2023

• Record 445 of
  
  Title:Layer by layer assembly CS/PAA for high sensitivity detection of heavy metal ions using mode interference sensor
  
  Author(s):Yan, Minglu(1); Wang, Ruiduo(1,2); Liu, Beibei(1); Li, Yangyang(1); Li, Yarong(1); Jiang, Man(1)
  Source: Optics Communications  Volume: 545  Issue: null  Article Number: 129725  DOI: 10.1016/j.optcom.2023.129725  Published: October 15, 2023  
  Abstract:A low-cost and ease-fabricated mode interference sensor for zinc ion detection is proposed in our work. The sensor is constructed by direct fusion splicing of single-mode fiber (SMF) and no-core fiber (NCF). Experiment and simulation results of the sensor exhibits consistent good response characteristics in the refractive index (RI) range of 1.3324–1.3791. The zinc ion sensitive film was functionalized on the sensor surface by electrostatic self-assembly of chitosan (CS) and polyacrylic acid (PAA), and the experimental results show the optimal detection performance with 12 layers of CS/PAA coated. RI changes in the CS/PAA polymeric film induced by adsorbing zinc ions, which affects the internal energy distribution inside NCF and eventually causes the wavelength shifts. Finally, the high sensitivity of 0.78 nm/ppb and lowest detection limit of 0.01 ppb for zinc ions detection were obtained. Furthermore, the sensing properties of cobalt, sodium and potassium ions were also investigated to evaluate the detection capability for different species metal ions. As a result, the proposed sensor shows well performance on the stability and sensitivity, it has good development prospect in the future water quality environmental monitoring. © 2023 Elsevier B.V.
  Accession Number: 20232914404218
• Record 446 of
  
  Title:Photoelectric characteristics of different micro structures of black silicon etched by femtosecond laser
  
  Author(s):Zhang, Xiaomo(1,2); Zhu, Xiangping(1,2); Liu, Yang(1,2); Zhao, Wei(1,2); Jin, Chuan(1,2); Zhang, Pu(1,2)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 12617  Issue: null  Article Number: 126170S  DOI: 10.1117/12.2663330  Published: 2023  
  Abstract:Black silicon, which is characterized as numerous nanospikes induced on bulk silicon, has recently attracted great attention due to its fascinating photoelectric property. Compared with the traditional silicon-based photoelectric sensor, photoelectric sensors based on the black silicon doped with supersaturated chalcogens have shown both excellent photoelectric corresponding efficiency in the visible range and considerable optical absorption efficiency in the near-infrared band due to the impurity energy-level introduced by the chalcogens element supersaturated doping. Nonetheless, the differences of surface morphology greatly affect the photoelectric efficiency of black silicon photoelectric sensors, which is quite difficult to control in practice. As one of the mainstream methods in black silicon fabrication, femtosecond laser etching exhibits the ability in manipulate different dimensionality and configurations, and provide a clear and flexible research platform. Black silicon can be etched on traditional silicon-based photoelectric sensor with different size of surface morphology according to the size of surface thickness. In this work, by varying the etching energy density of the femtosecond laser, three kinds of black silicon samples with different surface morphology were obtained. At the same time, the surface morphology, size, visible-infrared absorptivity and photoelectric conversion efficiency of black silicon were characterized by scanning electron microscope, spectrophotometer and confocal Raman spectroscopy, etc. We got three sample characterization data, the minimum morphology depth of black silicon can be controlled at 2 μm, the maximum visible light absorption efficiency can reach 90%, and the near-infrared absorption efficiency can reach 60% before annealing. Naturally, the photoelectric conversion efficiency has been proven to be significantly improved. Based on the observation of experimental results, it is an important step to understand the photoelectric characteristic of black silicon with different morphologies, which is the application of black silicon in different fields. © 2023 SPIE.
  Accession Number: 20232114130599
• Record 447 of
  
  Title:Light gap bullets in defocusing media with optical lattices
  
  Author(s):Chen, Zhiming(1,2); Wu, Zexing(2); Zeng, Jianhua(1,3)
  Source: Chaos, Solitons and Fractals  Volume: 174  Issue: null  Article Number: 113785  DOI: 10.1016/j.chaos.2023.113785  Published: September 2023  
  Abstract:Searching for three-dimensional spatiotemporal solitons (also known as light/optical bullets) has recently attracted keen theoretical and experimental interests in nonlinear physics. Currently, optical lattices of diverse kinds have been introduced to the stabilization of light bullets, while the investigation for the light bullets of gap type – nonlinear localized modes within the finite gap of the underlying linear Bloch spectrum – is lacking. Herein, we address the formation and stabilization properties of such light gap bullets in periodic media with defocusing nonlinearity, theoretically and in numerical ways. The periodic media are based on two-dimensional periodic standing waves created in a coherent three-level atomic system which is driven to the regime of electromagnetically induced transparency, which in principle can also be replaced by photonic crystals in optics or optical lattices in ground-state ultracold atoms system. The temporal dispersion term is tuned to normal (positive) group velocity dispersion so that to launch the light gap bullets under self-repulsive nonlinearity; two types of such light gap bullets constructed as three-dimensional gap solitons and vortices with topological charge m=1 within the first finite gap are reported and found to be robustly stable in the existence domains. On account of the light bullets were previously limited to the semi-infinite gap of periodic media and continuous nonlinear physical systems, the light gap bullets reported here thus supplement the missing type of three-dimensional spatiotemporal localized modes in periodic media which exhibit finite band gaps. © 2023 Elsevier Ltd
  Accession Number: 20232914417784
• Record 448 of
  
  Title:High-damage vanadium pentoxide film saturable absorber for sub-nanosecond Nd:YAG lasers
  
  Author(s):Wang, Jiang(1,4); Xie, Liang(1); Wang, Yunheng(2); Lan, Yu(3); Wu, Pengfei(1); Lv, Jing(1); Zhang, Guodong(1); Miao, Zongcheng(1); Cheng, Guanghua(1)
  Source: Infrared Physics and Technology  Volume: 129  Issue: null  Article Number: 104580  DOI: 10.1016/j.infrared.2023.104580  Published: March 2023  
  Abstract:Low-dimensional materials as saturable absorber (SA) for sub-nanosecond pulse laser have attracted extensive attention due to their excellent optoelectronic properties. However, high-quality low-dimensional materials’ nonlinear optical properties, such as larger damage threshold and higher modulation depth, are essential for generation of stable sub-nanosecond pulse laser. Herein, the large-area high-quality vanadium pentoxide (V2O5) films were prepared by magnetron sputtering deposition technology, and the usage of V2O5 films as a SA for sub-nanosecond pulse passively Q-switched Nd:YAG laser generation for the first time. It was found that V2O5-SA films exhibit excellent nonlinear optical characteristics, with a larger damage threshold of 509.8 mJ/cm2 and a higher modulation depth of 21.8 %, and the shortest pulse width of 59 ns. Our experimental results demonstrate that V2O5-SA films has the advantages of larger damage threshold and stable availability, which provides a promising solution for the development of high-quality low-dimensional SA devices in short pulse solid-state lasers. © 2023 Elsevier B.V.
  Accession Number: 20230613555964
• Record 449 of
  
  Title:Phase-type diffractive micro-optics elements in sulfur-based polymeric glass by femtosecond laser direct writing
  
  Author(s):Liu, Feng(1); Li, Peng(1); Liu, Sheng(1); Jin, Chuan(2); Wei, Bingyan(1); Min, Junwei(2); Liu, Zhichao(2); Zhu, Xiangping(2); Zhao, Jianlin(1)
  Source: Optics Letters  Volume: 48  Issue: 4  Article Number: null  DOI: 10.1364/OL.483654  Published: February 15, 2023  
  Abstract:Sulfur-based polymeric glasses are promising alternative low-cost IR materials due to their profoundly high IR transparency. In this Letter, femtosecond-laser-induced refractive index change (RIC) was investigated in one typical sulfurbased polymeric glass material, poly(S-r-DIB), for the first time, to the best of our knowledge. The RIC in the laserengineered region was quantitively characterized, which laid a foundation for phase-type optical element design. By the integration of RIC traces, embedded phase-type micro-optics elements, including Fresnel zone plates, and a Dammann grating were fabricated in bulk poly(S-r-DIB) polymeric glass substrate via the femtosecond laser direct writing technique. The imaging and beam shaping performance were demoed in the near-infrared (NIR) region. © 2023 Optica Publishing Group.
  Accession Number: 20231013661870
• Record 450 of
  
  Title:Research on fretting regime transition of DD6 single- crystal superalloy via femtosecond laser-induced asperity and hardened layer
  
  Author(s):Yu, Yanqing(1); Zhou, Liucheng(2); Li, Ming(3); Cai, Zhenbing(1); Luo, Sihai(2); He, Weifeng(2); Fang, Xiuyang(4)
  Source: Applied Surface Science  Volume: 610  Issue: null  Article Number: 155392  DOI: 10.1016/j.apsusc.2022.155392  Published: February 1, 2023  
  Abstract:In this study, the fretting wear test was performed on DD6 single-crystal superalloy after femtosecond laser modification (FLM) to evaluate the influence of femtosecond laser-induced asperity and hardened layer on its fretting regime. Results show that the ablation layer with a depth of ∼ 3.2 μm and the deformed layer are formed beneath the surface, with an increase in surface roughness and hardness. The ablation layer is composed of Al2O3, Cr2O3, and spinel structures. However, the diffraction peak and near-surface orientation after FLM remain similar to those in DD6 single-crystal superalloy substrate, indicating that no remarkable phase change and recrystallization occur despite thermal effect during FLM. The hardened layer has lower plasticity, and the asperities are easy to remove, which results in material removal predominating during the friction process. Therefore, the asperity and hardened layer induced by femtosecond laser could change the fretting regime of DD6 single-crystal superalloy from mixed slip regime (MSR) to gross slip regime (GSR). FLM provides a possibility to replace crack initiation with acceptable material removal in special conditions. © 2022 Elsevier B.V.
  Accession Number: 20224513072792
• Record 451 of
  
  Title:A comprehensive equivalent circuit model of silicon microring modulators for electronic and photonic integrated circuit codesign
  
  Author(s):Bao, Shenlei(1,2); Xue, Jintao(1,3); Wu, Jinyi(1,2); Wang, Binhao(1,3)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 12935  Issue: null  Article Number: 129352E  DOI: 10.1117/12.3007622  Published: 2023  
  Abstract:We present an equivalent circuit model for a silicon microring modulator (MRM), aiming to accurately describe its behavior in high-speed modulation. The model consists of two parts: the first part accounts for electrical parasitics arising from PN phase shifters and pads, while the second part represents the RLC circuit responsible for capturing optical dynamics of MRMs. Model parameters were derived through curve fitting, utilizing Si MRM characterization data. At data rates of 80Gb/s and 106Gb/s, simulated eye diagrams align perfectly with measured eye diagrams. The equivalent circuit model can be effectively used for electronics and photonics co-design. © 2023 SPIE.
  Accession Number: 20235015220841
• Record 452 of
  
  Title:Silicon-Based Polarization and Wavelength Synchronous Demultiplexing Arrayed Waveguide Grating
  
  Author(s):Bai, Yawen(1,2); Li, Chenguang(3); Zhang, Qiang(4); Wang, Pengfei(1,2)
  Source: IEEE Photonics Journal  Volume: 15  Issue: 5  Article Number: 2201706  DOI: 10.1109/JPHOT.2023.3320195  Published: October 1, 2023  
  Abstract:In this work, we propose an 8-channel arrayed waveguide grating (AWG) designed for synchronized de-multiplexing of both polarization and wavelength. The AWG device is fabricated on a 220 nm-thick top-silicon Silicon-On-Insulator (SOI) wafer using a straightforward single-etch process. It demonstrates the ability for wavelength division de-multiplexing across both TE and TM polarization states, ranging from 1530 to 1542 nm. Measurements reveal that the insertion loss for each channel is less than 3 dB. Additionally, the polarization-dependent loss measures at 1 dB. These experimental results underline the superior performance characteristics of the designed polarization-insensitive AWG. To the best of our knowledge, this is the first reported C-band silicon AWG that accomplishes polarization-wavelength synchronous demultiplexing. This development introduces a new perspective in the design and functionality of AWGs, highlighting the significant potential of this device in the realm of optical communication. © 2009-2012 IEEE.
  Accession Number: 20234014841680
• Record 453 of
  
  Title:Multi-harmonic structured illumination-based optical diffraction tomography
  
  Author(s):Liu, Ruihua(1,2,3); Wen, Kai(1,2,3); Li, Jiaoyue(1,2,3); Ma, Ying(1,2,3,4); Zheng, Juanjuan(1,2,3,4); An, Sha(1,2,3,4); Min, Junwei(5); Zalevsky, Zeev(6); Yao, Baoli(5); Gao, Peng(1,2,3,4)
  Source: Applied Optics  Volume: 62  Issue: 35  Article Number: null  DOI: 10.1364/AO.508138  Published: December 10, 2023  
  Abstract:Imaging speed and spatial resolution are key factors in optical diffraction tomography (ODT), while they are mutually exclusive in 3D refractive index imaging. This paper presents a multi-harmonic structured illuminationbased optical diffraction tomography (MHSI-ODT) to acquire 3D refractive index (RI) maps of transparent samples. MHSI-ODT utilizes a digital micromirror device (DMD) to generate structured illumination containing multiple harmonics. For each structured illumination orientation, four spherical spectral crowns are solved from five phase-shifted holograms, meaning that the acquisition of each spectral crown costs 1.25 raw images. Compared to conventional SI-ODT, which retrieves two spectral crowns from three phase-shifted raw images, MHSI-ODT enhances the imaging speed by 16.7% in 3D RI imaging.Meanwhile, MHSI-ODT exploits both the 1st-order and the 2nd-order harmonics; therefore, it has a better intensity utilization of structured illumination. We demonstrated the performance of MHSI-ODT by rendering the 3D RI distributions of 5 mpolystyrene (PS) microspheres and biological samples. ©2023 Optica Publishing Group.
  Accession Number: 20235115230724
• Record 454 of
  
  Title:VCSEL Cavity Loss and Gain Measurement for High-Speed Optical Interconnects
  
  Author(s):Wang, Binhao(1,2); Sorin, Wayne V.(3); Tan, Michael R.T.(4)
  Source: Journal of Lightwave Technology  Volume: 41  Issue: 16  Article Number: null  DOI: 10.1109/JLT.2023.3262193  Published: August 15, 2023  
  Abstract:Over 100 Gb/s Four-level Pulse-Amplitude Modulation (PAM4) Vertical-Cavity Surface-Emitting Laser (VCSEL) based optical interconnects require high speed, damped, and low relative intensity noise (RIN) VCSELs. Measurement techniques for intrinsic parameters are essential for optimizing VCSEL designs. The proposed VCSEL cavity round-trip loss and gain coefficient measurement provides the insight of VCSEL distributed Bragg reflectors (DBRs) and quantum well (QW) design. A simple VCSEL cavity model is described and excellent matching between the model and measurement is achieved. © 2023 IEEE.
  Accession Number: 20231413849337
• Record 455 of
  
  Title:Hydrogen-Related Anti-Radiation Effect and Its Suppression Mechanism in Er3+/Al3+/Ge4+ Co-Doped Silica Fibers
  
  Author(s):Wang, Gencheng(1,2); She, Shengfei(1,2); Zhang, Yuting(1,2); Wang, Yanan(3); Li, Miao(3); Ma, Zhenchao(3); Zhang, Yan(1); Gao, Song(1); Cui, Xiaoxia(1,2); Li, Zhe(1,2); Hou, Chaoqi(1,2); Guo, Haitao(1,2)
  Source: Journal of Lightwave Technology  Volume: 41  Issue: 18  Article Number: null  DOI: 10.1109/JLT.2023.3275982  Published: September 15, 2023  
  Abstract:The antiradiation effect and evolution process of color center defects in hydrogen-treated Er3+/Al3+/Ge4+ codoped fiber under radiation were studied. The radiation-induced absorption spectra and continuous wave electron paramagnetic resonance spectra of glass slice samples were tested to explain the mechanism of internal defect transformation. The hydrogen treatment reduces radiation-induced absorption and increases loss in the working band by the combination of the Ge-related short wavelength absorption edge effect and the absorption peak of hydrogen vibration. Thus, there is an optimal hydrogen concentration for decreasing the radiation-induced gain variation (RIGV) of optical fibers, and the fiber with 3 × 1019 cm-3 hydrogen content had the lowest RIGV of approximately 0.038 dB/krad. The radiation-induced absorption and continuous wave electron paramagnetic property revealed that the hydrogen treatment suppresses Al-OHC and Ge dangling bands in optical fibers. Hydrogen also generates H(I), Si-E', and Ge-E' defects in the irradiation environment. This work helps to elucidate how hydrogen improves the radiation resistance of Er3+/Al3+/Ge4+ codoped silica fibers. © 1983-2012 IEEE.
  Accession Number: 20232214159224
• Record 456 of
  
  Title:All-fiber acetylene-referenced optical frequency comb
  
  Author(s):Li, Yongqi(1); Hu, Xiaohong(2); Cheng, Haihao(2); Wang, Yishan(2); Yang, Yanzhao(3); Wu, Shun(1)
  Source: Optics Communications  Volume: 531  Issue: null  Article Number: 129233  DOI: 10.1016/j.optcom.2022.129233  Published: March 15, 2023  
  Abstract:We demonstrated an all-fiber compact Erbium-doped optical frequency comb based on optical reference. Compared with the traditional RF reference, the whole system adopts the all-fiber design of optical reference. Comb stabilization is achieved by simultaneously locking the repetition rate (fr) to an RF reference and an optical comb tooth to a CW reference. The standard deviation of the fr frequency in 4.5 hours was recorded as 0.37 mHz, leading to a fraction instability of 4.3 ×10−12 at 1 s gate time and 2.8 ×10−13 at 10 s gate time. The locking of single comb tooth is achieved by locking the optical comb and the beat note of the CW laser. We used the P(16) overtone transition line of 13C2H2 as the CW reference and optimized the stabilization by choosing appropriate lock point on the Doppler-limited absorption transition. The comb was able to achieve stable locking for almost five hours. The short-term fraction instability of the optical frequency was measured to be 6.56 ×10−10 at 1 s gate time, which is mostly from the CW reference. Our approach of acetylene-stabilized fiber comb offers a feasible solution to help fiber combs move from laboratory to outdoors applications based on fiber sensing, laser stabilization and spectrum analysis. © 2022 Elsevier B.V.
  Accession Number: 20230213367034