A thin-disk multipass amplifier in an industrial package provides pulse energy and power scaling up to an average power in the kW regime with 10 mJ compressed pulses or 40 mJ CPA free pulses. The flexibility of the slab (TRUMPF TruMicro 6000 based) seed laser, such as choice of repetition rate, pulse duration, bursts or pulse on demand is maintained. Due to its mechanical and thermal stability, different applications like surface structuring or generation of EUV or X-ray radiation can be addressed.
We demonstrate ultrafast high-power laser operation, both at multi-kW average power in ultrashort-pulsed operation over extended bursts with hundreds of MHz intra-burst repetition rate from a modified TruMicro 6020 industrial laser, as well as uninterrupted, quasi-CW operation at an average power beyond 1 kW obtained with a TEM00 multipass thin-disk laser booster amplifier. The pulse repetition rate can be varied from 50 MHz to beyond 1 GHz, with single-pulse energies well above 10 μJ and single-pulse peak powers far beyond 10 MW without a post-compressor. These systems are attractive, e.g., for high-throughput materials processing or for driving nonlinear processes.
Using lasers for permanent markings is a well-known method and standard in many areas in industrial manufacturing. Various processes on all kinds of materials are used to achieve durable markings, where the content is often serial numbers, codes and company logos. Whereas laser marking processes are mostly easy to handle it becomes challenging if the markings need to fulfill the requirements of the medical industry. The demand for markings in the medical industry is increasing because of the regulations in this sector. The labelling of medical devices with a traceable Unique Device Identification (UDI) code has become mandatory. Laser marking of medical steel needs to fulfill certain criteria where corrosion resistance, a toxicologically uncritical surface and good contrast, are key factors. Standard laser marking systems are reaching their limits to fulfill these criteria. The best choice to accomplish this challenge is the usage of ultrashort pulsed (USP) lasers. The process using USP lasers, fulfilling the criteria of medical industry, is often called “black marking”. We use the TruMicro Mark 2030 G2 S. This laser has the advantage of full flexibility of the important parameters, such as pulse energy, pulse frequency and pulse duration. Due to the great necessity for reliable medical devices, we investigate the effect of varying different laser parameters on the resulting structures of the black marking process on stainless steel in an experimental study. Analyzed is the dependency of the resulting structures on the energy density by varying the laser spotsize. This is adjusted by a parameter in the marking software and can be set continuously. The dependency of the resulting structures on the pulse duration is investigated by varying the pulse duration. The pulse duration is adjusted by a parameter in the marking software and can be tuned in the range of 400 fs to 20 ps at 100 fs increments. The fundamental parameters like beam quality, beam pointing or energy stability are not affected by changing the pulse duration. The fast switching time of < 800 ms enables for intra-process tuning of the temporal energy deposition. Analyzing the results by a Scanning Electron Microscope (SEM) reveals different surface structures. The structures change in its appearance, periodicity, and groove depth. Various of the described structures can give a permanent black contrast and fulfill the requirements of medical industry.
In laser drilling, one challenge is to achieve a high drilling quality in high aspect ratio drilling. Ultra-short pulsed lasers use different concepts like thin disks, fibers and rods. The slab technology is implemented because of their flexibility and characteristics. They bring together both advantages and deliver high pulse energies at high repetition rates. Materials with a thickness > 1.5 mm demand specialized optics handling the high power and pulse energies with adapted processing strategies, integrated in a machine setup. In this contribution, we focus on all the necessary components and strategies for drilling high precision holes with aspect ratios up to 1:40.
Ultrashort-pulse micromachining has found a rising number of applications in numerous industrial and scientific fields. Modern ultrafast lasers like the TruMicro series enable a high degree of pulse parameter flexibility. Yet, this flexibility also brings challenges for optimization due to complexity with respect to endless parameter combinations. Unique laser features such as a fast tunable pulse duration, MHz- and GHz-bursts offer the possibility to address several machining challenges depending on the application. Even for a single application, useful pulse parameters are generally related to the particular process phase. For example, high ablation rates are commonly in contrast to highest surface qualities. In this contribution we focus on applications that benefit from multi-step processes with advanced successive parameter sequences, enabled by fast and controlled intra-process pulse parameter switching. As a result, multiple samples are demonstrated where highest processing speeds are enabled in combination with superior qualities and various surface finishes. Besides an optimized temporal energy deposition for a variety of applications, benefits of ultrafast processing with shorter wavelength, position synchronized output and an integrated hollow-core fiber delivery are demonstrated.
In this contribution we focus on micro-machining of several materials in different processing regimes. The temporal energy deposition is influenced during operation on a femto- up to a microsecond timescale. Using an off-axis microscope, we present camera image sequences automatically obtained during the ablation process, capturing the surface changes during machining, and revealing spatially and temporally resolved developments. This aids in further process understanding such as parameter dependencies and critical process regimes (formation of unwanted surface morphologies). To optimize both productivity and quality, combined processes with successive parameter sequences are demonstrated, enabled by fast and controlled intra-process pulse parameter switching.
The thin-disk multipass amplifier provides pulse energy and power scaling up to more than 100 mJ of pulse energy and average power in the kW regime with a system amplification factor in the range of 100. The flexibility of the seed laser, such as choice of repetition rate, pulse duration, bursts or pulse on demand is maintained. Due to its mechanical and thermal stability, different applications like glass cutting or high harmonic generation for EUV or X-ray radiation can be addressed even in a harsh industrial environment.
Ultrashort pulse micromachining has found a rising number of applications in a variety of scientific and industrial fields. In order to address the growing field of applications, target materials and customer requirements, a high degree of pulse parameter flexibility and ease of integration is needed. The newest generation of the TruMicro Series 2000 delivers unique features such as fast tunable pulse duration, MHz- up to GHz-burst modes in combination with flexible Pulse on Demand and elevated average power of 100W for improved productivity scaling. Three available wavelengths (343nm, 515nm, 1030nm), an integrated hollow-core fiber interface, as well as a new advanced ultrashort pulse laser control, all combined into a new one box optomechanical design with identical interfaces and dimensions opens new paths for cutting-edge applications. The improved flexibility enables fast (<800ms) and controlled (without affecting beam pointing or energy stability) tuning of pulse parameters such as pulse duration, pulse energy, pulse frequency, QCW-mode and pulse spacing up to GHz-bursts (patent pending technology). Inter- as well as intra-process parameter switching offers advanced successive parameter sequences for tailored machining. Combined processes are demonstrated that optimize both productivity (ablation rate) and quality (surface roughness, color, gloss etc.) for ablation of various metals, semiconductors and ceramics by choosing suitable timescales for energy deposition. Automated parameter studies are shown to quickly generate quantitative surface quality characteristics and foster in-depth process understanding depending on pulse parameters. Furthermore, the latest benefits for ultrafast processing employing position synchronized output and the integrated hollow-core fiber delivery with TruMicro Series 2000 are demonstrated.
Ultrashort laser pulses in the deep ultraviolet (DUV) based on nonlinear-optical conversion of NIR solid state sources promise advantages for the machining of wide-bandgap materials such as compound semiconductors like indium / aluminum / gallium nitride (InAlGaN, AlN, GaN), silicon carbide (SiC), zinc sulfide (ZnS), or boron nitride (BN). We present systems providing few-picosecond pulses at 257.5 nm with high average power exceeding 20 W of DUV obtained by frequency quadrupling of our proven TruMicro Series of industrial ultrafast amplifiers. High beam quality and decent lifetime of the DUV optics are demonstrated.
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