Pub Date : 2026-01-12DOI: 10.1016/j.rio.2026.100966
Ouya Zhang, Shiqi Huang, Yan Li
All-dielectric metasurfaces that support resonators with multiple dipole resonances offer a versatile and effective approach for controlling electromagnetic fields at the nanoscale. Toroidal dipoles, as a peculiar component of multipole resonances, have attracted significant attention due to their unique ability to facilitate light–matter interactions, enabling enhanced absorption, amplified nonlinear responses, advanced data processing and storage capabilities, and highly sensitive sensing applications. The active control of toroidal dipoles in all-dielectric metasurfaces holds great significance for the development of adaptable photonic devices. However, achieving tunable toroidal dipoles in all-dielectric metasurfaces remains challenging due to the volumetric mode property of toroidal dipoles. To address this challenge, we propose a solution by integrating a thin layer of indium tin oxide (ITO) into the all-dielectric metasurfaces. Active modulation of the transmittance amplitude in toroidal dipole-based all-dielectric metasurfaces is achieved by precisely tuning the coupling between the metasurface modes and the ITO thin film. Furthermore, a tunable diffractive grating has been developed based on these findings, demonstrating its prospects for beam direction control applications.
{"title":"Dynamic transmission control based on all-dielectric toroidal dipole metasurfaces","authors":"Ouya Zhang, Shiqi Huang, Yan Li","doi":"10.1016/j.rio.2026.100966","DOIUrl":"10.1016/j.rio.2026.100966","url":null,"abstract":"<div><div>All-dielectric metasurfaces that support resonators with multiple dipole resonances offer a versatile and effective approach for controlling electromagnetic fields at the nanoscale. Toroidal dipoles, as a peculiar component of multipole resonances, have attracted significant attention due to their unique ability to facilitate light–matter interactions, enabling enhanced absorption, amplified nonlinear responses, advanced data processing and storage capabilities, and highly sensitive sensing applications. The active control of toroidal dipoles in all-dielectric metasurfaces holds great significance for the development of adaptable photonic devices. However, achieving tunable toroidal dipoles in all-dielectric metasurfaces remains challenging due to the volumetric mode property of toroidal dipoles. To address this challenge, we propose a solution by integrating a thin layer of indium tin oxide (ITO) into the all-dielectric metasurfaces. Active modulation of the transmittance amplitude in toroidal dipole-based all-dielectric metasurfaces is achieved by precisely tuning the coupling between the metasurface modes and the ITO thin film. Furthermore, a tunable diffractive grating has been developed based on these findings, demonstrating its prospects for beam direction control applications.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"23 ","pages":"Article 100966"},"PeriodicalIF":3.0,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979972","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 : 2026-01-12DOI: 10.1016/j.rio.2026.100973
M. Mehrabani , M.M. Shahidi , M.H. Ehsani , F. Shokrian
Aluminum-doped zinc oxide (AZO) thin films are promising for optoelectronic applications, such as transparent electrodes and photodetectors, due to their excellent optical and electrical properties. In this study, AZO thin films were synthesized on glass substrates via co-sputtering using separate ZnO and Al targets. By varying the DC power applied to the Al target (10–25 W), the aluminum doping concentration was controlled, producing samples labeled AZO-10, AZO-15, AZO-20, and AZO-25. The structural, optical, electrical, and photoconductive properties were characterized using XRD, EDX, UV–vis spectroscopy, Hall effect measurements, and I–T (current–time) analysis. XRD revealed an amorphous structure due to low deposition temperatures. EDX confirmed an increase in aluminum content from 0.30% to 1.82% with higher sputtering power. Optical properties exhibited reduced transmittance and a widened bandgap (3.38 eV –3.55 eV), attributed to the Burstein-Moss effect and lattice strain. Electrical properties showed enhanced conductivity, with sheet resistance decreasing from 1.43 × 106 to 1.21 × 104 Ω/□ and carrier concentration increasing from 1.30 × 1013 to 5.35 × 1014 cm−2, though carrier mobility was limited by the amorphous structure. Photoconductivity measurements under periodic LED illumination demonstrated stable, repeatable photoresponse, with photocurrent decreasing from 120 mA in AZO-10 to 20 mA and 8 mA in AZO-20 and AZO-25, respectively, due to defect states acting as traps and recombination centers induced by higher doping. This study highlights the critical role of optimizing aluminum doping to balance optical transparency, electrical conductivity, and photoconductive performance, establishing co-sputtering as an effective method for tailoring AZO thin films for optoelectronic applications.
{"title":"Tuning ZnO thin films via aluminum doping synthesized by co-sputtering: structure, optics, and photoconductivity","authors":"M. Mehrabani , M.M. Shahidi , M.H. Ehsani , F. Shokrian","doi":"10.1016/j.rio.2026.100973","DOIUrl":"10.1016/j.rio.2026.100973","url":null,"abstract":"<div><div>Aluminum-doped zinc oxide (AZO) thin films are promising for optoelectronic applications, such as transparent electrodes and photodetectors, due to their excellent optical and electrical properties. In this study, AZO thin films were synthesized on glass substrates via co-sputtering using separate ZnO and Al targets. By varying the DC power applied to the Al target (10–25 W), the aluminum doping concentration was controlled, producing samples labeled AZO-10, AZO-15, AZO-20, and AZO-25. The structural, optical, electrical, and photoconductive properties were characterized using XRD, EDX, UV–vis spectroscopy, Hall effect measurements, and I–T (current–time) analysis. XRD revealed an amorphous structure due to low deposition temperatures. EDX confirmed an increase in aluminum content from 0.30% to 1.82% with higher sputtering power. Optical properties exhibited reduced transmittance and a widened bandgap (3.38 eV –3.55 eV), attributed to the Burstein-Moss effect and lattice strain. Electrical properties showed enhanced conductivity, with sheet resistance decreasing from 1.43 × 10<sup>6</sup> to 1.21 × 10<sup>4</sup> Ω/□ and carrier concentration increasing from 1.30 × 10<sup>13</sup> to 5.35 × 10<sup>14</sup> cm<sup>−2</sup>, though carrier mobility was limited by the amorphous structure. Photoconductivity measurements under periodic LED illumination demonstrated stable, repeatable photoresponse, with photocurrent decreasing from 120 mA in AZO-10 to 20 mA and 8 mA in AZO-20 and AZO-25, respectively, due to defect states acting as traps and recombination centers induced by higher doping. This study highlights the critical role of optimizing aluminum doping to balance optical transparency, electrical conductivity, and photoconductive performance, establishing co-sputtering as an effective method for tailoring AZO thin films for optoelectronic applications.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"23 ","pages":"Article 100973"},"PeriodicalIF":3.0,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023851","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 : 2026-01-07DOI: 10.1016/j.rio.2026.100960
Md. Mushfiqur Rahman , Md. Shabiul Islam , Wong Hin Yong , Touhidul Alam , Md. Moniruzzaman , Md. Mhedi Hasan , Mohammad Tariqul Islam
In this paper, an arrow-shaped CLS (capacitively loaded strips) structure with a truncated head is inserted between two trapezoid-shaped CLS structures to get a wideband response in the low-frequency region. When the CLS structure without the arrow-shaped structure is excited, a low-frequency resonance is obtained with a 35 GHz bandwidth only. But when the combination is excited by an appropriate feeding network, a low-frequency resonance with a very large bandwidth of about 223 GHz is achieved in the sub-terahertz region of 6G. This combination also causes an unwanted spike-like resonance at low frequency. A T-shaped structure is added to the truncated arrowhead to notch this unnecessary spike. In addition, this structure shifts the lower cutoff frequency by 6 GHz. Simulation results show that the proposed antenna shows a fractional operating bandwidth of 87.24 % from 148 GHz to 377 GHz for |S11| <-10 dB, where a peak realized gain of 4.54 dBi is observed. The antenna also achieves a good bandwidth to dimension ratio of about 995.71. The overall dimension of the antenna is 600 µm × 600 µm × 10 µm, where the height is only 0.005λ, where λ is the operating wavelength at the lower cut-off frequency.
{"title":"A low-profile wideband antenna loaded with CLS structures for sub-terahertz applications of 6G","authors":"Md. Mushfiqur Rahman , Md. Shabiul Islam , Wong Hin Yong , Touhidul Alam , Md. Moniruzzaman , Md. Mhedi Hasan , Mohammad Tariqul Islam","doi":"10.1016/j.rio.2026.100960","DOIUrl":"10.1016/j.rio.2026.100960","url":null,"abstract":"<div><div>In this paper, an arrow-shaped CLS (capacitively loaded strips) structure with a truncated head is inserted between two trapezoid-shaped CLS structures to get a wideband response in the low-frequency region. When the CLS structure without the arrow-shaped structure is excited, a low-frequency resonance is obtained with a 35 GHz bandwidth only. But when the combination is excited by an appropriate feeding network, a low-frequency resonance with a very large bandwidth of about 223 GHz is achieved in the sub-terahertz region of 6G. This combination also causes an unwanted spike-like resonance at low frequency. A T-shaped structure is added to the truncated arrowhead to notch this unnecessary spike. In addition, this structure shifts the lower cutoff frequency by 6 GHz. Simulation results show that the proposed antenna shows a fractional operating bandwidth of 87.24 % from 148 GHz to 377 GHz for |S11| <-10 dB, where a peak realized gain of 4.54 dBi is observed. The antenna also achieves a good bandwidth to dimension ratio of about 995.71. The overall dimension of the antenna is 600 µm × 600 µm × 10 µm, where the height is only 0.005λ, where λ is the operating wavelength at the lower cut-off frequency.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"23 ","pages":"Article 100960"},"PeriodicalIF":3.0,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979863","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 : 2026-01-06DOI: 10.1016/j.rio.2026.100957
A. Martinez-Rios , G. Anzueto-Sanchez , J.L. Pichardo-Molina , L.F. Enriquez-Gomez , R.E. Nuñez-Gomez , L.A. Rodriguez-Morales , O. Pottiez , A. Kir’yanov
We report a two-wavelength, dual-regime Q-switched erbium-doped fiber laser employing a microfiber loop coated with gold nanostars as the saturable absorber. The gold nanostars are designed to have three resonances, with the broad spectral tail of the longest resonance overlapping the erbium emission band, enabling strong saturable absorption in the coated microfiber loop, resulting in a modulation depth of 12.19 % and a nonsaturable absorption of 39.89 %. When inserted into an erbium-doped fiber laser ring, this device produced dual Q-switched regimes separated by a continuous-wave window, along with stable dual-wavelength emission at 1529 nm and 1531 nm. In the pump range of 55.7–188 mW, stable Q-switched pulses with repetition rates ranging from 15.8 to 53.36 kHz and pulse widths as short as 5.2 µs were observed. At pump powers of ∼ 190–210 mW, the laser switched to continuous-wave operation; at higher pump levels (211–257 mW), it returned to a Q-switched regime with shorter pulses. This behavior is attributed to the interplay between saturable bleaching and reverse saturable absorption or thermally induced losses in the gold nanostars. These results highlight the potential of multi-resonant plasmonic nanostructures for broadband, intensity-dependent control of fiber lasers.
{"title":"Two-wavelength, dual regime Q-switched erbium-doped fiber laser based on a microfiber loop coated with gold nanostars as the saturable absorber","authors":"A. Martinez-Rios , G. Anzueto-Sanchez , J.L. Pichardo-Molina , L.F. Enriquez-Gomez , R.E. Nuñez-Gomez , L.A. Rodriguez-Morales , O. Pottiez , A. Kir’yanov","doi":"10.1016/j.rio.2026.100957","DOIUrl":"10.1016/j.rio.2026.100957","url":null,"abstract":"<div><div>We report a two-wavelength, dual-regime Q-switched erbium-doped fiber laser employing a microfiber loop coated with gold nanostars as the saturable absorber. The gold nanostars are designed to have three resonances, with the broad spectral tail of the longest resonance overlapping the erbium emission band, enabling strong saturable absorption in the coated microfiber loop, resulting in a modulation depth of 12.19 % and a nonsaturable absorption of 39.89 %. When inserted into an erbium-doped fiber laser ring, this device produced dual Q-switched regimes separated by a continuous-wave window, along with stable dual-wavelength emission at 1529 nm and 1531 nm. In the pump range of 55.7–188 mW, stable Q-switched pulses with repetition rates ranging from 15.8 to 53.36 kHz and pulse widths as short as 5.2 µs were observed. At pump powers of ∼ 190–210 mW, the laser switched to continuous-wave operation; at higher pump levels (211–257 mW), it returned to a Q-switched regime with shorter pulses. This behavior is attributed to the interplay between saturable bleaching and reverse saturable absorption or thermally induced losses in the gold nanostars. These results highlight the potential of multi-resonant plasmonic nanostructures for broadband, intensity-dependent control of fiber lasers.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"23 ","pages":"Article 100957"},"PeriodicalIF":3.0,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023849","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}
In this study, carbon quantum dots (CQDs) were synthesized using pyrolysis method and monochromatic LED light sources were used to control the chemical reaction during the synthetic time. Four monochromatic LEDs with different wavelengths (violet, blue, green and red) were used in these synthetic routes. CQDs were characterized using different methods such as visible-ultraviolet spectroscopy (UV–Vis), dynamic light scattering (DLS), photoluminescence spectroscopy (PL), Fourier transform infrared (FTIR), and Transmission electron spectroscopy (TEM). According to different optical properties of the synthesized CQDs, third order nonlinear absorption coefficients of CQDs have been measured using the open aperture Z-scan technique. Experiments with close aperture Z-scan setup led only to dense patterns of diffraction rings. There was a perfect correlation between the data of all experiments where indicates the effect of monochromatic light radiation on the synthesis process is mainly on the loading of surface agents of the CQDs. With the increase in the wavelength of the irradiated light, it has been witnessed the decrease of surface agents as surface agents, the decrease of hydrodynamic diameter, increase of absorption in the visible region, increase of luminescence and its red shift, the granularity of the particles in the TEM images and increase of the nonlinear properties of the resulting nanocolloids. The present study can be a new window towards control and engineering in the synthesis of CQDs with the help of only a monochromatic light source.
{"title":"Carbon quantum dots synthesized by monochromatic light driven method toward controlling optical and nonlinear optical properties","authors":"Shaghayegh Khalilzadeh , Ehsan Koushki , Mohammad-Reza Zamani-Meymian","doi":"10.1016/j.rio.2025.100956","DOIUrl":"10.1016/j.rio.2025.100956","url":null,"abstract":"<div><div>In this study, carbon quantum dots (CQDs) were synthesized using pyrolysis method and monochromatic LED light sources were used to control the chemical reaction during the synthetic time. Four monochromatic LEDs with different wavelengths (violet, blue, green and red) were used in these synthetic routes. CQDs were characterized using different methods such as visible-ultraviolet spectroscopy (UV–Vis), dynamic light scattering (DLS), photoluminescence spectroscopy (PL), Fourier transform infrared (FTIR), and Transmission electron spectroscopy (TEM). According to different optical properties of the synthesized CQDs, third order nonlinear absorption coefficients of CQDs have been measured using the open aperture Z-scan technique. Experiments with close aperture Z-scan setup led only to dense patterns of diffraction rings. There was a perfect correlation between the data of all experiments where indicates the effect of monochromatic light radiation on the synthesis process is mainly on the loading of surface agents of the CQDs. With the increase in the wavelength of the irradiated light, it has been witnessed the decrease of surface agents as surface agents, the decrease of hydrodynamic diameter, increase of absorption in the visible region, increase of luminescence and its red shift, the granularity of the particles in the TEM images and increase of the nonlinear properties of the resulting nanocolloids. The present study can be a new window towards control and engineering in the synthesis of CQDs with the help of only a monochromatic light source.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"23 ","pages":"Article 100956"},"PeriodicalIF":3.0,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145904051","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 : 2026-01-01DOI: 10.1016/j.rio.2025.100950
M. Uktamova, Sh. Mamadaliev
This article investigates the Franz–Keldysh effect and the tunneling processes observed in tunnel diodes. The relationship between the optical absorption coefficient and the tunneling probability is analyzed using both theoretical and graphical methods. The dependence of both processes on energy is illustrated through 3D graphs. The surfaces defined according to the energy level distribution may contribute to improving the efficiency of optoelectronic devices based on tunnel diodes.
{"title":"Three-dimensional modeling of the relationship between static tunneling and the optical absorption coefficient in tunnel diodes","authors":"M. Uktamova, Sh. Mamadaliev","doi":"10.1016/j.rio.2025.100950","DOIUrl":"10.1016/j.rio.2025.100950","url":null,"abstract":"<div><div>This article investigates the Franz–Keldysh effect and the tunneling processes observed in tunnel diodes. The relationship between the optical absorption coefficient and the tunneling probability is analyzed using both theoretical and graphical methods. The dependence of both processes on energy is illustrated through 3D graphs. The surfaces defined according to the energy level distribution may contribute to improving the efficiency of optoelectronic devices based on tunnel diodes.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"22 ","pages":"Article 100950"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938522","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 : 2026-01-01DOI: 10.1016/j.rio.2025.100954
Zaineb Gharsallah , V R Balaji , Monia Najjar , Gopalkrishna Hegde , Massoudi Radhouene
In this work, we present a high-performance Optical biosensor for the non-invasive detection of vitiligo, a skin disorder characterized by depigmentation resulting from melanin loss.. The sensor is designed on a two-dimensional (2D) Photonic Crystal (PhC) slab fabricated on a silicon-on-insulator (SOI) platform with a triangular lattice of air holes. The proposed design incorporates an input bus waveguide, a circular ring cavity, a hexagonal centre ring, a triangular ring, and an output drop waveguide to achieve strong resonance coupling and field confinement. The biosensor operates by monitoring refractive index variations of the skin analyte, which correlate with changes in melanin and keratin concentration. Resonant wavelength shifts are used to quantify these variations, enabling accurate identification of vitiligo-related anomalies.This sensor exhibits high-performance specifications, with a maximum quality factor of 16,388 for keratin-related conditions, a minimum spectral line width of 0.1 nm for all conditions, and a maximum sensitivity of 175 nm/RIU for melanin-related conditions. The device has a compact footprint of 97.52 µm2 makes it suitable for on-chip biomedical integration. Unlike conventional PhC biosensors that restrict analyte infiltration to limited regions, this device is designed to fill the entire PhC structure with the analyte, rather than confining it to a specific region of the structure, which helps increase the reliability and repeatability of measurements. The sensor offers a promising platform for non-invasive and accurate detection of vitiligo.
{"title":"Design and simulation of a high sensitivity 2D photonic crystal waveguide biosensor for vitiligo detection","authors":"Zaineb Gharsallah , V R Balaji , Monia Najjar , Gopalkrishna Hegde , Massoudi Radhouene","doi":"10.1016/j.rio.2025.100954","DOIUrl":"10.1016/j.rio.2025.100954","url":null,"abstract":"<div><div>In this work, we present a high-performance Optical biosensor for the non-invasive detection of vitiligo, a skin disorder characterized by depigmentation resulting from melanin loss.. The sensor is designed on a two-dimensional (2D) Photonic Crystal (PhC) slab fabricated on a silicon-on-insulator (SOI) platform with a triangular lattice of air holes. The proposed design incorporates an input bus waveguide, a circular ring cavity, a hexagonal centre ring, a triangular ring, and an output drop waveguide to achieve strong resonance coupling and field confinement. The biosensor operates by monitoring refractive index variations of the skin analyte, which correlate with changes in melanin and keratin concentration. Resonant wavelength shifts are used to quantify these variations, enabling accurate identification of vitiligo-related anomalies.This sensor exhibits high-performance specifications, with a maximum quality factor of 16,388 for keratin-related conditions, a minimum spectral line width of 0.1 nm for all conditions, and a maximum sensitivity of 175 nm/RIU for melanin-related conditions. The device has a compact footprint of 97.52 µm<sup>2</sup> makes it suitable for on-chip biomedical integration. Unlike conventional PhC biosensors that restrict analyte infiltration to limited regions, this device is designed to fill the entire PhC structure with the analyte, rather than confining it to a specific region of the structure, which helps increase the reliability and repeatability of measurements. The sensor offers a promising platform for non-invasive and accurate detection of vitiligo.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"22 ","pages":"Article 100954"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938521","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 : 2026-01-01DOI: 10.1016/j.rio.2025.100955
Gaelle Carine Mbanda Nsoungui , Abdullah S. Karar , Kaboko Jean-Jacques Monga , Ehsan Adibnia , Hafedh Mahmoud Zayani , Mohamed Salhi , Faouzi Bahloul , Khmaies Ouahada
Figure-of-9 fiber lasers (F9FL) represent a significant advancement in the field of ultrafast photonics, offering improved environmental stability, enhanced self-starting behavior, and efficient pulse shaping. However, optimizing the performance of F9FL remains a challenging task due to the complex interplay between nonlinear dynamics, dispersion management, and gain saturation effects. This study presents a systematic approach to optimize the operating conditions of an F9FL using an advanced two-particle swarm optimization (PSO) algorithm. The optimization process aims to maximize pulse energy, improve temporal stability, and enhance mode-locking efficiency by tuning critical laser parameters such as fiber lengths, gain coefficients, and phase shift conditions. A comprehensive numerical model incorporating bidirectional pulse propagation and nonlinear effects is employed to evaluate performance metrics under realistic constraints. Simulation results demonstrate that the proposed PSO-based strategy effectively identifies optimal parameter sets that lead to high-energy single pulses with stable temporal profiles. The findings offer practical guidelines for experimental implementation and highlight the potential of evolutionary algorithms for accelerating fiber laser design and optimization in advanced nonlinear optical systems.
{"title":"Algorithmic optimization of figure-of-9 fiber lasers via particle swarm methods","authors":"Gaelle Carine Mbanda Nsoungui , Abdullah S. Karar , Kaboko Jean-Jacques Monga , Ehsan Adibnia , Hafedh Mahmoud Zayani , Mohamed Salhi , Faouzi Bahloul , Khmaies Ouahada","doi":"10.1016/j.rio.2025.100955","DOIUrl":"10.1016/j.rio.2025.100955","url":null,"abstract":"<div><div>Figure-of-9 fiber lasers (F9FL) represent a significant advancement in the field of ultrafast photonics, offering improved environmental stability, enhanced self-starting behavior, and efficient pulse shaping. However, optimizing the performance of F9FL remains a challenging task due to the complex interplay between nonlinear dynamics, dispersion management, and gain saturation effects. This study presents a systematic approach to optimize the operating conditions of an F9FL using an advanced two-particle swarm optimization (PSO) algorithm. The optimization process aims to maximize pulse energy, improve temporal stability, and enhance mode-locking efficiency by tuning critical laser parameters such as fiber lengths, gain coefficients, and phase shift conditions. A comprehensive numerical model incorporating bidirectional pulse propagation and nonlinear effects is employed to evaluate performance metrics under realistic constraints. Simulation results demonstrate that the proposed PSO-based strategy effectively identifies optimal parameter sets that lead to high-energy single pulses with stable temporal profiles. The findings offer practical guidelines for experimental implementation and highlight the potential of evolutionary algorithms for accelerating fiber laser design and optimization in advanced nonlinear optical systems.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"22 ","pages":"Article 100955"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938523","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}
The IoT in PV systems monitors the performance, fault diagnostics, predicts its performance, and improves the accuracy of the monitoring compared to the previous ones because of the continuous connectivity between sensing, communication, and processing tiers. This paper will provide a detailed literature review of IoT-supported solar PV systems with respect to their architecture and real-time monitoring systems that enable effective system operation and reliability. Different IoT based architectures are discussed such as the cloud architecture, edge architecture, and the fog computing architecture whereby each has their own unique roles in data acquisition, transmission, and analytics. Additionally, the paper examines the efficiency optimization methods, including adaptive maximum power point tracking, AI-driven data analytics, predictive maintenance, and intelligent cleaning technologies. The fact that these are complex features that have been integrated shows that the IoT can be used to make traditional PV systems smart enough to turn them into self-optimizing energy infrastructure. Lastly, the paper defines the important research opportunities and future directions, including the necessity to have scalable, secure, and interoperable IoT systems to enable next-generation sustainable energy systems.
{"title":"IoT-enabled solar PV systems: real-time monitoring and efficiency optimization","authors":"Geetam Shukla , Akash Kumar Shukla , K.N. Shukla , Shishir Dixit","doi":"10.1016/j.rio.2025.100949","DOIUrl":"10.1016/j.rio.2025.100949","url":null,"abstract":"<div><div>The IoT in PV systems monitors the performance, fault diagnostics, predicts its performance, and improves the accuracy of the monitoring compared to the previous ones because of the continuous connectivity between sensing, communication, and processing tiers. This paper will provide a detailed literature review of IoT-supported solar PV systems with respect to their architecture and real-time monitoring systems that enable effective system operation and reliability. Different IoT based architectures are discussed such as the cloud architecture, edge architecture, and the fog computing architecture whereby each has their own unique roles in data acquisition, transmission, and analytics. Additionally, the paper examines the efficiency optimization methods, including adaptive maximum power point tracking, AI-driven data analytics, predictive maintenance, and intelligent cleaning technologies. The fact that these are complex features that have been integrated shows that the IoT can be used to make traditional PV systems smart enough to turn them into self-optimizing energy infrastructure. Lastly, the paper defines the important research opportunities and future directions, including the necessity to have scalable, secure, and interoperable IoT systems to enable next-generation sustainable energy systems.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"22 ","pages":"Article 100949"},"PeriodicalIF":3.0,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797925","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}
In this paper, an ideal highly sensitive THz biological sensor based on a polarization-insensitive graphene absorber with three bands is designed and optimized. The concept of a polarization-insensitive sensor involves a ring of graphene and eight symmetrical ring resonators. Finite element modeling reveals that the developed absorber may be fine-tuned for a sensing capacity and an absorption efficiency of over 99.8 %. At frequencies of 3.769 THz, 5.888 THz, and 9.453 THz, respectively, three distinct narrow absorption peaks with efficiencies of 98.6 %, 99.2 %, and 99.8 % are produced as a result of field confinement induced by graphene surface plasmon resonances. This study delineates our sensitive refractive index sensor, including circular micro ring resonator and multiple graphene rings. A periodic design consisting of a center ring and eight peripheral rings that rotate π/4 rad produces a three-band absorber arrangement independent of wave polarization. Moreover, it has been demonstrated that modifying the graphene layer’s chemical potential may change the resonance frequencies while improving absorber performance. A maximum sensitivity of 3045 GHz/RIU, a Q-factor of 26.01, and a figure-of-merit of 9.18 RIU−1 are achieved by the proposed refractive index sensor with an analyte thickness of 2.3 μm. The suggested THz RI sensor offers an identical response for TE and TM polarizations because of its rotational symmetry. The performance of RI sensors is assessed using two biological samples: breast cancer and healthy breast cells. The findings unequivocally demonstrate the THz sensor’s possible biological applications. Achieving high absorption and sensitivity is the main feature of this paper.
{"title":"Highly sensitive multi-mode tunable THz graphene-based refractive index biosensor","authors":"Ehsan Veisi , Mahmood Seifouri , Mina Amirmazlaghani , Fatemeh Geran Gharakhili , Saeed Olyaee","doi":"10.1016/j.rio.2025.100948","DOIUrl":"10.1016/j.rio.2025.100948","url":null,"abstract":"<div><div>In this paper, an ideal highly sensitive THz biological sensor based on a polarization-insensitive graphene absorber with three bands is designed and optimized. The concept of a polarization-insensitive sensor involves a ring of graphene and eight symmetrical ring resonators. Finite element modeling reveals that the developed absorber may be fine-tuned for a sensing capacity and an absorption efficiency of over 99.8 %. At frequencies of 3.769 THz, 5.888 THz, and 9.453 THz, respectively, three distinct narrow absorption peaks with efficiencies of 98.6 %, 99.2 %, and 99.8 % are produced as a result of field confinement induced by graphene surface plasmon resonances. This study delineates our sensitive refractive index sensor, including circular micro ring resonator and multiple graphene rings. A periodic design consisting of a center ring and eight peripheral rings that rotate π/4 rad produces a three-band absorber arrangement independent of wave polarization. Moreover, it has been demonstrated that modifying the graphene layer’s chemical potential may change the resonance frequencies while improving absorber performance. A maximum sensitivity of 3045 GHz/RIU, a Q-factor of 26.01, and a figure-of-merit of 9.18 RIU<sup>−1</sup> are achieved by the proposed refractive index sensor with an analyte thickness of 2.3 μm. The suggested THz RI sensor offers an identical response for TE and TM polarizations because of its rotational symmetry. The performance of RI sensors is assessed using two biological samples: breast cancer and healthy breast cells. The findings unequivocally demonstrate the THz sensor’s possible biological applications. Achieving high absorption and sensitivity is the main feature of this paper.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"22 ","pages":"Article 100948"},"PeriodicalIF":3.0,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797943","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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