now it is not really regarded as unusual. In summary, the opinion of industrialists

today is that the laser has arrived, and they are learning to live and work with it.

Are there any particular applications of laser technology you’ve enjoyed watching develop since your retirement in 1998? There are many applications I have enjoyed working on, but additive manufacturing comes immediately to mind as something special – a game changer in the thinking of how to make things. In the 1980s Rolls Royce asked us to blow powder into the laser beam and so we invented the laser cladding process. It worked so well it became similar to writing with metal, then one day one of my students, Mark McLean, repeatedly overlaid a clad line and produced a wall. One look at that wall, particularly after a metallurgical examination showed the columnar grains running up the wall instead of across the wall – as in a standard casting – showed that we had a serious new manufacturing process on our hands. Mark went onto make a stainless-steel wine glass, and additive manufacturing was

Professor Steen having been awarded the AILU Award in 2005, recognising his outstanding contribution to the industrial use of lasers in the UK

laser from BOC developed by The Welding Institute (TWI). That gave me the most powerful university-based laser in the UK. Students and contracts flowed from this with the wide-open space for research using this entirely new form of industrial energy.

As a pioneer of laser technology for industrial materials processing, how has industry’s view of laser technology changed? The very early years were dominated by numerous small start-up laser companies wishing to sell their lasers and compete to find useful applications at sensible prices, this was the main challenge – a solution looking for a problem. Cutting and welding were the only applications at that time with some curious results. Martin Adams, at TWI, was publishing cutting figures significantly better than everyone else, but because of the atmosphere of competition, this was explained as commercial optimism. Later we came to realise he was able to cut nearly twice as fast as others because TWI had

not the space for the cutting table other than in line with the laser, and the beam polarisation favoured his layout as opposed to those with transverse tables; a feature of optical energy not fully understood in those exciting times. There were many more surprises to be found as we explored this new form of energy! For the next 20 years or so, the reliability and ease of maintenance of lasers improved, with most industries keeping a watching brief on what was going on. I felt at the time I could go to any company and sell the idea of a laser application as a result of this interest.

In the 1990s the fibre laser arrived on the

scene and the game changed. The fibre laser was smaller, required less cooling, had no alignment problems and a superb low- order mode beam. To some extent it was like a dream come true. Today, reliability and quality are taken for

granted, and the only thing holding the laser back now is cost, which is rapidly coming down as more units are required. It used to be good to see the look of awe on people’s faces when you said you worked with lasers,


“In the laser business the rewards can be great, with much excitement and potential novelty at any time”

born. Students of mine over the world have now worked on this promising development. I watch with both amazement and joy at the ingenuity of what is being done with additive manufacturing, and await the day that someone makes a hand-held device, either wire or powder-fed whereby the craft community can actually sculpt in reverse – building things up instead of chiselling material away. The precision is such that in the hands of a craftsman, stunning works of art would be created. If the price is right there would be a huge market for such equipment.

Are you satisfied with how university laser research groups around the world are interacting and collaborating? There is quite a network of friends among my ex-students based at various institutes around the world who have a strong collaboration, while still remaining competitive, which is as it should be.



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