Pub Date : 2025-02-27DOI: 10.1016/j.ijleo.2025.172281
Aayushi Soni , Dalip Singh Mehta
In response to the growing health issues linked to prolonged screen time in indoor settings, there is a need for artificial lighting that mimics natural sunlight to support anti-aging, enhance work productivity, regulate sleep patterns, and ensure secure communication. This study presents the development of a cost-effective, laser-driven solid-state lighting source utilizing a combination of inorganic yellow, green, red, and deep-red phosphor. The broad-spectrum laser source (BSLS) shows distinct advantages, particularly high color purity (76.8 % ± 0.5 %), high color rendering index (96 ± 0.5 %), and a 200 % enhancement in color gamut compared to the primary tri-colors. BSLS demonstrates a 91.4 ± 2.5 % reduction in blue light hazard relative to a narrow band source, such as conventional white LED. Simultaneously, the feasibility of visible light communication utilizing BSLS demonstrates a data rate of up to 20 kbps for baseband signals. A comprehensive guidance on health-friendly illumination source with real-time communication features is provided. The correlated and uncorrelated noise factors, such as jitter (time-error) and interference, quality factor, extinction ratio, and rise and fall time of the link designed using BSLS, are presented in detail.
{"title":"Diode laser-based broad spectrum solid-state lighting and visible light communication","authors":"Aayushi Soni , Dalip Singh Mehta","doi":"10.1016/j.ijleo.2025.172281","DOIUrl":"10.1016/j.ijleo.2025.172281","url":null,"abstract":"<div><div>In response to the growing health issues linked to prolonged screen time in indoor settings, there is a need for artificial lighting that mimics natural sunlight to support anti-aging, enhance work productivity, regulate sleep patterns, and ensure secure communication. This study presents the development of a cost-effective, laser-driven solid-state lighting source utilizing a combination of inorganic yellow, green, red, and deep-red phosphor. The broad-spectrum laser source (BSLS) shows distinct advantages, particularly high color purity (76.8 % ± 0.5 %), high color rendering index (96 ± 0.5 %), and a 200 % enhancement in color gamut compared to the primary tri-colors. BSLS demonstrates a 91.4 ± 2.5 % reduction in blue light hazard relative to a narrow band source, such as conventional white LED. Simultaneously, the feasibility of visible light communication utilizing BSLS demonstrates a data rate of up to 20 kbps for baseband signals. A comprehensive guidance on health-friendly illumination source with real-time communication features is provided. The correlated and uncorrelated noise factors, such as jitter (time-error) and interference, quality factor, extinction ratio, and rise and fall time of the link designed using BSLS, are presented in detail.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"327 ","pages":"Article 172281"},"PeriodicalIF":3.1,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-26DOI: 10.1016/j.ijleo.2025.172282
Boyi Yang , Jia Li Zhang , Xiaojie Guo , Hangzhou Dong , Yinghao Guo , Haisu Li , Guobin Ren
We design for the first time a dual-core hollow core negative curvature fiber mode-selective coupler (HCNCF-MSC) in the 1 μm band. The designed HCNCF-MSC consists of two structures, and we have analyzed the performance of these two structures separately. The shortest device length of HCNCF-MSC-A is 3.2 cm, achieving a mode conversion efficiency higher than 75 % within the transmission wavelength range of 0.8–1.7 μm. HCNCF-MSC-B can achieve mode conversion under four different core diameters, with the shortest device lengths being 4.5 cm, 3.8 cm, 3.0 cm, and 2.4 cm, respectively, and it realizes a mode conversion efficiency greater than 80 % within the transmission wavelength range of 0.8–1.7 μm.
{"title":"Broadband mode-selective couplers of dual-core hollow core negative curvature fiber in the 1 μm band","authors":"Boyi Yang , Jia Li Zhang , Xiaojie Guo , Hangzhou Dong , Yinghao Guo , Haisu Li , Guobin Ren","doi":"10.1016/j.ijleo.2025.172282","DOIUrl":"10.1016/j.ijleo.2025.172282","url":null,"abstract":"<div><div>We design for the first time a dual-core hollow core negative curvature fiber mode-selective coupler (HCNCF-MSC) in the 1 μm band. The designed HCNCF-MSC consists of two structures, and we have analyzed the performance of these two structures separately. The shortest device length of HCNCF-MSC-A is 3.2 cm, achieving a mode conversion efficiency higher than 75 % within the transmission wavelength range of 0.8–1.7 μm. HCNCF-MSC-B can achieve mode conversion under four different core diameters, with the shortest device lengths being 4.5 cm, 3.8 cm, 3.0 cm, and 2.4 cm, respectively, and it realizes a mode conversion efficiency greater than 80 % within the transmission wavelength range of 0.8–1.7 μm.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"327 ","pages":"Article 172282"},"PeriodicalIF":3.1,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.ijleo.2025.172279
Jian-Hong Wu , Qi Bian , Yong Bo , Da-Fu Cui , Qin-Jun Peng
We present a high-power all-solid-state Tm:YAG laser operating at 2.02 μm in both continuous-wave (CW) and quasi-continuous-wave (QCW) regimes. Through rigorous testing of CW laser diodes (LDs) for QCW pulsed operation, the system achieves an average output power of up to 33.97 W at 100 Hz with a pulse width of 670 μs and a beam quality of M2= 8.66. In the CW regime, it delivers a record-high output power of 317.3 W. The beam quality is degraded to be M2= 22.75 due to the severe thermal effects in the crystal. This is the first demonstration of CW and QCW dual-regime operation in a single diode-pumped Tm:YAG laser oscillator. This versatile laser system offers a reliable solution for applications requiring high-power mid-infrared sources.
{"title":"High power continuous-wave and quasi-continuous-wave operation of diode-pumped Tm:YAG all-solid-state laser oscillator at 2.02 μm","authors":"Jian-Hong Wu , Qi Bian , Yong Bo , Da-Fu Cui , Qin-Jun Peng","doi":"10.1016/j.ijleo.2025.172279","DOIUrl":"10.1016/j.ijleo.2025.172279","url":null,"abstract":"<div><div>We present a high-power all-solid-state Tm:YAG laser operating at 2.02 μm in both continuous-wave (CW) and quasi-continuous-wave (QCW) regimes. Through rigorous testing of CW laser diodes (LDs) for QCW pulsed operation, the system achieves an average output power of up to 33.97 W at 100 Hz with a pulse width of 670 μs and a beam quality of <em>M</em><sup><em>2</em></sup>= 8.66. In the CW regime, it delivers a record-high output power of 317.3 W. The beam quality is degraded to be <em>M</em><sup><em>2</em></sup>= 22.75 due to the severe thermal effects in the crystal. This is the first demonstration of CW and QCW dual-regime operation in a single diode-pumped Tm:YAG laser oscillator. This versatile laser system offers a reliable solution for applications requiring high-power mid-infrared sources.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"326 ","pages":"Article 172279"},"PeriodicalIF":3.1,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143510357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-23DOI: 10.1016/j.ijleo.2025.172277
Ghulam Abbas Lashari , Farhan Mumtaz , Abdul Aziz , Mumtaz Ali
This research proposes and experimentally demonstrates a polymer-filled Hollow Core Fiber (HCF) based compact Fabry-Perot Interferometer (FPI) for temperature sensing. The two beams: one reflectd at the interface between multimode fiber and the hollow core fiber and the other beam reflected at the interface between the hollow core fiber and the thermosensitive polymer form the Fabry-Perot cavity. The thermosensitive material filled in the core of the HCF acts as the sensing element. The HCF core is partially filled with transparent photopolymer, which has high Thermo-Optic Coefficient (TOC) and Thermo-Expansion Coefficient (TEC) as compared to silica, therefore it can provide high temperature sensitivity. The temperature sensitivity of the proposed FPI sensor can reach up to 53.5 pm/℃. The results indicate that the polymer-filled hollow-core fiber based FPI offers a promising approach for achieving high temperature sensing than pure silica based sensors. The proposed device consists of compact design with easy and low-cost fabrication. Moreover, the temperature measuring device provides stable and linear output response and brings numerous prospects for ocean temperature measurements, food, medical and chemical sensing applications.
{"title":"Temperature measurement with compact Fabry-Perot Interferometer employing polymer-filled Hollow Core Fiber","authors":"Ghulam Abbas Lashari , Farhan Mumtaz , Abdul Aziz , Mumtaz Ali","doi":"10.1016/j.ijleo.2025.172277","DOIUrl":"10.1016/j.ijleo.2025.172277","url":null,"abstract":"<div><div>This research proposes and experimentally demonstrates a polymer-filled Hollow Core Fiber (HCF) based compact Fabry-Perot Interferometer (FPI) for temperature sensing. The two beams: one reflectd at the interface between multimode fiber and the hollow core fiber and the other beam reflected at the interface between the hollow core fiber and the thermosensitive polymer form the Fabry-Perot cavity. The thermosensitive material filled in the core of the HCF acts as the sensing element. The HCF core is partially filled with transparent photopolymer, which has high Thermo-Optic Coefficient (TOC) and Thermo-Expansion Coefficient (TEC) as compared to silica, therefore it can provide high temperature sensitivity. The temperature sensitivity of the proposed FPI sensor can reach up to 53.5 pm/℃. The results indicate that the polymer-filled hollow-core fiber based FPI offers a promising approach for achieving high temperature sensing than pure silica based sensors. The proposed device consists of compact design with easy and low-cost fabrication. Moreover, the temperature measuring device provides stable and linear output response and brings numerous prospects for ocean temperature measurements, food, medical and chemical sensing applications.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"327 ","pages":"Article 172277"},"PeriodicalIF":3.1,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optical phase modulators find critical applications in classical and quantum communication for data modulation and in high-power fiber lasers for linewidth broadening. In this paper, we propose a simple interferometer-free method to accurately characterize an optical phase modulator. A radio frequency source is used to drive the phase modulator, and its output is observed on an optical spectrum analyzer (OSA). The relative power levels of the first and second-order side bands with respect to the optical carrier measured from the OSA are plotted as a function of the input RF power. These results are compared with the values expected through simulations where a parametric variation is carried out to find the value of . We also present the details of characterization of other critical parameters of the phase modulator, such as electro-optic bandwidth, polarization-dependent loss, and its residual amplitude modulation.
{"title":"Interferometer-free method for accurate characterization of an optical phase modulator","authors":"Geethakrishnan Purushothaman, Mrudula Krishna, Deepa Venkitesh","doi":"10.1016/j.ijleo.2025.172264","DOIUrl":"10.1016/j.ijleo.2025.172264","url":null,"abstract":"<div><div>Optical phase modulators find critical applications in classical and quantum communication for data modulation and in high-power fiber lasers for linewidth broadening. In this paper, we propose a simple interferometer-free method to accurately characterize an optical phase modulator. A radio frequency source is used to drive the phase modulator, and its output is observed on an optical spectrum analyzer (OSA). The relative power levels of the first and second-order side bands with respect to the optical carrier measured from the OSA are plotted as a function of the input RF power. These results are compared with the values expected through simulations where a parametric variation is carried out to find the value of <span><math><msub><mrow><mi>V</mi></mrow><mrow><mi>π</mi></mrow></msub></math></span>. We also present the details of characterization of other critical parameters of the phase modulator, such as electro-optic bandwidth, polarization-dependent loss, and its residual amplitude modulation.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"327 ","pages":"Article 172264"},"PeriodicalIF":3.1,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-21DOI: 10.1016/j.ijleo.2025.172276
Suraj Saha, Sanjoy Mandal
The article introduces a novel attempt to design and simulate a high-contrast grating embedded micro-optical triple ring-resonance temperature sensor in the Z-domain. The sensor is configured with three waveguide rings, having different ring radii, and establishes ring resonance with the two linear waveguides. The only sensor element incorporated is the Bragg grating, which offers a high-index contrast between the adjacent cells and is modelled as an individual cell transfer function in the Z-domain. The transfer function formulation considers a cascade structure orientation and a uniform cell width of the grating and includes a phase term to address the refractive index differences. The signal flow graph representation of the composite triple ring-resonated Bragg grating sensor is also obtained, and, using Mason’s gain formula, the transmission transfer function is determined. The stated methodology exclusively relies on the unity-delay perturbation from to and the execution of the delay line signal processing technique, and illustrating the sensor’s spectral response for 0–500 C temperature variation. The MATLAB platform is preferred for the simulation work and frequency response visualization. Finally, optical attributes like free spectral range, peak transmission, and spectrum shift magnitude are measured to examine the sensor response profiles.
{"title":"High contrast grating embedded multi-bus micro-optical triple ring-resonated temperature sensor design and simulation","authors":"Suraj Saha, Sanjoy Mandal","doi":"10.1016/j.ijleo.2025.172276","DOIUrl":"10.1016/j.ijleo.2025.172276","url":null,"abstract":"<div><div>The article introduces a novel attempt to design and simulate a high-contrast grating embedded micro-optical triple ring-resonance temperature sensor in the Z-domain. The sensor is configured with three waveguide rings, having different ring radii, and establishes ring resonance with the two linear waveguides. The only sensor element incorporated is the Bragg grating, which offers a high-index contrast between the adjacent cells and is modelled as an individual cell transfer function in the Z-domain. The transfer function formulation considers a cascade structure orientation and a uniform cell width of the grating and includes a phase term to address the refractive index differences. The signal flow graph representation of the composite triple ring-resonated Bragg grating sensor is also obtained, and, using Mason’s gain formula, the transmission transfer function is determined. The stated methodology exclusively relies on the unity-delay perturbation from <span><math><msup><mrow><mi>z</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span> to <span><math><msup><mrow><mi>z</mi></mrow><mrow><mo>−</mo><mo>(</mo><mn>1</mn><mo>+</mo><mo>∆</mo><mi>M</mi><mo>)</mo></mrow></msup></math></span> and the execution of the delay line signal processing technique, and illustrating the sensor’s spectral response for 0–50<sup>0</sup> C temperature variation. The MATLAB platform is preferred for the simulation work and frequency response visualization. Finally, optical attributes like free spectral range, peak transmission, and spectrum shift magnitude are measured to examine the sensor response profiles.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"327 ","pages":"Article 172276"},"PeriodicalIF":3.1,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-19DOI: 10.1016/j.ijleo.2025.172262
M.H. Anit Monisha , M.R. Geetha
Free Space Optical (FSO) communication has gained significant attention as a high-speed data transmission technology due to its ability to leverage light waves for transmitting information through the atmosphere. However, it faces several atmospheric turbulence challenges that can adversely affect its performance, including weather-induced attenuation, polarization-induced fading, polarization mismatches, and spectral efficiency loss. This paper presents the Resilient Adaptive Polarized Optical Transmission (RAPOT) framework, which integrates Adaptive M-ary Differential Quadrature Phase-Shift Keying (AM-DQPSK), Spatial Polarization Multiplexing (SPM), Dynamic Spatial Mode Switching (DSMS), and Polarization-Time Coding (PTC) to enhance modulation, multiplexing, and overall system resilience. AM-DQPSK allows the system to dynamically adjust modulation order based on real-time channel conditions, mitigating the impact of weather-induced attenuation and maintaining reliable communication. SPM increases spectral efficiency by utilizing orthogonally polarized carriers, while also providing polarization diversity to reduce the effects of polarization-induced fading. DSMS enhances robustness by adapting spatial modes to real-time environmental changes, effectively countering polarization mismatches. Finally, PTC encodes data across polarization and time domains, overcoming spectral efficiency loss and providing redundancy for signal recovery in challenging environments. The performance of the RAPOT system is evaluated through extensive experimental simulations and the simulation results for RAPOT system operating at 20 Gbps indicate substantial performance improvements under moderate turbulence conditions. The system achieved a Bit Error Rate (BER) of 10⁻⁵ at Signal to Noise Ratio (SNR) 25, demonstrating robust error performance. The outage probability (OP) is minimized to 0.03, while the link range extended to 2.8 km, showcasing the system's capability to maintain reliable communication even in challenging environments. Additionally, the RAPOT system demonstrated a 25 % increase in spectral efficiency, reaching 8 bits/Hz, compared to conventional systems. These results highlight the RAPOT system's effectiveness in mitigating the challenges posed by atmospheric turbulence and ensuring high-speed FSO communication.
{"title":"Resilient adaptive polarized optical transmission for mitigating atmospheric turbulence in free space optics communication","authors":"M.H. Anit Monisha , M.R. Geetha","doi":"10.1016/j.ijleo.2025.172262","DOIUrl":"10.1016/j.ijleo.2025.172262","url":null,"abstract":"<div><div>Free Space Optical (FSO) communication has gained significant attention as a high-speed data transmission technology due to its ability to leverage light waves for transmitting information through the atmosphere. However, it faces several atmospheric turbulence challenges that can adversely affect its performance, including weather-induced attenuation, polarization-induced fading, polarization mismatches, and spectral efficiency loss. This paper presents the Resilient Adaptive Polarized Optical Transmission (RAPOT) framework, which integrates Adaptive M-ary Differential Quadrature Phase-Shift Keying (AM-DQPSK), Spatial Polarization Multiplexing (SPM), Dynamic Spatial Mode Switching (DSMS), and Polarization-Time Coding (PTC) to enhance modulation, multiplexing, and overall system resilience. AM-DQPSK allows the system to dynamically adjust modulation order based on real-time channel conditions, mitigating the impact of weather-induced attenuation and maintaining reliable communication. SPM increases spectral efficiency by utilizing orthogonally polarized carriers, while also providing polarization diversity to reduce the effects of polarization-induced fading. DSMS enhances robustness by adapting spatial modes to real-time environmental changes, effectively countering polarization mismatches. Finally, PTC encodes data across polarization and time domains, overcoming spectral efficiency loss and providing redundancy for signal recovery in challenging environments. The performance of the RAPOT system is evaluated through extensive experimental simulations and the simulation results for RAPOT system operating at 20 Gbps indicate substantial performance improvements under moderate turbulence conditions. The system achieved a Bit Error Rate (BER) of 10⁻⁵ at Signal to Noise Ratio (SNR) 25, demonstrating robust error performance. The outage probability (OP) is minimized to 0.03, while the link range extended to 2.8 km, showcasing the system's capability to maintain reliable communication even in challenging environments. Additionally, the RAPOT system demonstrated a 25 % increase in spectral efficiency, reaching 8 bits/Hz, compared to conventional systems. These results highlight the RAPOT system's effectiveness in mitigating the challenges posed by atmospheric turbulence and ensuring high-speed FSO communication.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"326 ","pages":"Article 172262"},"PeriodicalIF":3.1,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-15DOI: 10.1016/j.ijleo.2025.172258
D. Zárate-Villegas, Ivan Moreno
Designing lenses for wavelengths below 121 nm is challenging due to the strong absorption of optical materials. This study introduces a metalens composed of ring-shaped silica nano-elements that efficiently focus extreme ultraviolet (EUV) radiation. Each ring features an air or vacuum core () surrounded by silica with a refractive index , optimized for EUV operation. Finite-difference time-domain (FDTD) simulations demonstrate a phase coverage of 1.85 , high EUV transmission, and an optical efficiency of 83.6%. These results represent a significant advancement over existing EUV metalenses, and underscore the potential of this design for compact and efficient EUV optical systems.
{"title":"Extreme UV metalens consisting of ring meta-atoms","authors":"D. Zárate-Villegas, Ivan Moreno","doi":"10.1016/j.ijleo.2025.172258","DOIUrl":"10.1016/j.ijleo.2025.172258","url":null,"abstract":"<div><div>Designing lenses for wavelengths below 121 nm is challenging due to the strong absorption of optical materials. This study introduces a metalens composed of ring-shaped silica nano-elements that efficiently focus extreme ultraviolet (EUV) radiation. Each ring features an air or vacuum core (<span><math><mrow><mi>n</mi><mo>=</mo><mn>1</mn></mrow></math></span>) surrounded by silica with a refractive index <span><math><mrow><mi>n</mi><mo><</mo><mn>1</mn></mrow></math></span>, optimized for EUV operation. Finite-difference time-domain (FDTD) simulations demonstrate a phase coverage of 1.85 <span><math><mi>π</mi></math></span>, high EUV transmission, and an optical efficiency of 83.6%. These results represent a significant advancement over existing EUV metalenses, and underscore the potential of this design for compact and efficient EUV optical systems.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"326 ","pages":"Article 172258"},"PeriodicalIF":3.1,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-14DOI: 10.1016/j.ijleo.2025.172260
Alireza Zarei , Srikanth Pilla
When a laser pulse impinges on a composite material, a portion of the light is absorbed by the matrix, while the remainder is absorbed by the embedded fibers. Conventional models overlook the substantial differences in optical properties between these two constituents. This paper, however, introduces a novel analytical model for laser light absorption in fiber-reinforced composite materials. This macroscopic model incorporates distinct optical absorptivity for both the matrix and embedded fibers, offering adaptability to various scenarios without introducing additional computational cost to simulations. The dynamic thermal expansion and elastic wave generation inside the material is considered to study the effects of the presented model on the generated waves. Investigations are conducted on a Carbon Fiber Reinforced Plastic (CFRP) plate with variable epoxy layer thickness using Nd:YAG and mid-IR lasers. Results demonstrate a significant enhancement in temperature distribution within the material, elucidating experimental observations previously unexplained by conventional models. Under consistent laser energy, pulse duration, and beam radius, the Nd:YAG laser induces notably higher temperatures in the CFRP-epoxy interface compared to the mid-IR laser. Furthermore, thicker epoxy layers result in lower temperatures and higher displacement amplitudes, aligning with the desirable characteristics for laser ultrasonic testing applications.
{"title":"A novel laser light absorption model for composite materials in the context of laser ultrasonic testing","authors":"Alireza Zarei , Srikanth Pilla","doi":"10.1016/j.ijleo.2025.172260","DOIUrl":"10.1016/j.ijleo.2025.172260","url":null,"abstract":"<div><div>When a laser pulse impinges on a composite material, a portion of the light is absorbed by the matrix, while the remainder is absorbed by the embedded fibers. Conventional models overlook the substantial differences in optical properties between these two constituents. This paper, however, introduces a novel analytical model for laser light absorption in fiber-reinforced composite materials. This macroscopic model incorporates distinct optical absorptivity for both the matrix and embedded fibers, offering adaptability to various scenarios without introducing additional computational cost to simulations. The dynamic thermal expansion and elastic wave generation inside the material is considered to study the effects of the presented model on the generated waves. Investigations are conducted on a Carbon Fiber Reinforced Plastic (CFRP) plate with variable epoxy layer thickness using Nd:YAG and mid-IR lasers. Results demonstrate a significant enhancement in temperature distribution within the material, elucidating experimental observations previously unexplained by conventional models. Under consistent laser energy, pulse duration, and beam radius, the Nd:YAG laser induces notably higher temperatures in the CFRP-epoxy interface compared to the mid-IR laser. Furthermore, thicker epoxy layers result in lower temperatures and higher displacement amplitudes, aligning with the desirable characteristics for laser ultrasonic testing applications.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"326 ","pages":"Article 172260"},"PeriodicalIF":3.1,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-13DOI: 10.1016/j.ijleo.2025.172263
Salah Abdulrhmann
This article investigates the effects of strong optical feedback on the operational states and relative intensity noise fluctuations of long external cavity semiconductor lasers. Using modified rate equations, the findings show that the pulsation amplitude increases significantly, and the time to reach steady-state operation decreases when noise sources are included. Under strong optical feedback, the laser exhibits pulsating behavior, with relative intensity noise reduced to quantum noise level at high injection currents. In chaotic conditions, two peaks appear at the external and relaxation frequencies, indicating instability due to two threshold conditions related to the laser and external cavity. Consequently, the low-frequency relative intensity noise is elevated above quantum noise levels. Increasing the optical feedback and enhancing the injection current are essential for stable, low-noise pulsating laser operation.
{"title":"Operational states and intensity noise characteristics of time-delayed semiconductor lasers subject to strong optical feedback","authors":"Salah Abdulrhmann","doi":"10.1016/j.ijleo.2025.172263","DOIUrl":"10.1016/j.ijleo.2025.172263","url":null,"abstract":"<div><div>This article investigates the effects of strong optical feedback on the operational states and relative intensity noise fluctuations of long external cavity semiconductor lasers. Using modified rate equations, the findings show that the pulsation amplitude increases significantly, and the time to reach steady-state operation decreases when noise sources are included. Under strong optical feedback, the laser exhibits pulsating behavior, with relative intensity noise reduced to quantum noise level at high injection currents. In chaotic conditions, two peaks appear at the external and relaxation frequencies, indicating instability due to two threshold conditions related to the laser and external cavity. Consequently, the low-frequency relative intensity noise is elevated above quantum noise levels. Increasing the optical feedback and enhancing the injection current are essential for stable, low-noise pulsating laser operation.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"326 ","pages":"Article 172263"},"PeriodicalIF":3.1,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号