Which types of lasers the future belongs to is the subject of an often heated debate. Depending on the application, there are very different results. The complexity of the ecosystem in which different concepts are trying to assert themselves makes it likely that diversity of different types will continue to prevail for a long time.  Talks on this subject always lead to "standing-room-only" crowds in the lecture hall.

The tension rises when opponents state their cases in extreme terms. Some say that fiber lasers will roll up the market, and rapidly increasing sales figures seem to prove their point. Others claim that disk lasers have greater potential for industry, and indicate corresponding capital expenditures as evidence. Despite all this, conventional beam lasers seem to have a pretty unshakable grip on certain areas of application. But can all of them win?
The different types of lasers mentioned are based on very different concepts, with correspondingly different strengths and weaknesses. For example, disk and fiber lasers are both extremely energy efficient, which reduces the costs of the pump diodes.  However, the effect of higher brightness requirements of pump diodes for fiber lasers on the price remains an area of contention. Both concepts offer good beam quality.  The disk laser probably has a greater potential for high performance, but whether or not this has an effect will depend on the requirements of the applications.  Since multi-kW lasers with higher beam quality have only been available for a short time, it remains unclear what users will decide to do with them.  However, if intensive pulses are required, then the disk laser is definitely more powerful - although the old beam laser could still be better in some cases.
In the end the applications are the deciding factor. These are still much more diverse than the laser itself, and create a confusing and also constantly changing landscape, in which various concepts are trying to assert themselves.  Within this landscape there are a few fields in which different types of lasers are actually running into head-to-head competition. On the other hand, there are also many niches in which one type of laser is clearly superior - not necessarily due to technical potentials, but rather due to economically attractive solutions. For example, despite all the advances with diode-pumped lasers, it still makes sense to use lamp-pumped lasers to create laser pulses with high energies and low repetition rates. And who really cares if a few new lamps are required every few years, especially when it does not cost much to replace them? Of course the situation appears completely different if, for example, high average performance is required in addition to high beam quality.
As complicated as the state of affairs appears to be, it's still possible to venture a prognosis:  In ten years we will see many fiber lasers, but also many disk lasers, and there will continue to be many beam lasers, including ones with lamps. Additionally, there will also be directly deployed diode lasers as well as new types, such as optically pumped semiconductor lasers with external resonators (VECSELs).  In biology it is no different: In diverse habitats with different niches one finds great species diversity - even when it is difficult to foresee how precisely the balance existing between the different species will be transformed by different influences.

Author: Dr. Rüdiger Paschotta, RP Photonics Consulting GmbH
Internet: http://www.rp-photonics.com/
Dr. Paschotta is an expert in the fields of lasers and amplifiers, non-linear optics, fiber-laser optics, and ultra-short laser pulses. Through his company RP Photonics Consulting GmbH, he supports other companies in the field of laser technology and photonics with product designs, feasibility studies, independent assessments and customized training programs.