You’ve devoted fifty years of your life to lasers. How could a handful of photons hold your attention over the course of half a century?
I’ve always had a passion for lasers and the opportunities they offer. And over the years I’ve often recaptured that feeling of excitement and enthusiasm that thrilled me from the start. I certainly had to overcome plenty of difficulties and setbacks along the way, but that never diminished my passion. If anything, it increased it! Because ultimately it’s the challenges that keep you focused on an idea, even after fifty years.
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Born in 1938 in Bretten, Germany, Dr. Paul Seiler studied precision mechanics at the University of Applied Sciences in Karlsruhe. He is regarded as a pioneer in solid-state lasers for industrial use. From 1992 until 2003, Dr. Seiler was the managing director of TRUMPF Laser GmbH & Co. KG in Schramberg.
When the first laser made its debut on the world stage in 1960, Dr. Paul Seiler discovered a passion for laser tech-nology. As of 1973, his systems of lasers and components were instrumental in combining lasers and machines.
In 2003 Dr. Seiler was award-ed the Baden-Württemberg Business Med-al in recognition of his outstanding achieve-ments. This marked the culmination of his professional career. In 2008 he received an honorary doctorate from the University of Stuttgart.
Lasers in modern watchmaking:
The manufacture of mechanical watches has always demanded extreme accuracy. So it is no surprise that the watchmaking industry relies on laser tools for nearly every subassembly. read…
And yet your first contact with lasers came about quite by chance …
When I finished engineering college in Karlsruhe I started my career at Carl Zeiss in Oberkochen. That’s where, in 1963, I encountered a laser for the very first time while conducting preliminary tests for a range-finding system for tanks. We were already familiar with Q-switched lasers from America. The intensity of the light pulse made it possible to conduct time-of-flight measurements over greater distances in the field. As a lab engineer I was given the task of putting together a test setup with a ruby laser and Q-switching using Kerr cell shutters.
And was when you got hooked?
The test setup filled a whole room, and it took lots of adjustments before the first pulses finally bathed the room in a deep red light. When we saw the emitted and reflected pulses on the oscilloscope screen, it just made our success even sweeter. Making the speed of light visible was a fascinating and defining experience.
You mentioned that it was difficult to get hold of laser-active media in good quality. What other difficulties did you face in the early years of the laser ?
The Americans were already far ahead of us in the 1960s. That meant we already knew virtually everything about lasers, at least in theory, but in fact there were still plenty of unresolved details: resonators for suitable laser-active media, pump configurations including the power supply, measurement techniques for the intensive laser light. Even the stability of the optical components was still unknown at that time. The advantage was that I learned everything there was to know about lasers — and did so very quickly.
And you employed that knowledge to develop your first laser “tool?”
That’s right. It was a microscope laser device and it had all the functions needed to use the laser as a tool. As much as possible, we tried to use components from the Zeiss range of equipment, such as a photomicroscope stand or the zoom lens from a movie camera. The laser-active medium came from Schott, a company affiliated with Zeiss. At that time, Schott was supplying neodymium-doped glass to Lawrence Livermore in the USA for experiments with nuclear fusion. This glass could be used to make long rods, and we were able to polish and coat the end surfaces at Zeiss. The resulting laser rod was therefore an active medium and resonator at the same time, just like the first laser developed by Theodore Maiman.
Then the Osram company, in the nearby town of Herbrechtingen, asked us if it would be possible to use the laser to drill the orifices in diamond drawing dies. We gave it a try — and it worked. Basically, we had found the right laser for an exciting application at just the right time. Sometimes everything falls into place!
You had a secure job at Zeiss and clearly plenty of opportunities, but you decided to move to Haas in 1971. What prompted you to do that?
Everyone said I was crazy because I was planning to give up a secure job with a pension plan, even though I had four kids. But I did it anyway because I felt that Haas offered the opportunity to use lasers in industrial applications. I had a hunch that lasers would be particularly useful in manufacturing technology — it was certainly in a league of its own when it came to welding.
At Zeiss, people’s interest in the laser as a tool petered out when my super visor and mentor Dr. Siegfried Panzer passed away. Lasers as tools simply had no place in the company’s portfolio. I first met Dr. Wolfgang Müller, the head of development at Haas, at a lecture at Esslingen Technical Academy. Zeiss had already carried out successful experiments for Haas in welding flat spiral springs for watches. Dr. Müller told me that Haas was intending to commission the Battelle Memorial Institute with the development of a laser for this application. Right off the top of my head I said, “That’s something I can do, too.”
And so you did!
The first machine incorporating a built-in laser and intended to weld springs automatically was launched in 1973 and was a huge success. The weld was very strong and very precise at the same time, and the process was ten times faster. The machines had been used for adhesive bonding in the past and required only minor modifications, thanks to the laser components system (LCS) which we had developed. The LCS was designed for incorporation into machines, so we tried to sell the system to other companies, too.
You tried to? Weren’t other industrial users virtually begging to use your new laser system?
Unfortunately not. The process was still entirely unknown, and in most cases was only cost-effective with the appropriate automation equipment. And, at least in the immediate “Federle-Haas” environment, nobody had approved a development of that kind. So it was very hard work. I gave presentations, put together brochures and sales materials, and gradually ended up turning into an entrepreneur in my own right.
When did your big breakthrough come?
AEG-Telefunken successfully used our system to automatically weld the cathode components in television picture tubes. The competitors took note of that, since color television was gaining steam and they knew it would be impossible to produce the required quantities without automation. Then the company Philips decided to introduce laser welding on a broader basis. That was a courageous step for the factory in Sittard, Netherlands. That was where all the assemblies for the CRT electron guns were manufactured, so the laser had to be 100 percent reliable. The management sat me down and asked me very seriously whether Haas could be confident of achieving that. My answer was an emphatic yes, and we immediately received an order for six laser systems. Now, that was a cause for celebration for both myself and the Haas laser team, which consisted of just ten people at that time, but it was also a huge challenge.
Philips was our biggest customer, and collaboration was fruitful in many ways, not just in terms of the ongoing technical development. Having such a high-profile customer gave our laser components sys-tem international prestige, and Haas Laser was suddenly a brand name.
The development of the laser light cable was a quantum leap for solid-state lasers. How did it come about?
As so often happens, we had another lucky break. On a trip to Japan, the Philips mechanical engineers discovered that scientists there were attempting to transmit laser light along glass fibers. It was clear this would offer a major advantage when integrating lasers into machines. Philips provided us with the first glass fibers and we used those to develop what we call the laser light cable. But of course this also meant that instead of needing three lasers to weld simultaneously at three points, you now only needed one laser with three laser light cables.
That might have hindered laser sales, but this factor ultimately proved to be a good thing, right?
Exactly. It turned out to be an advantage not only for Philips, but for us, too. Suddenly it was more economical to use laser systems, which gave them a significant boost in popularity.
With the emergence of solid-state lasers in the kilowatt range, laser light cable took on a whole new significance. That development came about through a joint research project run by the German Federal Ministry of Education and Research. At first we didn’t believe that the solid-state laser stood a chance against the CO2 laser in this power range. But when we presented a 2-kilowatt laser with a laser light cable at a 1991 trade show, the carmakers showed interest. The acquisition of Haas Laser by TRUMPF gave us the financial backing we needed to further these devel-opments. If it weren’t for the laser light cable, solid-state lasers would never be as important as they are now, in many areas of industrial manufacturing.
How would you personally sum up the first 50 years of the laser?
They were difficult but very rewarding years. Our personal lives often had to take a back seat, but everyone who has a passion for their work would probably say that. Even now, 11 years after retirement, I’m still just as fascinated by lasers. And when I see how far the laser has come, I’m proud that I always believed in its success.