- For micromachining applications
- Up to 30 W at 355 nm
- Up to 40 W at 532 nm
- Up to 80 W at 1064 nm
- 10 ± 3 ps pulse duration
- Low life-time ownership cost
- For micromachining applications
- Up to 30 W at 355 nm
- Up to 40 W at 532 nm
- Up to 80 W at 1064 nm
- 10 ± 3 ps pulse duration
- Low life-time ownership cost
Features & Applications
- Up to 80 W at 1064 nm
- Optional 532 nm and 355 nm wavelengths (could be all 3 electronically switchable wavelengths)
- Up to 1 MHz repetition rate
- Up to 200 µJ pulse energy
- Short pulse duration 10 ps
- Excellent beam quality M²<1.3
- Versatile laser control and syncronisation capabilities
- Smart triggering for synchronous operation with polygon scanner and PSO
- Monolythic, sealed and rugged design
- Low life-time ownership cost
- Nanosecond pulse duration mode (optional)
- LCD, OLED cutting
- Laser induced forward transfer
- Sapphire structuring and dicing
- Ceramics micromachining
- PCD drilling and tracing
- Silicon scribing
- PET, PP, PTFE, Silicone cutting and drilling
- Various metals
- Brittle materials including glass, ceramics, sapphire and PCD
- PET, PP, PI, PTFE
- LCD, LED, OLED, microLED display panels
- Solar cells
High-energy and high-power water-cooled Atlantic series picosecond lasers are designed for a variety of industrial applications such as LCD or OLED display cutting and drilling, laser induced forward transfer (LIFT), glass and sapphire processing, micromachining of ultra-hard materials, ablation of metals, cutting and drilling of polymers, silicon scribing, solar cell scribing and many more. Superior beam quality parameters, maximum available average power (80W@IR / 40W@VIS / 30W@UV), maximum available pulse energy (200μJ@IR / 100μJ@VIS / 75μJ@UV) and maximum pulse repetition rate (up to 1MHz) are beneficial where high processing quality and high throughput are required.
To tailor laser performance for specific industrial applications, advanced electronics enable external gating (including PSO), synchronization and precise laser triggering as well as instant signal amplitude control. To maintain reliability and assure long-term stable operation in an industrial environment, optical components are installed in a sealed, robust, precisely machined monolithic aluminum block.
Designed for robust, low maintenance operation, Atlantic series lasers offer maximum reliability due to an optimized layout, PC controlled operation, a built-in self-diagnostic system and advanced status reporting.
For industrial high-power UV laser applications, high reliability and low ownership cost of UV components is crucial. To meet these requirements, the optical layouts of Atlantic UV models are optimized for longevity and stable operation in the UV range, resulting in a UV optics lifetime of 8,000 hours.
A unique optional feature of Atlantic high-power lasers is that they can work in both picosecond and nanosecond modes. This 2-in-1 laser solution is beneficial for some materials processing (such as glass or ceramics), where both very high accuracy, low processed surface roughness and high throughput are required at low cost.
|Model||Atlantic 6HE||Atlantic 25||Atlantic 50||Atlantic 80|
|GENERAL SPECIFICATIONS 1)|
|With second harmonics option||532 nm (optional 1064 nm output) 2)|
|With third harmonics option||355 nm (optional 1064 nm and/or 532 nm outputs) 2)|
|Laser pulse repetition rate (PRRL) range 3)||30 kHz||200 – 1000 kHz||300 – 1000 kHz||400 – 1000 kHz|
|Pulse repetition rate after frequency divider||PRR = PRRL / N, N=1, 2, 3, … , 1025|
|Maximal average output power 4)|
|at 1064 nm||6 W||25 W||50 W||80 W|
|at 532 nm||3 W||12 W||25 W||40 W|
|at 355 nm||2 W||8 W||18 W||30 W|
|Pulse energy at lowest PRRL 4)|
|at 1064 nm||200 µJ||125 µJ||165 µJ||200 µJ|
|at 532 nm||100 µJ||60 µJ||85 µJ||100 µJ|
|at 355 nm||75 µJ||40 µJ||60 µJ||75 µJ|
|at 1064 nm||> 300 : 1|
|at 532 nm||> 500 : 1|
|at 355 nm||> 1000 : 1|
|Power long term stability over 8 h after warm-up (Std. dev.) 5)||< 1.0 %|
|Pulse energy stability (Std. dev.) 6)|
|at 1064 nm||< 1.0 %|
|at 532 nm||< 2.0 %|
|at 355 nm||< 2.5 %|
|Pulse duration (FWHM) at 1064 nm||10 ± 3 ps|
|Polarization||linear, vertical 100 : 1|
|Beam circularity, far field||> 0.85|
|Beam divergence, full angle||< 1.5 mRad|
|Beam pointing stability (pk-to-pk) 7)||< 50 µRad|
|Beam diameter (1/e²) at 50 cm distance from laser aperture|
|at 1064 nm||1.8 ± 0.3 mm|
|at 532 nm||2.2 ± 0.3 mm|
|at 355 nm||2.0 ± 0.3 mm|
|Triggering mode||internal / external|
|Pulse output control||frequency divider, pulse picker, instant amplitude control, power attenuation|
|Control interfaces||keypad / USB / RS232 / LAN|
|Mains requirements||100…240 V AC, single phase 47...63 Hz|
|Maximal power consumption||< 2.8 kW||< 2.8 kW||< 3.1 kW||< 3.5 kW|
|Operating ambient temperature||18 – 27 °C|
|Relative humidity||10 – 80 % (non-condensing)|
|Air contamination level||ISO 9 (room air) or better|
|Laser head size (W × H × L)|
|single output 1064 nm||396 × 173 × 755 mm|
|single output 355 nm||396 × 173 × 1000 mm|
|3 outputs 1064 / 532 / 355 nm||396 × 173 × 926 mm|
|Power supply unit size (W × H × L)||553 × 1019 × 852 mm|
|Umbilical length||4 m|
|Classification according EN60825-1||CLASS 4 laser product|
- Due to continuous improvement, all specifications are subject to change without notice. Parameters marked typical are not specifications. They are indications of typical performance and will vary with each unit we manufacture.
- Can be ordered either in a single output or in 2 or 3 separate harmonics outputs versions.
- When frequency divider is set to transmit every pulse.
- See typical power and energy curves for other pulse repetition rates.
- At the lowest PRRL after warm-up under constant environmental conditions.
- At the lowest PRRL under constant environmental conditions.
- Beam pointing stability is evaluated as a movement of the beam centroid in the focal plane of a focusing element.
Drawings & Images
High power, speed and precision processing with picosecond laser and polygon scanner
Picosecond lasers in many cases have shown excellent results of material processing for diverse applications. Limiting issues remains cost and efficiency of the processes.Current developments in high repetition rate lasers provides plenty of laser pulses which are able to ablate the material. However, spatial control of focused laser beam with the high precision is needed.Assessment of Next Scan Technologies polygon scanner LSE 170 (line 170 mm; 1064/532 nm) and Ekspla Atlantic 60 picosecond laser (60 W, 13 ps, 1 MHz). Polygon scanner is equipped with f-theta objective with focal length of 190 mm and provide telecentric imaging over 170 mm long scan line. Laser pulsing was controlled synchronizing it with polygon using SuperSync™ technology from Next Scan Technologies.Applicability of laser-polygon pair in precise laser processing was tested, checking adjustment and corrections options in precise beam spot deposition to the material.
CIGS thin-film solar cell scribing
The picosecond laser Atlantic was used to scribe the thin-film layers in CIGS solar cells with the top contact made of ITO and ZnO. Irradiation with the 355 nm laser radiation has shown better results due to selective energy coupling.
Scribing of a-Si thin-film solar cells
The picosecond laser Atlantic was used to scribe the thin-film layers in ZnO/a-Si/ZnO/glass solar cells.
Thermal control of SZ2080 photopolymerization in four-beam interference lithography
Photopolymerization by four-beam interference lithography on a preheated SZ2080 sample was explored at different initial temperatures of the sample: 20 °C, 50 °C, 75 °C, 100 °C, 125 °C, and 150 °C, and at exposure times ranging from 0.5 s to 5 s. The average laser power selected was ∼100 mW for the 300 ps duration pulses at a 1 kHz repetition rate. The experimental results demonstrate that the higher initial temperature of the sample positively influences the crosslinking of the patterns. These findings will improve polymerization protocols for multi-beam interference lithography.
Nanoscale thermal diffusion during the laser interference ablation using femto-, pico-, and nanosecond pulses in silicon
Laser interference ablation in silicon using femto-, pico-, and nanosecond pulses was investigated. The experimental and computational results provide information about nanoscale thermal diffusion during the ultra-short laser–matter interaction. The temperature modulation depth was introduced as a parameter for quality assessment of laser interference ablation. Based on the experiments and calculations, a new semi-empirical formula which combines the interference period with the laser pulse duration, the thermal modulation depth and the thermal diffusivity of the material was derived. This equation is in excellent agreement with the experimental and modelling results of laser interference ablation. This new formula can be used for selecting the appropriate pulse duration for periodical structuring with the required resolution and quality.
Thermochemical writing with high spatial resolution on Ti films utilising picosecond laser
Related applications: Direct Laser Writing
In this paper, we investigate the local oxidation of titanium thin films under the action of picosecond laser pulses. Periodical structures were recorded by the multi-beam interference scheme utilizing various numbers of laser beams, and the relationship between spatial resolution and the contrast of the structures was studied. The Raman spectra of the laser processing regions confirmed the oxidation even under the action of a single picosecond pulse. An analytical simulation of titanium film oxidation in the interference field was provided, and obtained results are correlated with the experimental data. The results of theoretical modeling show that the thermochemical effects of picosecond laser pulses allow recording periodic structures with a period of 0.65 lines per μm. The demonstrated results are important in the adaptation of technological laser systems for the manufacture of diffractive optical elements.
Laser-Ablated Silicon in the Frequency Range From 0.1 to 4.7 THz
The optical performance of high-resistivity silicon with a laser-ablated surface was studied in the transmission mode in the frequency range of 0.1-4.7 THz. A reciprocal relationship between the transmission brightness and the surface roughness was observed at discrete THz frequencies. The measured dispersion was reproduced by the THz wave scattering theory using an effective refractive index model. No significant differences between the samples processed either with psor ns-duration laser pulses in ambient air or in argon enriched atmosphere were found in the THz regime. It was demonstrated that the majority of optical losses of the silicon with the laser modified surface were due to the scattering of THz waves and not due to the absorption in silicon-compounds formed during the laser ablation.
Irradiation of Diamond-Like Carbon Films by Picosecond Laser Pulses
The picosecond laser irradiation of diamond-like carbon (DLC) film on the silicon wasinvestigated. The DLC films were irradiated by Nd:YVO4 laser with the infrared (1064 nm, fluency 1.02 J/cm2) and ultraviolet (355 nm, fluency 0.79 J/cm2) wavelengths with 1, 10, and 100 pulse numbers per spot. The energy dispersive X-ray spectroscopy and microRaman spectroscopy measurements indicated that the full ablation area of the DLC was narrower than laser beam radius of the 1064 nm wavelength with 10 and 100 pulses. The increase of the oxygen concentration was obtained near the ablation areas after irradiation with the first harmonic. The microRaman and SEM measurements demonstrated that the DLC film was fully ablated in the laser spot when the third harmonic was used. The formation of silicon carbide (SiC) in the center of the irradiated spot was found after 100 pulses.
Direct laser beam patterning technique for fast high aspect ratio surface structuring
New results on development of the Direct Laser Interference Patterning (DLIP) technique using the interference of several beams to directly ablate the material are presented. The method is capable of producing sub-wavelength features not limited by a beam spot size and is an effective method of forming two-dimensional periodic structures on relatively large area with just a single laser shot. Surface texturing speed of DLIP method and the direct laser writing was compared. Fabrication time reduction up to a few orders of magnitude using DLIP was evaluated. The sub-period scanning technique was applied for formation of the complex periodic structures. A new method of laser scanning for fabrication of periodic structures on large areas without any visible stitching signs between laser irradiation spots was tested.
In situ formation and photo patterning of emissive quantum dots in organic small molecules
Nanostructured composites of inorganic and organic materials are attracting extensive interest for electronic and optoelectronic device applications. Here we report a novel method for the fabrication and patterning of metal selenide nanoparticles in organic semiconductor films that is compatible with solution processable large area device manufacturing. Our approach is based upon the controlled in situ decomposition of a cadmium selenide precursor complex in a film of the electron transporting material 1,3,5-tris(N-phenyl-benzimidazol-2-yl)-benzene (TPBI) by thermal and optical methods. In particular, we show that the photoluminescence quantum yield (PLQY) of the thermally converted CdSe quantum dots (QDs) in the TPBI film is up to 15%. We also show that laser illumination can form the QDs from the precursor. This is an important result as it enables direct laser patterning (DLP) of the QDs. DLP was performed on these nanocomposites using a picosecond laser. Confocal microscopy shows the formation of emissive QDs after laser irradiation. The optical and structural properties of the QDs were also analysed by means of UV-Vis, PL spectroscopy and transmission electron microscopy (TEM). The results show that the QDs are well distributed across the film and their emission can be tuned over a wide range by varying the temperature or irradiated laser power on the blend films. Our findings provide a route to the low cost patterning of hybrid electroluminescent devices.
Flexible periodical micro- and nano-structuring of stainless steel surface by dual-wavelength double-pulse picosecond laser irradiation
The picosecond laser-induced ripple formation on the stainless steel surface upon irradiation with linearly-polarized single-pulse and dual-wavelength cross-polarized double-pulse trains in air was studied experimentally. The characteristic switching of the ripple period and orientation were observed depending on the inter-pulse delay in the dual-wavelength cross-polarized double-pulse train irradiation experiments.
Colour-difference measurement method for evaluation of quality of electrolessly deposited copper on polymer after laser-induced selective activation
In this work a novel colour-difference measurement method for the quality evaluation of copper deposited on a polymer is proposed. Laser-induced selective activation (LISA) was performed onto the surface of the polycarbonate/acrylonitrile butadiene styrene (PC/ABS) polymer by using nanosecond laser irradiation. The laser activated PC/ABS polymer was copper plated by using the electroless copper plating (ECP) procedure. The sheet resistance measured by using a four-point probe technique was found to decrease by the power law with the colour-difference of the sample images after LISA and ECP procedures. The percolation theory of the electrical conductivity of the insulator conductor mixture has been adopted in order to explain the experimental results. The new proposed method was used to determine an optimal set of the laser processing parameters for best plating conditions.
Laser-induced selective copper plating of polypropylene surface
Laser writing for selective plating of electro-conductive lines for electronics has several significant advantages, compared to conventional printed circuit board technology. Firstly, this method is faster and cheaper at the prototyping stage. Secondly, material consumption is reduced, because it works selectively. However, the biggest merit of this method is potentiality to produce moulded interconnect device, enabling to create electronics on complex 3D surfaces, thus saving space, materials and cost of production. There are two basic techniques of laser writing for selective plating on plastics: the laser-induced selective activation (LISA) and laser direct structuring (LDS). In the LISA method, pure plastics without any dopant (filler) can be used. In the LDS method, special fillers are mixed in the polymer matrix. These fillers are activated during laser writing process, and, in the next processing step, the laser modified area can be selectively plated with metals.
In this work, both methods of the laser writing for the selective plating of polymers were investigated and compared. For LDS approach, new material: polypropylene with carbon-based additives was tested using picosecond and nanosecond laser pulses. Different laser processing parameters (laser pulse energy, scanning speed, the number of scans, pulse durations, wavelength and overlapping of scanned lines) were applied in order to find out the optimal regime of activation. Areal selectivity tests showed a high plating resolution. The narrowest width of a copper-plated line was less than 23 μm. Finally, our material was applied to the prototype of the electronic circuit board on a 2D surface.
Picosecond Laser Modification of CIGS Active Layer
Cu-chalcopyrite based solar cells such as Cu(In,Ga)Se2 (CIGS) have been established as the most efficient thin-film technology in converting sunlight into electricity. Laser scribed monolithic interconnects are one of the key technologies which will play a significant role in future develop-ments of CIGS technology. Laser scribing is needed to maintain module efficiency by dividing large scale device to smaller cells interconnected in series. CIGS layer is a thermally sensitive material, and laser modification can induce local structural changes of the active layer and significantly modi-fy the electrical properties. Therefore, the laser modified region can act as series interconnect be-tween the adjacent cells. In this study, we investigated the laser modification of the CIGS active layer with picosecond laser. The EDS analysis revealed the increase of Cu/(In+Ga) ratio in laser treated areas while Raman measurements indicated changes in main CIGS peak and formation of the Cu-rich CuGaSe2 phase. Therefore, this resulted in significant electrical conductivity increase in laser-treated areas. Electrical testing of the laser performed P2 micro-welds showed scribe conduc-tivities up to 9.3 Ω·cm which are acceptable for the cell serial interconnection.
CIGS thin-film solar module processing: case of high-speed laser scribing
In this paper, we investigate the laser processing of the CIGS thin-film solar cells in the case of the high-speed regime. The modern ultra-short pulsed laser was used exhibiting the pulse repetition rate of 1 MHz. Two main P3 scribing approaches were investigated – ablation of the full layer stack to expose the molybdenum back-contact, and removal of the front-contact only. The scribe quality was evaluated by SEM together with EDS spectrometer followed by electrical measurements. We also modelled the electrical behavior of a device at the mini-module scale taking into account the laser-induced damage. We demonstrated, that high-speed process at high laser pulse repetition rate induced thermal damage to the cell. However, the top-contact layer lift-off processing enabled us to reach 1.7 m/s scribing speed with a minimal device degradation. Also, we demonstrated the P3 processing in the ultra-high speed regime, where the scribing speed of 50 m/s was obtained. Finally, selected laser processes were tested in the case of mini-module scribing. Overall, we conclude, that the top-contact layer lift-off processing is the only reliable solution for high-speed P3 laser scribing, which can be implemented in the future terawatt-scale photovoltaic production facilities.
Picosecond laser registration of interference pattern by oxidation of thin Cr films
The laser oxidation of thin metallic films followed by its selective chemical etching is a promising method for the formation of binary metal structures on the glass substrates. It is important to confirm that even a single ultrashort laser pulse irradiation is able to create the protective oxide layer that makes possible to imprint the thermochemical image. Results of the thermo-chemical treatment of thin chromium films irradiated by picosecond laser pulse utilizing two and four beam interference combined with the chemical etching are presented. The spatial resolution of this method can be high enough due to thermo-chemical sharpening and can be close to the diffraction limit. Micro-Raman spectroscopy was applied for characterization of the chemical composition of the protective oxide layers formed under atmospheric conditions on the surface of thin chromium films.
Photo-polymerization differences by using nanosecond and picosecond laser pulses
Formation of polymeric pillars by using laser interference lithography is compared for nanosecond and picosecond laser pulses. The experimental results are explained by dynamics of laser-excited radicals. The shape of fabricated structures demonstrates that thermal accumulation and oxygen diffusion from the surrounding air make an influence on polymerization when the pulse duration is in the nanosecond range. By using picosecond laser pulses, the thermal accumulation and oxygen diffusion effects are not important for low repetition rate (500 Hz), and they become relevant only at the repetition rates higher than ≥ 1 kHz. It is shown that thermal accumulation is caused by a low-temperature diffusivity and heat accumulation at the polymer-glass interface, and it plays a significant role in the final shape of the structures fabricated using the nanosecond laser pulses.
Laser processing for precise fabrication of the THz optics
Zone plates with integrated band-pass filters and binary Fresnel lenses designed for the THz spectral range were fabricated by direct laser ablation in metal films and the silicon substrate. Results on the process performance and quality of the products are reviewed. The focusing performance was measured using the THz source that produces the 580 GHz radiation. The beam was directed to the centre of the fabricated optical elements. Zone plates with integrated band-pass filters have shown the double performance in focusing and spectral selection. The dependence of ablation rate and surface roughness on the laser process parameters was thoroughly investigated on the silicon. The depth of the ablated grooves linearly depends on the number of laser scans number with a particular slope for each scanning speed. The process regime with the 125 mm/s scanning speed provided the most precise control over the ablation depth. The topography measurements of the laser fabricated multilevel phase zone plates (Fresnel lenses) with the 10 mm focal length showed good agreement with the calculated topography. The intensity distribution of the focus spots using the laser fabricated 2, 4 and 8 level binary Fresnel lenses showed better focusing performance when more depth levels were applied in the lens production.
Multi-photon absorption enhancement by dual-wavelength double-pulse laser irradiation for efficient dicing of sapphire wafers
The evidence of multi-photon absorption enhancement by the dual-wavelength double-pulse laser irradiation in transparent sapphire was demonstrated experimentally and explained theoretically for the first time. Two collinearly combined laser beams with the wavelengths of 1064 nm and 355 nm, inter-pulse delay of 0.1 ns, and pulse duration of 10 ps were used to induce intra-volume modifications in sapphire. The theoretical prediction of using a particular orientation angle of 15 degrees of the half-wave plate for the most efficient absorption of laser irradiation is in good agreement with the experimental data. The new innovative effect of multi-photon absorption enhancement by dual-wavelength double-pulse irradiation allowed utilisation of the laser energy up to four times more efficiently for initiation of internal modifications in sapphire. The new absorption enhancement effect has been used for efficient intra-volume dicing and singulation of transparent sapphire wafers. The dicing speed of 150 mm/s was achieved for the 430 μm thick sapphire wafer by using the laser power of 6.8 W at the repetition rate of 100 kHz. This method opens new opportunities for the manufacturers of the GaN-based light-emitting diodes by fast and precise separation of sapphire substrates.
Fluorescence Microscopy Study of CdS quantum dots Obtained by Laser Irradiation from a Single Source Precursor in Polymeric Film
Recently the quantum dots (QDs) synthesis from single source precursors (SSPs) showed a potential interest for patterning formation of nano-composites. In this approach the SSPs have to be mixed with a matrix that afterwards is treated selectively to obtain the desired nanocomposite. The study of the generation of the QDs from the SSPs is, therefore, crucial for the definition of its behaviour within the polymeric matrix.
The formation of the CdS QDs via thermolysis of the cadmium diethyldithiocarbamate (CdDDTC) was performed and studied in the presence of a non coordinating solvent such as octadecene (ODE) in presence of myristic acid (MA) as ligand.
The precursor is then studied in combination with the poly(methyl methacrylate) (PMMA) polymer for the generation of the CdS QDs under the laser irradiation within a film. The effect of the laser has been studied both on neat PMMA and on the polymer/precursor blend film with the aid of the fluorescence microscope.
The results are used to identify the optimal laser parameters to obtain the decomposition of the precursor and to evaluate the effect of the laser irradiation on the polymer.
Compact diffractive optics for THz imaging
We present a compact diffractive silicon-based multilevel phase Fresnel lens (MPFL) with up to 50 mm in diameter and a numerical aperture up to 0.86 designed and fabricated for compact terahertz (THz) imaging systems. The laser direct writing technology based on a picosecond laser was used to fabricate diffractive optics on silicon with a different number of phase quantization levels P reaching an almost kinoform spherical surface needed for efficient THz beam focusing. Focusing performance was investigated by measuring Gaussian beam intensity distribution in the focal plane and along the optical axis of the lens. The beam waist and the focal depth for each MPFL were evaluated. The influence of the phase quantization number on the focused beam amplitude was estimated, and the power transmission efficiency reaching more than 90% was revealed. The THz imaging of less than 1 mm using a robust 50 mm diameter multilevel THz lens was achieved and demonstrated at 580 GHz frequency.
Fibonacci terahertz imaging by silicon diffractive optics
Fibonacci or bifocal terahertz (THz) imaging is demonstrated experimentally employing a silicon diffractive zone plate in continuous wave mode. Images simultaneously recorded in two different planes are exhibited at 0.6 THz frequency with the spatial resolution of wavelength. Multifocus imaging operation of the Fibonacci lens is compared with a performance of the conventional silicon phase zone plate. Spatial profiles and focal depth features are discussed varying the frequency from 0.3 to 0.6 THz. Good agreement between experimental results and simulation data is revealed.
Processing of ultra-hard materials with picosecond pulses: From research work to industrial applications
Related applications: Material Processing (Industrial)
The ultrashort laser processing of the cutting tools and cutting inserts from tungsten carbide, ceramic and metal composites (CERMET), and polycrystalline diamond materials was demonstrated, and the ablation rates of mentioned ultra-hard materials were evaluated for a laser wavelength of 1064 and 532 nm. The optimal processing throughput was estimated. Laser manufacturing was performed with the five-axis computer numerical control (CNC) machine and scanner for beam translation with the high speed and the ultrashort ∼12 ps pulse duration high repetition rate laser source. The systematic approach was implemented in an experimental variation of process parameters that play a significant role in processing quality. By varying the laser fluence, pulse overlap, and layers’ count, different material removing rates can be achieved from 300 nm/layer to ∼18 μm/layer. The submicrometer removing rate involves a high precision control of the structure depth. It was demonstrated that only by a minor change of the processing parameters, the surface roughness of the material could be minimized down to Ra < 300 nm. Rough and smooth processing can be combined to optimize the structure processing throughput.
Advanced laser scanning for highly-efficient ablation and ultrafast surface structuring: experiment and model
Ultra-short laser pulses are frequently used for material removal (ablation) in science, technology and medicine. However, the laser energy is often used inefficiently, thus, leading to low ablation rates. For the efficient ablation of a rectangular shaped cavity, the numerous process parameters such as scanning speed, distance between scanned lines, and spot size on the sample, have to be optimized. Therefore, finding the optimal set of process parameters is always a time-demanding and challenging task. Clear theoretical understanding of the influence of the process parameters on the material removal rate can improve the efficiency of laser energy utilization and enhance the ablation rate. In this work, a new model of rectangular cavity ablation is introduced. The model takes into account the decrease in ablation threshold, as well as saturation of the ablation depth with increasing number of pulses per spot. Scanning electron microscopy and the stylus profilometry were employed to characterize the ablated depth and evaluate the material removal rate. The numerical modelling showed a good agreement with the experimental results. High speed mimicking of bio-inspired functional surfaces by laser irradiation has been demonstrated.
Glass dicing with elliptical Bessel beam
In this paper the possibility to optimize the glass dicing process by controlling the axicon-generated Bessel beam ellipticity is presented. Single-shot intra-volume modifications in soda-lime glass followed by dicing experiments of 1 mm-thick samples are performed. The Bessel beam ellipticity is essential for glass dicing process. Such beam generates intra-volume modifications with transverse crack propagation in dominant direction. Orientation of these modifications parallel to the dicing direction gives significant advantages in terms of processing speed, glass breaking force and cutting quality.
Rapid high-quality 3D micro-machining by optimised efficient ultrashort laser ablation
Solid-state lasers with pulse duration of 10 ps and radiation wavelength of 1064 nm were used to investigate the laser ablation efficiency dependence on processing parameters: laser fluence (pulse energy and beam spot size), beam scanning speed, pulse repetition rate, and scanned line (hatch) distance for the copper sample. Utilising a 40 W power laser, the highest ablation efficiency of 2.5 µm3/µJ and the ablation rate of 100 µm3/µs with the smallest surface roughness of 0.2 µm was obtained. Three-dimensional (3D) fabrication using a galvanometer scanner and layer-by-layer removal technique with optimal parameters defined for efficient ablation were demonstrated at a rate of 6 mm3/min. Combination of high material removal rate with excellent quality and complex 3D structure formation is in a high interest for mimicking bio-inspired surfaces, micro-mould fabrication and decorative applications.
Laser-assisted selective copper deposition on commercial PA6 by catalytic electroless plating – process and activation mechanism
Results of in-depth experimental analysis of the laser-assisted local copper deposition on commercial Polyamide 6 (PA 6) are presented. Pico- and nanosecond lasers were validated for surface modification of the polymer followed by silver (I) activation and finished by autocatalytic electroless copper plating on the laser-modified areas. Detailed investigations were dedicated to finding out the origin of selective metal plating, including the surface profiling and wettability dynamics, XPS analysis and electric resistance measurements of the deposited copper layer. Based on the experimental data, the mechanism of the polymer surface activation by the laser modification is proposed.
Mechanism of pillars formation using four-beam interference lithography
Three different experiments were performed in order to determine the mechanism of pillars formation using four-beam interference lithography. The experimental results demonstrate that pillars, fabricated in argon gas, were wider and higher compared with the pillars fabricated in nitrogen gas, low vacuum or air. It clearly indicates that the pillar bottom widening effect is not affected by the depletion of atmospheric oxygen as in all environments the fabricated pillars have a wider bottom part. Moreover, the shape of the fabricated pillars is not affecting by the back reflection from the positioning stage and by the light irradiation conditions. These results clearly indicate that the photopolymerization process is enhanced by the heat current and it determines the pillar bottom widening effect.
High-efficiency laser fabrication of drag reducing riblet surfaces on pre-heated Teflon
Bio-inspired surfaces are able to decrease friction with fluids and gases. The most recognizable are shark-skin-like riblet surface structures. Such bio-inspired surfaces can be formed by the laser ablation technique. In this work, bio-inspired riblet surfaces with grooves were formed using picosecond ultraviolet laser ablation on pre-heated polytetrafluoroethylene (PTFE) at various sample temperatures. The ablation of hot PTFE was found to be 30% more efficient than the conventional laser structuring at the room temperature. The friction of structured PTFE surfaces with the flowing air was investigated by using drag a measurement setup. Results show the decrease of friction force by 6% with dimensionless riblet spacing around 14–20.
Picosecond Pulsed Laser Ablation for the Surface Preparation of Epoxy Composites
As part of a technical challenge under the Advanced Composites Program, methods for improving pre-bond process control for aerospace composite surface treatments and inspections, in conjunction with Federal Aviation Administration guidelines, are under investigation. The overall goal is to demonstrate high fidelity, rapid and reproducible surface treatment and surface characterization methods to reduce uncertainty associated with the bonding process. The desired outcomes are reliable bonded airframe structure, and reduced timeline to certification. In this work, laser ablation was conducted using a q-switched Nd:YVO4 laser capable of nominal pulse durations of 8 picoseconds (ps). Aerospace structural carbon fiber reinforced composites with an epoxy resin matrix were laser treated, characterized, processed into bonded assemblies and mechanically tested. The characterization of ablated surfaces were conducted using scanning electron microscopy (SEM), water contact angle (WCA) goniometry, micro laser induced breakdown spectroscopy (μLIBS), and electron spin resonance (ESR). The bond performance was assessed using a double cantilever beam (DCB) test with an epoxy adhesive. The surface characteristics and bond performance obtained from picosecond ablated carbon fiber reinforced plastics (CFRPs) are presented herein.
High Power, Speed and Precision Processing with Picosecond Laser and Polygon Scanner
Picosecond lasers in many cases have shown excellent results of material processing for diverse applications. Limiting issues remains cost and efficiency of the processes. Current developments in high repetition rate lasers provides plenty of laser pulses which are able to ablate the material. However, spatial control of focused laser beam with the high precision is needed. Assessment of Next Scan Technologies polygon scanner LSE 170 (line 170 mm; 1064/532 nm) and Ekspla Atlantic 60 picosecond laser (60 W, 13 ps, 1 MHz). Polygon scanner is equipped with f-theta objective with focal length of 190 mm and provide telecentric imaging over 170 mm long scan line. Laser pulsing was controlled synchronizing it with polygon using SuperSync™ technology from Next Scan Technologies. Applicability of laser-polygon pair in precise laser processing was tested, checking adjustment and corrections options in precise beam spot deposition to the material.
Corrosion Resistive Laser Marking of Stainless Steel by Atlantic Series Picosecond Laser
Medical tools and other devices made of stainless steel (SS) require laser markings for unique device identification (UDI). These markings need to be corrosion resistant in order to withstand numerous autoclave cycles. EKSPLA with FTMC has developed a picosecond laser marking system – for reliable UDI marks on surgical and spring grade of stainless steel for corrosion resistive applications.