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- 实验方案
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Mode-locked near-infrared thulium doped fibre laser using evanescent field effect with Bi <sub/>2</sub> O <sub/>3</sub> saturable absorber
摘要： Using the evanescent field effect, a high power passively mode-locked laser with a pulse duration of 1.85 ps and the pulse energy of 13.15 pJ is demonstrated. A Bi2O3 solution is used as a saturable absorber (SA) on a side polished fibre incorporated into a thulium doped fibre laser cavity for operation in the mid-infrared range. The 37.61% SA has a modulation depth and creates a highly stable mode-locked pulse output with a short pulse duration. The calculated net cavity dispersion at central wavelength is ?1.4 ps2, indicating operation is in the anomalous dispersion regime and confirmed by the presence of Kelly’s side-bands observed in the generated optical spectrum. Radio frequency analysis reveals a high signal to noise ratio, making this laser stable for use in telecommunication systems.
关键词： thulium doped fibre laser,evanescent field effect,Bi2O3 saturable absorber
更新于2025-11-28 14:23:57
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Single-frequency fibre laser at 1030?nm based on gain bandwidth compression
摘要： We demonstrate a single-frequency linear cavity fiber laser at 1030 nm with a distributed Bragg reflector cavity configuration. Despite the fact that the combination of the cavity length of the fiber laser and the reflection band of the output FBG cannot satisfy the condition of single-longitudinal mode oscillation, the single-frequency lasing is still realized by the proper temperature control of two FBGs to narrow the gain bandwidth. Under the respective temperature of two FBGs of 43.4 °C and 9 °C, the laser linewidth of around 9.6 kHz is achieved at a pump power of 113 mW. The relative noise intensity for frequencies of above 1.5 MHz is about ?140 dB Hz?1. The maximum output power of 126.2 mW is obtained with the slope efficiency of about 28%.
关键词： fibre laser,single-frequency,gain bandwidth compression,distributed Bragg reflector
更新于2025-11-28 14:23:57
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Fe <sub/>3</sub> O <sub/>4</sub> nanoparticles as the saturable absorber for a mode-locked fiber laser at 1558 nm
摘要： We demonstrated a mode-locked erbium doped fiber laser (EDFL) operating at 1558 nm by exploiting ferroferric-oxide nanoparticles (FONPs) as the saturable absorber (SA) material. FONPs, with an average diameter of ~20 nm, were prepared by a thermal decomposition method, then mixed with sodium carboxymethylcelluose to form an FONP film. The FONP SA was fabricated through a sandwiched FONP film between two fiber connectors. By inserting the FONPs SA into an EDFL cavity pumped by a 980 nm laser diode, stable passive mode-locking was achieved with a threshold pump power of ~120 mW. The obtained mode-locked laser had a central wavelength of ~1558 nm, a spectral bandwidth of ~0.8 nm, a pulse width of ~4.35 ns, and a repetition rate of ~37.32 MHz. Furthermore, a maximum average power of ~17 mW was obtained for a pump power of 340 mW. To the best of our knowledge, this is the first time that it has been demonstrated that FONPs can be used for constructing mode-locked fiber lasers.
关键词： mode-locked,fibre laser,Fe3O4 nanoparticles,saturable absorber (SA)
更新于2025-11-28 14:23:57
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Tunable self-excited multiwavelength Brillouin-erbium fiber laser based on a variable temperature sensor
摘要： We propose and demonstrate a tunable self-excited multiwavelength Brillouin-erbium fiber laser based on a novel in-line Mach–Zehnder interferometer sensor (NMZIS) with variable temperature. The configuration of the NMZIS is a section of uncoated single-mode fiber sandwiched between an up-taper and multimode fiber. With the temperature changing from 30 °C to 90 °C, the transmission spectrum of the NMZIS shifts towards longer wavelengths. By embedding the NMZIS to act as a fiber filter in the ring cavity, the wavelength of the output multiwavelength comb is tuned from 1552.35 to 1564.48 nm. The corresponding generation of 21 Brillouin–Stokes lines with 25 dB optical signal-to-noise ratio is achieved.
关键词： Brillouin-erbium fibre laser (BEFL),tunable,self-excited
更新于2025-11-28 14:23:57
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[Laser Institute of America ICALEO?? 2014: 33rd International Congress on Laser Materials Processing, Laser Microprocessing and Nanomanufacturing - San Diego, California, USA (October 19a??23, 2014)] International Congress on Applications of Lasers & Electro-Optics - Optimisation of underwater laser cutting for decommissioning purposes
摘要： In both the nuclear and offshore sectors, there are many potential applications for underwater cutting. Although underwater cutting using lasers was demonstrated many years ago, the limitations imposed at that time by the 10 micron laser beam wavelength available, meant realisation of underwater laser cutting was almost impossible. With the advent of fibre delivered laser power this situation has changed. This paper will describe recent work using a 5kW Yb fibre laser source, equipped with a specially designed process head for underwater laser cutting. Results will be presented for cutting both 304 stainless and C-Mn (S275JR) steel, at thicknesses of up to 32mm. The paper will also describe the various parameters thought to be important in underwater cutting and their effects on the cut achieved. It will be shown that for different applications, different sets of parameters can be used to achieve different results. As an example of this, in the application of nuclear decommissioning, for maximising dross height on the parts being cut will be described. In nuclear decommissioning, maximising the dross adhesion is important, as it means less radioactive material from the kerf is released into the water and therefore more remains on the parts being size reduced for future long term storage.
关键词： underwater laser cutting,decommissioning,dross height,nuclear,offshore,mass reduction,fibre laser
更新于2025-09-23 15:21:01
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Effect of laser patterning on the material behaviour of 22MnB5 steel with induced local strengthening
摘要： When using a supporting laser patterning method, it is possible to adaptively tailor the strength variations and formability of a pre-fabricated single panel. This paper focuses on the effect of line and geometrical laser patterning on the strength enhancement and material behaviour of steel sheets. To validate the performance of the laser patterning specimens, a tensile test for evaluating the in-plane deformation behaviour and a 3-point bending test for out-of-plane have been conducted while maintaining the area fraction for the laser-treated area. Close-type laser patterns, e.g., 0°, auxetic, and honeycomb, not only induce a substantial increase in strength but also enhance bending resistance without sacrificing the springback tendency of the initial sheet material.
关键词： Fibre laser,Martensite,Laser patterning,Local hardening,22MnB5
更新于2025-09-23 15:21:01
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High-contrast, fast chemical imaging by coherent Raman scattering using a self-synchronized two-colour fibre laser
摘要： Coherent Raman scattering (CRS) microscopy is widely recognized as a powerful tool for tackling biomedical problems based on its chemically specific label-free contrast, high spatial and spectral resolution, and high sensitivity. However, the clinical translation of CRS imaging technologies has long been hindered by traditional solid-state lasers with environmentally sensitive operations and large footprints. Ultrafast fibre lasers can potentially overcome these shortcomings but have not yet been fully exploited for CRS imaging, as previous implementations have suffered from high intensity noise, a narrow tuning range and low power, resulting in low image qualities and slow imaging speeds. Here, we present a novel high-power self-synchronized two-colour pulsed fibre laser that achieves excellent performance in terms of intensity stability (improved by 50 dB), timing jitter (24.3 fs), average power fluctuation (<0.5%), modulation depth (>20 dB) and pulse width variation (<1.8%) over an extended wavenumber range (2700–3550 cm?1). The versatility of the laser source enables, for the first time, high-contrast, fast CRS imaging without complicated noise reduction via balanced detection schemes. These capabilities are demonstrated in this work by imaging a wide range of species such as living human cells and mouse arterial tissues and performing multimodal nonlinear imaging of mouse tail, kidney and brain tissue sections by utilizing second-harmonic generation and two-photon excited fluorescence, which provides multiple optical contrast mechanisms simultaneously and maximizes the gathered information content for biological visualization and medical diagnosis. This work also establishes a general scenario for remodelling existing lasers into synchronized two-colour lasers and thus promotes a wider popularization and application of CRS imaging technologies.
关键词： Coherent Raman scattering,CRS microscopy,biomedical imaging,fibre laser,nonlinear optical imaging
更新于2025-09-23 15:21:01
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A review on the laser welding of coated 22MnB5 press-hardened steel and its impact on the production of tailor-welded blanks
摘要： The current demand for vehicles with high fuel efficiency, improved safety and enhanced crash-worthiness qualities is being met by making use of high strength components with tailored mechanical properties which are made using tailor-welded blanks. During their production, the surface of the blank needs to be protected against oxidation and decarburisation. Protective coatings are used to protect the steel surface, with Aluminium-Silicon or Zinc-based coatings being the most popular. This work provides a review on the state-of-the-art as well as the issues associated with the laser welding of coated 22MnB5 grade steel to be used in the production of tailor-welded blanks. The paper provides a summary of existing solutions available to overcome these issues while discussing their limitations and the potential for future work.
关键词： Fibre laser welding,tailor-welded blanks,22MnB5,Zn-Coating,press-hardened steel,ultra-high strength steel,Al–Si coating,hotstamped parts
更新于2025-09-23 15:21:01
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The impact of laser surface treatment on the microstructure, wear resistance and hardness of the AlMg5 aluminum alloy
摘要： Light metal alloys due to several unique properties such as low density and high corrosion resistance are increasingly used in various technical applications, where the automotive industry is one of the most important sectors. The automotive applications use mostly aluminum alloys, where the strength to density ratio of the material plays a crucial factor. Unfortunately, relatively low mechanical properties limit their applications for parts where a high surface hardness and wear resistance is expected. The classic heat treatment of aluminum alloys can only in some limited ranges improve the bulk material properties. Despite this, surface treatment with laser processing has developed significantly over the past 20 years. The laser beam treatment allows the introduction of a wide range of alloying elements to the surface layer of an aluminum alloy and thus, as a result of the precipitation of numerous intermetallic phases, significantly increases hardness, and abrasion resistance. The purpose of this work was to modify the aluminum surface layer using high-power fiber laser (HPFL). During this process, a mixture of titanium and iron powders (90/10 wt.%) was introduced onto the surface of the AlMg5 alloy. The microhardness tests carried out by the Vickers method and tribological tests showed a significant increase in mechanical properties in the entire volume of the obtained layer. Research on light and scanning microscopy revealed fragmentation of primary precipitates and the formation of numerous intermetallic phases rich in titanium and aluminum.
关键词： Aluminium alloy,Laser treatment,EDS analysis,Tribological properties,High power fibre laser
更新于2025-09-23 15:19:57
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Real-time temporal-spectral analysis of complex dynamics involving multiple soliton states in a dual-wavelength passively mode-locked fiber ring laser
摘要： We present an experimental study of complex dissipative solitons dynamics in a passively mode-locked fiber ring laser. Recently, thanks to real-time spectroscopy techniques such as the dispersive Fourier transform (DFT), it has been possible to study the complex internal dynamics of soliton molecules. However, most of the works have been limited to the study of intermolecular or intramolecular dynamics involving a small number of solitons within a single compact soliton packet, to which the DFT technique applies naturally. In this work, we study the dynamics of complex arrangements of multiple solitons, extending the analysis to regimes where multiple soliton packets at different wavelengths coexist and interact in the cavity, probing simultaneously the internal dynamics of various short-lived soliton molecules, as well as the collective dynamics of the different soliton packets distributed in the cavity, all of which is made possible by simultaneous analysis in the temporal and spectral domains. This allows to relate temporal dynamics at different time scales, as well as temporal and spectral events. In particular, we report the experimental observation of the dynamics of the Kelly sidebands that flank the soliton spectra, and relate it to temporal and spectral events such as extinctions of soliton packets with pulsating amplitude, spectral narrowing, and with energy fluctuations.
关键词： dissipative solitons,Kelly sidebands,mode-locked fibre laser,soliton molecules
更新于2025-09-23 15:19:57