- 标题
- 摘要
- 关键词
- 实验方案
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Laser Direct Writing Assisted Fabrication of Skin Compatible Metal Electrodes
摘要： Skin-compatible electrodes have been studied intensively for its application in wearable electronics. To satisfy various deformations of electronic skin, it requires to fabricate a highly conductive, mechanically stable, flexible, and stretchable electrode. Here, a feasible laser direct writing (LDW) process is carried out to fabricate micro-spring structured metal electrodes. The metal electrodes show high conductivity and transparency with sheet resistance of 4.8 ohm per square and at transmittance of 83%. It is worthy of noting that, the metal electrodes have an excellent mechanical–electrical stability, where stretching over 75% and bending over 5000 times induces resistance variance less than 5% and 2%, respectively. The excellent mechanical and electrical behavior of the micro-spring metal electrodes are promising to be useful for wearable electronics. The LDW process may facilitate the design and prototype of the skin compatible metal electrodes in the coming future.
关键词： wearable electronics,skin-compatible electrodes,electro-deposition,laser direct writing
更新于2025-09-23 15:21:01
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Selection of the confining beam for laser direct writing with scanning absorbance modulation
摘要： Absorbance-modulation optical lithography has been proposed to obtain super-resolution grating patterns with far-field optics. However, the patterns are monotonous since the interference fringes are used as the confining beam. We propose laser direct writing with scanning absorbance modulation to produce free super-resolution patterns. Four kinds of optical vortex beams are studied as the confining beam and the performance of scanning absorbance modulation using each of them is simulated. In conclusion, the selection of the best confining beam has to follow three criteria and an example is the 2-level, 1.5-order optical vortex beam.
关键词： laser direct writing,optical vortex beam,absorbance modulation
更新于2025-09-23 15:19:57
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[Laser Institute of America ICALEO?? 2017: 36th International Congress on Applications of Lasers & Electro-Optics - Atlanta, Georgia, USA (October 22a??26, 2017)] International Congress on Applications of Lasers & Electro-Optics - Laser direct writing lithography for rapid fabrication on non-planar surfaces
摘要： A modified laser direct writing lithography system with dynamic focusing is presented. This improved system can realize rapid fabrication on non-planar surfaces with large curvature and it offers new possibilities for fabricating micro-patterns on curved surfaces in an easy and fast way. A dynamic focusing lens group which is driven by a linear voice coil motor is introduced and it can rapidly control the laser spot to focus on the curved surface when processing in real-time. The focus range is almost 10 mm and it can be larger when working with the z-stage. The mathematic expression of dynamic focusing is deduced and the corresponding experiment results agree with the numerical analysis, which shows the practicability of the system. The effects of slopes with different tilted angles on exposure linewidth are studied. Finally, a concentric-circle grating is fabricated on a convex substrate with a diameter of 30 mm and a radius of curvature of 19.918 mm. The grating has homogeneous linewidth of 10 μm and line space of 20 μm, and the total processing time is within 40s. This technique can greatly improve the efficiency and has great potentials, such as rapid fabrication of diffractive optical elements (DOEs) or microelectromechanical systems (MEMS) on arbitrary 3D curved surfaces.
关键词： non-planar surfaces,dynamic focusing,micro-patterns,rapid fabrication,laser direct writing lithography
更新于2025-09-23 15:19:57
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Femtosecond-laser direct-writing volume phase gratings inside Gea??Asa??S chalcogenide glass
摘要： In this study, volume-phase gratings (VPGs) were fabricated inside Ge–As–S chalcogenide glasses (ChG) with femtosecond-laser writing technology. VPGs with high thicknesses were obtained through single-step writing by exploiting the self-focusing effect of highly nonlinear ChGs. The clear diffraction patterns and high diffraction efficiency of the prepared gratings indicated their high optical performance. Testing results showed that the diffraction efficiency of VPGs first increased with laser pulse energies and then decreased when the laser damage threshold of the glass reached 9.42 nJ. Grating thickness also exhibited the same trend as laser pulse energies and reached the maximum value of 28 μm at 9.42 nJ. The changes in the refractive indexes of volume gratings fabricated under different laser pulse energies were carefully investigated. The changes in the refractive indexes of the gratings remained at the same level while laser pulse energy was increased. Meanwhile, grating thickness played a key role in diffraction efficiency. The maximum diffraction efficiency of the prepared VPGs reached 50% at 808 nm under optimized laser parameters.
关键词： chalcogenide glass,volume-phase grating,laser direct-writing,nonlinear optics
更新于2025-09-23 15:19:57
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Investigation of a Bragg Grating-Based Fabrya??Perot Structure Inscribed Using Femtosecond Laser Micromachining in an Adiabatic Fiber Taper
摘要： This paper presents the fabrication of a fiber Bragg grating (FBG)-based Fabry–Perot (FP) structure (7 mm total length) in an adiabatic fiber taper, investigates its strain and temperature characteristics, and compares the sensing characteristics with a standard polyimide coated FBG sensor. Firstly, a simulation of the said structure is presented, followed by the fabrication of an adiabatic fiber taper having the outer diameter reduced to 70 μm (core diameter to 4.7 μm). Next, the sensing structure, composed of two identical uniform FBG spaced apart by a small gap, is directly inscribed point-by-point using infrared femtosecond laser (fs-laser) micromachining. Lastly, the strain and temperature behavior for a range up to 3400 με and 225 ?C, respectively, are investigated for the fabricated sensor and the FBG, and compared. The fabricated sensor attains a higher strain sensitivity (2.32 pm/με) than the FBG (0.73 pm/με), while both the sensors experience similar sensitivity to temperature (8.85 pm/?C). The potential applications of such sensors include continuous health monitoring where precise strain detection is required.
关键词： Fabry–Perot,microfiber sensor structure,direct writing,sensor for structural health monitoring,point-by-point fabrication,femtosecond laser micromachining,harsh environment fiber sensor
更新于2025-09-23 15:19:57
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Programmable graphene-based humidity and heat driven actuators prepared by one-step laser direct writing
摘要： Smart materials are gathering increasing attention and play important roles in intelligent actuators, among which films with Janus structure are widely used because of their intrinsic response ability. Herein, we report a highly simplified method, laser direct writing, for preparing GO (Graphene Oxide)/rGO (Reduced Graphene Oxide) Janus films. By adjusting the output power of laser, GO homogeneous films can be accurately reduced in a single step and a certain thickness can be controllably reduced to form GO/rGO Janus films. The structure and chemical composition of the resulting GO/rGO films were characterized. Their response to ambient temperature and humidity is determined experimentally. The response performance of Janus films with different thickness was tested, and the one with thickness of 15 μm performed the best. The Janus films are made into diverse actuators, including a bionic movable creeper and a grabber that can grab a leaf upon changing the humidity in a planned way. Furthermore, we designed a finger-guessing robot that can be programmed in advance and perform the predetermined actions.
关键词： reduced graphene oxide,actuator,Janus structure,graphene oxide,laser direct writing
更新于2025-09-23 15:19:57
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Femtosecond laser direct written off-axis fiber Bragg gratings for sensing applications
摘要： First order off-axis fiber Bragg gratings (FBGs) were fabricated in a standard single mode fiber (SMF-28e) through femtosecond laser direct writing. A minimum offset distance between the grating and core center of 2.5 μm was found to create a multimode section, which supports two separate fiber modes (LP0,1 and LP1,1), each split into two degenerate polarization modes. The resulting structure breaks the cylindrical symmetry of the fiber, introducing birefringence (≈10?4) resulting in a polarization dependent Bragg wavelength for each mode. Based on the modal and birefringence behavior, three off-axis FBGs were fabricated with 3.0, 4.5 and 6.0 μm offsets from the core center, and then characterized in strain, temperature, and curvature. The tested off-axis FBGs exhibited a similar strain sensitivity of ~1.14 pm/μ? and a temperature sensitivity of ~12 pm/C. The curvature and orientation angle were simultaneously monitored by analyzing the intensity fluctuation and the wavelength shift of the LP1,1 Bragg resonance. A maximum curvature sensitivity of 0.53 dB/m?1 was obtained for the off-axis FBG with a 3.0 μm offset.
关键词： optical fiber sensors,femtosecond laser direct writing,single mode fiber,off-axis fiber Bragg gratings,Birefringence
更新于2025-09-23 15:19:57
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Controlled Fabrication of Optical Signal Input/Output Sites on Plasmonic Nanowires
摘要： Silver nanowires have attracted considerable attention as sub-diffraction limited diameter waveguides in a variety of applications including cell endoscopy and photonic integrated circuitry. Optical signal transport occurs by coupling light into propagating surface plasmons which scatter back into light further along the wire. However these inter-conversions only occur efficiently at wire ends, or at defects along the wire, which are not controlled during synthesis. Here we overcome this limitation, demonstrating the visible laser light-induced fabrication of gold nanostructures at desired positions on silver nanowires, and their utility as efficient in/out coupling points for light. The gold nanostructures grow via plasmon-induced reduction of Au(III) and are shown to be excellent ‘hotspots’ for surface-enhanced Raman scattering.
关键词： optical antenna,surface enhanced Raman scattering,Chemically synthesized noble metal nanowires,gold nanoparticle,laser direct writing
更新于2025-09-19 17:13:59
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Fabrication of curved diffractive optical elements by means of laser direct writing, electroplating, and injection compression molding
摘要： In this work, a new process chain for the fabrication of curved micro-structured optical elements by injection compression molding is investigated. The fabrication is demonstrated for the example of a curved di?ractive optical element (DOE). In a ?rst process step a master substrate is fabricated using laser direct writing on a curved glass substrate. Blazed di?ractive micro-structures with lateral feature sizes down to 5 μm and height of 1.6 μm are created. A subsequent electroplating process is applied to create a nickel stamper to be used as a tool insert for the molding process. During electroplating, a 3 mm nickel layer is formed, transferring the di?ractive structures from the master substrate into a solid mold insert. The nickel stamper shows an accurate reproduction of the micro-structures. The mold insert is integrated into an injection compression molding tool to replicate the optical elements. Results show that the blazed di?ractive structures are replicated with a high quality. Tests of the components within a chromatic-confocal measurement setup con?rm that they can potentially replace expensive conventional elements.
关键词： Polymer optics,Injection compression molding,Laser direct writing,Di?ractive optical element
更新于2025-09-19 17:13:59
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - The fabrication mechanism and spectral characteristics of Fiber Gratings fabricated by point-by-point direct-writing based on femtosecond laser pulses
摘要： In this paper, a series of fiber gratings with different spectrum characteristics are fabricated in standard telecommunication fiber without hydrogen loading by point-by-point direct writing method based on 100 femtosecond laser amplifier system at 800-nm central wavelength. They are including the fourth-order fiber Bragg grating, fiber Bragg grating Fabry-Perot cavity, sampling fiber Bragg grating and cascaded long period fiber grating. The experimental results show that the spectrum characteristics of fourth-order fiber Bragg gratings with Λ=1.93 μm period are obtained at the center wavelength λ=1394.5 nm, and the fiber Bragg grating Fabry-Perot cavity can be inscribed when the gating period is Λ=1.95 μm. Furthermore, the sampled fiber Bragg gratings with different sampled periods are fabricated by adjusting the sampling period. Finally, the spectrum of the cascaded long period fiber gratings is achieved by changing the grating pitch of long period grating with 3 mm, 5 mm and 7 mm, respectively. This study will provide a powerful experimental gist and theoretical basis for the fabrication of different types of fiber gratings by femtosecond laser point-by-point writing directly method.
关键词： fiber Bragg gratings (FBGs),sampled fiber Bragg grating (S-FBG),point-by-point (PBP) direct-writing method,cascaded long period fiber grating(C-LPFG)
更新于2025-09-16 10:30:52