ratios, posing challenges for compact and multi-channel systems. This necessitates distinct frequency selective surfaces (FSS) on a single substrate, a complex task due to inherent substrate resonance modes. In this study, we use a digital metasurface platform to design W-band FSS on a glass substrate, optimized through binary optimization assisted by active learning. The digital metasurface is composed of a periodic array of sub-wavelength unit cells, each containing hundreds of metal or dielectric pixels that act as binary states. By utilizing a machine learning model, we apply active learning-aided binary optimization to determine the optimal binary state configurations for a given target FSS profile. Specifically, we identify optimal designs for distinct FSS on a conventional glass substrate, with transmittance peaks at 79.3 GHz and Q-factors of 32.7.
{"title":"W-band frequency selective digital metasurface using active learning-based binary optimization","authors":"Young-Bin Kim, Jaehyeon Park, Jun-Young Kim, Seok-Beom Seo, Sun-Kyung Kim, Eungkyu Lee","doi":"10.1515/nanoph-2024-0628","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0628","url":null,"abstract":"The W-band is essential for applications like high-resolution imaging and advanced monitoring systems, but high-frequency signal attenuation leads to poor signal-to-noise ratios, posing challenges for compact and multi-channel systems. This necessitates distinct frequency selective surfaces (FSS) on a single substrate, a complex task due to inherent substrate resonance modes. In this study, we use a digital metasurface platform to design W-band FSS on a glass substrate, optimized through binary optimization assisted by active learning. The digital metasurface is composed of a periodic array of sub-wavelength unit cells, each containing hundreds of metal or dielectric pixels that act as binary states. By utilizing a machine learning model, we apply active learning-aided binary optimization to determine the optimal binary state configurations for a given target FSS profile. Specifically, we identify optimal designs for distinct FSS on a conventional glass substrate, with transmittance peaks at 79.3 GHz and Q-factors of 32.7.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"55 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143258643","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 : 2025-02-06DOI: 10.1515/nanoph-2024-0554
Iris Niehues, Daniel Wigger, Korbinian Kaltenecker, Annika Klein-Hitpass, Philippe Roelli, Aleksandra K. Dąbrowska, Katarzyna Ludwiczak, Piotr Tatarczak, Janne O. Becker, Robert Schmidt, Martin Schnell, Johannes Binder, Andrzej Wysmołek, Rainer Hillenbrand
Color centers in hexagonal boron nitride (hBN) are promising candidates as quantum light sources for future technologies. In this work, we utilize a scattering-type near-field optical microscope (s-SNOM) to study the photoluminescence (PL) emission characteristics of such quantum emitters in metalorganic vapor phase epitaxy grown hBN. On the one hand, we demonstrate direct near-field optical excitation and emission through interaction with the nanofocus of the tip resulting in a subdiffraction limited tip-enhanced PL hotspot. On the other hand, we show that indirect excitation and emission via scattering from the tip significantly increases the recorded PL intensity. This demonstrates that the tip-assisted PL (TAPL) process efficiently guides the generated light to the detector. We apply the TAPL method to map the in-plane dipole orientations of the hBN color centers on the nanoscale. This work promotes the widely available s-SNOM approach to applications in the quantum domain including characterization and optical control.
{"title":"Nanoscale resolved mapping of the dipole emission of hBN color centers with a scattering-type scanning near-field optical microscope","authors":"Iris Niehues, Daniel Wigger, Korbinian Kaltenecker, Annika Klein-Hitpass, Philippe Roelli, Aleksandra K. Dąbrowska, Katarzyna Ludwiczak, Piotr Tatarczak, Janne O. Becker, Robert Schmidt, Martin Schnell, Johannes Binder, Andrzej Wysmołek, Rainer Hillenbrand","doi":"10.1515/nanoph-2024-0554","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0554","url":null,"abstract":"Color centers in hexagonal boron nitride (hBN) are promising candidates as quantum light sources for future technologies. In this work, we utilize a scattering-type near-field optical microscope (s-SNOM) to study the photoluminescence (PL) emission characteristics of such quantum emitters in metalorganic vapor phase epitaxy grown hBN. On the one hand, we demonstrate direct near-field optical excitation and emission through interaction with the nanofocus of the tip resulting in a subdiffraction limited tip-enhanced PL hotspot. On the other hand, we show that indirect excitation and emission via scattering from the tip significantly increases the recorded PL intensity. This demonstrates that the tip-assisted PL (TAPL) process efficiently guides the generated light to the detector. We apply the TAPL method to map the in-plane dipole orientations of the hBN color centers on the nanoscale. This work promotes the widely available s-SNOM approach to applications in the quantum domain including characterization and optical control.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"50 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143258454","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 : 2025-02-06DOI: 10.1515/nanoph-2024-0619
Seok-Beom Seo, Jong-Goog Lee, Jae-Seon Yu, Jae-Hyun Kim, Serang Jung, Gumin Kang, Hyungduk Ko, Run Hu, Eungkyu Lee, Sun-Kyung Kim
The increasing global temperatures have escalated the demand for indoor cooling, thus requiring energy-saving solutions. Traditional approaches often integrate metal layers in cooling windows to block near-infrared (NIR) sunlight, which, albeit effective, lack the broad modulation of visible transmission and lead to heat accumulation due to sunlight absorption. Here, we address these limitations by developing cooling windows using ZnS/MgF2 multilayers, optimized through a binary optimization-based active learning process. We demonstrated that these multilayers, with a total thickness below 1 µm, effectively reduced indoor temperatures by blocking NIR sunlight while achieving desired visible transmittance. The designed multilayers exhibited visible transmittance ranging from 0.41 to 0.89 while retaining decent NIR reflectance between 0.37 and 0.52. These spectral characteristics remained consistent up to incident angles of >60°, ensuring their practical applicability for vertically oriented windows. Outdoor experiments showed substantial temperature reductions of up to 8.8 °C on floors compared to uncoated glass windows. The active learning-based multilayers exhibited superior performance compared to analytical ZnS/MgF2 distributed Bragg reflectors with equivalent thicknesses by improving NIR reflectance and modulating visible transmittance. In addition, multilayers with a greater number of bits extensively tuned transmission color, enabling customization for aesthetic purposes. These findings suggest that all-dielectric multilayers can provide a scalable, cost-effective alternative for reducing energy consumption in buildings and vehicles with large glass surfaces, supporting efforts to mitigate climate change through enhanced energy efficiency.
{"title":"Visible transparency modulated cooling windows using pseudorandom dielectric multilayers","authors":"Seok-Beom Seo, Jong-Goog Lee, Jae-Seon Yu, Jae-Hyun Kim, Serang Jung, Gumin Kang, Hyungduk Ko, Run Hu, Eungkyu Lee, Sun-Kyung Kim","doi":"10.1515/nanoph-2024-0619","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0619","url":null,"abstract":"The increasing global temperatures have escalated the demand for indoor cooling, thus requiring energy-saving solutions. Traditional approaches often integrate metal layers in cooling windows to block near-infrared (NIR) sunlight, which, albeit effective, lack the broad modulation of visible transmission and lead to heat accumulation due to sunlight absorption. Here, we address these limitations by developing cooling windows using ZnS/MgF<jats:sub>2</jats:sub> multilayers, optimized through a binary optimization-based active learning process. We demonstrated that these multilayers, with a total thickness below 1 µm, effectively reduced indoor temperatures by blocking NIR sunlight while achieving desired visible transmittance. The designed multilayers exhibited visible transmittance ranging from 0.41 to 0.89 while retaining decent NIR reflectance between 0.37 and 0.52. These spectral characteristics remained consistent up to incident angles of >60°, ensuring their practical applicability for vertically oriented windows. Outdoor experiments showed substantial temperature reductions of up to 8.8 °C on floors compared to uncoated glass windows. The active learning-based multilayers exhibited superior performance compared to analytical ZnS/MgF<jats:sub>2</jats:sub> distributed Bragg reflectors with equivalent thicknesses by improving NIR reflectance and modulating visible transmittance. In addition, multilayers with a greater number of bits extensively tuned transmission color, enabling customization for aesthetic purposes. These findings suggest that all-dielectric multilayers can provide a scalable, cost-effective alternative for reducing energy consumption in buildings and vehicles with large glass surfaces, supporting efforts to mitigate climate change through enhanced energy efficiency.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"15 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143258467","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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