Pub Date : 2024-11-15DOI: 10.1016/j.optlastec.2024.112135
Erke Wu , Mingzhi Chen , Kai Zhao , Zhandong Wang , Guifang Sun
The current study focuses on investigating the corrosion behavior of 316LN nuclear steel that has been repaired with the underwater laser directed metal deposition (UDMD) technique at a simulated water depth of 30 m and with in-air laser directed metal deposition (in-air DMD). The findings highlight a refined grain size, higher dislocation density, more oxide inclusions, and M7C3 in the samples repaired by UDMD in comparison to the samples repaired by in-air DMD. Moreover, all samples developed a passive film comprising Cr2O3, Fe2O3, and MoO3 on their surface in 3.5 wt% NaCl solution. The corrosion and pitting behavior of the UDMD samples differed from those of the in-air DMD samples due to variations in grain size, oxide inclusions, carbide, and dislocation density. The UDMD samples exhibited better corrosion resistance compared to the in-air DMD samples.
{"title":"Corrosion behavior of underwater laser deposition remanufactured nuclear steel 316LN stainless steel at a pressure of 0.3 MPa","authors":"Erke Wu , Mingzhi Chen , Kai Zhao , Zhandong Wang , Guifang Sun","doi":"10.1016/j.optlastec.2024.112135","DOIUrl":"10.1016/j.optlastec.2024.112135","url":null,"abstract":"<div><div>The current study focuses on investigating the corrosion behavior of 316LN nuclear steel that has been repaired with the underwater laser directed metal deposition (UDMD) technique at a simulated water depth of 30 m and with in-air laser directed metal deposition (in-air DMD). The findings highlight a refined grain size, higher dislocation density, more oxide inclusions, and M<sub>7</sub>C<sub>3</sub> in the samples repaired by UDMD in comparison to the samples repaired by in-air DMD. Moreover, all samples developed a passive film comprising Cr<sub>2</sub>O<sub>3</sub>, Fe<sub>2</sub>O<sub>3</sub>, and MoO<sub>3</sub> on their surface in 3.5 wt% NaCl solution. The corrosion and pitting behavior of the UDMD samples differed from those of the in-air DMD samples due to variations in grain size, oxide inclusions, carbide, and dislocation density. The UDMD samples exhibited better corrosion resistance compared to the in-air DMD samples.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112135"},"PeriodicalIF":4.6,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701295","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 : 2024-11-15DOI: 10.1016/j.optlastec.2024.112129
Liqun Liu , Bo Wang
In this paper, with the combination of metal assisted guided-mode resonance (MaGMR) and graphene, a graphene-layered MaGMR refractive index sensor is proposed. With the optimization by finite difference time domain method, the sensor can achieve perfect absorption at the near infrared band. The electric intensity distribution of the sensor is studied and shows descent resonance phenomena at the resonant wavelength. The investigation on the detection of analytes with different refractive indices around the sensor is conducted and it shows that the proposed sensor has superior sensing performance with a sensitivity of 590 nm/RIU and figure of merit 180.98 RIU−1. The influence of the Fermi level of graphene on the tunability of the sensor is also analyzed. To measure the performance deviation when there is a manufacturing error, the structural parameters of the sensor are also investigated. The proposed sensor exhibits great sensing performance and therefore has many potential applications in sensing, environmental monitoring and detection fields.
{"title":"Graphene-layered refractive index sensor by metal-assisted guided mode resonance structure","authors":"Liqun Liu , Bo Wang","doi":"10.1016/j.optlastec.2024.112129","DOIUrl":"10.1016/j.optlastec.2024.112129","url":null,"abstract":"<div><div>In this paper, with the combination of metal assisted guided-mode resonance (MaGMR) and graphene, a graphene-layered MaGMR refractive index sensor is proposed. With the optimization by finite difference time domain method, the sensor can achieve perfect absorption at the near infrared band. The electric intensity distribution of the sensor is studied and shows descent resonance phenomena at the resonant wavelength. The investigation on the detection of analytes with different refractive indices around the sensor is conducted and it shows that the proposed sensor has superior sensing performance with a sensitivity of 590 nm/RIU and figure of merit 180.98 RIU<sup>−1</sup>. The influence of the Fermi level of graphene on the tunability of the sensor is also analyzed. To measure the performance deviation when there is a manufacturing error, the structural parameters of the sensor are also investigated. The proposed sensor exhibits great sensing performance and therefore has many potential applications in sensing, environmental monitoring and detection fields.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112129"},"PeriodicalIF":4.6,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701369","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 : 2024-11-15DOI: 10.1016/j.optlastec.2024.112111
S. Joyal Isac ME , P. Vinothkumar , A Paul Dhinakaran , S. Praveenkumar
The glass containing the following compositions: Te2O3 − B2O3 − Li2CO3 − ZnO − NaF: Sm2O3 were made using the melt-quench process and identified as Sm3+ Tellurite glass. The present work shows their Physical, optical, luminescent, and radiative characteristics in this paper. The glass’s amorphous form was confirmed by an analysis of powder X-ray diffraction. Fourier transform infrared spectroscopy was used to identify the functional groups of glass. The glass was inspected using ultraviolet–visible spectroscopy and JO analysis was discussed. Its refractive index and optical band gap were among these characteristics. Emission peaks at 565 nm, 600 nm, and 646 nm were seen in the emission spectra. Based on the Commission International de l’éclairage (CIE 1931) diagram, all samples’ color coordinates showed outstanding emission between neutral white and sunshine white, suitable for yellow laser. Using the Phy-X program, the mass attenuation coefficient, half-value layer, mean free path, tenth value layer, and energy absorption buildup factor (EABF) were examined about the glass’s gamma-ray shielding properties.
{"title":"Physical, optical, and luminescent characteristics of Sm3+ doped tellurite glass suitable for yellow laser, warm white LED, and radiation shielding applications","authors":"S. Joyal Isac ME , P. Vinothkumar , A Paul Dhinakaran , S. Praveenkumar","doi":"10.1016/j.optlastec.2024.112111","DOIUrl":"10.1016/j.optlastec.2024.112111","url":null,"abstract":"<div><div>The glass containing the following compositions: Te<sub>2</sub>O<sub>3</sub> − B<sub>2</sub>O<sub>3</sub> − Li<sub>2</sub>CO<sub>3</sub> − ZnO − NaF: Sm<sub>2</sub>O<sub>3</sub> were made using the melt-quench process and identified as Sm<sup>3+</sup> Tellurite glass. The present work shows their Physical, optical, luminescent, and radiative characteristics<!--> <!-->in this paper. The glass’s amorphous form was confirmed by an analysis of powder X-ray diffraction. Fourier transform infrared spectroscopy was used to identify the functional groups of glass. The glass was inspected using ultraviolet–visible spectroscopy and JO analysis was discussed. Its refractive index and optical band gap were among these characteristics. Emission peaks at 565 nm, 600 nm, and 646 nm were seen in the emission spectra. Based on the Commission International de l’éclairage (CIE 1931) diagram, all samples’ color coordinates showed outstanding emission between neutral white and sunshine white, suitable for yellow laser. Using the Phy-X program, the mass attenuation coefficient, half-value layer, mean free path, tenth value layer, and energy absorption buildup factor<!--> <!-->(EABF) were examined about the glass’s gamma-ray shielding properties.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112111"},"PeriodicalIF":4.6,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701296","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 : 2024-11-15DOI: 10.1016/j.optlastec.2024.112124
Lihua Ye, Deyang Niu, Chunguang Lu, Bing Gu, Shuhong Xu
This article explores the characteristics of random laser emission in CdSe/ZnS quantum dots (QDs) anchored by SiO2, demonstrating the achievement of low thresholds and high stability random laser. The incorporation of CdSe/ZnS QDs onto the SiO2 surface builds SiO2-QDs (SQ). SQ promotes the dispersion of quantum dots, effectively reducing Förster resonance energy transfer (FRET) and fluorescence quenching. In this system, SiO2 acts as a scattering particle, providing multiple scattering events for random laser generation, and consequently achieving a low threshold for random laser emission. Various SiO2 nanoparticles with average sizes of 120 nm, 200 nm, 300 nm, 450 nm, and 600 nm are synthesized, and corresponding SQ are prepared. The random laser thresholds exhibit a gradual decrease with increasing SiO2 particle size, measuring 2.3 mJ/cm2 (120 nm SiO2) to 1.4 mJ/cm2 (600 nm SiO2). The above trend can be attributed to the concurrent increase in the scattering cross-section of SiO2 particles, leading to enhanced multiple scattering intensities within the random laser system. Furthermore, a SiO2-QDs-SiO2 (SQS) is developed by encapsulating SQ with a silicon shell, offering protection against environmental factors such as water and oxygen. The additional out layer improves the stability of SQS, resulting in a random laser with both low threshold and high stability.
{"title":"Random lasing enhancement effect on SiO2 anchored CdSe/ZnS quantum dots","authors":"Lihua Ye, Deyang Niu, Chunguang Lu, Bing Gu, Shuhong Xu","doi":"10.1016/j.optlastec.2024.112124","DOIUrl":"10.1016/j.optlastec.2024.112124","url":null,"abstract":"<div><div>This article explores the characteristics of random laser emission in CdSe/ZnS quantum dots (QDs) anchored by SiO<sub>2</sub>, demonstrating the achievement of low thresholds and high stability random laser. The incorporation of CdSe/ZnS QDs onto the SiO<sub>2</sub> surface builds SiO<sub>2</sub>-QDs (SQ). SQ promotes the dispersion of quantum dots, effectively reducing Förster resonance energy transfer (FRET) and fluorescence quenching. In this system, SiO<sub>2</sub> acts as a scattering particle, providing multiple scattering events for random laser generation, and consequently achieving a low threshold for random laser emission. Various SiO<sub>2</sub> nanoparticles with average sizes of 120 nm, 200 nm, 300 nm, 450 nm, and 600 nm are synthesized, and corresponding SQ are prepared. The random laser thresholds exhibit a gradual decrease with increasing SiO<sub>2</sub> particle size, measuring 2.3 mJ/cm<sup>2</sup> (120 nm SiO<sub>2</sub>) to 1.4 mJ/cm<sup>2</sup> (600 nm SiO<sub>2</sub>). The above trend can be attributed to the concurrent increase in the scattering cross-section of SiO<sub>2</sub> particles, leading to enhanced multiple scattering intensities within the random laser system. Furthermore, a SiO<sub>2</sub>-QDs-SiO<sub>2</sub> (SQS) is developed by encapsulating SQ with a silicon shell, offering protection against environmental factors such as water and oxygen. The additional out layer improves the stability of SQS, resulting in a random laser with both low threshold and high stability.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112124"},"PeriodicalIF":4.6,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701298","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 : 2024-11-15DOI: 10.1016/j.optlastec.2024.112125
Tianchen Yao , Liwen Qi , Fangfang Zheng , Wei Zhou , Hui Kang , Qiang Zhu , Xiaozhao Song , Guangmiao Liu , Shengzhou Xu , Qianwei Zhang , Haotian Wang , Fei Wang , Yishan Wang , Baohua Jia , Deyuan Shen
The negative dispersion of silica fibers near 2 µm wavelength leads to formations of attractive soliton-patterns in Thulium-doped mode-locked fiber lasers (TDMLFL), including single-solitons(SS), bound-solitons(BS), multi-solitons(MS), soliton molecules(SM), as well as noise-like pulses(NLP). However, the current manual or physically controlled methods cannot accurately identify and quickly adjust the diverse solitons. Here, we successfully realized the fine identification and automatic searching of continuous waves, Q-switching, noise-like pulses, multi-solitons, and single-solitons by constructing a genetic algorithm based self-tuning pump power and time-spectrum feedback agent in a TDMLFL. The searched SS have a duration of 1.269 ps, a central wavelength of 1966 nm and a typical Kelly-sideband spectrum. The minimum consuming time of globally finding a single-soliton is ∼40 mins, and the corresponding recovery-time is ∼2 mins. To the best of our knowledge, this is the first time that an intelligent searching and recognition of single soliton in 2 µm TDMLFL and also the first report of soliton-patterns fully intelligent identification and searching without prior parameters in soliton mode locked fiber lasers.
{"title":"Soliton patterns recognition and searching from a 2 µm intelligent mode-locked fiber laser agent","authors":"Tianchen Yao , Liwen Qi , Fangfang Zheng , Wei Zhou , Hui Kang , Qiang Zhu , Xiaozhao Song , Guangmiao Liu , Shengzhou Xu , Qianwei Zhang , Haotian Wang , Fei Wang , Yishan Wang , Baohua Jia , Deyuan Shen","doi":"10.1016/j.optlastec.2024.112125","DOIUrl":"10.1016/j.optlastec.2024.112125","url":null,"abstract":"<div><div>The negative dispersion of silica fibers near 2 µm wavelength leads to formations of attractive soliton-patterns in Thulium-doped mode-locked fiber lasers (TDMLFL), including single-solitons(SS), bound-solitons(BS), multi-solitons(MS), soliton molecules(SM), as well as noise-like pulses(NLP). However, the current manual or physically controlled methods cannot accurately identify and quickly adjust the diverse solitons. Here, we successfully realized the fine identification and automatic searching of continuous waves, Q-switching, noise-like pulses, multi-solitons, and single-solitons by constructing a genetic algorithm based self-tuning pump power and time-spectrum feedback agent in a TDMLFL. The searched SS have a duration of 1.269 ps, a central wavelength of 1966 nm and a typical Kelly-sideband spectrum. The minimum consuming time of globally finding a single-soliton is ∼40 mins, and the corresponding recovery-time is ∼2 mins. To the best of our knowledge, this is the first time that an intelligent searching and recognition of single soliton in 2 µm TDMLFL and also the first report of soliton-patterns fully intelligent identification and searching without prior parameters in soliton mode locked fiber lasers.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112125"},"PeriodicalIF":4.6,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700673","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 : 2024-11-14DOI: 10.1016/j.optlastec.2024.112123
Xianwei Xiong , Junqing Zhao , Liqiang Mo , Yewang Chen , Deqin Ouyang , Xu Wu , Meng Wang , Minqiu Liu , Xing Liu , Dezhi Liang , Yufeng Zhang , Mingxia Qiu , Chunyu Guo , Qitao Lv , Shuangchen Ruan
We demonstrate experimentally a nonlinear absorbing-loop mirror (NAbLM) mode-locked fiber laser that can generate optical pulses as short as ∼ 135 fs. An isolator/wavelength division multiplexer integrated fiber device is employed to shorten the fiber cavity, which enables that a single pulse mode-locking regime is attainable. Further dispersion management lowers the net cavity dispersion to ∼−0.011 ps2. Assisted with external-cavity dechirping, the finally obtained pulses reaches a duration short down to ∼135 fs. To the best of our knowledge, this is the first time observing that femtosecond single pulse can be enabled by using an NAbLM as the mode-locker.
{"title":"Nonlinear absorbing-loop mirror mode-locked fiber laser enabling 135 fs dechirped pulses","authors":"Xianwei Xiong , Junqing Zhao , Liqiang Mo , Yewang Chen , Deqin Ouyang , Xu Wu , Meng Wang , Minqiu Liu , Xing Liu , Dezhi Liang , Yufeng Zhang , Mingxia Qiu , Chunyu Guo , Qitao Lv , Shuangchen Ruan","doi":"10.1016/j.optlastec.2024.112123","DOIUrl":"10.1016/j.optlastec.2024.112123","url":null,"abstract":"<div><div>We demonstrate experimentally a nonlinear absorbing-loop mirror (NAbLM) mode-locked fiber laser that can generate optical pulses as short as ∼ 135 fs. An isolator/wavelength division multiplexer integrated fiber device is employed to shorten the fiber cavity, which enables that a single pulse mode-locking regime is attainable. Further dispersion management lowers the net cavity dispersion to ∼−0.011 ps<sup>2</sup>. Assisted with external-cavity dechirping, the finally obtained pulses reaches a duration short down to ∼135 fs. To the best of our knowledge, this is the first time observing that femtosecond single pulse can be enabled by using an NAbLM as the mode-locker.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112123"},"PeriodicalIF":4.6,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701302","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 : 2024-11-14DOI: 10.1016/j.optlastec.2024.112115
Yan Xu , Zhen Chai , Jianli Li
The design of the optical paths for pumping and probing plays an essential role in miniaturized nuclear magnetic resonance (NMR) co-magnetometers by constraining sensor size limitations. Traditional bulky optical systems for expanding, collimating, and reflecting laser beams hinder the achievement of compact designs. This study introduces an optical path design using an off-axis freeform surface that combines beam expansion, collimation, and reflection into one. For a vertical cavity surface-emitting laser (VCSEL) with a divergence angle of 15°, the off-axis collimation spot has a diameter of 2.3 mm, a divergence angle of 1.5 milliradians, and a degree of linear polarization of reflection more than 98 % at an optical path of 8.7 mm. The overall reflective collimator structure is less than 0.5 cm3, simplifying the optical path significantly. The device is purposed for spin polarizing electrons and nucleons, demonstrating the feasibility and effectiveness of the design to achieve atomic polarization and meets the requirements for atomic pumping and probing. This approach holds promise for broad applications and introduces a novel method to miniaturize compact atomic sensors like gyroscopes and magnetometers.
{"title":"Off-axis freeform surface reflective collimator for pumping in miniaturized NMR co-magnetometers","authors":"Yan Xu , Zhen Chai , Jianli Li","doi":"10.1016/j.optlastec.2024.112115","DOIUrl":"10.1016/j.optlastec.2024.112115","url":null,"abstract":"<div><div>The design of the optical paths for pumping and probing plays an essential role in miniaturized nuclear magnetic resonance (NMR) co-magnetometers by constraining sensor size limitations. Traditional bulky optical systems for expanding, collimating, and reflecting laser beams hinder the achievement of compact designs. This study introduces an optical path design using an off-axis freeform surface that combines beam expansion, collimation, and reflection into one. For a vertical cavity surface-emitting laser (VCSEL) with a divergence angle of 15°, the off-axis collimation spot has a diameter of 2.3 mm, a divergence angle of 1.5 milliradians, and a degree of linear polarization of reflection more than 98 % at an optical path of 8.7 mm. The overall reflective collimator structure is less than 0.5 cm<sup>3</sup>, simplifying the optical path significantly. The device is purposed for spin polarizing electrons and nucleons, demonstrating the feasibility and effectiveness of the design to achieve atomic polarization and meets the requirements for atomic pumping and probing. This approach holds promise for broad applications and introduces a novel method to miniaturize compact atomic sensors like gyroscopes and magnetometers.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112115"},"PeriodicalIF":4.6,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700589","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 : 2024-11-14DOI: 10.1016/j.optlastec.2024.112121
Zhongyao Yan , Fengyang Ma , Kaixin Liu , Debao Zhang , Xun Zhang , Yan Wang , Songyou Wang , Jian Sun , Dongchen Wang , Ming Lu
The conventional tilted-wave light source (TWL) features high intensity and thick passive waveguide with thickness of hundreds of micrometers or more. However, this large thickness of waveguide prevents its application in the current Si photonic integrated circuits or chips (PICs) due to the requirement of planar technique. Hence, TWL with thin passive waveguide is demanded for Si PICs. In this work, firstly, Si nanocrystal-based TW light emission in thin passive waveguide is simulated in search of allowed TW optical modes. Then, a TWL device identical to the simulated one is fabricated and its photoluminescence (PL) emission is measured. The emitting light covers the range from 650 to 850 nm in wavelength. PL peaks with narrow line widths are observed and are consistent with the simulated TW modes in peak position, mode spacing and emission angle dependence of the allowed modes. Meanwhile, light amplification of the TW modes is observed. Since Si nanocrystals are a lasing material with a wide gain spectrum covering the whole PL range, typical criteria of lasing of the TWL are tested. The results suggest that Si nanocrystal-based TW lasing in thin passive waveguide can be available.
{"title":"Tilted-wave optical modes in thin passive waveguide: Theoretical simulation and experimental realization","authors":"Zhongyao Yan , Fengyang Ma , Kaixin Liu , Debao Zhang , Xun Zhang , Yan Wang , Songyou Wang , Jian Sun , Dongchen Wang , Ming Lu","doi":"10.1016/j.optlastec.2024.112121","DOIUrl":"10.1016/j.optlastec.2024.112121","url":null,"abstract":"<div><div>The conventional tilted-wave light source (TWL) features high intensity and thick passive waveguide with thickness of hundreds of micrometers or more. However, this large thickness of waveguide prevents its application in the current Si photonic integrated circuits or chips (PICs) due to the requirement of planar technique. Hence, TWL with thin passive waveguide is demanded for Si PICs. In this work, firstly, Si nanocrystal-based TW light emission in thin passive waveguide is simulated in search of allowed TW optical modes. Then, a TWL device identical to the simulated one is fabricated and its photoluminescence (PL) emission is measured. The emitting light covers the range from 650 to 850 nm in wavelength. PL peaks with narrow line widths are observed and are consistent with the simulated TW modes in peak position, mode spacing and emission angle dependence of the allowed modes. Meanwhile, light amplification of the TW modes is observed. Since Si nanocrystals are a lasing material with a wide gain spectrum covering the whole PL range, typical criteria of lasing of the TWL are tested. The results suggest that Si nanocrystal-based TW lasing in thin passive waveguide can be available.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112121"},"PeriodicalIF":4.6,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700588","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}
We studied the mechanism of low-threshold lasing of InGaN/GaN double quantum well (DQW) vertical-cavity surface-emitting lasers (VCSELs) showing a low threshold energy density of about 0.37mJ/cm2 via optical pumping at room temperature (RT). The QW with thin well (2.5 nm) and barrier (6 nm) led to the stronger carrier localization effect and weaker quantum confined Stark effect (QCSE). Temperature-dependent photoluminescence (TDPL) and time-resolved photoluminescence (TRPL) were employed on half-cavity samples (VCSEL without top distributed Bragg reflector) to study the carrier dynamics in VCSEL microcavity. Compared with epitaxial layer, half-cavity samples showed the higher turning point temperature of TDPL peak energy, and the carrier lifetime measured by TRPL was shorter. The experimental results suggest that the stronger localization effect of thin QW and the strong coupling of QW and internal optical field can contribute to the low-threshold lasing of GaN-based VCSELs.
{"title":"Low threshold lasing of GaN-based vertical-cavity surface-emitting lasers with thin InGaN/GaN quantum well active region","authors":"Rongbin Xu , Keisei Shibata , Hidefumi Akiyama , Jiazhe Zhang , Leiying Ying , Baoping Zhang","doi":"10.1016/j.optlastec.2024.112117","DOIUrl":"10.1016/j.optlastec.2024.112117","url":null,"abstract":"<div><div>We studied the mechanism of low-threshold lasing of InGaN/GaN double quantum well (DQW) vertical-cavity surface-emitting lasers (VCSELs) showing a low threshold energy density of about 0.37mJ/cm<sup>2</sup> via optical pumping at room temperature (RT). The QW with thin well (2.5 nm) and barrier (6 nm) led to the stronger carrier localization effect and weaker quantum confined Stark effect (QCSE). Temperature-dependent photoluminescence (TDPL) and time-resolved photoluminescence (TRPL) were employed on half-cavity samples (VCSEL without top distributed Bragg reflector) to study the carrier dynamics in VCSEL microcavity. Compared with epitaxial layer, half-cavity samples showed the higher turning point temperature of TDPL peak energy, and the carrier lifetime measured by TRPL was shorter. The experimental results suggest that the stronger localization effect of thin QW and the strong coupling of QW and internal optical field can contribute to the low-threshold lasing of GaN-based VCSELs.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112117"},"PeriodicalIF":4.6,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700583","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}
Surface roughness scattering significantly affects the performance of microcavity lasers by influencing various design parameters. This study focuses on the design and fabrication of polymer-based microcavity lasers to achieve optimal specifications. We employed femtosecond direct laser writing on SU-8 films doped with Rhodamine B dye. Key parameters, including size, quality factor, mode volume, filling factor, and losses (bending and surface scattering), were theoretically analyzed. We specifically investigated the impact of sidewall roughness-induced scattering loss on polymer microring lasers, validating our findings through simulations and experimental characterization. Assuming a surface roughness of less than 10 nm, we designed and fabricated a single-mode double microring laser with radii of 30 µm and 32 µm, featuring a waveguide cross-sectional area of 1 × 2 µm2. These high-performance single-mode lasers have potential applications in optical sensing, nonlinear optics, and quantum photonics.
{"title":"Design optimization for manufacturing polymer microring lasers: Focus on surface scattering losses","authors":"Parvin Sorayaie , Leila Hajshahvaladi , Mohammadreza Kolahdouz , Kimia Golshan , Gholam-Mohammad Parsanasab","doi":"10.1016/j.optlastec.2024.112101","DOIUrl":"10.1016/j.optlastec.2024.112101","url":null,"abstract":"<div><div>Surface roughness scattering significantly affects the performance of microcavity lasers by influencing various design parameters. This study focuses on the design and fabrication of polymer-based microcavity lasers to achieve optimal specifications. We employed femtosecond direct laser writing on SU-8 films doped with Rhodamine B dye. Key parameters, including size, quality factor, mode volume, filling factor, and losses (bending and surface scattering), were theoretically analyzed. We specifically investigated the impact of sidewall roughness-induced scattering loss on polymer microring lasers, validating our findings through simulations and experimental characterization. Assuming a surface roughness of less than 10 nm, we designed and fabricated a single-mode double microring laser with radii of 30 µm and 32 µm, featuring a waveguide cross-sectional area of 1 × 2 µm<sup>2</sup>. These high-performance single-mode lasers have potential applications in optical sensing, nonlinear optics, and quantum photonics.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112101"},"PeriodicalIF":4.6,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700590","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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