Luis A. Razo-López, Geoffroy J. Aubry, Felipe A. Pinheiro, and Fabrice Mortessagne
Strong localization of electromagnetic waves in 3D has never been experimentally achieved in uncorrelated disordered systems. By going beyond the paradigm of disordered systems, this goal has been recently reached in deterministic aperiodic planar Vogel spiral arrays in the microwave regime. Here we present a comprehensive description of the experimental details that have been used to observe electromagnetic localization in Vogel spirals beyond 2D. By providing an experimental roadmap to describe microwave transport in Vogel spirals we introduce a novel system platform to demonstrate electromagnetic localization in 3D that outperforms traditional disordered systems for that purpose.
{"title":"Aperiodicity is more effective than disorder in localizing electromagnetic waves [Invited]","authors":"Luis A. Razo-López, Geoffroy J. Aubry, Felipe A. Pinheiro, and Fabrice Mortessagne","doi":"10.1364/ome.514886","DOIUrl":"https://doi.org/10.1364/ome.514886","url":null,"abstract":"Strong localization of electromagnetic waves in 3D has never been experimentally achieved in uncorrelated disordered systems. By going beyond the paradigm of disordered systems, this goal has been recently reached in deterministic aperiodic planar Vogel spiral arrays in the microwave regime. Here we present a comprehensive description of the experimental details that have been used to observe electromagnetic localization in Vogel spirals beyond 2D. By providing an experimental roadmap to describe microwave transport in Vogel spirals we introduce a novel system platform to demonstrate electromagnetic localization in 3D that outperforms traditional disordered systems for that purpose.","PeriodicalId":19548,"journal":{"name":"Optical Materials Express","volume":"252 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140009019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexandre Selvestrel, Julia Rocha, Rémi Carminati, and Romain Pierrat
We theoretically study the propagation of light in one-dimensional space- and time-dependent disorder. The disorder is described by a fluctuating permittivity ε(x, t) exhibiting short-range correlations in space and time, without cross correlation between them. Depending on the illumination conditions, we show that the intensity of the average field decays exponentially in space or in time, with characteristic length or time defining the scattering mean-free path ℓs and the scattering mean-free time τs. In the weak scattering regime, we provide explicit expressions for ℓs and τs, that are checked against rigorous numerical simulations.
{"title":"Multiple scattering theory in one dimensional space and time dependent disorder: average field [Invited]","authors":"Alexandre Selvestrel, Julia Rocha, Rémi Carminati, and Romain Pierrat","doi":"10.1364/ome.517488","DOIUrl":"https://doi.org/10.1364/ome.517488","url":null,"abstract":"We theoretically study the propagation of light in one-dimensional space- and time-dependent disorder. The disorder is described by a fluctuating permittivity ε(<i>x, t</i>) exhibiting short-range correlations in space and time, without cross correlation between them. Depending on the illumination conditions, we show that the intensity of the average field decays exponentially in space or in time, with characteristic length or time defining the scattering mean-free path ℓ<sub><i>s</i></sub> and the scattering mean-free time <i>τ</i><sub><i>s</i></sub>. In the weak scattering regime, we provide explicit expressions for ℓ<sub><i>s</i></sub> and <i>τ</i><sub><i>s</i></sub>, that are checked against rigorous numerical simulations.","PeriodicalId":19548,"journal":{"name":"Optical Materials Express","volume":"73 2 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140009251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tianchi Zhang, Yucong Yang, Di Wu, Junxian Wang, Zixuan Wei, Wei Yan, and Lei Bi
Silicon photonics for data communication requires key components in the O-band (1260 nm−1310 nm). However, very few studies report silicon integrated magneto-optical thin films operating at this wavelength range. In this study, we report a method to fabricate polycrystalline Bi2Tb1Fe5O12 thin films on silicon substrates for O-band nonreciprocal photonic device applications. The films are fabricated by magnetron sputtering at room temperature followed by rapid thermal annealing for crystallization. Pure garnet phase is stabilized by a Y3Fe5O12 seed layer on silicon. The film deposited on silicon-on-insulator (SOI) waveguides showed saturation Faraday rotation of −3300 ± 183 deg/cm, propagation loss of 53.3 ± 0.3 dB/cm and a high figure of merit of 61.9 ± 3.8 deg/dB at 1310 nm wavelength, demonstrating promising potential for O-band integrated nonreciprocal photonic devices.
用于数据通信的硅光子学需要 O 波段（1260 纳米-1310 纳米）的关键元件。然而，很少有研究报告称硅集成磁光薄膜可在此波长范围内工作。在本研究中，我们报告了一种在硅衬底上制造多晶 Bi2Tb1Fe5O12 薄膜的方法，用于 O 波段非互惠光子器件应用。薄膜是在室温下通过磁控溅射制造的，然后经过快速热退火结晶。纯石榴石相由硅上的 Y3Fe5O12 种子层稳定。沉积在硅绝缘体（SOI）波导上的薄膜显示出 -3300 ± 183 度/厘米的饱和法拉第旋转、53.3 ± 0.3 分贝/厘米的传播损耗以及在 1310 纳米波长下 61.9 ± 3.8 分贝/分贝的高优点，显示出 O 波段集成非互惠光子器件的巨大潜力。
{"title":"Silicon integrated Bi2TbFe5O12 thin films for O-band nonreciprocal photonic device applications","authors":"Tianchi Zhang, Yucong Yang, Di Wu, Junxian Wang, Zixuan Wei, Wei Yan, and Lei Bi","doi":"10.1364/ome.519523","DOIUrl":"https://doi.org/10.1364/ome.519523","url":null,"abstract":"Silicon photonics for data communication requires key components in the O-band (1260 nm−1310 nm). However, very few studies report silicon integrated magneto-optical thin films operating at this wavelength range. In this study, we report a method to fabricate polycrystalline Bi<sub>2</sub>Tb<sub>1</sub>Fe<sub>5</sub>O<sub>12</sub> thin films on silicon substrates for O-band nonreciprocal photonic device applications. The films are fabricated by magnetron sputtering at room temperature followed by rapid thermal annealing for crystallization. Pure garnet phase is stabilized by a Y<sub>3</sub>Fe<sub>5</sub>O<sub>12</sub> seed layer on silicon. The film deposited on silicon-on-insulator (SOI) waveguides showed saturation Faraday rotation of −3300 ± 183 deg/cm, propagation loss of 53.3 ± 0.3 dB/cm and a high figure of merit of 61.9 ± 3.8 deg/dB at 1310 nm wavelength, demonstrating promising potential for O-band integrated nonreciprocal photonic devices.","PeriodicalId":19548,"journal":{"name":"Optical Materials Express","volume":"137 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139977573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shubham Dawda, Aristide Dogariu, and Kenneth L. Schepler
Optimization of an Fe2+-doped chalcogenide fiber is considered for mid-IR lasing. The concept of using a chalcogenide glass as a fiber matrix to support optically active Fe2+ ions in ZnSe crystal particles requires use of a protective shell to prevent dissolution of the ZnSe particles. Here, we investigate the effect that the shell has on optical scattering and subsequently the relative gain and loss for a range of particle size, shell thickness and loading fraction of the ZnSe particles. Scattering loss depends on the particle size and is found to be acceptably low for fiber lasing for sizes larger than a threshold size. Furthermore, upon considering collective scattering from the particle group, increasing the concentration is shown to reduce the scattering loss and to be helpful in improving the gain coefficient to scattering loss coefficient ratio. Proper optimization is expected to result in a viable Fe2+ mid-IR fiber laser.
{"title":"Structural, chemical, and optical design optimization of an Fe2+-doped chalcogenide fiber for mid-infrared lasing","authors":"Shubham Dawda, Aristide Dogariu, and Kenneth L. Schepler","doi":"10.1364/ome.511066","DOIUrl":"https://doi.org/10.1364/ome.511066","url":null,"abstract":"Optimization of an Fe<sup>2+</sup>-doped chalcogenide fiber is considered for mid-IR lasing. The concept of using a chalcogenide glass as a fiber matrix to support optically active Fe<sup>2+</sup> ions in ZnSe crystal particles requires use of a protective shell to prevent dissolution of the ZnSe particles. Here, we investigate the effect that the shell has on optical scattering and subsequently the relative gain and loss for a range of particle size, shell thickness and loading fraction of the ZnSe particles. Scattering loss depends on the particle size and is found to be acceptably low for fiber lasing for sizes larger than a threshold size. Furthermore, upon considering collective scattering from the particle group, increasing the concentration is shown to reduce the scattering loss and to be helpful in improving the gain coefficient to scattering loss coefficient ratio. Proper optimization is expected to result in a viable Fe<sup>2+</sup> mid-IR fiber laser.","PeriodicalId":19548,"journal":{"name":"Optical Materials Express","volume":"94 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139768599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heer Yang, Yuanjun Li, Cai Sun, Xuepeng Pan, Shanren Liu, Bo Wang, Mengmeng Gao, Qi Guo, and Yongsen Yu
A new tapered fiber relative humidity (RH) sensor based on polydimethylsiloxane (PDMS) and graphene oxide (GO) film coatings is proposed and demonstrated. Tapered fiber is fabricated in single mode fiber by the tapering machine. The PDMS film is coated on the surface of the fiber using the hydroxide flame sintering technique, while the GO film is deposited using the physical deposition technique. This structure can achieve strong interference effect by the smaller range of tapering process. In the RH measurement experiment, the humidity sensitivity of the sensor is measured to be as high as 0.371 dB/%RH within the RH range of 35% to 90%. The experiment investigates the impact of different numbers of PDMS coating on sensitivity. As the number of PDMS coatings increases, the RH sensitivity of the sensor also increases and reaches the highest sensitivity when coated with 10 layers of PDMS film. The sensor has high sensitivity to RH, good stability and mechanical strength, which also shows great performance in both moisture absorption and desorption. These advantages make the sensor suitable for the wide range of humidity sensing applications.
{"title":"High-sensitivity tapered fiber relative humidity sensor based on PDMS and GO films","authors":"Heer Yang, Yuanjun Li, Cai Sun, Xuepeng Pan, Shanren Liu, Bo Wang, Mengmeng Gao, Qi Guo, and Yongsen Yu","doi":"10.1364/ome.519037","DOIUrl":"https://doi.org/10.1364/ome.519037","url":null,"abstract":"A new tapered fiber relative humidity (RH) sensor based on polydimethylsiloxane (PDMS) and graphene oxide (GO) film coatings is proposed and demonstrated. Tapered fiber is fabricated in single mode fiber by the tapering machine. The PDMS film is coated on the surface of the fiber using the hydroxide flame sintering technique, while the GO film is deposited using the physical deposition technique. This structure can achieve strong interference effect by the smaller range of tapering process. In the RH measurement experiment, the humidity sensitivity of the sensor is measured to be as high as 0.371 dB/%RH within the RH range of 35% to 90%. The experiment investigates the impact of different numbers of PDMS coating on sensitivity. As the number of PDMS coatings increases, the RH sensitivity of the sensor also increases and reaches the highest sensitivity when coated with 10 layers of PDMS film. The sensor has high sensitivity to RH, good stability and mechanical strength, which also shows great performance in both moisture absorption and desorption. These advantages make the sensor suitable for the wide range of humidity sensing applications.","PeriodicalId":19548,"journal":{"name":"Optical Materials Express","volume":"28 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139768598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y.-M. Robin Hu, Elena A. Ostrovskaya, and Eliezer Estrecho
In this work, we review different generalizations of the quantum geometric tensor (QGT) in two-band non-Hermitian systems and propose a protocol for measuring them in experiments. We present the generalized QGT components, i.e., the quantum metric and Berry curvature, for a non-Hermitian hybrid photonic (exciton-polariton) system and show that the generalized non-Hermitian QGT can be constructed from experimental observables. In particular, we extend the existing method of measuring the QGT that uses the pseudospins in photonic and exciton-polariton systems by suggesting a method to construct the left eigenstates from experiments. We also show that the QGT components have clear signatures in wave-packet dynamics, where the anomalous Hall drift arises from both the non-Hermitian Berry curvature and Berry connection, suggesting that both left and right eigenstates are necessary for defining non-Hermitian band geometries and topologies.
{"title":"Generalized quantum geometric tensor in a non-Hermitian exciton-polariton system [Invited]","authors":"Y.-M. Robin Hu, Elena A. Ostrovskaya, and Eliezer Estrecho","doi":"10.1364/ome.497010","DOIUrl":"https://doi.org/10.1364/ome.497010","url":null,"abstract":"In this work, we review different generalizations of the quantum geometric tensor (QGT) in two-band non-Hermitian systems and propose a protocol for measuring them in experiments. We present the generalized QGT components, i.e., the quantum metric and Berry curvature, for a non-Hermitian hybrid photonic (exciton-polariton) system and show that the generalized non-Hermitian QGT can be constructed from experimental observables. In particular, we extend the existing method of measuring the QGT that uses the pseudospins in photonic and exciton-polariton systems by suggesting a method to construct the left eigenstates from experiments. We also show that the QGT components have clear signatures in wave-packet dynamics, where the anomalous Hall drift arises from both the non-Hermitian Berry curvature and Berry connection, suggesting that both left and right eigenstates are necessary for defining non-Hermitian band geometries and topologies.","PeriodicalId":19548,"journal":{"name":"Optical Materials Express","volume":"42 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139768592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bismuth-substituted lutetium iron garnets have exhibited a remarkable enhancement in Faraday rotation (FR) for films thinner than 50 nm. A sevenfold amplification in the magneto-optic gyrotropy was found to occur within 2 nm of the air-surface interface at 532 nm wavelength. The present study delves into the underlying physical mechanisms contributing to such amplification. Near-surface changes in band structure in these materials and their connection to the magneto-optic response are explored. Density functional theory is employed to investigate the changes in density of states and overall band structure reconfiguration of surface atoms. The transition dipole matrix (TDM) model is then applied to both bulk and surface states, correctly predicting a Faraday rotation enhancement at the surface as a result of overall surface band structure reconfiguration and resulting bandgap reduction. Surface versus bulk FR spectral response is extended beyond prior studies over the full visible and the near-infrared spectral ranges, predicting significant amplification across the telecom band. Experimental analysis through X-ray photoelectron spectroscopy (XPS) and UV-Vis spectroscopy reveal a reduction in bandgap as films are thinned down from 200 nm to 40 nm. By providing a deeper physical understanding of the origin of enhanced Faraday rotation at the surface, this work opens up avenues for more efficient miniaturized Faraday rotation applications. Knowledge of the band structure information thus uncovered may be used to demonstrate novel and more advanced applications.
{"title":"Band structure reconfiguration and surface Faraday rotation in Bi-substituted iron garnets","authors":"Sushree S. Dash, Gregory Odegard, and Miguel Levy","doi":"10.1364/ome.516148","DOIUrl":"https://doi.org/10.1364/ome.516148","url":null,"abstract":"Bismuth-substituted lutetium iron garnets have exhibited a remarkable enhancement in Faraday rotation (FR) for films thinner than 50 nm. A sevenfold amplification in the magneto-optic gyrotropy was found to occur within 2 nm of the air-surface interface at 532 nm wavelength. The present study delves into the underlying physical mechanisms contributing to such amplification. Near-surface changes in band structure in these materials and their connection to the magneto-optic response are explored. Density functional theory is employed to investigate the changes in density of states and overall band structure reconfiguration of surface atoms. The transition dipole matrix (TDM) model is then applied to both bulk and surface states, correctly predicting a Faraday rotation enhancement at the surface as a result of overall surface band structure reconfiguration and resulting bandgap reduction. Surface versus bulk FR spectral response is extended beyond prior studies over the full visible and the near-infrared spectral ranges, predicting significant amplification across the telecom band. Experimental analysis through X-ray photoelectron spectroscopy (XPS) and UV-Vis spectroscopy reveal a reduction in bandgap as films are thinned down from 200 nm to 40 nm. By providing a deeper physical understanding of the origin of enhanced Faraday rotation at the surface, this work opens up avenues for more efficient miniaturized Faraday rotation applications. Knowledge of the band structure information thus uncovered may be used to demonstrate novel and more advanced applications.","PeriodicalId":19548,"journal":{"name":"Optical Materials Express","volume":"48 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139768488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniel M. Heligman, Alex M. Potts, and R. Valdés Aguilar
We report on the results of finite difference time domain (FDTD) simulations of the terahertz response of a split ring resonator (SRR) metamaterial coupled to a hypothetical antiferromagnetic material (AFM) characterized by a magnon resonance. We find a hybridization of the SRR’s local magnetic field and the magnon, which manifests as an avoided crossing in the far-field transmission spectrum. We show that the strong light-matter coupling can be modelled via a two coupled oscillator model. We further evaluate the SRR-AFM coupling strength by varying the physical separation with a dielectric spacer between them. We find strong coupling for spacers thinner than 3 μm, suggesting far-field transmission measurements of metamaterial near-fields to be a versatile platform to investigate magnetic excitations of quantum materials.
{"title":"Numerical simulation of split ring resonator near-fields and antiferromagnetic magnon hybridization","authors":"Daniel M. Heligman, Alex M. Potts, and R. Valdés Aguilar","doi":"10.1364/ome.510831","DOIUrl":"https://doi.org/10.1364/ome.510831","url":null,"abstract":"We report on the results of finite difference time domain (FDTD) simulations of the terahertz response of a split ring resonator (SRR) metamaterial coupled to a hypothetical antiferromagnetic material (AFM) characterized by a magnon resonance. We find a hybridization of the SRR’s local magnetic field and the magnon, which manifests as an avoided crossing in the far-field transmission spectrum. We show that the strong light-matter coupling can be modelled via a two coupled oscillator model. We further evaluate the SRR-AFM coupling strength by varying the physical separation with a dielectric spacer between them. We find strong coupling for spacers thinner than 3 <i>μ</i>m, suggesting far-field transmission measurements of metamaterial near-fields to be a versatile platform to investigate magnetic excitations of quantum materials.","PeriodicalId":19548,"journal":{"name":"Optical Materials Express","volume":"150 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139768905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solitary waves (solitons) are fundamental modes supported by nonlinear guiding structures and propagate without any distortion due to dispersion. They can be used in the synthesis of waveforms with desired spectral or time-domain characteristics. However, the nonlinearity inherent to solitons complicates their analysis on general guiding structures. This paper proposes an iterative algorithm that can compute soliton solutions supported by general periodic electrical networks loaded by nonlinear capacitors. The proposed technique accounts for the exact dispersion of the structure and allows the capacitance to take on an arbitrary function of voltage. The algorithm computes the solution throughout the entire structure while only modeling a single unit cell, thus reducing the computational cost significantly. It is implemented within an in-house solver and verified against a commercially available circuit simulator. Different circuits which include lumped inductors, ideal transmission lines, and co-planar waveguides are simulated and shown to agree with commercial harmonic balance solvers. The presented technique will allow microwave and optical engineers to design and optimize a wide variety of nonlinear guiding structures efficiently.
{"title":"Iterative technique for computing soliton solutions to periodic nonlinear electrical networks","authors":"Joel Johnson and Cody Scarborough","doi":"10.1364/ome.510843","DOIUrl":"https://doi.org/10.1364/ome.510843","url":null,"abstract":"Solitary waves (solitons) are fundamental modes supported by nonlinear guiding structures and propagate without any distortion due to dispersion. They can be used in the synthesis of waveforms with desired spectral or time-domain characteristics. However, the nonlinearity inherent to solitons complicates their analysis on general guiding structures. This paper proposes an iterative algorithm that can compute soliton solutions supported by general periodic electrical networks loaded by nonlinear capacitors. The proposed technique accounts for the exact dispersion of the structure and allows the capacitance to take on an arbitrary function of voltage. The algorithm computes the solution throughout the entire structure while only modeling a single unit cell, thus reducing the computational cost significantly. It is implemented within an in-house solver and verified against a commercially available circuit simulator. Different circuits which include lumped inductors, ideal transmission lines, and co-planar waveguides are simulated and shown to agree with commercial harmonic balance solvers. The presented technique will allow microwave and optical engineers to design and optimize a wide variety of nonlinear guiding structures efficiently.","PeriodicalId":19548,"journal":{"name":"Optical Materials Express","volume":"7 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140009013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wei Liu, Xiaochuan Ji, Jianglin Dai, Jinlong Zhang, Hongfei Jiao, Xinbin Cheng, and Zhanshan Wang
Ultra-low loss optical thin films find broad applications in fields such as vertical-cavity surface-emitting lasers and optical atomic clocks. The main optical losses in AlGaAs/GaAs distributed Bragg reflectors (DBRs) prepared using metal-organic chemical vapor deposition (MOCVD) arise from absorption loss caused by free carriers within the layers and scattering loss caused by surface roughness. In this study, we fabricated AlGaAs and GaAs single-layer thin films with varying Al compositions on substrates of three crystal orientations and under different V/III ratios. The dependence of carrier concentration and surface morphology on different substrates and growth conditions was investigated. Thin films grown on substrates with three different crystal orientations exhibited three distinct growth modes (step-flow mode, SK mode, and FM mode). The impact of the V/III ratio on the growth mode was found to be complex. Higher V/III ratios resulted in poorer morphology for films grown on (100) substrates, while better morphology was observed on (211) B substrates. Furthermore, the surface morphology of films grown on (100) 15° off substrates showed less sensitivity to changes in the V/III ratio. With increasing Al composition, the carrier concentration of the films significantly increased. Elevating the V/III ratio proved effective in suppressing the incorporation of carbon, thereby reducing the carrier concentration of AlGaAs films. GaAs films exhibited a low carrier concentration at an appropriate V/III ratio. Additionally, the distinct abilities of different substrates to adsorb impurities exerted a significant impact on the carrier concentration of the films. This study demonstrates that, under optimal conditions, it is feasible to fabricate AlGaAs/GaAs Bragg mirrors with low carrier concentration and relatively small roughness on (100) 15° off substrates.
{"title":"Study of the free carrier characteristics and surface morphology of AlGaAs/GaAs thin films deposited using MOCVD","authors":"Wei Liu, Xiaochuan Ji, Jianglin Dai, Jinlong Zhang, Hongfei Jiao, Xinbin Cheng, and Zhanshan Wang","doi":"10.1364/ome.515432","DOIUrl":"https://doi.org/10.1364/ome.515432","url":null,"abstract":"Ultra-low loss optical thin films find broad applications in fields such as vertical-cavity surface-emitting lasers and optical atomic clocks. The main optical losses in AlGaAs/GaAs distributed Bragg reflectors (DBRs) prepared using metal-organic chemical vapor deposition (MOCVD) arise from absorption loss caused by free carriers within the layers and scattering loss caused by surface roughness. In this study, we fabricated AlGaAs and GaAs single-layer thin films with varying Al compositions on substrates of three crystal orientations and under different V/III ratios. The dependence of carrier concentration and surface morphology on different substrates and growth conditions was investigated. Thin films grown on substrates with three different crystal orientations exhibited three distinct growth modes (step-flow mode, SK mode, and FM mode). The impact of the V/III ratio on the growth mode was found to be complex. Higher V/III ratios resulted in poorer morphology for films grown on (100) substrates, while better morphology was observed on (211) B substrates. Furthermore, the surface morphology of films grown on (100) 15° off substrates showed less sensitivity to changes in the V/III ratio. With increasing Al composition, the carrier concentration of the films significantly increased. Elevating the V/III ratio proved effective in suppressing the incorporation of carbon, thereby reducing the carrier concentration of AlGaAs films. GaAs films exhibited a low carrier concentration at an appropriate V/III ratio. Additionally, the distinct abilities of different substrates to adsorb impurities exerted a significant impact on the carrier concentration of the films. This study demonstrates that, under optimal conditions, it is feasible to fabricate AlGaAs/GaAs Bragg mirrors with low carrier concentration and relatively small roughness on (100) 15° off substrates.","PeriodicalId":19548,"journal":{"name":"Optical Materials Express","volume":"217 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139769066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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