Pub Date : 2024-09-26DOI: 10.1016/j.optlastec.2024.111845
Plasmon-induced photoacoustic streaming, considered as a potential application for micro-pumps in microfluidics, currently encounters ongoing debates concerning its fundamental mechanisms. In this study, we investigate the crucial role played by microbubbles in generation of jets in an ethanol aqueous solution. The power density threshold for bubble generation and its dependency on jet initiation are confirmed and the microbubble behavior is well regulated by manipulating the laser and liquid properties. Through simulations coupling fluidic and thermal fields, the significant role of Marangoni effect is validated in jet formation. Specifically, the temperature gradient of microbubbles is determined to be a pivotal factor in the generation of collimated jets. Additionally, factors influencing jetting, such as microbubble size and temperature gradients are studied, and noticeably, a stabilized jet lasting over 4 h is achieved based upon.
{"title":"Control of photothermal liquid jets through microbubble Regulation: Fundamental mechanisms and Developing Strategies","authors":"","doi":"10.1016/j.optlastec.2024.111845","DOIUrl":"10.1016/j.optlastec.2024.111845","url":null,"abstract":"<div><div>Plasmon-induced photoacoustic streaming, considered as a potential application for micro-pumps in microfluidics, currently encounters ongoing debates concerning its fundamental mechanisms. In this study, we investigate the crucial role played by microbubbles in generation of jets in an ethanol aqueous solution. The power density threshold for bubble generation and its dependency on jet initiation are confirmed and the microbubble behavior is well regulated by manipulating the laser and liquid properties. Through simulations coupling fluidic and thermal fields, the significant role of Marangoni effect is validated in jet formation. Specifically, the temperature gradient of microbubbles is determined to be a pivotal factor in the generation of collimated jets. Additionally, factors influencing jetting, such as microbubble size and temperature gradients are studied, and noticeably, a stabilized jet lasting over 4 h is achieved based upon.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-26DOI: 10.1016/j.optlastec.2024.111852
Graphene’s unique properties have made it a promising material for high-performance photodetectors due to its interesting features including broadband absorption, fast speed, and strong photothermoelectric effect. Here, an optimized waveguide photodetector incorporating double graphene layers with two cores is presented to boost the responsivity (∼twice), at Mid-IR range. The proposed structure operates in the zero-bias regime to eliminate the dark current issue associated with the zero bandgap nature of graphene and leads to lower noise equivalent power. The presented photodetector operating based on split gates to electrostatically induce the p-n junction in graphene channels, operates based on the photothermoelectric effect and provides responsivity, NEP, and 3 dB bandwidth of 6.3 V/W, 0.34 nW/Hz1/2, and 1.54 GHz, respectively for the detection at λ = 5.2 μm. The feasibility of the proposed structure is proved according to recent experimentally demonstrated photodetectors. Hence, the obtained results are reliable, in practice. The study has been accomplished by numerical simulation of mode profiles and solving the heat equation to extract the characteristics of the proposed photodetector. The zero-power consumption and tunability of the proposed structure make it a promising candidate for sensing, industrial, defense, and environmental monitoring applications with high accuracy.
{"title":"High responsivity zero-biased Mid-IR graphene photodetector based on chalcogenide glass waveguide","authors":"","doi":"10.1016/j.optlastec.2024.111852","DOIUrl":"10.1016/j.optlastec.2024.111852","url":null,"abstract":"<div><div>Graphene’s unique properties have made it a promising material for high-performance photodetectors due to its interesting features including broadband absorption, fast speed, and strong photothermoelectric effect. Here, an optimized waveguide photodetector incorporating double graphene layers with two cores is presented to boost the responsivity (∼twice), at Mid-IR range. The proposed structure operates in the zero-bias regime to eliminate the dark current issue associated with the zero bandgap nature of graphene and leads to lower noise equivalent power. The presented photodetector operating based on split gates to electrostatically induce the p-n junction in graphene channels, operates based on the photothermoelectric effect and provides responsivity, NEP, and 3 dB bandwidth of 6.3 V/W, 0.34 nW/Hz<sup>1/2</sup>, and 1.54 GHz, respectively for the detection at λ = 5.2 μm. The feasibility of the proposed structure is proved according to recent experimentally demonstrated photodetectors. Hence, the obtained results are reliable, in practice. The study has been accomplished by numerical simulation of mode profiles and solving the heat equation to extract the characteristics of the proposed photodetector. The zero-power consumption and tunability of the proposed structure make it a promising candidate for sensing, industrial, defense, and environmental monitoring applications with high accuracy.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-26DOI: 10.1016/j.optlastec.2024.111808
To address the challenge of reconstructing high-quality images under low sampling during the Ghost Imaging (GI) procedure, we propose a semantic GI method based on semantic encoding. Through training, the obtained continuous weights of the convolution kernels are served as the speckle patterns. A processing module and a Recurrent Neural Network (RNN) are then employed to decode and reconstruct the images. Both the speckle patterns and their corresponding bucket values are optimized, so that the semantic information of the target object can be better extracted. With different gated recurrent units (GRU) layers for the target objects in different datasets, the feasibility of the proposed GI method is validated by the numerical simulations and experiments on the simple target objects (the handwriting digits “0” to “9”) and more complex target objects (“NUPT”). The results show that the target objects (the handwriting digits) can be reconstructed with higher quality even at a lower sampling rate of 1.28%. Additionally, the proposed method has applicability for more complex objects (such as “NUPT”) in real applications. In comparison with those results by using traditional ghost imaging (TGI), deep convolution auto-encoder network (DCAN), and RNN-based GI (GI-RNN), the proposed GI method shows a better performance in terms of the quality of reconstructed images and the training time, that is, the proposed method can have both good reconstructed image quality and less training time. By introducing the concept of semantic communication into GI, the proposed method provides a new idea for the model-based GI.
为了解决幽灵成像（GI）过程中在低采样率下重建高质量图像的难题，我们提出了一种基于语义编码的语义 GI 方法。通过训练，卷积核的连续权重被用作斑点模式。然后采用处理模块和循环神经网络（RNN）对图像进行解码和重建。为了更好地提取目标物体的语义信息，对斑点模式及其相应的桶值都进行了优化。针对不同数据集的目标对象采用不同的门控递归单元（GRU）层，通过数值模拟和对简单目标对象（手写数字 "0 "至 "9"）和复杂目标对象（"NUPT"）的实验，验证了所提出的 GI 方法的可行性。结果表明，即使在 1.28% 的较低采样率下，目标对象（手写数字）也能以较高的质量重建。此外，所提出的方法还适用于实际应用中更为复杂的对象（如 "NUPT"）。与使用传统鬼影成像（TGI）、深度卷积自动编码器网络（DCAN）和基于 RNN 的 GI（GI-RNN）的结果相比，所提出的 GI 方法在重建图像质量和训练时间方面都有更好的表现，即所提出的方法既能获得良好的重建图像质量，又能获得较少的训练时间。通过在 GI 中引入语义通信的概念，所提出的方法为基于模型的 GI 提供了一种新的思路。
{"title":"Semantic ghost imaging based on semantic coding","authors":"","doi":"10.1016/j.optlastec.2024.111808","DOIUrl":"10.1016/j.optlastec.2024.111808","url":null,"abstract":"<div><div>To address the challenge of reconstructing high-quality images under low sampling during the Ghost Imaging (GI) procedure, we propose a semantic GI method based on semantic encoding. Through training, the obtained continuous weights of the convolution kernels are served as the speckle patterns. A processing module and a Recurrent Neural Network (RNN) are then employed to decode and reconstruct the images. Both the speckle patterns and their corresponding bucket values are optimized, so that the semantic information of the target object can be better extracted. With different gated recurrent units (GRU) layers for the target objects in different datasets, the feasibility of the proposed GI method is validated by the numerical simulations and experiments on the simple target objects (the handwriting digits “0” to “9”) and more complex target objects (“NUPT”). The results show that the target objects (the handwriting digits) can be reconstructed with higher quality even at a lower sampling rate of 1.28%. Additionally, the proposed method has applicability for more complex objects (such as “NUPT”) in real applications. In comparison with those results by using traditional ghost imaging (TGI), deep convolution auto-encoder network (DCAN), and RNN-based GI (GI-RNN), the proposed GI method shows a better performance in terms of the quality of reconstructed images and the training time, that is, the proposed method can have both good reconstructed image quality and less training time. By introducing the concept of semantic communication into GI, the proposed method provides a new idea for the model-based GI.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-26DOI: 10.1016/j.optlastec.2024.111850
Beam quality is critical for laser applications in both scientific and industrial fields. Stimulated Brillouin scattering phase conjugate mirror (SBS-PCM) serves as an effective beam cleanup scheme due to its phase conjugation properties. In this work, a SBS-PCM using fused silica was constructed and employed in a double-pass amplifier setup. With an input energy of 75.2 mJ, the system achieved a maximum magnification of approximately 9 times, resulting in an output energy of 672 mJ. Comparative analysis with a high-reflection mirror revealed that the SBS-PCM effectively mitigated unfavorable diffraction patterns induced by the hard-edge aperture in the near-field pattern, improving the beam quality factor from 1.23 to 1.085 times the diffraction limit. Additionally, the coefficient of determination (R2) of the beam profile improved by 2.18 % compared to that of the high-reflection mirror. These results indicate that the free-space all-solid-state SBS-PCM can provide a promising approach to improving beam quality for high-power laser systems.
{"title":"Enhanced beam quality of high-energy lasers utilizing fused silica as an all-solid-state SBS-PCM","authors":"","doi":"10.1016/j.optlastec.2024.111850","DOIUrl":"10.1016/j.optlastec.2024.111850","url":null,"abstract":"<div><div>Beam quality is critical for laser applications in both scientific and industrial fields. Stimulated Brillouin scattering phase conjugate mirror (SBS-PCM) serves as an effective beam cleanup scheme due to its phase conjugation properties. In this work, a SBS-PCM using fused silica was constructed and employed in a double-pass amplifier setup. With an input energy of 75.2 mJ, the system achieved a maximum magnification of approximately 9 times, resulting in an output energy of 672 mJ. Comparative analysis with a high-reflection mirror revealed that the SBS-PCM effectively mitigated unfavorable diffraction patterns induced by the hard-edge aperture in the near-field pattern, improving the beam quality factor from 1.23 to 1.085 times the diffraction limit. Additionally, the coefficient of determination (<em>R</em><sup>2</sup>) of the beam profile improved by 2.18 % compared to that of the high-reflection mirror. These results indicate that the free-space all-solid-state SBS-PCM can provide a promising approach to improving beam quality for high-power laser systems.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-26DOI: 10.1016/j.optlastec.2024.111851
In this paper, an efficient high-power 1.9 µm picosecond Raman laser through pure vibrational stimulated Raman scattering (SRS) in H2-filled hollow-core fiber (HCF) is demonstrated. The maximum Raman conversion efficiency of 34 % and the Raman power of 7.3 W (36.5 µJ) is achieved within a 130 cm length of our in-house fabricated fiber. By controlling the H2 pressure, the high-order Stokes and rotational Stokes/anti-Stokes will not be generated, thereby enhancing the efficacy of the 1st Stokes conversion. In addition, the vibrational anti-Stokes are produced inevitably, which can be explained by the phase-matching of higher-order modes. Our results show SRS in H2-filled HCF to be a promising method for generating high-power 1.9 µm picosecond pulses, which are valuable in spectroscopy, defense, and efficient nonlinear conversion.
{"title":"Efficient high-power 1.9 µm picosecond Raman laser in H2-filled hollow-core fiber without generation of rotational lines","authors":"","doi":"10.1016/j.optlastec.2024.111851","DOIUrl":"10.1016/j.optlastec.2024.111851","url":null,"abstract":"<div><div>In this paper, an efficient high-power 1.9 µm picosecond Raman laser through pure vibrational stimulated Raman scattering (SRS) in H<sub>2</sub>-filled hollow-core fiber (HCF) is demonstrated. The maximum Raman conversion efficiency of 34 % and the Raman power of 7.3 W (36.5 µJ) is achieved within a 130 cm length of our in-house fabricated fiber. By controlling the H<sub>2</sub> pressure, the high-order Stokes and rotational Stokes/anti-Stokes will not be generated, thereby enhancing the efficacy of the 1st Stokes conversion. In addition, the vibrational anti-Stokes are produced inevitably, which can be explained by the phase-matching of higher-order modes. Our results show SRS in H<sub>2</sub>-filled HCF to be a promising method for generating high-power 1.9 µm picosecond pulses, which are valuable in spectroscopy, defense, and efficient nonlinear conversion.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-26DOI: 10.1016/j.optlastec.2024.111835
To efficiently and accurately realize four-surface measurements with flexible cavity lengths and sampling frequencies, a wavelength-tuning phase-shifting matching algorithm based on harmonic selection modes is developed. The developed MPSA-AHR method utilizes pre-iterative wavefront reconstruction errors to quantitatively analyze the multi-harmonic reconstruction performance and to obtain efficient sample combinations. Combined with the densified power spectral density method, the harmonic frequencies can be obtained with high accuracy, enabling the simultaneous measurement of front/rear surfaces, thickness variation, and inhomogeneous distribution of refractive index for the tested transparent plates. The proposed method outperforms the existing methods and can realize multi-surface measurements with fewer sampling frames under the designed harmonic selecting mode, which is verified by sufficient simulations and error analysis under several measurement conditions. Repeatability measurements of a transparent plate with an average thickness of 50 mm using a Fizeau wavelength-tuning phase-shifting interferometer also verify the practical validity of our method.
{"title":"Multi-parameter reconstruction of interference harmonics by effective tuning combination selection and sampling boundary fitting","authors":"","doi":"10.1016/j.optlastec.2024.111835","DOIUrl":"10.1016/j.optlastec.2024.111835","url":null,"abstract":"<div><div>To efficiently and accurately realize four-surface measurements with flexible cavity lengths and sampling frequencies, a wavelength-tuning phase-shifting matching algorithm based on harmonic selection modes is developed. The developed MPSA-AHR method utilizes pre-iterative wavefront reconstruction errors to quantitatively analyze the multi-harmonic reconstruction performance and to obtain efficient sample combinations. Combined with the densified power spectral density method, the harmonic frequencies can be obtained with high accuracy, enabling the simultaneous measurement of front/rear surfaces, thickness variation, and inhomogeneous distribution of refractive index for the tested transparent plates. The proposed method outperforms the existing methods and can realize multi-surface measurements with fewer sampling frames under the designed harmonic selecting mode, which is verified by sufficient simulations and error analysis under several measurement conditions. Repeatability measurements of a transparent plate with an average thickness of 50 mm using a Fizeau wavelength-tuning phase-shifting interferometer also verify the practical validity of our method.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-25DOI: 10.1016/j.optlastec.2024.111842
Selective laser melting (SLM) is regarded as a promising alternative technology for manufacturing customized cardiovascular stents with complex geometries. In this study, a systematic study on the printability, densification and surface roughness regarding SLM of NiTi alloy were explored. It was revealed that macro cracks were mainly formed at volume energy density (VED) of 25-86 J/mm3 due to insufficient energy input with un-melted powders. However, even with the same VED, the different combinations of processing parameters exhibited unique surface characteristics. After optimization, the samples with laser power of 90 W, and scanning speed of 600 mm/s exhibit a superior relative density of 99.96 % and the minimal surface roughness Sq of 5.992 μm. Subsequently, The SLM capability for intricate structures was demonstrated by fabricating cardiovascular stents with varying radial thicknesses. The results indicated that the surface morphologies of SLMed stents exhibit varying degrees of powder adhesion phenomenon. However, the dimensional deviation for the radial thickness of 0.2 mm exhibits a higher percentage of 72 %, whereas the deviation reaches 104 % for that of 0.6 mm. For the compression test, the thinner radial thickness stent has better recovery ability.
{"title":"Selective laser melting of NiTi cardiovascular stents: Processibility, surface quality and mechanical properties","authors":"","doi":"10.1016/j.optlastec.2024.111842","DOIUrl":"10.1016/j.optlastec.2024.111842","url":null,"abstract":"<div><div>Selective laser melting (SLM) is regarded as a promising alternative technology for manufacturing customized cardiovascular stents with complex geometries. In this study, a systematic study on the printability, densification and surface roughness regarding SLM of NiTi alloy were explored. It was revealed that macro cracks were mainly formed at volume energy density (VED) of 25-86 J/mm<sup>3</sup> due to insufficient energy input with un-melted powders. However, even with the same VED, the different combinations of processing parameters exhibited unique surface characteristics. After optimization, the samples with laser power of 90 W, and scanning speed of 600 mm/s exhibit a superior relative density of 99.96 % and the minimal surface roughness <em>Sq</em> of 5.992 μm. Subsequently, The SLM capability for intricate structures was demonstrated by fabricating cardiovascular stents with varying radial thicknesses. The results indicated that the surface morphologies of SLMed stents exhibit varying degrees of powder adhesion phenomenon. However, the dimensional deviation for the radial thickness of 0.2 mm exhibits a higher percentage of 72 %, whereas the deviation reaches 104 % for that of 0.6 mm. For the compression test, the thinner radial thickness stent has better recovery ability.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-25DOI: 10.1016/j.optlastec.2024.111831
Metasurfaces, which are increasingly popular for creating ultra-thin optical components, offer a way to reduce the bulkiness of traditional optics, especially in the THz band. Typically, metasurfaces are fabricated using lithographic techniques in clean rooms, but a simpler fabrication method could expand their applicability. In this study, we present a femtosecond laser-based direct fabrication of complementary metasurfaces, highlighting the benefits of a single-step, mask-free process using structured light beams. A q-plate is used to generate an annular vortex beam with femtosecond duration, which is further tailored to imprint individual meta-atoms by perforating an Au film deposited on a Si substrate through laser ablation. This technique enables the creation of various metasurfaces designed for THz operation, as verified by full-wave simulations, featuring distinct shapes and periodicities for efficient electromagnetic radiation delivery. The fabricated devices are experimentally tested using time-domain spectroscopy, confirming the expected transmission properties and demonstrating the reliability and versatility of the proposed approach.
{"title":"Femtosecond laser direct writing of complementary THz metasurfaces using a structured vortex beam","authors":"","doi":"10.1016/j.optlastec.2024.111831","DOIUrl":"10.1016/j.optlastec.2024.111831","url":null,"abstract":"<div><div>Metasurfaces, which are increasingly popular for creating ultra-thin optical components, offer a way to reduce the bulkiness of traditional optics, especially in the THz band. Typically, metasurfaces are fabricated using lithographic techniques in clean rooms, but a simpler fabrication method could expand their applicability. In this study, we present a femtosecond laser-based direct fabrication of complementary metasurfaces, highlighting the benefits of a single-step, mask-free process using structured light beams. A q-plate is used to generate an annular vortex beam with femtosecond duration, which is further tailored to imprint individual meta-atoms by perforating an Au film deposited on a Si substrate through laser ablation. This technique enables the creation of various metasurfaces designed for THz operation, as verified by full-wave simulations, featuring distinct shapes and periodicities for efficient electromagnetic radiation delivery. The fabricated devices are experimentally tested using time-domain spectroscopy, confirming the expected transmission properties and demonstrating the reliability and versatility of the proposed approach.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-25DOI: 10.1016/j.optlastec.2024.111838
The use of multivariate analysis techniques and prediction models represents a novel alternative in sensors based on optical fibers, since they have a great potential to estimate the properties and quality of the response of optical fiber sensors. This work focuses on comparing and determining the accuracy of prediction models such as multivariate projection to latent structures regression (PLSR) and principal component regression (PCR) techniques applied to tapered optical fiber sensors as well as experimental studies of the different sensing films used, such as polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), Apiezon T (ApT) and Apiezon L (ApL) for acetone detection. Acetone is a biomarker of diabetes mellitus which is found in concentrations in the order of 1.8 ppm in the human breath of diabetic patients. The results showed that the sensor developed with the PMMA sensor film improved the limit of detection (LOD) up to 5.56 ppm using PLSR with four latent variables compared to PCR using the same number of components.
{"title":"A comparative study between PCR and PLSR in a tapered optical fiber sensor for acetone detection","authors":"","doi":"10.1016/j.optlastec.2024.111838","DOIUrl":"10.1016/j.optlastec.2024.111838","url":null,"abstract":"<div><div>The use of multivariate analysis techniques and prediction models represents a novel alternative in sensors based on optical fibers, since they have a great potential to estimate the properties and quality of the response of optical fiber sensors. This work focuses on comparing and determining the accuracy of prediction models such as multivariate projection to latent structures regression (PLSR) and principal component regression (PCR) techniques applied to tapered optical fiber sensors as well as experimental studies of the different sensing films used, such as polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), Apiezon T (ApT) and Apiezon L (ApL) for acetone detection. Acetone is a biomarker of diabetes mellitus which is found in concentrations in the order of 1.8 ppm in the human breath of diabetic patients. The results showed that the sensor developed with the PMMA sensor film improved the limit of detection (LOD) up to 5.56 ppm using PLSR with four latent variables compared to PCR using the same number of components.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-09-24DOI: 10.1016/j.optlastec.2024.111848
This study demonstrates the generation of both harmonic mode-locking (HML) and noise-like pulses (NLPs) in an all-polarization-maintaining (PM) Tm-doped fiber laser mode-locked by a linear-cavity interferometric nonlinear polarization evolution (NPE) mechanism. Adjusting the pump power and manipulating the intra-cavity pulse distribution along the axes of the PM fiber enable transitions between fundamental mode-locking, various harmonic orders, and NLPs. In the HML regime, a 19th-order harmonic soliton pulse is achieved, marking a record-breaking repetition rate of ∼229 MHz for NPE-based all-PM linear-cavity fiber lasers. Detailed analyses of pulse characteristics across different harmonic orders are presented, with the 3rd-order HML exhibiting a high supermode suppression level. The stability of 3rd-order HML operation is further confirmed through noise evaluations and long-term assessments of power and spectrum. In the NLPs regime, the output is centered at 1962 nm with a 3-dB bandwidth of ∼30 nm, achieving an average power of 284 mW and a pulse energy of ∼24 nJ. The long-term stability and noise profile of the laser are examined to ensure sustained NLPs operation. Furthermore, the influence of pump power variations on the optical properties of NLPs is investigated, revealing an increased spectral width, red-shifted spectrum, and reduced duration of coherent peaks with higher pump intensities.
{"title":"Generation of harmonic mode-locked pulses and noise-like pulses in an all-PM Tm-doped fiber laser via linear-cavity interferometric NPE","authors":"","doi":"10.1016/j.optlastec.2024.111848","DOIUrl":"10.1016/j.optlastec.2024.111848","url":null,"abstract":"<div><div>This study demonstrates the generation of both harmonic mode-locking (HML) and noise-like pulses (NLPs) in an all-polarization-maintaining (PM) Tm-doped fiber laser mode-locked by a linear-cavity interferometric nonlinear polarization evolution (NPE) mechanism. Adjusting the pump power and manipulating the intra-cavity pulse distribution along the axes of the PM fiber enable transitions between fundamental mode-locking, various harmonic orders, and NLPs. In the HML regime, a 19th-order harmonic soliton pulse is achieved, marking a record-breaking repetition rate of ∼229 MHz for NPE-based all-PM linear-cavity fiber lasers. Detailed analyses of pulse characteristics across different harmonic orders are presented, with the 3rd-order HML exhibiting a high supermode suppression level. The stability of 3rd-order HML operation is further confirmed through noise evaluations and long-term assessments of power and spectrum. In the NLPs regime, the output is centered at 1962 nm with a 3-dB bandwidth of ∼30 nm, achieving an average power of 284 mW and a pulse energy of ∼24 nJ. The long-term stability and noise profile of the laser are examined to ensure sustained NLPs operation. Furthermore, the influence of pump power variations on the optical properties of NLPs is investigated, revealing an increased spectral width, red-shifted spectrum, and reduced duration of coherent peaks with higher pump intensities.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
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