DIODE LASERS
being able to shape the beam, applications such as beam-cutting become more difficult. Reinl explained that one way around this was
by stacking multiple diodes that produce a different wavelength and combining them using a waveplate – the process is known as multiplexing – and so the power can be improved while keeping the beam quality high. Trumpf’s Jones said that for cutting
applications the other SSL types, such as disk and fibre, possess a higher beam quality and are preferred over diode lasers as they produce better results. However, for brazing and welding Jones thinks customers can and should seriously consider diode technology.
The CTA building in Martin Place, Sydney was the site of projections for the Urban Tree Project as part of Vivid Sydney 2014, which was synchronised with a laser lighting show
said: ‘Te laser entertainment market is one where we are seeing a lot of activity. Tey are eating up these diode lasers for a couple of reasons. Te convenience of the diode lasers is a large part of the reason. In the past, the ion laser projectors that people used were physically larger and required more electricity, cooling, and a larger housing. Regardless of the application, it was not as easy to integrate the laser. Te new lasers are less expensive and much easier to work with. Te reliability of diode lasers is much greater; the older gas lasers would be useable for a maximum of 8,000 hours, but with diode lasers you can typically get around 20,000 hours of lifetime before it requires replacing. It’s a substantially better product to work with.’ He continued: ‘You can also extract more
colours from a diode laser than from traditional sources and this allows you to create much more vivid and beautiful shows. Tis means that a lot of [laser entertainment] companies are advertising that they use diode solutions, and this was certainly one area in which we have seen a surge in the use of the technology.
40 LASER SYSTEMS EUROPE ISSUE 23 • SUMMER 2014 ‘From what we have gathered from several
trade shows, the market is growing across the board. Another new application that we have seen is in 3D printing. Many of the patents for a stereo lithography machine expired and now products are being developed that are at a price point that a typical household can afford, and we are seeing that market segment explode now. So because of diode lasers’ affordability and convenience, new areas and applications are becoming possible.’ At the higher-power end of the
applications for diode lasers, companies are coming up against the issue that as the power increases, the beam quality deteriorates. Perry explained that, with poor beam quality: ‘Te light tends not to be as tightly bound straight out of the diode, and users may have an issue shaping it. We have heard clients say they have issues with the shaping of the beam and so we are looking into it and we have experimented with a couple of projects.’ Without
Preventing a nasty shock It’s not just the higher power sources that have to overcome issues if they are to find new applications. Pangolin’s Perry stated: ‘Smaller product design, more efficient production of the laser, are allowing the diodes to be used in a greater number of consumer applications such as in cars for headlamps. As the technology becomes cheaper, it’s hard to say where the market is going to go, it has an almost limitless potential. I don’t see laser technology going down at all. From all accounts, every industry report shows that it will grow.’ But there are limiting factors for the diode.
Perry warned that the lower-power sources are vulnerable to voltage fluctuations from common phenomena such as electrostatic discharge (ESD), saying: ‘Te internal structure of the diode is what makes it so vulnerable to the discharge. Te new green lasers that are coming to the market are susceptible to ESD. Also UV, VCSEL, higher power IR, and quantum cascade diodes are at risk.’ Perry pointed out: ‘In a manufacturing facility,
coming up against the issue that as the power increases, the beam quality deteriorates
Companies are
there is dust, people walking around, and they may not be wearing the correct clothing. All this can cause a build up of electrostatic charge which could accidently be transferred to the diode, causing either degradation or complete failure of the diode. It can be generated just about anywhere, and is one of the main causes of diode failure.’ To combat this, Pangolin developed Lasorb, which is
attached directly to the anode and cathode of the diode. Perry said: ‘Te main thing that we look for is a change in voltage. Ten Lasorb absorbs this damaging voltage spike before it enters the diode which eliminates the chance of it causing damage.’
@lasersystemsmag |
www.lasersystemseurope.com
Rodney Campbell
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