FBG with wide-range cladding mode comb inscribed by femtosecond laser and phase mask

2020 ◽  
Author(s):  
Weijia Bao ◽  
Shen Liu ◽  
Yiping Wang
Keyword(s):  
Femtosecond Laser ◽  
Phase Mask ◽  
Wide Range ◽  
Cladding Mode

scholarly journals Fiber Bragg Grating with Enhanced Cladding Modes Inscribed by Femtosecond Laser and a Phase Mask

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7004
Author(s):  
Weijia Bao ◽  
Shen Liu ◽  
Wenjie Feng ◽  
Yiping Wang
Keyword(s):  
Femtosecond Laser ◽  
Fiber Bragg Grating ◽  
Single Mode ◽  
Phase Mask ◽  
Bragg Grating ◽  
Chemical Parameters ◽  
Anticlockwise Direction ◽  
Wide Range ◽  
Intensity Response ◽  
Cladding Mode

In this paper, we demonstrate a fiber Bragg grating (FBG) with a wide range and a comb with continuous cladding mode resonances inscribed in non-photosensitive single mode fibers using a femtosecond laser and a phase mask. The FBG is inscribed in the core and cladding, exciting a series of cladding modes in transmission. The birefringence induced by this FBG structure offers significant polarization-dependence for cladding modes, thus allowing the vector fiber twist to be perceived. By measuring the peak-to-peak differential intensity of orthogonally polarized cladding mode resonances, the proposed sensor presents totally opposite intensity response in the anticlockwise direction for the torsion angle ranging from −45° to 45°. The cladding mode comb approximately covers wavelengths over the O-, E-, S-, and C-bands in transmission. The cutoff cladding mode of air can be observed in the spectrum. Thus, the sensible refractive index range is estimated to be from 1.00 to 1.44. Temperature responsivity of the grating is also characterized. The proposed device potentially provides new solutions to the various challenges of physical vector and bio-chemical parameters sensing.

scholarly journals Review of Femtosecond-Laser-Inscribed Fiber Bragg Gratings: Fabrication Technologies and Sensing Applications

2021 ◽  
Author(s):  
Jun He ◽  
Baijie Xu ◽  
Xizhen Xu ◽  
Changrui Liao ◽  
Yiping Wang
Keyword(s):  
Femtosecond Laser ◽  
Optical Fiber ◽  
Oil And Gas ◽  
Optical Fiber Sensor ◽  
Phase Mask ◽  
Fiber Types ◽  
Direct Writing ◽  
Excellent Thermal Stability ◽  
Sensing Applications ◽  
Compact Size

AbstractFiber Bragg grating (FBG) is the most widely used optical fiber sensor due to its compact size, high sensitivity, and easiness for multiplexing. Conventional FBGs fabricated by using an ultraviolet (UV) laser phase-mask method require the sensitization of the optical fiber and could not be used at high temperatures. Recently, the fabrication of FBGs by using a femtosecond laser has attracted extensive interests due to its excellent flexibility in creating FBGs array or special FBGs with complex spectra. The femtosecond laser could also be used for inscribing various FBGs on almost all fiber types, even fibers without any photosensitivity. Such femtosecond-laser-induced FBGs exhibit excellent thermal stability, which is suitable for sensing in harsh environment. In this review, we present the historical developments and recent advances in the fabrication technologies and sensing applications of femtosecond-laser-inscribed FBGs. Firstly, the mechanism of femtosecond-laser-induced material modification is introduced. And then, three different fabrication technologies, i.e., femtosecond laser phase mask technology, femtosecond laser holographic interferometry, and femtosecond laser direct writing technology, are discussed. Finally, the advances in high-temperature sensing applications and vector bending sensing applications of various femtosecond-laser-inscribed FBGs are summarized. Such femtosecond-laser-inscribed FBGs are promising in many industrial areas, such as aerospace vehicles, nuclear plants, oil and gas explorations, and advanced robotics in harsh environments.

Femtosecond laser structuring of permeable and resorbable biomaterial

2021 ◽  
Vol 7 (2) ◽  
pp. 713-716
Author(s):  
Swen Grossmann ◽  
Sabine Illner ◽  
Robert Ott ◽  
Grit Rhinow ◽  
Carsten Tautorat ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Biomedical Applications ◽  
Mechanical Characteristics ◽  
Membrane Properties ◽  
Fiber Network ◽  
Laser Technology ◽  
Laser Structuring ◽  
Wide Range ◽  
Nanofiber Membranes ◽  
Post Production

Abstract Bioresorbable nanofiber nonwovens with their fascinating properties provide a wide range of potential biomedical applications. Modification of the material enables the adjustment of mechanical and biological characteristics depending on the desired application. Due to the nanosized fiber network, post-production structuring is very challenging. Within this study, we use femtosecond laser technology for structuring permeable and resorbable electrospun poly-L-lactide (PLLA) membranes. We show that this post-production process can be used without disturbing the fiber network near the structured areas. Furthermore, the modification of the water permeability and mechanical characteristics due to the laser structuring was investigated. The results prove femtosecond laser technology to be a promising method for the adjustment of the membrane properties and which in consequence can help to optimize cell adhesion, enable revascularization and open up applications of nanofiber membranes in personalized medicine.

scholarly journals Electrical Impedance of Surface Modified Porous Titanium Implants with Femtosecond Laser

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 461
Author(s):  
Paula Navarro ◽  
Alberto Olmo ◽  
Mercè Giner ◽  
Marleny Rodríguez-Albelo ◽  
Ángel Rodríguez ◽  
...  
Keyword(s):  
Cell Culture ◽  
Femtosecond Laser ◽  
Laser Treatment ◽  
Electrical Impedance ◽  
Porous Titanium ◽  
Titanium Implants ◽  
Electrical Impedance Spectroscopy ◽  
Wide Range ◽  
Titanium Surfaces ◽  
Surface Modified

The chemical composition and surface topography of titanium implants are essential to improve implant osseointegration. The present work studies a non-invasive alternative of electrical impedance spectroscopy for the characterization of the macroporosity inherent to the manufacturing process and the effect of the surface treatment with femtosecond laser of titanium discs. Osteoblasts cell culture growths on the titanium surfaces of the laser-treated discs were also studied with this method. The measurements obtained showed that the femtosecond laser treatment of the samples and cell culture produced a significant increase (around 50%) in the absolute value of the electrical impedance module, which could be characterized in a wide range of frequencies (being more relevant at 500 MHz). Results have revealed the potential of this measurement technique, in terms of advantages, in comparison to tiresome and expensive techniques, allowing semi-quantitatively relating impedance measurements to porosity content, as well as detecting the effect of surface modification, generated by laser treatment and cell culture.

scholarly journals Effect of Laser Pulse Overlap and Scanning Line Overlap on Femtosecond Laser-Structured Ti6Al4V Surfaces

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 969 ◽  
Author(s):  
Georg Schnell ◽  
Ulrike Duenow ◽  
Hermann Seitz
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
Surface Topography ◽  
Cell Attachment ◽  
Surface Structures ◽  
Laser Source ◽  
Laser Machining ◽  
Scanning Strategy ◽  
Wide Range ◽  
Scanning Line

Surface structuring is a key factor for the tailoring of proper cell attachment and the improvement of the bone-implant interface anchorage. Femtosecond laser machining is especially suited to the structuring of implants due to the possibility of creating surfaces with a wide variety of nano- and microstructures. To achieve a desired surface topography, different laser structuring parameters can be adjusted. The scanning strategy, or rather the laser pulse overlap and scanning line overlap, affect the surface topography in an essential way, which is demonstrated in this study. Ti6Al4V samples were structured using a 300 fs laser source with a wavelength of 1030 nm. Laser pulse overlap and scanning line overlap were varied between 40% and 90% over a wide range of fluences (F from 0.49 to 12.28 J/cm²), respectively. Four different main types of surface structures were obtained depending on the applied laser parameters: femtosecond laser-induced periodic surface structures (FLIPSS), micrometric ripples (MR), micro-craters, and pillared microstructures. It could also be demonstrated that the exceedance of the strong ablation threshold of Ti6Al4V strongly depends on the scanning strategy. The formation of microstructures can be achieved at lower levels of laser pulse overlap compared to the corresponding value of scanning line overlap due to higher heat accumulation in the irradiated area during laser machining.

One-step facile fabrication of controllable microcone and micromolar silicon arrays with tunable wettability by liquid-assisted femtosecond laser irradiation

RSC Advances ◽  
2016 ◽  
Vol 6 (44) ◽  
pp. 37463-37471 ◽  
Author(s):  
Guoqiang Li ◽  
Zhen Zhang ◽  
Peichao Wu ◽  
Sizhu Wu ◽  
Yanlei Hu ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Optoelectronic Devices ◽  
Silicon Surfaces ◽  
Femtosecond Laser Irradiation ◽  
Research Attention ◽  
Nanostructured Silicon ◽  
Wide Range ◽  
One Step ◽  
Facile Fabrication ◽  
Silicon Arrays

Micro/nanostructured silicon surfaces are attracting more and more research attention because of the wide range of applications in optoelectronic devices, microelectronics, microfluidics, and biomedical devices.

scholarly journals A wide-range optical frequency generator based on the frequency comb of a femtosecond laser

2008 ◽  
Vol 16 (1) ◽  
pp. 258 ◽  
Author(s):  
Young-Jin Kim ◽  
Jonghan Jin ◽  
Yunseok Kim ◽  
Sangwon Hyun ◽  
Seung-Woo Kim
Keyword(s):  
Femtosecond Laser ◽  
Frequency Comb ◽  
Optical Frequency ◽  
Wide Range ◽  
Frequency Generator

scholarly journals Simulation of femtosecond laser absorption by metallic targets and their thermal evolution

2017 ◽  
Vol 35 (3) ◽  
pp. 415-428 ◽  
Author(s):  
A. Suslova ◽  
A. Hassanein
Keyword(s):  
Femtosecond Laser ◽  
Laser Intensity ◽  
Laser Energy ◽  
Absorption Efficiency ◽  
Optical Parameters ◽  
Temperature Dependent ◽  
Simulation Code ◽  
Laser Absorption ◽  
Plasma State ◽  
Wide Range

AbstractThe interaction of femtosecond laser with initially cold solid metallic targets (Al, Au, Cu, Mo, Ni) was investigated in a wide range of laser intensity with focus on the laser energy absorption efficiency. Our developed simulation code (FEMTO-2D) is based on two-temperature model in two-dimensional configuration, where the temperature-dependent optical and thermodynamic properties of the target material were considered. The role of the collisional processes in the ultrashort pulse laser–matter interaction has been carefully analyzed throughout the process of material transition from the cold solid state into the dense plasma state during the pulse. We have compared the simulation predictions of the laser pulse absorption with temperature-dependent reflectivity and optical penetration depth to the case of constant optical parameters. By considering the effect of the temporal and spatial (radial) distribution of the laser intensity on the light absorption efficiency, we obtained a good agreement between the simulated results and available experimental data. The appropriate model for temperature-dependent optical parameters defining the laser absorption efficiency will allow more accurate simulation of the target thermal response in the applications where it is critical, such as prediction of the material damage threshold, laser ablation threshold, and the ablation profile.

Hydrogen loading for fiber grating writing with a femtosecond laser and a phase mask

2004 ◽  
Vol 29 (18) ◽  
pp. 2127 ◽  
Author(s):  
Christopher W. Smelser ◽  
Stephen J. Mihailov ◽  
Dan Grobnic
Keyword(s):  
Femtosecond Laser ◽  
Phase Mask ◽  
Fiber Grating
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