In photorefractive waveguide arrays, the process and extent of spectral broadening of femtosecond laser pulse caused by self-phase modulation are studied theoretically and experimentally. The threshold of self-phase modulation is more than two times larger than the common threshold in a bulk sample, which affects the extent of spectral broadening dramatically. The coupling length and the ratio between the common threshold and the input peak intensity of the femtosecond laser pulse are the two key parameters dominating these phenomena. The experimental results confirm the theoretical expectation.
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http://dx.doi.org/10.1364/OE.18.010112 | DOI Listing |
Polymers (Basel)
January 2025
State Key Laboratory of Precision Manufacturing for Extreme Service Performance, College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China.
Vibration sensors are integral to a multitude of engineering applications, yet the development of low-cost, easily assembled devices remains a formidable challenge. This study presents a highly sensitive flexible vibration sensor, based on the piezoresistive effect, tailored for the detection of high-dynamic-range vibrations and accelerations. The sensor's design incorporates a polylactic acid (PLA) housing with cavities and spherical recesses, a polydimethylsiloxane (PDMS) membrane, and electrodes that are positioned above.
View Article and Find Full Text PDFSensors (Basel)
January 2025
Soreq NRC, Yavne 81800, Israel.
Fiber Bragg gratings (FBGs) inscribed by UV light and different femtosecond laser techniques (phase mask, point-by-point, and plane-by-plane) were exposed-in several irradiation cycles-to accumulated high doses of gamma rays (up to 124 MGy) and neutron fluence (8.7 × 10/cm) in a research-grade nuclear reactor. The FBG peak wavelengths were measured continuously in order to monitor radiation-induced shifts.
View Article and Find Full Text PDFMolecules
January 2025
Information Materials and Intelligent Sensing Laboratory of Anhui Province, Anhui University, Hefei 230601, China.
Carbon-based nanomaterials with excellent electrical and optical properties are highly sought after for a plethora of hybrid applications, ranging from advanced sustainable energy storage devices to opto-electronic components. In this contribution, we examine in detail the dependence of electrical conductivity and the ultrafast optical nonlinearity of graphene oxide (GO) films on their degrees of reduction, as well as the link between the two properties. The GO films were first synthesized through the vacuum filtration method and then reduced partially and controllably by way of femtosecond laser direct writing with varying power doses.
View Article and Find Full Text PDFMicromachines (Basel)
January 2025
School of Physics and Optoelectronic Engineering, Beijing University of Technology, Beijing 100124, China.
Gallium nitride (GaN) exhibits distinctive physical and chemical properties that render it indispensable in a multitude of electronic and optoelectronic devices. Given that GaN is a typical hard and brittle material that is difficult to machine, femtosecond laser technology provides an effective and convenient tool for processing such materials. However, GaN undergoes complex physical and chemical changes during high-power ablation, which poses a challenge to high-precision processing with controllable geometry.
View Article and Find Full Text PDFLangmuir
January 2025
Laboratory of the Intelligent Microsystem, Beijing Information Science and Technology University, Beijing 100192, China.
In this work, laser-induced graphene from kraft paper (kraft paper-LIG) was employed for the nonenzymatic electrochemical sensing of dopamine (DA). We reported the fabrication and characterization of a disposable, cost-effective, kraft-based electrochemical dopamine sensor with the sensing electrode consisting of laser-induced graphene derived from kraft paper. Kraft paper-LIG was formed by the femtosecond laser modification of kraft paper into a three-dimensional (3D) graphene arrangement.
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