30 Years of Laser Beam Shape Developments: A Unique Personal Perspective
February 28, 2022
3 min read
Read Christian Dini’s, Civan Lasers’ Europe General Manager, unique perspective of 30 years on the enormous breakthroughs and developments in the laser industry. The changes in the industries, innovators, and visionaries. How lasers were built, How new technologies take place in the industry and more fundamental changes.
Over thirty years ago (OMG, time is flying) as a working student in the labs of Carl Baasel Lasertechnik I got confronted to the topic of laser beam profile and beam quality the first time. I was tweaking laser resonators of CO2 slow flow lasers built on a granite block as big as for a graveyard and flash lamp pumped Nd:YAG lasers. For single mode operation of the YAG, there was a very small aperture that needed alignment inside the Resonator. So, the resonator mirrors, an acousto-optic modulator (Q-Switch) and that aperture needed alignment every time one component was changed somehow. As a customer these days, there was the choice between low wall plug efficient single mode or high M² (Large beam diameter and divergency means large focal spot) multimode for raw power.
On my first job I got in touch with single mode, low M² sealed off CO2 lasers made by Synrad. The founder/owner of Synrad, Peter Laakmann was a strong personality with an even stronger vision of these lasers being built in the thousands. The sealed of technology was considered child’s play by the “real laser community” and typical laser production volumes for any of the suppliers were mostly in the lower several tens a year. It took a few years for the industry to understand the advantages of these compact and reliable sealed-off lasers and also to make the difference between output power and power density. Today these lasers are built in several 10.000’s per year and although we’re talking CO2, the numbers keep growing. So much about Peters vision.
In the 90’s new technologies were introduced. Solid state lasers and fiber lasers, with the latter changing the industrial laser landscape the most. Lasers were built differently and again, it was mainly the vision of one person: Dr. Valentin P. Gapontsev, founder of IPG Laser. I never met him in person, but Peter Laakmann and Dr. Gapondsev both followed a similar idea of reliable, low-cost laser technology to further pave the way for industrial laser use.
On my first job I met another visionary co-founder of a company. Dr. Ephraim Greenfield. He started together with Dr.Jacov Zerem Ophir Optronics as the CTO in Jerusalem and he indirectly contributed a lot to most of the above innovations since he provided sensors for power and energy measurement allowing the laser community to reliably characterize their products under development and in production or in the field. I should include the beam profiler side of the business added later on, Spiricon Inc. in Utah, but I never met the founder of Spiricon though. However, my team at Ophir Spiricon Europe and I worked literally with everyone involved in lasers in the most broadest way of definition in their attempt to characterize their individual laser beam.
And here (are you still with me? 😉), the loop closes today. I met once yet another visionary. Dr. Eyal Shekel, founder of Civan Lasers in Jerusalem. In all these (my) over 30 years of Photonics Industry the laser mode was a given by design. Some beam delivery devices were developed to help demanding applications like laser welding to cope with the material properties. Laser welding is not that straightforward as it may look. Unwanted effects like cracking, humping or porosity are only some of the issues and the current technologies help mitigating some negative effects but still require a lot of compromises. Having witnessed a lot of the research done to resolve these issues there is only so much one can do with a given laser beam, hence priorities need to be set in term of what issue to avoid and which pain to live with.
Here a fundamental change comes into play now. As a result of 14 years of research and more there is the first time ever an industrial laser commercially available that will allow full control over the laser beam profile with MHz speed. What does that mean? Well, within a single application each of the negative effects mentioned above can be addressed individually, literally at the same time. Several beam profiles, each relevant to address one of the issues can alternate in µs and therefore avoid all of the “evil three” that are cracking, pores and humping. Since the beam quality doesn’t suffer from the beam shaping the laser performance remains of the one of a true single mode laser with kW in power.
For the first time ever there is a whole new set of laser parameters allowing the control over the melt pool and keyhole and other effects like cooldown time. For me, this is again the starting point of a new technology level in the Photonics Industry and I am excited to be part of it.