Last week something clever came up at a conference at Stanford: Gérard Mourou said that in the field of lasers there are no boundaries, only horizons. I think that's a very good phrase. The business is now at about 7 billion dollars and expanding. It's not going to keep on growing as fast as it did in the past, but there are still some exciting opportunities.

There's a limit to what a market analyst can forecast. Of course we can imagine a killer application, but to me there has to be a clear path to it. It can't be entirely imaginary. I'm a market analyst, not a cheerleader. One vision that's exciting and extremely challenging is laser-based fusion energy reactors. To me this is not science fiction because the path is entirely conceivable. It would be tremendous if we could achieve that in 20 to 30 years. And that's what Mourou is about. He is the head of the European project Extreme Light Infrastructure (ELI) that is building the world's largest peak power laser. It's in the exawatt class - that's a billion gigawatts. One thing this laser might be able to do is to complement linear particle accelerators to explore fundamental physics. Another exciting development is the highest-energy laser in the world, at Lawrence Livermore National Laboratory. It covers three football fields and its purpose is to try to achieve fusion energy. These are generational projects which will be remembered after the next 50 years.

With regard to technologies, there are no revolutionary, only evolutionary changes going on. There's a lot of room for progress in diode lasers*. Especially in high-power diodes there could be incredible success. Another thing that is happening now is that fiber lasers are developing quickly, as are ultra-fast lasers. They are using new wavelengths, too - such as green or ultraviolet lasers. These technologies have taken longer to come to maturity. The challenges are known but it takes time to get there and this process is going to continue.

There will certainly be surprises on the applications side, but mostly the changes will be evolutionary, too. If you sit back and look 50 years into the future, the big question is: what will be the biggest challenges in the world that technology could address ? One is health care. The laser will change how we come up with new and cheaper pharmaceuticals, how we treat and diagnose illness. It's not that photonic technology will change medicine as we know it, but it will help lead to some great breakthroughs. Another issue is security: systems that can sense intruders, that make your computer safer. I sincerely believe that the world in 50 years will be a completely different place. Security will be a much bigger part of our lives. The next big issue is resources: energy, water, clean air, rare minerals. Lasers can help with environmental monitoring, solar panel and fuel cell manufacturing, and grand challenges like fusion energy. Finally, there's mass customization. That sounds like a paradox, but it's not. Lasers can do volume production and allow for flexible manufacturing. The few global players that are pushing these developments ahead now will also be the main players in the future: Germany as well as North America. China is catching up but won't be able to capture the highperformance laser market.