Optik最新文献

{"title":"Weak mode locking dynamics in a thulium-doped fiber laser","authors":"L.M. Gonzalez-Vidal ,&nbsp;O. Pottiez ,&nbsp;L.A. Rodriguez-Morales ,&nbsp;H.E. Ibarra-Villalon ,&nbsp;M. Bello-Jimenez ,&nbsp;J.P. Lauterio-Cruz ,&nbsp;J.C. Hernandez-Garcia","doi":"10.1016/j.ijleo.2024.172153","DOIUrl":"10.1016/j.ijleo.2024.172153","url":null,"abstract":"<div><div>In this work, we study partial mode locking dynamics in a figure-eight thulium-doped fiber laser. With this particular laser design, which includes a long, highly power-imbalanced NOLM, two regimes are successively identified as pump power is raised, both characterized by a narrow-linewidth emission consisting of broad periodic pulses emerging from a dominant background radiation. In each case, peculiar dynamics are identified. In the first regime, the pulses undergo dynamical evolution at two different time scales: at the scale of hundreds of cycles, a slow quasi-periodic modulation affects both the pulse intensity and temporal position, whereas at the scale of the pulse duration, the inner details of its complex profile are found to drift under the pulse envelope. These phenomena are interpreted in terms of slow and fast gain dynamics, respectively. In the second regime, the waveform displays large Q-switched-like oscillations whose details reveal both the peak power clamping effect of the NOLM nonlinear transmission and competition between the pulse and the spurious background radiation. Finally, reducing pump power yields a quasi-continuous-wave regime in which the temporal waveform displays a self-imaging effect, as complex features in the temporal map repeat with a periodicity of 4.81 cavity cycles. Such behavior strongly contrasts with the stochasticity expected for this type of regime. These results illustrate the complex operation of long thulium-doped fiber lasers producing pulses in the 2-micron region, which are attractive for fundamental research, and also for applications such as surgery.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"321 ","pages":"Article 172153"},"PeriodicalIF":3.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142742995","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":"Design of cascaded diffractive optical elements generating different intensity distributions at several operating wavelengths","authors":"Georgy A. Motz ,&nbsp;Daniil V. Soshnikov ,&nbsp;Leonid L. Doskolovich ,&nbsp;Egor V. Byzov ,&nbsp;Evgeni A. Bezus ,&nbsp;Dmitry A. Bykov","doi":"10.1016/j.ijleo.2024.172140","DOIUrl":"10.1016/j.ijleo.2024.172140","url":null,"abstract":"<div><div>We consider the design of cascaded diffractive optical elements (DOEs) for generating specified intensity distributions for several incident beams with different wavelengths. For each incident beam with a given wavelength, the cascaded DOE forms a different specified intensity distribution. The problem of DOE design is formulated as the problem of minimizing a functional that depends on the functions of diffractive microrelief height of the cascaded DOE and represents the deviations of the intensity distributions generated at the operating wavelengths from the specified ones. Explicit expressions are obtained for the derivatives of the functional, and on this basis, a gradient method for calculating a cascaded DOE is formulated. The proposed gradient method is used for the calculation of cascaded DOEs focusing radiation of three different wavelengths into different areas. In particular, the calculation of a cascaded DOE generating a complex color image of parrots is considered. The presented numerical simulation results demonstrate high performance of the proposed method.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"320 ","pages":"Article 172140"},"PeriodicalIF":3.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747104","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":"Whispery gallery mode plasmonic biosensor based on intensifying graphene layer","authors":"Mohammad Amin Mohammadi,&nbsp;Zahra Adelpour,&nbsp;Mojtaba Sadeghi","doi":"10.1016/j.ijleo.2024.172152","DOIUrl":"10.1016/j.ijleo.2024.172152","url":null,"abstract":"<div><div>This study presents a novel whispery gallery mode (WGM) biosensor based on a plasmonic nanoring structure. The biosensor's design incorporates a unique combination of gold-coated plasmonic nanoring and graphene in which graphene serves as both an intensifying and receptor layer, allowing binding and detection. According to the classification of essential biomolecules, the proposed biosensor is capable of different biomolecules detection including DNA, RNA, adenine, cytosine, guanine, thymine, and uracil. The biosensor's performance was optimized using the FEM solution method, simulating the optimal sizes of the plasmonic layer and the dimensions of the silicon nanoring. The obtained results confirm high sensitivity within the studied range of refractive index, around 105 nm/RIU. Additionally, the highest Q-factor, figure of merit and minimum detection limit are around 4179.078, 276.315 <span><math><mrow><msup><mrow><mi>RIU</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mspace></mspace></mrow></math></span>and 3.619 ×<span><math><mrow><msup><mrow><mspace></mspace><mn>10</mn></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup><mspace></mspace></mrow></math></span>RIU, respectively. This biosensor demonstrates great potential in identifying biomolecular structures as presented in this paper, serving as a valuable tool for detecting and analyzing complex biological materials.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"321 ","pages":"Article 172152"},"PeriodicalIF":3.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142756866","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":"Chemometric advances in COD analysis: Overcoming turbidity interference with a Hybrid PLS-ANN approach","authors":"Meryem Nini,&nbsp;Mohamed Nohair","doi":"10.1016/j.ijleo.2024.172149","DOIUrl":"10.1016/j.ijleo.2024.172149","url":null,"abstract":"<div><div>In the current context of environmental protection, the accuracy of water quality analyses is crucial, especially chemical oxygen demand (COD) analyses. COD is a key indicator of organic pollutants in water, and is often compromised by turbidity interference at UV wavelengths. Faced with this turbidity challenge, this innovative study proposes an integrated approach, using in situ UV sensors and advanced Chemometric techniques, exploiting the synergy between PLS (Partial Least Square) and ANN (Artificial Neural Network). The research is divided into three main sections: (i) assessment of turbidity interference, (ii) development of a turbidity prediction model and (iii) elaboration of the COD compensation and prediction model. Turbidity significantly alters the UV-Visible absorbance spectrum of COD. By analyzing mixed solutions of COD and turbidity, we quantified this interference and established a turbidity prediction model using spectral areas between 303.5 and 700 nm. Interval PLS identified the most informative spectral regions for COD concentration, highlighting the 200–250 nm interval. To address turbidity interference, we developed a hybrid model combining PLS and ANN regression, and turbidity measurements are incorporated as an explanatory term in the model. This hybrid approach relies on in situ UV sensors to directly capture UV absorbance data in the field and applies robust chemometric models to accurately distinguish the UV absorbance contributions of organic compounds and turbidity. The method not only compensates for the interfering effect of turbidity, but also allows turbidity information to be used to refine COD predictions. Model performance, evaluated using R², RMSE, and MAE, showed a significant increase in R² to 0.9972, and decreases in RMSE to 0.94 and MAE to 0.64, demonstrating the method's effectiveness in correcting turbidity-induced deviations and improving COD prediction accuracy. The results of the evaluation on real data show high performance metrics, with recovery percentages close to 100 % and low RMSE and MAE values, indicating the model’s robust ability to predict COD in the presence of suspended particles.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"321 ","pages":"Article 172149"},"PeriodicalIF":3.1,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142742996","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":"A closely spaced dual-band dual-sense linear-to-circular polarization converter for X-band applications","authors":"Anusha Undrasi ,&nbsp;Debidas Kundu ,&nbsp;Kamalesh Kumar K. ,&nbsp;Vikas V. Khairnar","doi":"10.1016/j.ijleo.2024.172135","DOIUrl":"10.1016/j.ijleo.2024.172135","url":null,"abstract":"<div><div>This paper presents a novel design of closely spaced dual-band dual-sense linear-to-circular polarization converting metasurface for X-band applications. The unit cell of the metasurface consists of a pair of L-shaped dipoles and a pair of cross-dipoles, respectively, with diagonal symmetry. The proposed linear-to-circular polarization converter (LCPC) provides a 3-dB axial ratio bandwidth (ARBW) ranging from 7.84 to 9.08 GHz (14.65%) for the lower band, and from 10.89 to 12.94 GHz (17.11%) for the upper band. The two frequency bands are in close proximity to each other, with a calculated separation bandwidth of 33.95%. Moreover, the proposed metasurface provides dual-sense operation, enabling polarization conversion to left-hand circular polarization (LHCP) in the lower band and right-hand circular polarization (RHCP) in the upper band for a <span><math><mi>y</mi></math></span>-polarized incidence wave and vice versa for an <span><math><mi>x</mi></math></span>-polarized incidence wave, respectively. These characteristics hold significant importance in different applications, such as satellite communication, that demand polarization diversity. After numerical analysis based on full-wave simulations, the proposed converter is fabricated and measured. A good agreement is observed between the full-wave simulated and measurement results.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"320 ","pages":"Article 172135"},"PeriodicalIF":3.1,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747323","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":"Anisotropic tunning of MoS2-nanosheets by hydrodynamics force in microchannel: Reflection and transmission modes","authors":"Majid Shirazi,&nbsp;Rouhollah Karimzadeh","doi":"10.1016/j.ijleo.2024.172124","DOIUrl":"10.1016/j.ijleo.2024.172124","url":null,"abstract":"<div><div>In this research, a two-dimensional liquid crystal of molybdenum disulfide (LC-MoS₂) was prepared using the exfoliation method in the liquid phase. A mechanical-hydrodynamic approach was proposed for anisotropy tuning in a microfluidic microchannel in two modes: transmission and reflection. By measuring the ordinary and extraordinary refractive indices at six flow rates in the reflection mode, the birefringence value of the samples was measured up to 0.006. Additionally, these measurements for the transmission mode showed a birefringence of approximately 2×10⁻⁴. Furthermore, the effect of concentration was measured in addition to the flow rate. The results indicated that increasing the flow rate of MoS₂ nanosheets led to an increase in the induced birefringence. Similarly, increasing the concentration of LC-MoS₂ resulted in an increase in the birefringence of the sample.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"320 ","pages":"Article 172124"},"PeriodicalIF":3.1,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747185","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":"Light controlled dynamic hotspots on plasmonic surface utilizing plasmonic snowman arrays","authors":"Shirsendu Mitra","doi":"10.1016/j.ijleo.2024.172138","DOIUrl":"10.1016/j.ijleo.2024.172138","url":null,"abstract":"<div><div>In recent time, plasmon enhanced nanostructures, plasmonic arrays, and plasmonic meta-surfaces have gained utmost importance owing to their diverse applications in a wide range of fields that include biomedical engineering, surface enhanced Raman spectroscopy, photo-thermal, and more. Despite the advancement of nanofabrication technology, utilization of trivial fabrication techniques is equally important considering cost of fabrication and field of applications. In the present work, we simulate simpler plasmonic nano-structures for creating dynamic hotspots on a single plasmonic surface utilizing combinations of gold disks of different sizes. The gold disks of progressively diminishing sizes are brought in close proximity to make an array which we named as plasmonic snowman (PSM) array. Briefly, the article focuses on studying unique plasmonic characteristics of PSM array based plasmonic surfaces. The PSM array surfaces have multiple nano-gaps wherein on demand plasmonic hotspots can be created by controlling, size of the disks, wavelength of the background light, polarization of light, and the spatial arrangement of PSM arrays. The size and arrangement of the gold nano-disks decide the resonance wavelength and thereby most desirable operational wavelength. In this study, four different types of PSM arrangements are created for showcasing on demand tuning of plasmonic hotspots. The appearance of active hotspots for the proposed structures have been explored in detail. The effect of PSM array orientation, polarization of background, and plasmonic couplings are the major contributing parameters for controlling the positions of multiple hotspots on the proposed plasmonic surfaces. These tunable hotspots are capable of offering diverse bio-sensing and wearable electronics applications.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"321 ","pages":"Article 172138"},"PeriodicalIF":3.1,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142742877","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":"Analysis and experimental design to generate a family of vector optical vortices","authors":"Guillermo F. Quinteiro Rosen","doi":"10.1016/j.ijleo.2024.172108","DOIUrl":"10.1016/j.ijleo.2024.172108","url":null,"abstract":"<div><div>Optical vortices are highly inhomogeneous electromagnetic fields with phase and/or polarization singularities. Optical vortices are interesting per se and for their possible applications. In Quinteiro et al. (2019) we derived a mathematical expression representing a large family of vector optical vortices and explained how these fields could be measured. Here, we show how any member of this family can be composed by a superposition of plane waves, whose relative phases, polarization states and directions determine the family member, its polarization state, topological charge and degree of focusing. We exemplify this by numerically reproducing some peculiar optical vortices by interference of the appropriate plane waves. Furthermore, we propose an experimental setup to generate any such optical vortices and provide a detailed theory that supports the proposal. We conclude by presenting possible applications that the present research will facilitate.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"320 ","pages":"Article 172108"},"PeriodicalIF":3.1,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747183","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":"High-brightness acousto-optic Q-switched 532 nm laser coupled with 200 μm fiber","authors":"Jiapeng Hu ,&nbsp;Hongcai Liu ,&nbsp;Dong Li ,&nbsp;Nanhui Xia ,&nbsp;Yun Zhu ,&nbsp;Tianyu Zhang ,&nbsp;Xuesheng Liu ,&nbsp;Anru Yan ,&nbsp;Youqiang Liu ,&nbsp;Zhiyong Wang","doi":"10.1016/j.ijleo.2024.172136","DOIUrl":"10.1016/j.ijleo.2024.172136","url":null,"abstract":"<div><div>We have developed a diode side pumped intracavity frequency switched Nd:YAG laser with fiber coupled output, which has the characteristics of high power, high beam quality and high brightness, and has a unique application in the field of laser processing. In order to solve the influence of thermal effect of Nd:YAG crystal on optical resonator, the thermal focal length was measured and a stable cavity structure was designed. When the repetition rate was 10 kHz, the maximum output power of the 532 nm laser was 96 W, and the pulse width was 55.8 ns. The beam quality was measured as <span><math><msubsup><mrow><mi>M</mi></mrow><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msubsup></math></span>= 5.98 in the horizontal direction and <span><math><msubsup><mrow><mi>M</mi></mrow><mrow><mi>y</mi></mrow><mrow><mn>2</mn></mrow></msubsup></math></span>= 8.14 in the vertical direction, corresponding to the brightness of 6.97×10⁸ W·cm⁻²·Sr. The maximum fiber coupling output power was 94 W, with a fiber core of 200 μm and a fiber coupling efficiency of 98 %. As far as we know, the fiber–solid-state acousto-optic Q-switched 532 nm laser obtains the highest brightness.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"320 ","pages":"Article 172136"},"PeriodicalIF":3.1,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747182","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":"Investigation of the nonlinear optical characteristics of the La0.7Sr0.3MnO3 nano-perovskite under (iron, cobalt, and nickel) substitution for manganese by Z-Scan technique and Wemple–DiDomenico model","authors":"Kh. Zarei,&nbsp;A. Jafari,&nbsp;Kh. Mabhouti","doi":"10.1016/j.ijleo.2024.172137","DOIUrl":"10.1016/j.ijleo.2024.172137","url":null,"abstract":"<div><div>The investigation in this study focused on examining the nonlinear optical (NLO) properties of La_0.7Sr_0.3XO₃ (X= Mn, Co, Ni, or Fe) nano-perovskite powders utilizing the Z-scan technique. To achieve this objective, first, the samples were synthesized using the co-precipitation procedure, and after that, the prepared materials were examined using a field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD) to confirm the nanoscale morphology and structure of the prepared samples, respectively. Based on the FE-SEM and XRD outcomes, the nanosized nature of the materials has been verified. To analyze the NLO characteristics of the nanopowders, the Z-scan technique with a continuous wave 532 nm Nd: YAG laser was employed on laser incident powers of P₀ = 15 mW, and 30 mW. This is to determine the third-order nonlinear optical susceptibility, nonlinear refractive index (NLR, n₂), and nonlinear absorption coefficient (NLA, β) values. For La_0.7Sr_0.3MnO₃, the NLR and the NLA (precisely two phonon absorption) responses displayed at the 3.3339×10⁻⁹ m²/W and 0.0485 m/W values, respectively, measured for P₀ = 15 mW. It is evident from the results that after the Ni, Fe, or Co substitution for manganese in the La_0.7Sr_0.3MnO₃ measured for P₀ = 15 mW, the obtained results showed a decrement in the NLA response for all samples and a decrement in the NLR response for all samples except Co substitution. Moreover, to accurately ascertain linear susceptibility, dispersion energy, and the density of polarizable constituents from the acquired z-scan data, we employed Miller’s generalized rule as introduced by the Wemple–DiDomenico model and additionally utilized the relationship proposed by Fournier and Snitzer. The implications of the substitution process and the dimensions of the crystallites, along with their interrelation with nonlinear parameters, are thoroughly examined. The remarkable and encouraging nonlinear optical coefficients demonstrated by these synthesized nanopowders suggest their viability as significant materials for the fabrication of innovative optical devices.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"320 ","pages":"Article 172137"},"PeriodicalIF":3.1,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747181","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}