Ablation Of Copper Research Articles

Ultra-short pulse laser ablation of metals: A comprehensive 3D simulation perspective enlightening novel process insights

Intricate dynamics in ultra-short pulse laser ablation of metals necessitate deeper process understanding. This work presents an auspicious contribution in this direction, incorporating a sophisticated three-dimensional finite-volume simulation tool, building upon our previously validated models in continuous-wave laser material processing. Atop the existing multiphysics framework, a two-temperature and a Drude absorption model has been integrated. Focused on laser ablation of copper, preliminary results unveil novel perspectives on the dynamic interaction between thermal effects and material response. Surpassing limitations inherent in one- and two-dimensional descriptions, this model distinctively captures the complex interplay of electron heating, energy transfer to the lattice, and ensuing rapid phase transitions. Crucially, it complements existing insights into ablation mechanism by illustrating the influence of elusive temperature-dependent material properties, such as density and the bulk modulus for superheated liquid metal, on the process. While still in development, these advancements mark a promising stride towards a deeper process comprehension.

Numerical simulation and experimental study of femtosecond laser ablation of copper: A two-temperature model with temperature-dependent properties and multiple phase transitions

A fundamental study of the interaction between femtosecond laser and copper will be useful in optimizing laser parameters and processing quality in practice, and it faces challenges due to very short action time, complex energy transport and phase transition processes of this interaction. In this paper, A 2D two-temperature model was established and improved to include temperature-dependent optical and thermophysical properties and three phase transitions including melting, vaporization, and phase explosion. The temperature evolution of both the top surface and the sub-surface were simulated, thereafter, ablation experiments with different laser peak fluences were conducted using a femtosecond laser. It was found that the interface reflectivity would decrease rapidly, while the optical penetration depth and the ballistic electron penetration depth would increase significantly during laser irradiation. The temperature evolution of electron and lattice subsystems of the top surface could be divided into, respectively, 4 and 5 stages with different temperature trends in each stage. The variation of subsurface temperature was different from that of surface temperature and the temperature distribution showed that there was a temperature peak at near surface. A comparison of the experimental and simulation results showed that the simulated ablation depths were consistent with the experiment results.

Effect of sample temperature on femtosecond laser ablation of copper

We conduct an experimental study supported by theoretical analysis of single laser ablating copper to investigate the interactions between laser and material at different sample temperatures, and predict the changes of ablation morphology and lattice temperature. For investigating the effect of sample temperature on femtosecond laser processing, we conduct experiments on and simulate the thermal behavior of femtosecond laser irradiating copper by using a two-temperature model. The simulation results show that both electron peak temperature and the relaxation time needed to reach equilibrium increase as initial sample temperature rises. When the sample temperature rises from 300 K to 600 K, the maximum lattice temperature of the copper surface increases by about 6500 K under femtosecond laser irradiation, and the ablation depth increases by 20%. The simulated ablation depths follow the same general trend as the experimental values. This work provides some theoretical basis and technical support for developing femtosecond laser processing in the field of metal materials.

Ablation depth enhancement on a copper surface using a dual-color double-pulse femtosecond laser.

We investigate the femtosecond laser ablation of copper with a dual-color double-pulse femtosecond laser at the wavelengths of 515 nm and 1030 nm. By properly choosing the energy of the 515 nm pulse, the optical properties such as surface reflectivity and absorption coefficient on copper surface can be modified to increase the absorption of the subsequent 1030 nm pulse. The ablation depth of dual-color double-pulse laser is at least 50% higher than the total ablation depth of both the 515 nm and 1030 nm pulses, provided that the inter-pulse delay of the double-pulse laser is within the electron-phonon coupling time. The ablation depth enhancement on a copper surface using a dual-color double-pulse femtosecond laser is of significant interest for scientific research and industrial application.

Formation mechanism of micro/nanoscale structures on picosecond laser pulse processed copper

Modification of surfaces with ultrashort pulse laser surface processing techniques has shown to enhance surface properties for numerous applications. To more effectively tailor material properties, there needs to be a better understanding of the self-organization processes that lead to the quasi-periodic micro- and nano-scale surface features. In this paper, a multi-cross-section technique was used to gain understanding of how the surface features form during processing of copper with picosecond pulses. Incremental cross-sections were performed starting at the leading edge of the final laser pass. Each subsequent cross-section moved farther away from the leading edge and towards the final microstructure seen within the center of the processed region. Utilizing the cross-sectional and laser confocal data combined with the 2D projection of the Gaussian beam profile, a progression of formation mechanisms that includes a balance of ablation, redeposition, shielding, and sintering is explained. This formation mechanism progressed with initial ablation of copper that redeposits onto the surface. The redeposited copper then acts as a protection against the high fluence portion of the laser beam allowing for the mounds to grow. The redeposited copper particles are then sintered by the tail-end of the Gaussian profile into a porous layer.

Synthesis Nanoparticles of Copper and Dicopper Oxide via Change Atmosphere of Copper Ablation

Synthesis Nanoparticles of Copper and Dicopper Oxide via Change Atmosphere of Copper Ablation

Z-Scanning of Multiple-Pulse Laser Ablation of Copper Study for Application in Roll-Printed Electronics

The benefits of pulsed laser ablation in advanced manufacturing have been studied in terms of intensity, adequate orientation, damped noise, and great adaptability. During ultrashort laser ablation, the interaction between a copper surface and numerous pulses was explored to establish ideal focusing conditions. We present a simple theoretical description of morphological changes in the ablated channel and illustrate its utility in real-time placement of the interactive surface at the focus during multiple-pulse laser ablation of copper. The experimental results for copper ablation depth indicate that combining a dynamic focusing mechanism and a theoretical formula for ablation-cycle-dependent ablation depth allows one to regulate the geometry of ablated channels. This model can be applied to a wide range of high-efficiency ablation systems and could be crucial in the development of a high-precision ablation system for the curved surfaces in highly scaled copper gravures used in printed electronics, which currently presents an engineering problem.

Multi-timescale observation of ultrashort pulse laser ablation of copper

Ultrashort pulse lasers have attracted attention because they can be used to fabricate various types of solid materials, including metals, semiconductors, and insulators. To further improve ultrashort pulse laser processing, it is important to understand the phenomena that occur during processing. Optical-delay pump–probe observation is a powerful tool for investigating the ultrafast dynamics of ablation on a timescale ranging from sub-picoseconds to a few nanoseconds. However, the discrepancy in the timescales between ultrafast phenomena and the final processed shape is too large to understand the decisive process leading to the final processed shape. In this study, we combine optical-delay with electrical-delay pump–probe​ shadowgraphy to capture phenomena over a wide range of timescales ranging from a few nanoseconds to hundreds of nanoseconds to clarify the sequence of processes leading to static processing results. Particularly, we found that a ring-shaped molten structure was formed when the pulse duration was 9 ps or longer and revealed the mechanism of the formation by visualizing shock wave propagation and particle ejection from the ring position. This research is expected to contribute to the further understanding and improvement of ultrashort pulse laser processing.

Production of copper nanoparticles in the process of target ablation by radiation Cr3+:BeAl2O4 laser

The work is devoted to the synthesis of nanoparticles in the process of ablation of a copper target in a liquid by repetitively pulsed laser radiation. It has been noted that nanomaterials based on certain metals have unique physical and chemical properties. This ensures their use in various applications. In particular, copper nanoparticles are successfully used in medicine and biochemistry. To carry out the synthesis of copper nanoparticles, a previously developed Cr3+:BeAl2O4 laser is used. The laser is based on a plane-parallel resonator with a dispersive prism. Using a prism, the radiation wavelength is smoothly adjusted. To carry out copper ablation, the laser generation wavelength was tuned to 740 nm. It has been shown that when a target is exposed to a microsecond laser pulse consisting of a train of short pulses, copper nanoparticles of various sizes are formed. Comparison of the results with the results of previous works shows that exposure of the target to radiation with a shorter wavelength, commensurate with the energy density of the train and similar spatial parameters leads to a decrease in the average size of the synthesized nanoparticles.

Comparison of Submillimeter Spot Ablation of Copper and Nickel by Multipulse Picosecond and Femtosecond Laser

The current transmission and reflection laser ablation micropropulsion modes have the problem of a complex working medium supply system in engineering. Therefore, we propose large-spot laser ablation with a one-dimensional supply mode. In order to verify this ablation mode, a multipulse ablation experiment of submillimeter-scale light spots was carried out on the surface of pretreated copper and nickel under the atmosphere using an ultrafast laser with a pulse width of 290 fs and 10 ps. The results show that femtosecond laser multipulse ablation (FLMA) leads to the grain refinement of copper, the crater quality of the two metals under FLMA is better, and picosecond laser multipulse ablation (PLMA) causes the crater of nickel to form a dense remelting bulge that affects laser absorption; both metals have obvious heat-affected zones after FLMA and PLMA, the heat-affected zones of nickel are 5–10% larger than those of copper, and the ablation depth of copper is deeper. Under the same conditions, the ablation mass of copper is smaller than that of nickel, and the specific impulse performance of laser ablation micropropulsion is better.

Ultrafast laser ablation of copper with GHz bursts: A numerical study on the effects of repetition rate, pulse number and burst fluence on ablation efficiency and heat-affected zone

Ultrafast laser burst ablation (ULBA) with high repetition rates up to GHz has emerged as a promising method for improving ablation efficiency and reducing heat-affected zone (HAZ). However, the effects of different laser parameters are not well understood. This article presents a numerical study by an improved two-temperature model on the influences of repetition rate, pulse number and burst fluence on ablation efficiency and HAZ in ULBA of copper. Due to thermal accumulation, increasing the repetition rate enhances the maximum ablation efficiency, by over 150% at 3456 MHz. Interestingly, large pulse numbers also assist this effect by extending the period of thermal accumulation. However, if the burst fluence is too low, increased pulse numbers will reduce the ablation efficiency due to insufficient pulse fluences. Burst duration and fluence are determined to have the greatest impact on HAZ thickness. To minimize HAZ, the burst duration needs to be short, by raising repetition rates or reducing pulse numbers, to decrease the thermal diffusion time. The dependences of ablation optimum and threshold fluences on pulse numbers and repetition rates are analyzed and summarized in simple formulae. This study unveils the impacts of laser parameters in ULBA and provides guidelines for ablation efficiency and HAZ optimization.

Characterization of laser-induced shock waves generated during infrared laser ablation of copper by the optical beam deflection method

The shock waves generated during laser ablation of a copper target are investigated using the optical beam deflection method. The fluence of nanosecond pulsed infrared laser beam was in the range of 15-700J/cm2. The density jumps related with the influx of the shock wave at two interaction points were detected with the help of He-Ne laser probes. In general, a supersonic shock wave is produced, which propagates through air and gradually decays into an acoustic wave. Experiments were carried out to study the impact of laser fluence and propagation distance on the shock wave velocity and pressure. The shock wave velocity varies with laser fluence as v∝Fl0.3 and with propagation distance as v∝d-1.5. These results are compared with the predictions of the theoretical models. In the investigated fluence range, shock wave pressure rises by an order of magnitude (∼1-10MPa). We demonstrated that shock wave pressure and ablated mass can be related, yielding mass-specific shock wave pressure that increases linearly with laser fluence. We have also noticed the shock-wave-induced probe beam focusing under certain conditions, which indicates that the shock wave modifies the refractive index of the compressed layer of air. The reported results are useful for the fundamental understanding and pave the way for new applications of laser-induced shock waves.

Laser Ablation of Copper and YAG:Ce Targets in Liquid PDMS, Studied by Shadowgraph and Photoluminescence Imaging

Laser Ablation of Copper and YAG:Ce Targets in Liquid PDMS, Studied by Shadowgraph and Photoluminescence Imaging

Investigation of the exuberant cavitation bubble and shock wave dynamics in pulsed laser ablation of copper in distilled water

Investigation of the exuberant cavitation bubble and shock wave dynamics in pulsed laser ablation of copper in distilled water

Multi-Timescale Observation of Ultrashort Pulse Laser Ablation of Copper

Multi-Timescale Observation of Ultrashort Pulse Laser Ablation of Copper

Probing the cavitation bubbles produced during laser ablation of copper immersed in liquid under tightly focused conditions using shadowgraphy technique

Pulsed laser ablation in liquid (PLAL) has emerged as an efficient method for production of nanoparticles (NPs), especially noble metal NPs. The main advantage of synthesizing NPs by this method is that bare as well as functionalized NPs can be synthesized with great ease. Noble metal NPs have proven to be extremely useful in the fields of biomedicine, sensing technology, energy storage, etc. The properties of such NPs strongly depend on the transient dynamics that occur on the target surface. Hence, in order to control the properties of the NPs and increase their productivity, it is crucial to study the dynamics associated with the technique. Keeping this in mind, a study has been conducted to understand the effect of tight focusing of the pulsed laser beam on the cavitation bubbles generated during PLAL performed on copper (Cu) target using shadowgraphy technique. The results reveal novel dynamics of the formation of cavitation bubbles due to the breakdown of the liquid in addition to the bubble attached to the target. The analysis of such bubbles is carried out and its evolution is studied.

Effect of magnetic field-dependent effective thermal conductivity of melted layer on nanosecond laser ablation of copper and formation of nanoparticles at atmospheric air pressure

For a nanosecond laser ablation of metals, the key physical phenomena involved are thermal evaporation, melt ejection, instability of the molten metal, etc., which depend on the initial temperature evolution in the metal. Understanding the evolution of temperature of the metal needs an effective simulation. In the present paper, we report on the finite element method-based simulation of nanosecond laser ablation of copper in the absence and presence of the magnetic field. Our studies showed that the effective thermal conductivity of the melted layer on the copper surface in the presence of the magnetic field affects the viscosity of the layer, mass ablation rate, instability, and then particle formation. The calculations showed that the condensed nuclei of large critical size are produced in the magnetic field. It is attributed to an increase in the collision rate of plasma particles in the magnetically confined plasma. The simulations are in good agreement with the experimentally measured values.

Cavitation and charge separation in laser-produced copper and carbon plasma in transverse magnetic field

In the present work, we report the dynamics and geometrical features of the plasma plume formed by the laser ablation of copper and graphite (carbon) targets in the presence of different transverse magnetic field. This work emphasizes on the effect of atomic mass of the plume species on the diamagnetic behaviour and geometrical aspect of the expanding plasma plume in the magnetic field. The time-resolved analysis of the simultaneously captured two directional images in orthogonal to the expansion axis is carried out for the comparative study of projected three-dimensional structure of copper and carbon plasma plume. In the presence of magnetic field, sharp differences are observed between the copper and carbon plasma plumes in terms of formation of diamagnetic cavity and structure formation. An elliptical cavity-like structure is observed in case of copper plasma plume which attains the sharp conical shape with increasing the time delay or magnetic field strength. On the other hand, splitted carbon plasma plume appears as a Y-shape structure in the presence of magnetic field where the cavity-like structure is not observed for the considered time and magnetic field. Based on the modified energy balance relation for the elliptic cylindrical geometry, we have also simulated the dynamics of the plume which is in close agreement with observed plasma expansion in diamagnetic and non-diamagnetic regions.

Ultrafast laser ablation of copper by GHz bursts

The ablation of copper, using a 10 GHz burst ultrafast laser with a wavelength of 1030 nm, a pulse duration of 1 ps, a variable total laser fluence, and a number of sub-pulses per burst, is investigated theoretically. A two-temperature model with an extended Lorentz–Drude model for dynamic optical properties is used to simulate the melting and ablation process. Due to the heat accumulation from the preceding pulses, multipulse laser ablation could be advantageous over a single pulse. Moreover, the ablation performance can be maximized by properly selecting the pulse number, separation time, and energy in a laser burst. The numerical result shows that the present prediction is in fairly agreement with existing experimental result. Under the same total laser fluence of 32 J/cm2, a 10 GHz burst laser with an optimized 128 sub-pulse can significantly enhance the ablation depth, 4.2 times that a single pulse does. It is found that the optimized ablation depth is a linear function of the total fluence of ultrafast laser bursts.

Experimental investigation of temperature field and fusion zone microstructure in dissimilar pulsed laser welding of austenitic stainless steel and copper

Laser dissimilar welding of copper/ stainless steel was experimentally conducted to investigate the process parameters influence on the temperature field and formation mechanism of melt pool microstructures. The experimental approach is to estimate the influence of the Nd:YAG pulsed laser process parameters (e.g welding speed, laser power, focal length and laser beam deviation) on the temperature gradient and the resultant metallurgical aspects of the melt pool such as Solidification cracking, copper particle diffusion and microstructure of the fusion zone. Creating the appropriate temperature gradient during welding plays a crucial role to effectively control solidification cracking at the fusion zone in order to reduce heat conduction effect of the copper. Increasing welding speed from 2 to 6 mm/s not only reduces the temperature about 50 °C but also decreased the fusion zone cracking significantly. Evidently, increasing the laser power from 240 to 260 W transmitted the fusion zone cracks toward the stainless steel base due to creating higher temperature about 230 °C and 150 °C for steel and copper respectively. Therefore, higher discrepancy of the temperature field between copper and steel clearly changed the place and pattern of cracks propagation. The EDS analysis of the fusion zone confirms diffusion of copper particles inside the weld pool. The temperature measured near the molten pool region showed that clear discrepancy at the temperature gradient of the melt pool at the copper and stainless steel side has increased the possibility of cracking the stainless steel fusion zone. Also, high temperature gradient for compensating copper high rate of cooling could lead to excessive copper ablation or even diffusion of copper elements into the stainless steel fusion zone.