Industrial Laser Applications Research Articles

Research and integrate laser marking system on plastic materials using 355 nm UV laser

This article presents the results of research, design and integration of a laser equipment system on plastic materials using a UV laser of wavelength 355 nm, power of 5 W, integrated from semi-finished modules available on the market. The research team investigated the influence of technical parameters on the UV laser engraving process on plastic materials such as wavelength, output laser power, pulse width, engraving speed, engraving area size, electricity source... As a result, the research team has come up with a set of parameters for the manufacturing equipment system for a number of specific plastic materials. Some experimental UV laser engraving products on plastic materials of the manufactured equipment system show images with high sharpness and contrast, small heat-affected areas, can engrave sizes as small as micrometers, with a high speed. Research results showed that UV laser equipment is a good choice for laser applications in the semiconductor industry, micro-mechanics, medicine and peripheral equipment...

Electro-optic solution to overcome the transient regime of a cavity dumped UV laser source?

Laser marking is one of the main industrial applications of lasers. To mark many materials or to obtain patterns of small dimensions, triggered pulsed solid laser sources are increasingly used emitting in the fundamental in the infrared and to which two nonlinear (NL) stages are added to obtain an emission in the UV. The conversion efficiency as well as that of the marking then depends mainly on the peak power of the UV pulses generated. One of the solutions for obtaining a higher peak power is to reduce the duration of the laser pulses. To do this, it is possible to change the architecture of the laser cavity by switching from a Q-Switch operating mode (QS) to a cavity dumped mode (CD). With this architecture it is thus possible to reduce the duration of the pulses by an order of magnitude. This peak power gain is unfortunately achieved at the cost of a very long transient regime, up to a few tens of milliseconds, compared to the classic QS which generally only occurs for the first laser pulse. Unfortunately, laser marking is by nature based on chopped operation for the laser, which corresponds to working permanently in a transient state. Marking with a CD architecture laser is then often full of defects and therefore unacceptable in terms of quality. After a study of the problem specific to the use of a UV source with CD architecture in the context of marking, we propose an original solution to dissociate the chopped regime, specific to marking, from the transient regime of the laser. This solution is based on the use of an RTP (Rubidium Titanyle Phosphate RTiOPO4) electro-optical crystal placed between the laser output and the NL stages. This crystal is driven like a half-wave plate by high voltage square pulses of a duration corresponding to the duration of the marking laser pulse trains. This thus makes it possible to obtain laser operation in a stabilized regime, therefore outside the transient regime, and simultaneously chopped operation characteristic of laser marking. The new operating mode obtained is characterized in detail with the new marking performances which prove to be optimal and compatible with the requirements of a quality marking. In addition to making the CD architecture compatible with laser marking, this solution also makes it possible to adjust the average power, and therefore the energy of the laser pulses to adapt it according to the materials and this without changing the thermal behavior of the laser. Last advantage, by adjusting the extinction voltage applied to the RTP outside the cavity, it is also possible to keep a few milliwatts of the marking laser beam as the aiming beam, with the certainty of perfect alignment with the full power beam.

Effect of annealing by CO2 laser on Structural and optical properties of zinc oxide thin films prepared by Sol – gel method

Laser heat treatment is one of the important industrial applications of laser and being studied at the present time as a substitute for conventional thermal annealing. In this research (ZnO) thin films have been deposition on a glass by (Sol - Gel / Spin Coating) technique and annealed by two ways, the first one using a convection oven, where they were annealing with three temperatures (400, 500, 600) °C for one hour, and the second way using a continuous (CO2) laser with (10.6 μm) wavelength and (10 W) power and three intervals (10, 15, 20) min, were studied structural and optical properties of membranes prepared by both ways to determine the effect of laser annealing on them, and the results of (XRD) tests showed that these membranes with the structural of multi-crystalline hexagon compact type and increase the degree of temperature oven annealing, as well as increasing the duration of the laser annealing lead to increased volumes of granular membranes rates. The results of the (AFM) tests to the topography of the surfaces of the membranes to be of crystalline uniformity and homogeneity superficially good, especially for laser annealed membranes. The results of optical examinations of these membranes also showed that they having high permeability, especially in the regions of the visible spectrum and the near-infrared and increased with increase the degree of oven annealing temperature and the duration of laser annealing, and less energy gap of these membranes values with increase the temperature degree of annealing or increase of laser annealing time, In addition the optical properties studied in this research included absorbance, reflectivity, refractive index, coefficients of absorption and extinction, and real and imaginary dielectric constants.

Applications of lasers in industries and laser welding: A review

Laser can be focused up to 1/1000 of a millimeter. Laser machining is clean, and free from post machining burrs. Laser technologies are highly effective and efficient in industries which has created a massive impact in manufacturing. Laser is versatile, it can be performed efficiently on a large range of materials, High precision, speed, and quality of laser machining are a few advantages of this technology. The compatibility of this technology makes it extremely convenient to incorporate into industrial lines. The utilization of Laser Technology to improve precision in production, increased automation substituting the conventional methods, which would have various drawbacks in reflected through this review paper. This review paper compiles the impact of various laser sources, industrial applications of laser on industries over conventional methods. It also summarizes the Laser Welding being used in the industries for précised manufacturing. The precision and quality of laser welding is also demonstrated by performing bead-on-plate weld on steel.

Tailoring surface topographies on solids with Mid-IR femtosecond laser pulses

Irradiation of solids with ultrashort pulses using laser sources in the mid-infrared (mid-IR) spectral region is a yet predominantly unexplored field that opens broad possibilities for efficient and precise surface texturing for a wide range of applications. In the present work, we investigate both experimentally and theoretically the impact of laser sources on the generation of surface modification related effects and on the subsequent surface patterning of metallic and semiconducting materials. Through a parametric study we correlate the mid-IR pulsed laser parameters with the onset of material damage and the formation of a variety of periodic surface structures at a laser wavelength of λL = 3200 nm and a pulse duration of τp = 45 fs. Results for nickel and silicon indicate that the produced topographies comprise both high and low spatial frequency induced periodic structures, similar to those observed at lower wavelengths, while groove formation is absent. The investigation of the damage thresholds suggests the incorporation of nonlinear effects generated from three-photon-assisted excitation (for silicon) and the consideration of the role of the non-thermal excited electron population (for nickel) at very short pulse durations. The results demonstrate the potential of surface structuring with mid-IR pulses, which can constitute a systematic novel engineering approach with strong fields at long-wavelength spectral regions that can be used for advanced industrial laser applications.

3D beam shaping methods for ultrashort‐pulsed laser material processing

AbstractUltrashort‐pulse (USP) lasers enable microlevel manipulation of material surfaces and work on the bulk of transparent materials with almost no thermal effects. One major bottleneck that is limiting the processing speed with USP lasers is the effective spreading of laser energy in the processed material. Diffractive optical elements (DOE) are a leading method of solving this bottleneck. In this article, we review the concept of 3D diffractive light shaping for USP lasers and show its usefulness in various industrial USP laser applications.

PECVD-derived graphene saturable absorber mirror for 2.8 μm pulsed Er:ZBLAN fiber laser

Graphene has been emerging as an ideal mid-infrared saturable absorber (SA) due to its broadband absorption, ultrafast nonlinear optical response, high stability and thermal tolerance. However, the current routes (e.g. chemical vapor deposition and spin coating) for constructing graphene SAs are suffering from the limited flexibility in substrate choice and the introduction of impurities during the transfer process, resulting in poor film quality and unstable laser modulation. Here, we demonstrate a high-quality graphene SA mirror (GSAM) grown directly on calcium fluoride (CaF2) substrate by a low-temperature plasma enhanced chemical vapor deposition (PECVD) method for mid-infrared pulse modulation. The controllable growth of high-quality graphene film on the nickel-modified CaF2 substrate is realized by adjusting the growth time and hydrocarbon ratio during PECVD process. Consequently, the GSAM shows excellent nonlinear optical absorption with the modulation depth of 11.2%. By inserting the GSAM into the Er:ZBLAN fiber laser, a stable passive Q-switched (QS) operation can be achieved with an average output power of 142 mW and a pulse width of 300.2 ns. The slope efficiency of QS laser is up to 17.4% and the peak power is 7.76 W. Our strategy paves the way for developing high quality and modulation stability GSAM towards industrial applications of pulsed mid-infrared lasers.

A fast self-calibration method of line laser sensors for on-machine measurement of honeycomb cores

Line laser scanning is an effective method used to measure the 3D shape of machined honeycomb core surfaces. The lack of laser-sensor calibrations in 3D space relative to the machine coordinate system restricts the industrial applications of line lasers for on-machine measurements. In this paper, a sensor calibration method based on scanning a honeycomb core itself is proposed. The sensor rotational errors are reversely calculated from the data dislocation originating from the sensor without calibration, and then calibrated by mechanical adjustment and numerical compensation. The sensor calibration parameters are determined once rather than performing data stitching one by one, greatly improving the operation efficiency. The sensor calibration effect is verified from the data seam analysis with and without sensor calibration as well as without stitching, and the comparison results demonstrate that the proposed method is effective in solving the misalignment of the measurement data after stitching. The experimental stitching error verified through a solid block is less than 8 μm. The proposed self-calibration stitching method possesses advantages in large-sized on-machine measurements of honeycomb cores.

Characterisation of the stability and long-term evolution of the properties of a 45TW laser operating at 10Hz

Industrial quality applications of high-power lasers working at high repetition rates, including laserdriven particle acceleration, will require laser systems capable of operating in a stable and prolonged manner. Several factors can affect this stability, including the environment conditions, such as temperature or humidity, and the progressive heating of the optical components involved. Here we report on the evolution of the main laser parameters for a 45TW system operating at 10 Hz, showing that a significant change in the wavefront and direction of propagation, even when the laser energy remains sufficiently constant. These results highlight the importance for future laser systems to integrate closed-loop beam tracking diagnostics that can correct the temporal evolution.

Effect of Nd:YAG laser on the optical properties of nanoparticle CuO solutions

One of the most important industrial applications of lasers is the treatment of materials. In this work pulsed Nd:YAG laser of wavelength (1064 nm) was used to precipitate the prepared solution of CuO nanoparticles in the form of thin films using energies (300, 400, 500 and 600 mJ) at a distance (10 cm) and for an irradiation period (20 s) for each energy. The optical properties of the material were examined, which include transmittance, absorbance and some other optical constants, in addition to calculating the optical energy gap and knowing the effect of increasing the laser energy on its values.

New beam deflection technologies for ultra short pulse lasers

Ultra short pulse lasers pose new challenges on the beam deflection technologies. In this paper we present three recent developments that have an impact on the application of ultra short pulse lasers in industry. The three technologies include:This scanning solution extends a laser scan system‘s working field by simultaneously controlling and moving a scan head and an XY-stage, thus delivering clear laser processing advantages, such as high processing throughput with an unprecedented level of accuracy. Process accuracy significantly improves, too, because a scan system‘s positioning error rises linearly with the image field size. The XL SCAN solution‘s combined motions at higher accuracy will use a smaller image field, thereby reducing this error.This micromachining sub system enables laser micro processing and drilling of flexibly variable geometries as well as laser cutting and structuring. Designed for ultra-short-pulse (USP) lasers, bore holes and cutting edges are exceptionally clean cut and don’t require post-processing.The achieved identical dynamics of all three axes now opens up entirely new processing strategies and opportunities. Furthermore, this new technology uses only reflective optical components. This allows using different wavelengths without dispersion and reduces thermal lens effects at power laser applications.

Ionisation processes and laser induced periodic surface structures in dielectrics with mid-infrared femtosecond laser pulses

Irradiation of solids with ultrashort pulses and laser processing in the mid-Infrared (mid-IR) spectral region is a yet predominantly unexplored field with a large potential for a wide range of applications. In this work, laser driven physical phenomena associated with processes following irradiation of fused silica (SiO2) with ultrashort laser pulses in the mid-IR region are investigated in detail. A multiscale modelling approach is performed that correlates conditions for formation of perpendicular or parallel to the laser polarisation low spatial frequency periodic surface structures for low and high intensity mid-IR pulses (not previously explored in dielectrics at those wavelengths), respectively. Results demonstrate a remarkable domination of tunneling effects in the photoionisation rate and a strong influence of impact ionisation for long laser wavelengths. The methodology presented in this work is aimed to shed light on the fundamental mechanisms in a previously unexplored spectral area and allow a systematic novel surface engineering with strong mid-IR fields for advanced industrial laser applications.

Green High‐Power Disk Lasers and Industrial Applications

AbstractIn the publicly‐funded ProLasKu project, the laser manufacturer Trumpf has developed a high‐power laser with a wavelength of 515 nm. Substantial progress in the industrial applications of green lasers has been achieved in a cooperation between the Technical University of Munich and the companies Siemens and Continental. In addition, a camera‐based system for process monitoring and quality assurance in real‐time based on image processing methods has been developed.

Parameters Affecting the Welding of Transparent Materials Using Femtosecond Laser Pulses

There is a pressing need for an accurate process in industrial laser applications such as welding transparent materials. Femtosecond laser pulses, which depend on the nonlinear absorption properties, can be utilized to weld transparent materials. This technique can be applied not only in welding different transparent materials such as glass and polymers, but also in welding opaque materials such as metals, depending on the selection of an appropriate laser wavelength. The parameters that affect the technique such as Keldysh parameter, pulse energy, pulse repetition rate, pulse duration and nonlinear absorptivity were studied. To explain the welding process, an example of an experimental setup and its requirements was described. Besides that, the challenges for the welding process and their voids were also discussed.

Simultaneous 3-D Surface Profiling of Multiple Targets by Repetition Rate Scanning of a Single Femtosecond Laser

We present an integrated scheme of 3-D surface profile measurements made at multiple sites concurrently by employing only a single fiber femtosecond laser as the common light source of low coherence scanning interferometry. This versatile use of an ultrashort mode-locked laser is enabled by linear scanning control of the pulse repetition rate on the source site, while diverse forms of unequal-path, non-symmetric measurements are taken with nanometer precision for different targets simply by delivering fr-scanned pulses through a fiber network. This proposed scheme has no restriction on the number of interferometer sites being integrated concurrently, allowing more diverse industrial applications of ultrashort lasers despite increased system cost and complexity.

Expected X-ray dose rates resulting from industrial ultrafast laser applications

An analytical model is presented, which allows estimating the expected dose rates resulting from X-ray emission from ultra-short-pulse laser-produced plasma under industrial conditions. The model is based on the calculation of the Bremsstrahlung spectrum in the X-ray region between about 5 keV and 50 keV, which is created by the hot electrons in the plasma. The model was calibrated with both spectral and dose rate measurements. The scaling of the hot-electron temperature and the fraction of hot electrons in the plasma served as calibration values. The agreement between experiments and model for the investigated irradiances in range from 1012 to 1015 W/cm2 is excellent. The expected dot{H}(0.07) and dot{H}(10) dose rates at a distance of 20 cm from the process in air were calculated for upcoming lasers with 1 kW of average power. Although the dose rates close to the plasma significantly exceed the allowed dose of 50 mSv per year for an irradiance exceeding about 2·1015 W/cm2, the calculations show that shielding with a 2-mm sheet of iron already at a distance of 20 cm attenuates the radiation to a safe value below 0.4 µSv/h.

The First International Conference on Particles, Materials and Energy: Advanced Medical and Industrial Applications

PrefaceResearch Activities in Particles, Materials and Energy are considered nowadays as the pillars on which recent and future developments of human civilization are founded. Fruitful results of these activities should drastically improve the quality of human life and help in protecting the environmental balance on earth. The main objective of the present conference is to discuss very recent original investigations carried out in the areas of particle and astrophysics with possible existence of antiuniverse and antigravity, nanomaterials synthesizing and characterization, nuclear energy, sustainable energy and radiation protection. Special attention is devoted to medical and industrial applications of Laser and treatment of defects in solids via positron annihilation techniques.The scientific activities of the conference were displayed as Keynote Lecture given by a Leading International Invited Scholar, Plenary Talks presented by Invited Speakers, Regular Talks presented by distinguished participants and oral presentations of few selected s. The Poster Session is devoted to all other accepted s.The sessions of the Conference covered the following topics:TOPIC 1: Medical and Industrial Applications of LaserTOPIC 2: Particle and AstrophysicsTOPIC 3: Positron and Positronium PhysicsTOPIC 4: Materials CharacterizationsTOPIC 5: Nanomaterials and Nano TechnologyTOPIC 6: Nuclear Plants and Sustainable EnergyTOPIC 7: Radiation Physics

Room-temperature bonding with post-heat treatment for composite Yb:YAG ceramic lasers

There are many advantages of composite transparent ceramic materials in laser applications; hence, methods to improve bonding toughness are of great interest for scientific and industrial applications of high average-power lasers. We used a combination of room- temperature bonding (RTB), involving a fast-atom beam surface treatment and diffusion bonding via post-heating, to fabricate laser materials suitable for a variety of oscillators/amplifiers. Yb:YAG/YAG composite ceramics and Yb:YAG/sapphire hetero composites were fabricated by RTB. The continuous wave laser oscillation performance with a Yb:YAG/sapphire composite disk was superior to that without a sapphire heat-conducting layer. The post-heated Yb:YAG/YAG composite ceramics exhibited a bending strength of 470 MPa which was 8.9 times as high as that of similar composite ceramics fabricated by usual diffusion bonding. We optimized the post-heating conditions of the Yb:YAG/sapphire hetero composite, including the maximum temperature and heating time course to avoid crack generation.

“Industrial applications of lasers” at the University of Vigo as legacy of Professor Mariano Pérez-Amor

From the early days in a modest laboratory equipped with a low power CO2 laser, more than thirty years have gone under the direction of Prof. Mariano Pérez-Amor first and Prof. Juan Pou Saracho later, transforming the initial status of the young research group to the current one under a watchword: supportive team work. During these years we have diversified our research areas, including processes at the nano-scale, processing and synthesizing materials of diverse nature, as well as introducing and patenting new laser-assisted processes and opening horizons to some laser applications well-established in the industry. All of it, with the commitment of our founder, the team that he has formed, in constant renewal, and the collaborating researchers in other national and international centers supported with public and private funding from different regional, national and European organizations.This paper is a modest tribute to Prof. Mariano Pérez-Amor who passed away on January 14th 2018.

From PV to bio: Surviving the photovoltaic bubble at laser centre UPM

Laser Centre UPM is one of the leading Research Centers in Spain in the field of industrial applications of high power lasers. Founded in 1998 in the oldest and largest Spanish Technical University, Universidad Politécnica de Madrid, its activity is focused in technological transfer of laser-based processes to industry. With an important experience in laser micromachining using fast and ultrafast lasers, one of the fields in which its activity has produced more relevant results is laser process development for photovoltaic (PV) industry. Starting in 2004, its activity in this field in collaboration with other public Spanish institutions and other industrial partners has had a remarkable scientific and technological impact. Unfortunately, this activity was seriously restricted since 2010 due to the economic crisis in general and the photovoltaic industry evolution in particular. However, the background acquired in some particular applications and the inertia obtained with that activity has opened new fields of activity of Laser Center UPM in advanced laser-based processes for biomedicine. This paper summarizes the main achievements of Laser Center UPM in PV and how it performed the transition to new applications in a completely different sector, like biomedicine, using the experienced accumulated in the development of new laser based processes for PV.