Most powerful laser in Prague to spark industrial and scientific advances

Bivoj laser, photo: archive of HiLASE

The most powerful laser in the world is now up and running on the outskirts of Prague. The HiLASE laser centre is the result of Czech-British cooperation helped with European funds. It is hoped that many of the applications that will be tested there will have an almost immediate impact in certain fields such as aeronautics, medicine, and the car industry. Others could contribute to scientific advances further down the line.

Bivoj laser, photo: archive of HiLASE
It’s also hoped that the laser will put the Czech research centre on the map as a leading institution in the sector where the US, France, and Japan are also very active. We spoke to one of the laser research team leaders responsible for both industrial and scientific advances, Antonio Lucianetti. He explained first of all where the name of the laser came from.

“The name of the laser is actually Bivoj and according to the Czech legend Bivoj was so strong that he could catch a wild boar with his bare hands. In physics, however, we measure power in the unit of Watts, so one Kilowatt is one thousand Watts. How can we generate such a large amount of average power? The architecture of our laser is relatively simple. You have a low energy pulse at the beginning which is generated in a so-called oscillator and this pulse is amplified in a series of laser amplifiers with larger and larger apertures. There is a so-called regenerative amplifier, a booster amplifier, and at the end two cryogenically cooled amplifiers. And at the end the output parameters are 100 Joules and 10 Hertz which makes exactly 1 Kilowatt. An interesting feature is the pulse duration. For those not familiar with pulse duration is laser physics, as you know, the second is the measure of time but for these sophisticated machines can generate fractions of seconds so we are speaking about nanoseconds, and one nanosecond is one billionth of a second, so this means extremely short pulses. So this is a brief description of the laser.”

Okay, focusing just on the one Kilowatt, for how long had people been trying to get this sort of power in a laser. And if I could be a bit more exact maybe, I think the important thing with your laser is that it is continuous, it is not one burst of laser power but a continuous stream. Is that correct?

“There is no tool that can do these things with the same precision and accuracy.”

“Yes, yes, it’s correct. Actually this stream is a measure in frequency and as a unit we are using the Herz so actually we have a maximum of 10 Herz which means 10 pulses in a second. This is relatively easy to achieve. The main result here is that the average pulse which is the product of the energy and repetition rate. So to achieve high average power you need higher and higher energy and higher repetition rates. So just to give some numbers, the previous record was 60 Joules and that was achieved at Lawrence Livermore National Laboratory in the Bay Area of San Francisco. I was actually working there as a post doctoral [staff member] there, so I remember the excitement. And this value of 60 Joules remained for about 10 years. And finally we were able to achieve 100 Joules with this strategic partnership with the British laboratory. So it is a world record and now we have a lot of feedback from the scientific community because there are a lot of interesting applications you can do with 100 Joules and those nano second pulses.”

How might that affect research going forward and the world that we live in?

Antonio Lucianetti, photo: archive of HiLASE
“There are two kinds of applications: industrial applications and scientific applications. Let’s start with industrial applications because that is what our institute and research centre is mostly doing at the moment. An interesting industrial application is the so-called laser shock peening (LSP). If you consider the surface of a metal, an ordinary metal such as copper, iron, or steel, the surface is never perfect, it is never flat. If you have a microscope to look very carefully at the surface you will see that there are micro-cracks, very small cracks. Thanks to the LSP these micro-cracks thanks to surface treatment can be removed. A laser pulse is used to strengthen engineering materials and this is interesting for the aeronautical industry for applications such as gears, turbines, or fan blades. Boeing and Airbus are very interested in this process. And I was reading recently that in the next two decades more than 30,000 airplanes with LSP treated engines. So we will probably fly on one of those type of treated planes in the next 20 years, I am pretty sure. So the aeronautical industry…”

I can imagine also that in the nuclear industry this would be interesting because there are problems with the quality of metal in some reactors and if you could have better quality metal this would solve some headaches at the moment…

“Yes, yes, you re exactly right and in Japan this technique was used. It is a very special environment, you have these metals in a radioactive environment and so micro cracks can have a very bad effect on the whole power plant. So this technique is very interesting for the nuclear industry and we are planning to have some collaboration with the local nuclear industry because there have some nuclear power plants here in the Czech Republic. Another interesting industrial application is the cutting or drilling of materials for the automotive and aerospace industry. We have already done some work for the local industry…”

“These protons can be used for a new class of oncology or tumors treatment.”

Could I just stop you there… presumably you can a lot more precisely or is it that you can do it a lot quicker? What is the advantage?

“Yes, yes, both. Because you should think of the laser as a very precise tool when you focus the beam on a small spot you can have something like 50 or 100 microns, which is a tenth of a millimeter. So you have a very sharp and precise knife to cut or drill holes. So you can make very small holes of the order of 100 or 200 microns and this is very interesting for a number of applications in the automotive or aerospace industry. There is no tool that can do these things with the same precision and accuracy.

“Another area where we think that our lasers will be used in the next 10 years is the so-called laser induced damage threshold. As you know, we are using optics, optical elements such as lenses, mirrors etc. And these optical elements are damaged. To give an idea, 30 percent of the cost of this facility is optical components. It’s important to understand how this is happening, why, and so on. This is something unique that we can only do in our facility.

Bivoj laser, photo: archive of HiLASE
“Last but not least, medical applications. This is a very interesting area because society needs doctors and hospitals and we can also contribute because you can increase the resistance of orthopaedic implants for example. These implants are made of special metals and laser treatment will increase the resistance of these implants. Then we have scientific applications. I am a researcher so I am interested in scientific applications and in medical engineering as I would call it. With these lasers which are generating nanosecond pulses, which are relatively long for lasers, you can use our laser to pump another laser which is producing shorter pulses. We are talking about picoseconds. And if these pulses are focused on a target, they can generate high energy protons. And these protons can be used for a new classof oncology or tumors treatment. This is a big problem for many people and we can contribute in this area. Another interesting area is the generation of x-ray sources. Again, when you have a laser beam you can focus on a target and generate x-ray sources with high energy. And these x-rays can be used for advanced imaging and security inspection in airports. This is another critical issue. As you know, we are all travelling more and more and security is one of the biggest issues not just for Europe but for the rest of the world. So this is another big application for the next 10 years.”

So maybe we could go to the background. Why did the Czechs and the British team up on this and how did this partnership evolve?

“We hope there will be spin-off companies or patents and so on.”

“The main reason is that when we received the money, the funding from the Czech government we had only three years to build this laser with a top performance. So, the easiest way was to sub-contract the construction of the laser to a well known British laboratory called CLF which is located near Oxford. During construction we had discussions on various technical issues and we also sent people from the Czech Republic to the United Kingdom. And it turned out to be really successful. And at the end of the project we were both happy and we encouraged our British colleagues to apply for a joint grant to the European Union and finally we got 45 million euros from the EU and Czech government. Now we are in the stage of upgrading our research centre to a centre of excellence. So teaming up with the British was a good idea and we hope that for the next six years or more we will be at the front of laser technology together.”

Ok, it’s basically a research partnership but is there any likelihood that this will be spun off into research businesses or something like that?

“This is technology transfer and this is one area where again we could learn from the British because they have a lot of experience in this area. We will work with them learning the best practices. We will start soon to make our lasers available to the external world because our goal is to serve a broad based scientific and industrial community. Doing this, we hope there will be spin-off companies or patents and so on. So definitely technology transfer is one of the key issues for the next six to 10 years of the research centre.”