The European Physical Journal Plus最新文献

{"title":"Optimizing natural convection heat transfer in a square cavity filled with a hybrid nanofluid: combined effects of magnetic field, diamond-shaped obstacle position, and aspect ratio","authors":"Mohsine Qaffou,&nbsp;Youness Ighris,&nbsp;Younes Oulahou,&nbsp;Jamal Baliti,&nbsp;Yassine Sadiki,&nbsp;Mohamed Hssikou","doi":"10.1140/epjp/s13360-026-08149-8","DOIUrl":"10.1140/epjp/s13360-026-08149-8","url":null,"abstract":"<div><p>This study numerically analyses natural convection in a square cavity filled with an <span>({text{Al}}_{2} {text{O}}_{3} - {text{Fe}}_{3} {text{O}}_{4} /)</span> water hybrid nanofluid containing a heated obstacle. The LBM is employed to investigate the effects of the Rayleigh number (<span>({10}^{{3}})</span>—<span>({10}^{{6}})</span>), the Hartmann number (0—60), the angle of inclination of the magnetic field (0°—90°), the position of the obstacle, and the obstacle’s aspect ratio (<span>(AR_{0})</span>, <span>(AR_{1})</span>). The results show that increasing the Rayleigh number from <span>({10}^{{3}})</span> to <span>({ 10}^{{6}})</span> significantly enhances natural convection. The average Nusselt number increases from 1.912 to 6.783 for the square obstacle and from 1.917 to 7.108 for the diamond-shaped obstacle. At <span>({text{Ra = 10}}^{{6}})</span>, the diamond configuration improves the average Nusselt number by approximately 4.8% compared to the square obstacle, while the maximum stream function increases by approximately 9.5%. Conversely, an increase in the Hartmann number reduces natural convection, because the magnetic force opposes the buoyancy force. For <span>(AR_{0} = { }0.5)</span> and <span>({text{Ra = 10}}^{{6}})</span>, an increase in the Hartmann number from 0 to 60 results in a decrease of approximately 35% in the average Nusselt number, as well as a reduction of approximately 58% in the maximum value of the stream function, indicating that the intensification of the magnetic field weakens natural convection heat transfer. Furthermore, the magnetic field inclination angle alters the organization of the convective cells. The results also show that the middle position of the obstacle, combined with an appropriate choice of aspect ratios, improves fluid circulation and overall thermal performance.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751172","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}

{"title":"Quantum-resilient secure key distribution and deep adaptive intelligence for hybrid IIoT-SDN network defense","authors":"G. A. Senthil,&nbsp;S. U. Suganthi,&nbsp;R. Deepa,&nbsp;R. Deepa","doi":"10.1140/epjp/s13360-026-08115-4","DOIUrl":"10.1140/epjp/s13360-026-08115-4","url":null,"abstract":"<div><p>The integration of Industrial Internet of Things (IIoT) with Software-Defined Networking (SDN) enables centralized control, scalability, and flexible network management. However, IIoT-SDN environments remain vulnerable to intrusion attacks, unauthorized access, high-energy consumption, and latency under dynamic network conditions. Existing security mechanisms often struggle with real-time threat detection, adaptive trust enforcement, and efficient key management. To address these issues, this research proposes a High-dimensional Variational Zero-Trust Hopfield Network (HVZTHN) integrated into the SDN control plane for secure and efficient IIoT communication. The proposed model uses associative memory and zero-trust principles for authentication, access control, and intrusion detection. The Bermuda Triangle optimizer is applied to fine-tune the model parameters, improving detection accuracy and convergence speed. In addition, a lightweight secure key distribution mechanism is introduced to support reliable encryption and confidential data transmission. The proposed HVZTHN model achieved a network lifetime of 480 rounds, energy consumption of 430 J, latency of 70 s, encryption time of 15.6 s, decryption time of 8.4 s, throughput of 950 Mbps, CPU usage of 30%, and response time of approximately 950 ms. These results demonstrate that the proposed framework provides an efficient, scalable, and secure solution for IIoT-SDN networks under high-load conditions.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750953","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}

{"title":"Dynamics of extended ((3+1))-dimensional Jimbo–Miwa equation via binary Bell-polynomial approach","authors":"Junyue Zhang,&nbsp;Na Liu,&nbsp;Quansheng Liu,&nbsp;Ruigang Zhang","doi":"10.1140/epjp/s13360-026-08134-1","DOIUrl":"10.1140/epjp/s13360-026-08134-1","url":null,"abstract":"<div><p>High-dimensional nonlinear evolution equations are central to modeling complex wave dynamics in fluids, plasmas, and optical media. This paper presents a bilinear construction procedure for multidimensional localized solutions of the extended (3+1)-dimensional Jimbo–Miwa equation based on the binary Bell-polynomial approach. Starting from the bilinear form and a general N-soliton representation, resonant bifurcation solitons, M-lump waves, higher-order breather waves, and hybrid interaction solutions are constructed and analyzed. The resonant bifurcation family comprises Y-type and X-type fusion–fission patterns and heterotypic solitons with oscillatory resonant profiles. The <i>M</i>-lump waves, derived via a long-wave limit, exhibit rational localization and parameter-dependent propagation trajectories. Higher-order breathers are generated under complex-conjugate constraints, displaying both crossing interactions and parallel propagation patterns with amplitude modulation. The lump–soliton, lump–breather, and breather–soliton interactions are further constructed, showing localized mixed wave patterns in which different wave components interact and remain distinguishable within the plotted time intervals. The results provide analytical examples for constructing and analyzing multidimensional localized waves in extended Jimbo–Miwa-type equations and for characterizing their interaction patterns in nonlinear dispersive media.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750772","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}

{"title":"Effect of gypsum content on the microstructure, mechanical, and gamma-ray shielding performance of clay-based composite bricks","authors":"Mohamed Y. Hanfi,&nbsp;Mohamed Hasabelnaby,&nbsp;Mohammed J. Abd El Karim,&nbsp;Ghada Salaheldin","doi":"10.1140/epjp/s13360-026-08141-2","DOIUrl":"10.1140/epjp/s13360-026-08141-2","url":null,"abstract":"<div><p>The study involves the design and testing of clay–gypsum composite bricks, comprising a wide range of gypsums to determine their suitability as a construction material. Five distinct types of clay–gypsum composites were formulated, each containing 0, 10, 20, 30, or 40% gypsum, designated as G0, G1, G2, G3, and G4, respectively. Each brick was produced through molding, thermal drying and curing in water. The composite’s chemical and physical properties were characterized with XRD, SEM (using BSE), EDS and XRF and the resulting products were characterized based on density, porosity, water absorption, compressive strength, bending strength, and elastic modulus. Physical features such as density, porosity, and water absorption and different kinds of strength were calculated. The gamma-ray screening capacity of the clay composites was measured using a NaI(Tl) detector at some specific photon energies: 662, 1173, and 1332 keV. It was shown that increasing the amount of gypsum caused transformation of clay into a porous gypsum-based composition. As gypsum content increased from 10 to 40 wt.%, density dropped from 1.765 to 1.430 g/cm³ and compressive strength decreased from 3.91 to 1.22 MPa. The untreated clay sample (G0) had the highest gamma-ray attenuation performance due to its higher level of density. Among the samples that contained gypsum, G1 (with 10 wt.% gypsum) showed the highest shielding performance with linear attenuation coefficient (LAC) values of 0.133, 0.099, and 0.092 cm⁻¹ at 662, 1173, and 1332 keV, respectively, as compared to G4, which had the lowest attenuation capability. With an increase of the gypsum content, half value layer (HVL), mean free path (MFP), Pb-equivalent thickness, and transmission factor (TF) values increased, while the radiation protection efficiency (RPE) decreased meaning less effectiveness in shielding due to more porosity and lower effective density. At the same time, the MAC values of the composites were found to be in the range of 0.0753–0.0757 cm²/g which can be compared to many traditional construction and shielding materials presented in the literature. All in all, the obtained results show that a low addition of gypsum (10 wt.%) provides an essential balance of lightweight properties, suitable mechanical performance, and proper shielding against exposure to gamma rays.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750847","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}

{"title":"Silicon-on-insulator-based antisymmetric meandering resonator: exploration and characterization","authors":"Muhammad Rehan Chaudhry,&nbsp;Farhan Azeem,&nbsp;Sultan Shah Bukhari Syed,&nbsp;Haseeb Ahmad Khan,&nbsp;Muhammad Zakwan,&nbsp;Chengcai Tian,&nbsp;Li Ma,&nbsp;Wenjie Wan","doi":"10.1140/epjp/s13360-026-08135-0","DOIUrl":"10.1140/epjp/s13360-026-08135-0","url":null,"abstract":"<div><p>In this work, we study an antisymmetric meandering resonator (AMR) photonic structure based on the silicon-on-insulator (SOI) platform through both simulation and experiment in the near-infrared regime. The resonator is realized by coupling one- and half-meandering loop mirrors (MLMs) and fabricated using waveguides with 500 nm width and 220 nm height. The transmission spectra of the AMR exhibit features resembling electromagnetically induced transparency (EIT). Two identical directional couplers, with varying lengths, are employed to tune the spectral response. Three-dimensional finite-difference time-domain (3D FDTD) simulations correlate well with experiments, reporting a fiber-to-fiber insertion loss of approximately −17 dB, while the intrinsic AMR loss after de-embedding grating coupler losses is approximately 1.2 dB. EIT-like peaks begin to emerge at a coupling constant <i>C</i> of 0.39, with the highest quality factor of <span>(5 times 10^{4})</span> and extinction ratio of 17.5 dB observed at <span>(L_{c} = {30,mathrm{upmu text {m}}})</span> (<span>(C=0.94)</span>). The AMR structure holds potential for applications in optical switching, wavelength division multiplexing filters, data networks, and optical sensing within silicon photonics platforms.\u0000</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750721","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}

{"title":"Quantum ergodic capacity and outage probability for time-varying quantum channels","authors":"Tiancheng Wang,&nbsp;Tsuyoshi Sasaki Usuda","doi":"10.1140/epjp/s13360-026-08108-3","DOIUrl":"10.1140/epjp/s13360-026-08108-3","url":null,"abstract":"<div><p>This paper investigates the performance limits of classical–quantum communication over time-varying quantum channels subject to fading. We consider two regimes defined by the timescale of transmissivity fluctuations—fast fading and slow fading—and analyze them using appropriate performance metrics. For fast fading channels, in which fluctuations vary on a symbol-by-symbol basis, we derive the quantum ergodic capacity. A key theoretical result follows from Jensen’s inequality: for qubit systems, the capacity is convex in the transmissivity, implying a performance gain over the channel with fixed average transmissivity, whereas, for coherent state systems, the capacity is concave, leading to a performance penalty. For slow-fading channels, for which transmissivity remains constant over an entire code block, we derive the quantum outage probability. We specifically evaluate this metric under a beam-wandering model to illustrate how noise intensity and transmission rate jointly affect communication reliability. Together, these results provide a unified framework that connects physical fading phenomena with information-theoretic measures, offering guidance for the design of robust quantum communication systems.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750968","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}

{"title":"Spin–curvature interaction and dynamics of spinning particles around the Balart–Vagenas regular black hole spacetime","authors":"Abdujalil Gulomov,&nbsp;Farruh Atamurotov,&nbsp;Ahmadjon Abdujabbarov,&nbsp;Imtiaz Khan,&nbsp;Chengxun Yuan","doi":"10.1140/epjp/s13360-026-08123-4","DOIUrl":"10.1140/epjp/s13360-026-08123-4","url":null,"abstract":"<div><p>We investigate the dynamics of spinning test particles in the regular, electrically charged black hole spacetime recently constructed by Balart and Vagenas within Einstein’s nonlinear electrodynamics theory. For the specific case of the metric parameter <span>(alpha = 3)</span>, the spacetime is static, spherically symmetric, asymptotically Reissner–Nordström, and possesses a regular core like Sitter like de that satisfies the weak energy condition. Employing the Mathisson-Papapetrou-Dixon equations supplemented by the Tulczyjew spin condition, we derive explicit expressions for the conserved energy and angular momentum, the effective potential, and the radial momentum for equatorial motion. The effective potential exhibits characteristic peaks whose height and location are significantly modulated by both the black hole charge <i>Q</i> and the particle spin <i>s</i>. We determine the innermost stable circular orbit (ISCO) as a function of <i>Q</i> and <i>s</i>, showing that increasing either parameter shifts the ISCO inward, albeit with opposite effects on the orbital angular momentum. The superluminal bound imposes a critical spin <span>(s_{text {max}})</span> that decreases monotonically with <i>Q</i>, reaching approximately <span>(s_{text {max}} simeq 0.22,M)</span> near the extremal charge <span>(Q_{text {ext}} simeq 1.0257,M)</span>. The centre-of-mass energy of head-on collisions near the event horizon grows as the particles approach the horizon and is maximised for anti-parallel spin configurations. Numerical integration of the orbit equation reveals pronounced rosette-shaped trajectories with spin-dependent precession, where larger charge confines the orbit while non-zero spin enlarges the orbital envelope. Our results demonstrate that the regular core and the nonlinear electromagnetic field imprint distinctive signatures on spinning particle dynamics, offering potential observational discriminants between regular black holes and their singular counterparts.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750718","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}

{"title":"Hyperchaotic transitions and extreme events in hybrid-driven coupled photosensitive memristive FitzHugh–Nagumo neurons","authors":"Dinesh Vijay Sadhasivam,&nbsp;Abirami Karunanidhi,&nbsp;Mohanasubha Ramasamy,&nbsp;Karthikeyan Rajagopal","doi":"10.1140/epjp/s13360-026-08145-y","DOIUrl":"10.1140/epjp/s13360-026-08145-y","url":null,"abstract":"<div><p>We investigate the dynamical transitions in coupled photosensitive memristive FitzHugh–Nagumo neurons (PMFHN) subjected to hybrid driving consisting of periodic sinusoidal forcing and chaotic memristive Hindmarsh–Rose (mHR) neuronal excitation. In the absence of chaotic mHR driving, the coupled PMFHN system exhibits hyperchaotic dynamics characterized by two positive Lyapunov exponents, whereas the introduction of chaotic mHR driving suppresses the hyperchaotic behavior and induces a transition to a weakly chaotic state with a single positive maximal Lyapunov exponent. The underlying dynamical transitions are systematically analyzed through Lyapunov exponent spectra, bifurcation analysis, and extensive two-parameter phase diagrams. The synchronization and desynchronization regions of the coupled neuronal system are also identified over broad parameter domains. Furthermore, the study examines the emergence of intermittent large-amplitude oscillations associated with crisis-induced intermittency in both hyperchaotic and weak chaotic regimes. These rare, extreme events (EEs) are quantified using statistical measures, including significant threshold analysis and probability density functions, where long-tail distributions confirm the rare occurrence of large-amplitude oscillations. In addition, the parameter regions supporting extreme events are comprehensively explored using two-parameter phase-space analysis. The results demonstrate that chaotic mHR driving plays a crucial role in controlling the collective dynamics of coupled neuronal systems by suppressing hyperchaotic oscillations while preserving crisis-induced extreme events.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750684","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}

{"title":"Multi-slit time-reversed Young interference: source-space grating laws, quadratic-phase effects, and Talbot-like revivals","authors":"Jianming Wen","doi":"10.1140/epjp/s13360-026-08126-1","DOIUrl":"10.1140/epjp/s13360-026-08126-1","url":null,"abstract":"<div><p>We develop a compact theory of time-reversed Young (TRY) interference beyond the symmetric two-slit geometry by considering equally spaced three-slit, finite <i>N</i>-slit, and infinite periodic slit arrays. In the TRY configuration, a point emitter illuminates the aperture, a position-fixed detector records the signal, and the response is reconstructed in source space by correlating the detector record with the source-coordinate label. We show that the three-slit case already reveals the essential new physics beyond-two slits: A quadratic Fresnel phase survives, modifies the reconstructed interference law, and lifts the nominal dark fringes in the generic case. For a general equally spaced <i>N</i>-slit array, we derive the reconstructed response within a scalar, monochromatic, paraxial, narrow-slit, equal-amplitude model and show that the familiar textbook grating factor is recovered only when the quadratic phase is negligible, compensated, or reduced to a common phase across the array. In that ideal limit, the reconstructed peaks are source-space analogs of classical grating orders rather than outgoing diffraction beams. For an infinite periodic TRY array, we further show that the same discrete quadratic phase generates full and fractional Talbot-like revivals in source space, governed by a reciprocal-distance condition rather than the conventional Talbot propagation law. These results show that the symmetric two-slit TRY geometry is exceptional, while multi-slit TRY systems naturally combine source-space discrimination with sensitivity to aperture-wide phase structure and periodic-array revival physics.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-026-08126-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficacy of MIL-101 (Cr) saturable absorber-based erbium-doped fiber laser via optimized output coupling ratios","authors":"Shahid Sadiq,&nbsp;T. A. Alrebdi,&nbsp;Javed Iqbal,&nbsp;Bushra Azam,&nbsp;M. Aslam Baig,&nbsp;Haroon Asghar","doi":"10.1140/epjp/s13360-026-08109-2","DOIUrl":"10.1140/epjp/s13360-026-08109-2","url":null,"abstract":"<div><p>This study investigates the synthesis of Cr-metal–organic-framework (Cr-MOF) microstructures and explores their effectiveness as saturable absorber (SA) for pulse generation in a passively Q-switched (PQS) erbium-doped fiber laser (EDFL). Once the Cr-MOF sample was prepared, various characterization techniques were applied to confirm the successful synthesis of Cr-MOF microstructures. The Raman spectroscopy was employed to confirm the vibrational bonding and functional groups of the synthesized material. The morphological features of the prepared samples were investigated using a field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDX) that confirmed the elemental composition of the prepared material. To assess the nonlinear optical characteristic, a balanced twin-detector method was employed. The proposed Cr-MOF-SA showed a modulation depth of 5.38% and a saturation intensity of 30.06 MW/cm². The tape-assisted mechanical deposition technique was used to fabricate a thin film of Cr-MOF and was transferred onto a fiber ferrule to act as an SA. We conducted a thorough investigation into how the output coupling ratio affects the pulse dynamics and overall stability of the EDFL. The EDFL cavity was configured with three different output couplers: 50:50, 75:25, and 90:10, where 50%, 75%, and 90% of the optical power fed back into the laser cavity (intracavity power), and 50%, 25%, and 10% of the power were output. The results obtained through passive Q-switching (PQS) showed that stable pulse operation was conducted for three coupling ratios at a pump power range within 28–255.5 mW. Particularly, the 50% output coupler provided average output power and pulse energy (PE) with values 5.7 mW and 105.7 nJ. In contrast, the couplers with 75% and 90% intracavity power enabled higher pulse repetition rates (PRRs) (up to 80 kHz and 85 kHz) and shorter pulse widths (PWs) (down to 4.2 µs and 3.88 µs), respectively. Besides, output coupling ratio-dependent variations in central wavelength and 3-dB bandwidth further demonstrate controllable spectral tuning through output coupling adjustment. In the RF spectra, we recorded signal-to-noise ratios (SNRs) of approximately 44 dB<b>,</b> 48 dB<b>,</b> and 42 dB for 50%<b>,</b> 25%<b>,</b> and 10% output couplers, respectively, indicating good pulse stability of the laser system. The long-term stability was performed by monitoring PRRs, PW, and output power over two hours at a fixed pump power of 75.3 mW, confirming stable and reliable operation of Cr-MOF material as an SA in EDFLs. This study demonstrates that by systematically varying the output coupling ratio, we can control the intracavity energy storage and extraction, thereby flexibly tuning PRR, PW, and PE, making it suitable for numerous applications in the field of photonics and material science.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148652223","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}