Pub Date : 2024-05-12DOI: 10.1088/2515-7647/ad46aa
Guoxiang Si, Wen Zhao, Hongyu Zhang and Cuicui Lu
Topological disclination states are highly localized and stable by means of introducing disclination, which provide a robust platform for realizing optical information transition. A photonic encoder, as a kind of optical information transition element, can record, transmit, and protect optical information. However, there is no effective methods to realize topological photonic encoders. In this work, we propose a method to realize topological photonic encoder through topological disclination states. After the introduction of a disclination in the honeycomb structure, four types of disclination states can be generated. To demonstrate the device to carry more information, nine disclination structures with different cylindrical radii are combined, and the disclination states can be denoted by digital signals 1–4 to prepare a topological photonic encoder. In addition, to improve the security of information transition, we build an encryption algorithm based on Morse code. This work provides a new idea for the construction of encoding devices and promotes the practical application of the topological disclination states.
{"title":"Topological photonic encoder based on the disclination states","authors":"Guoxiang Si, Wen Zhao, Hongyu Zhang and Cuicui Lu","doi":"10.1088/2515-7647/ad46aa","DOIUrl":"https://doi.org/10.1088/2515-7647/ad46aa","url":null,"abstract":"Topological disclination states are highly localized and stable by means of introducing disclination, which provide a robust platform for realizing optical information transition. A photonic encoder, as a kind of optical information transition element, can record, transmit, and protect optical information. However, there is no effective methods to realize topological photonic encoders. In this work, we propose a method to realize topological photonic encoder through topological disclination states. After the introduction of a disclination in the honeycomb structure, four types of disclination states can be generated. To demonstrate the device to carry more information, nine disclination structures with different cylindrical radii are combined, and the disclination states can be denoted by digital signals 1–4 to prepare a topological photonic encoder. In addition, to improve the security of information transition, we build an encryption algorithm based on Morse code. This work provides a new idea for the construction of encoding devices and promotes the practical application of the topological disclination states.","PeriodicalId":44008,"journal":{"name":"Journal of Physics-Photonics","volume":"206 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140933607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-12DOI: 10.1088/2515-7647/ad46a8
Taoran Le, Jiarui Li, Haoyun Wei and Yan Li
Impulsive stimulated Brillouin scattering (ISBS) is a variant of stimulated Brillouin scattering, which can overcome the shortcomings of the long acquisition time of traditional Brillouin microscopy. We introduce the difference between ISBS and other Brillouin microscopies in calculating longitudinal modulus. The Brillouin frequency shift obtained by ISBS is only related to the system parameters and the speed of sound (SOS) in the sample, not to the refractive index. Non-contact SOS measurement of homogeneous samples is an important application of Brillouin scattering, used in the early study of Brillouin spectroscopy and the mechanical properties of liquids. However, the measurement requires prior knowledge of the sample refractive index, which limits the measurement of the unknown refractive index sample. Here, we propose a method to measure the SOS based on ISBS, which in principle avoids the need for refractive index parameters. The SOS of several liquids are measured and compared with the standard values. The mean relative standard deviation is 1.13%. Moreover, we measure the SOS of a mixture of ethanol and water to demonstrate an application of measuring SOS without refractive index information. We also demonstrate the high spatial resolution of ISBS with a methanol-filled PDMS sample.
脉冲刺激布里渊散射（ISBS）是刺激布里渊散射的一种变体，它可以克服传统布里渊显微镜采集时间长的缺点。我们介绍了 ISBS 与其他布里渊显微镜在计算纵向模量方面的区别。ISBS 获得的布里渊频移只与系统参数和样品中的声速（SOS）有关，而与折射率无关。对均匀样品进行非接触式 SOS 测量是布里渊散射的一项重要应用，早期用于研究布里渊光谱和液体的机械特性。然而，测量需要事先了解样品的折射率，这就限制了对未知折射率样品的测量。在此，我们提出了一种基于 ISBS 的 SOS 测量方法，原则上无需折射率参数。我们测量了几种液体的 SOS，并将其与标准值进行了比较。平均相对标准偏差为 1.13%。此外，我们还测量了乙醇和水的混合物的 SOS，展示了在没有折射率信息的情况下测量 SOS 的应用。我们还利用充满甲醇的 PDMS 样品展示了 ISBS 的高空间分辨率。
{"title":"Speed of sound measurement and mapping in transparent materials by impulsive stimulated Brillouin microscopy","authors":"Taoran Le, Jiarui Li, Haoyun Wei and Yan Li","doi":"10.1088/2515-7647/ad46a8","DOIUrl":"https://doi.org/10.1088/2515-7647/ad46a8","url":null,"abstract":"Impulsive stimulated Brillouin scattering (ISBS) is a variant of stimulated Brillouin scattering, which can overcome the shortcomings of the long acquisition time of traditional Brillouin microscopy. We introduce the difference between ISBS and other Brillouin microscopies in calculating longitudinal modulus. The Brillouin frequency shift obtained by ISBS is only related to the system parameters and the speed of sound (SOS) in the sample, not to the refractive index. Non-contact SOS measurement of homogeneous samples is an important application of Brillouin scattering, used in the early study of Brillouin spectroscopy and the mechanical properties of liquids. However, the measurement requires prior knowledge of the sample refractive index, which limits the measurement of the unknown refractive index sample. Here, we propose a method to measure the SOS based on ISBS, which in principle avoids the need for refractive index parameters. The SOS of several liquids are measured and compared with the standard values. The mean relative standard deviation is 1.13%. Moreover, we measure the SOS of a mixture of ethanol and water to demonstrate an application of measuring SOS without refractive index information. We also demonstrate the high spatial resolution of ISBS with a methanol-filled PDMS sample.","PeriodicalId":44008,"journal":{"name":"Journal of Physics-Photonics","volume":"123 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140933463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-16DOI: 10.1088/2515-7647/ad3d1b
Saeid Ebrahimzadeh, Sakib Adnan, Yishen Li, Vito F Pecile, Jakob Fellinger, Sarper Salman, Christoph M Heyl, Ingmar Hartl, Oliver H Heckl, Gil Porat
Applications of mode-locked fiber lasers benefit from robust and self-starting mode-locking, spectral tuning, high pulse energy and high average power. All-polarization-maintaining (PM) fiber lasers mode-locked with a phase-biased nonlinear amplifying loop mirror (NALM) have been shown to be very robust and reliably self-starting, and provide either spectral tuning or high pulse energy, but not both. We report on a simple method for concurrent spectral tuning and nanojoule-level pulse energy scaling of an all-PM phase-biased NALM mode-locked Yb:fiber laser, which we demonstrate over a 54 nm tuning range, reaching up to 1.67 nJ pulse energy and 126 mW average power. Unlike other laser configurations, our results show that net normal dispersion is not necessary or optimal for scaling the pulse energy of this type of mode-locked fiber laser.
{"title":"Spectrally tunable phase-biased NALM mode-locked Yb:fiber laser with nJ-level pulse energy","authors":"Saeid Ebrahimzadeh, Sakib Adnan, Yishen Li, Vito F Pecile, Jakob Fellinger, Sarper Salman, Christoph M Heyl, Ingmar Hartl, Oliver H Heckl, Gil Porat","doi":"10.1088/2515-7647/ad3d1b","DOIUrl":"https://doi.org/10.1088/2515-7647/ad3d1b","url":null,"abstract":"Applications of mode-locked fiber lasers benefit from robust and self-starting mode-locking, spectral tuning, high pulse energy and high average power. All-polarization-maintaining (PM) fiber lasers mode-locked with a phase-biased nonlinear amplifying loop mirror (NALM) have been shown to be very robust and reliably self-starting, and provide either spectral tuning or high pulse energy, but not both. We report on a simple method for concurrent spectral tuning and nanojoule-level pulse energy scaling of an all-PM phase-biased NALM mode-locked Yb:fiber laser, which we demonstrate over a 54 nm tuning range, reaching up to 1.67 nJ pulse energy and 126 mW average power. Unlike other laser configurations, our results show that net normal dispersion is not necessary or optimal for scaling the pulse energy of this type of mode-locked fiber laser.","PeriodicalId":44008,"journal":{"name":"Journal of Physics-Photonics","volume":"261 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140615892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-14DOI: 10.1088/2515-7647/ad2b4c
Silvi Bundo, Shweta Pal, Marco Ernst, Rebecca Saive
Bifacial photovoltaic modules along highways provide energy supply and act as sound barriers simultaneously. This study examines the impact on energy production when incorporating sound barriers with varying light reflection properties into this integrated solar infrastructure along roadways. Specifically, we use advanced computational simulations to analyze the effects of integrating black, ideal specular, and ideal diffuse (Lambertian) reflectors into an existing highway solar power plant located in the Netherlands. Our analysis combines realistic spectro-angular irradiance data as input with our in-house reverse ray tracing software. Our calculations show that for an east-west facing system, an ideal diffuse reflector increases the annual yield by 70%, while a specular reflector decreases the yield due to shading. Most notably, the diffuse reflector doubles the energy yield during winter months, thereby offering a pathway to decrease the seasonal energy demand and supply gap.
{"title":"Spectro-angular analysis of roadside-integrated bifacial solar power systems with reflecting sound barriers","authors":"Silvi Bundo, Shweta Pal, Marco Ernst, Rebecca Saive","doi":"10.1088/2515-7647/ad2b4c","DOIUrl":"https://doi.org/10.1088/2515-7647/ad2b4c","url":null,"abstract":"Bifacial photovoltaic modules along highways provide energy supply and act as sound barriers simultaneously. This study examines the impact on energy production when incorporating sound barriers with varying light reflection properties into this integrated solar infrastructure along roadways. Specifically, we use advanced computational simulations to analyze the effects of integrating black, ideal specular, and ideal diffuse (Lambertian) reflectors into an existing highway solar power plant located in the Netherlands. Our analysis combines realistic spectro-angular irradiance data as input with our in-house reverse ray tracing software. Our calculations show that for an east-west facing system, an ideal diffuse reflector increases the annual yield by 70%, while a specular reflector decreases the yield due to shading. Most notably, the diffuse reflector doubles the energy yield during winter months, thereby offering a pathway to decrease the seasonal energy demand and supply gap.","PeriodicalId":44008,"journal":{"name":"Journal of Physics-Photonics","volume":"30 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140314578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-14DOI: 10.1088/2515-7647/ad2bd2
Virendra Kumar, Parag Sharma, Dalip Singh Mehta
The applicability of diode-lasers in automobile headlights is an advanced innovation for the automobile illumination industry due to the extraordinary properties of laser light over conventional light sources, such as high brightness, wide colour gamut, high directionality, low energy consumptions and long lifetime. Lasers are highly coherent in nature, so they encounter the problem of unwanted speckles and spurious fringes and always require a high level of opto-thermal engineering along with speckle reduction mechanisms for high lumen laser applications. Targeting such challenges, in this paper, we report an innovative design and development scheme for a high lumen laser-based automotive headlamp module. The headlamp prototype comprises a set of four cylindrical diffusers which distribute the high energy laser radiation via scattering along the length of the diffusers within a metallic mirro-based pyramidal cavity reflector. The scattered laser light from cylindrical diffusers interacts with a remote phosphor layer that prevents phosphor–resin burning. The pyramidal cavity reflector plays an important role in making the laser light uniform and speckle-free, via spatial and angular diversity, as light exits from the cavity after multiple internal reflections. This reflector redirects the highly concentrated white light over a long range without using any projection lens. The design and performance of the headlight system was studied using TracePro simulation software and tested experimentally in a photometric laboratory. The International Commission on Illumination (CIE) coordinates of the light generated by the headlamp was (0.3947, 0.4908) and the correlated colour temperature was 4240 K, which represents warm white light illumination.
{"title":"Design and development of speckle-free high-power laser-driven phosphor converted compact automotive headlamp module","authors":"Virendra Kumar, Parag Sharma, Dalip Singh Mehta","doi":"10.1088/2515-7647/ad2bd2","DOIUrl":"https://doi.org/10.1088/2515-7647/ad2bd2","url":null,"abstract":"The applicability of diode-lasers in automobile headlights is an advanced innovation for the automobile illumination industry due to the extraordinary properties of laser light over conventional light sources, such as high brightness, wide colour gamut, high directionality, low energy consumptions and long lifetime. Lasers are highly coherent in nature, so they encounter the problem of unwanted speckles and spurious fringes and always require a high level of opto-thermal engineering along with speckle reduction mechanisms for high lumen laser applications. Targeting such challenges, in this paper, we report an innovative design and development scheme for a high lumen laser-based automotive headlamp module. The headlamp prototype comprises a set of four cylindrical diffusers which distribute the high energy laser radiation via scattering along the length of the diffusers within a metallic mirro-based pyramidal cavity reflector. The scattered laser light from cylindrical diffusers interacts with a remote phosphor layer that prevents phosphor–resin burning. The pyramidal cavity reflector plays an important role in making the laser light uniform and speckle-free, via spatial and angular diversity, as light exits from the cavity after multiple internal reflections. This reflector redirects the highly concentrated white light over a long range without using any projection lens. The design and performance of the headlight system was studied using TracePro simulation software and tested experimentally in a photometric laboratory. The International Commission on Illumination (CIE) coordinates of the light generated by the headlamp was (0.3947, 0.4908) and the correlated colour temperature was 4240 K, which represents warm white light illumination.","PeriodicalId":44008,"journal":{"name":"Journal of Physics-Photonics","volume":"33 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140314914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-11DOI: 10.1088/2515-7647/ad2e0d
Pietro Ricci, Giuseppe Sancataldo, Vladislav Gavryusev, Francesco Saverio Pavone, Peter Saggau, Martí Duocastella
Cutting-edge methodologies and techniques are required to understand complex neuronal dynamics and pathological mechanisms. Among them, optical tools stand out due to their combination of non-invasiveness, speed, and precision. Examples include optical microscopy, capable of characterizing extended neuronal populations in small vertebrates at high spatiotemporal resolution, or all-optical electrophysiology and optogenetics, suitable for direct control of neuronal activity. However, these approaches necessitate progressively higher levels of accuracy, efficiency, and flexibility of illumination for observing fast entangled neuronal events at a millisecond time-scale over large brain regions. A promising solution is the use of acousto-optic deflectors (AODs). Based on exploiting the acousto-optic effects, AODs are high-performance devices that enable rapid and precise light deflection, up to MHz rates. Such high-speed control of light enables unique features, including random-access scanning or parallelized multi-beam illumination. Here, we survey the main applications of AODs in neuroscience, from fluorescence imaging to optogenetics. We also review the theory and physical mechanisms of these devices and describe the main configurations developed to accomplish flexible illumination strategies for a better understanding of brain function.
{"title":"Acousto-optic deflectors in experimental neuroscience: overview of theory and applications","authors":"Pietro Ricci, Giuseppe Sancataldo, Vladislav Gavryusev, Francesco Saverio Pavone, Peter Saggau, Martí Duocastella","doi":"10.1088/2515-7647/ad2e0d","DOIUrl":"https://doi.org/10.1088/2515-7647/ad2e0d","url":null,"abstract":"Cutting-edge methodologies and techniques are required to understand complex neuronal dynamics and pathological mechanisms. Among them, optical tools stand out due to their combination of non-invasiveness, speed, and precision. Examples include optical microscopy, capable of characterizing extended neuronal populations in small vertebrates at high spatiotemporal resolution, or all-optical electrophysiology and optogenetics, suitable for direct control of neuronal activity. However, these approaches necessitate progressively higher levels of accuracy, efficiency, and flexibility of illumination for observing fast entangled neuronal events at a millisecond time-scale over large brain regions. A promising solution is the use of acousto-optic deflectors (AODs). Based on exploiting the acousto-optic effects, AODs are high-performance devices that enable rapid and precise light deflection, up to MHz rates. Such high-speed control of light enables unique features, including random-access scanning or parallelized multi-beam illumination. Here, we survey the main applications of AODs in neuroscience, from fluorescence imaging to optogenetics. We also review the theory and physical mechanisms of these devices and describe the main configurations developed to accomplish flexible illumination strategies for a better understanding of brain function.","PeriodicalId":44008,"journal":{"name":"Journal of Physics-Photonics","volume":"5 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140314917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-07DOI: 10.1088/2515-7647/ad2bd3
Vincent Wanie, Pasquale Barbato, Josina Hahne, Sergey Ryabchuk, Ammar Bin Wahid, David Amorim, Erik P Månsson, Andrea Trabattoni, Roberto Osellame, Rebeca Martínez Vázquez, Francesca Calegari
We investigate the generation of ultrabroadband femtosecond ultraviolet (UV) radiation via third-order harmonic generation in highly confined gas media. A dual-stage differential-pumping scheme integrated into a glass microfluidic chip provides an exceptional gas confinement up to several bar and allows the apparatus to be operated under high-vacuum environment. UV pulses are generated both in argon and neon with up to ∼0.8 μJ energy and 0.2% conversion efficiency for spectra that cover the UVB and UVC regions between 200 and 325 nm. Numerical simulations based on the unidirectional pulse propagation equation reveal that ionization plays a critical role for extending the spectral bandwidth of the generated third-harmonic pulse beyond the tripled 800 nm driving laser pulse bandwidth. By delivering UV supercontinua supporting Fourier transform limits below 2 fs, as well as comparable pulse energies with respect to capillary-based techniques that typically provide high spectral tunability but produce narrower bandwidths, our compact device makes a step forward towards the production and application of sub-fs UV pulses for the investigation of electron dynamics in neutral molecules.
{"title":"Ultraviolet supercontinuum generation using a differentially-pumped integrated glass chip","authors":"Vincent Wanie, Pasquale Barbato, Josina Hahne, Sergey Ryabchuk, Ammar Bin Wahid, David Amorim, Erik P Månsson, Andrea Trabattoni, Roberto Osellame, Rebeca Martínez Vázquez, Francesca Calegari","doi":"10.1088/2515-7647/ad2bd3","DOIUrl":"https://doi.org/10.1088/2515-7647/ad2bd3","url":null,"abstract":"We investigate the generation of ultrabroadband femtosecond ultraviolet (UV) radiation via third-order harmonic generation in highly confined gas media. A dual-stage differential-pumping scheme integrated into a glass microfluidic chip provides an exceptional gas confinement up to several bar and allows the apparatus to be operated under high-vacuum environment. UV pulses are generated both in argon and neon with up to ∼0.8 <italic toggle=\"yes\">μ</italic>J energy and 0.2% conversion efficiency for spectra that cover the UVB and UVC regions between 200 and 325 nm. Numerical simulations based on the unidirectional pulse propagation equation reveal that ionization plays a critical role for extending the spectral bandwidth of the generated third-harmonic pulse beyond the tripled 800 nm driving laser pulse bandwidth. By delivering UV supercontinua supporting Fourier transform limits below 2 fs, as well as comparable pulse energies with respect to capillary-based techniques that typically provide high spectral tunability but produce narrower bandwidths, our compact device makes a step forward towards the production and application of sub-fs UV pulses for the investigation of electron dynamics in neutral molecules.","PeriodicalId":44008,"journal":{"name":"Journal of Physics-Photonics","volume":"139 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140314829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-16DOI: 10.1088/2515-7647/ad2529
Tanguy Colleu, Adam Fekete, Xavier Gonze, Alexandre Cloots, Vincent Liégeois, Gian-Marco Rignanese, Luc Henrard
Surface enhanced infrared absorption (SEIRA) is an experimental method where trace amount of a compound can be detected with high sensibility. This high detection sensibility is the result of the interaction of the molecules with a localized plasmon, usually from a metallic nanoparticle. In this study we numerically investigate by discrete dipole approximation the origin of the Fano-like response of the system, including the induced transparency when the plasmon resonance and the molecular vibrational mode coincide. The detailed analysis of the localization of the absorption shows that the modification of the absorption cross-section when the molecule is present comes from a change of the plasmonic resonance, not from the direct molecular response which is negligible. This sheds a new light on the SEIRA mechanism. In particular, it demonstrates that the sensibility is associated with the influence of the molecule on the plasmon resonance rather than with the local field enhancement itself.
{"title":"Surface enhanced infrared absorption mechanism and modification of the plasmonic response","authors":"Tanguy Colleu, Adam Fekete, Xavier Gonze, Alexandre Cloots, Vincent Liégeois, Gian-Marco Rignanese, Luc Henrard","doi":"10.1088/2515-7647/ad2529","DOIUrl":"https://doi.org/10.1088/2515-7647/ad2529","url":null,"abstract":"Surface enhanced infrared absorption (SEIRA) is an experimental method where trace amount of a compound can be detected with high sensibility. This high detection sensibility is the result of the interaction of the molecules with a localized plasmon, usually from a metallic nanoparticle. In this study we numerically investigate by discrete dipole approximation the origin of the Fano-like response of the system, including the induced transparency when the plasmon resonance and the molecular vibrational mode coincide. The detailed analysis of the localization of the absorption shows that the modification of the absorption cross-section when the molecule is present comes from a change of the plasmonic resonance, not from the direct molecular response which is negligible. This sheds a new light on the SEIRA mechanism. In particular, it demonstrates that the sensibility is associated with the influence of the molecule on the plasmon resonance rather than with the local field enhancement itself.","PeriodicalId":44008,"journal":{"name":"Journal of Physics-Photonics","volume":"6 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140003945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research aims to understand colouring technologies in 5th–7th centuries glass imported to Atlantic Britain by correlating the iron (Fe) and manganese (Mn) ratios and oxidation states with colour. Despite having a similar matrix chemical composition and concentrations of Fe and Mn oxides, these vessels display different colours (from green to yellow/amber, sometimes with purple streaks). Colour changes can be induced by controlling the reduction-oxidation reactions that occur during glass production, which are influenced by the raw materials, furnace and melt atmosphere, and recycling. To evaluate these parameters, reference glasses were prepared, following the composition of Late Antique archaeological glass recovered from Tintagel (UK) and Whithorn (UK). A corpus of archaeological and experimental glass samples was analysed using bulk Fe and Mn K-edge x-ray absorption near edge structure (XANES) spectroscopy, micro-XANES and micro x-ray fluorescence (μ-XRF) at beamline ID21, at the European Synchrotron Radiation Facility. Fe and Mn XANES spectra of the archaeological glass indicate that Fe and Mn are in a similar oxidation state in all the yellow samples, predominantly Fe3+ and Mn2+. No detectable difference in Mn and Fe oxidation state occurs in the purple streaks compared to the yellow glass bulk but μ-XRF maps of the distribution of Fe and Mn show that Mn is more concentrated in the purple streaks. This indicates that the purple colour of the streaks is mainly due to a higher Mn/Fe ratio and persistence of more oxidised manganese in the purple areas, even though it is difficult to detect. Many archaeological fragments appear pale green in transmitted light but amber in reflected light. XANES studies detected the presence of surface layers where manganese is more oxidised. This layer is believed to scatter transmitted and reflected light differently and might be responsible for the optical features of the archaeological glass.
这项研究旨在通过将铁（Fe）和锰（Mn）的比率和氧化状态与颜色联系起来，了解 5-7 世纪进口到大西洋不列颠的玻璃的着色技术。尽管基质化学成分以及铁和锰氧化物的浓度相似，但这些器皿却呈现出不同的颜色（从绿色到黄色/琥珀色，有时还带有紫色条纹）。玻璃生产过程中发生的还原-氧化反应受原材料、熔炉和熔融气氛以及回收利用的影响，通过控制这些反应可以诱发颜色变化。为了评估这些参数，我们按照从廷塔吉尔（英国）和惠索恩（英国）出土的晚期古代考古玻璃的成分制备了参考玻璃。在欧洲同步辐射设施的 ID21 光束线，使用体铁和锰 K 边 X 射线吸收近缘结构 (XANES) 光谱、微 XANES 和微 X 射线荧光 (μ-XRF) 分析了大量考古和实验玻璃样品。考古玻璃的铁和锰 XANES 光谱表明，所有黄色样品中的铁和锰都处于相似的氧化态，主要是 Fe3+ 和 Mn2+。紫色条纹中的锰和铁的氧化态与黄色玻璃块体中的锰和铁的氧化态相比没有可检测到的差异，但是铁和锰的μ-XRF 分布图显示，锰在紫色条纹中更为集中。这表明，条纹的紫色主要是由于锰/铁比率较高，以及紫色区域持续存在较多氧化锰，尽管很难检测到。许多考古碎片在透射光下呈淡绿色，但在反射光下呈琥珀色。XANES 研究发现了锰氧化程度较高的表层。据信，这一层对透射光和反射光的散射不同，可能是造成考古玻璃光学特征的原因。
{"title":"Unravelling the role of iron and manganese oxides in colouring Late Antique glass by micro-XANES and micro-XRF spectroscopies","authors":"Francesca Gherardi, Clément Hole, Ewan Campbell, Marine Cotte, Rachel Tyson, Sarah Paynter","doi":"10.1088/2515-7647/ad2259","DOIUrl":"https://doi.org/10.1088/2515-7647/ad2259","url":null,"abstract":"This research aims to understand colouring technologies in 5th–7th centuries glass imported to Atlantic Britain by correlating the iron (Fe) and manganese (Mn) ratios and oxidation states with colour. Despite having a similar matrix chemical composition and concentrations of Fe and Mn oxides, these vessels display different colours (from green to yellow/amber, sometimes with purple streaks). Colour changes can be induced by controlling the reduction-oxidation reactions that occur during glass production, which are influenced by the raw materials, furnace and melt atmosphere, and recycling. To evaluate these parameters, reference glasses were prepared, following the composition of Late Antique archaeological glass recovered from Tintagel (UK) and Whithorn (UK). A corpus of archaeological and experimental glass samples was analysed using bulk Fe and Mn K-edge x-ray absorption near edge structure (XANES) spectroscopy, micro-XANES and micro x-ray fluorescence (<italic toggle=\"yes\">μ</italic>-XRF) at beamline ID21, at the European Synchrotron Radiation Facility. Fe and Mn XANES spectra of the archaeological glass indicate that Fe and Mn are in a similar oxidation state in all the yellow samples, predominantly Fe<sup>3+</sup> and Mn<sup>2+</sup>. No detectable difference in Mn and Fe oxidation state occurs in the purple streaks compared to the yellow glass bulk but <italic toggle=\"yes\">μ</italic>-XRF maps of the distribution of Fe and Mn show that Mn is more concentrated in the purple streaks. This indicates that the purple colour of the streaks is mainly due to a higher Mn/Fe ratio and persistence of more oxidised manganese in the purple areas, even though it is difficult to detect. Many archaeological fragments appear pale green in transmitted light but amber in reflected light. XANES studies detected the presence of surface layers where manganese is more oxidised. This layer is believed to scatter transmitted and reflected light differently and might be responsible for the optical features of the archaeological glass.","PeriodicalId":44008,"journal":{"name":"Journal of Physics-Photonics","volume":"146 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139753530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-01DOI: 10.1088/2515-7647/ad2258
Ole Bjarlin Jensen, Xinrong Chen, Jian Xu, Dennis Dan Corell, Carsten Dam-Hansen
Laser lighting is emerging as a viable replacement for other light sources in applications requiring high luminance not achievable with LEDs. Phosphor materials for laser lighting are often optimized in terms of luminous efficiency and/or colorimetric properties, while the light homogeneity is often neglected. We present a thorough investigation of the homogeneity of the chromaticity and the luminance profile for the most common types of phosphors used in laser lighting. We find that the achievable luminance and homogeneity of the light spot depends significantly on the phosphor used to convert the blue laser light to white light. The findings of these investigations will present guidelines for optimal phosphor material parameters to achieve high luminance combined with homogeneous chromaticity.
{"title":"Luminance and chromaticity characteristics of different phosphor types in laser lighting","authors":"Ole Bjarlin Jensen, Xinrong Chen, Jian Xu, Dennis Dan Corell, Carsten Dam-Hansen","doi":"10.1088/2515-7647/ad2258","DOIUrl":"https://doi.org/10.1088/2515-7647/ad2258","url":null,"abstract":"Laser lighting is emerging as a viable replacement for other light sources in applications requiring high luminance not achievable with LEDs. Phosphor materials for laser lighting are often optimized in terms of luminous efficiency and/or colorimetric properties, while the light homogeneity is often neglected. We present a thorough investigation of the homogeneity of the chromaticity and the luminance profile for the most common types of phosphors used in laser lighting. We find that the achievable luminance and homogeneity of the light spot depends significantly on the phosphor used to convert the blue laser light to white light. The findings of these investigations will present guidelines for optimal phosphor material parameters to achieve high luminance combined with homogeneous chromaticity.","PeriodicalId":44008,"journal":{"name":"Journal of Physics-Photonics","volume":"28 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139753528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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