High power erbium fibre laser for laser cleaning applications

激光清洗是一种高效、环保的非接触式方法，可用于去除人造结构上的油漆和不必要的表面污染，以提高寿命、性能和外观，而无需使用化学品、水或研磨机械工具。由于其功率缩放优势，基于镱或钕的脉冲光纤激光器和固态激光器已成为激光清洁的首选激光器，现在有许多商业产品服务于该市场。然而，这些激光器的缺点在于，在眼睛损伤开始之前的最大允许曝光（MPE）极限相对较低，因此，激光清洁操作被限制在封闭环境中。该项目将研究一种新的策略，用于缩放光纤激光器以满足激光清洁的需求，但在波长带（~1.55 - 1.6 um）中，MPE限制远高于~1 um激光器的数量级。这将允许在户外场景中部署，而不需要外壳，允许激光清洁在更广泛的情况下使用。如果成功，这将彻底改变激光清洁，并打开前景，甚至更多的应用成为可能，由于大大放松的安全考虑。在激光性能方面，目标是开发一种激光功率缩放技术，该技术可以提供能量在~10-100 mJ范围内的脉冲输出，持续时间<50 ns，平均功率在几百瓦到千瓦范围内，如预期应用所需。

Laser cleaning is an efficient and environmentally-friendly non-contact method for removing paint and unwanted surface contamination from manmade structures to improve longevity, performance and appearance without the need for chemicals, water or abrasive mechanical tools. Owing to their power scaling advantages, pulsed fibre lasers and solid-state lasers based on ytterbium or neodymium have become the lasers of choice for laser cleaning and there are now a number of commercial products serving this market. However, these lasers suffer from the shortcoming that the maximum permissible exposure (MPE) limit before the onset of eye damage is relatively low and, as a consequence, laser cleaning operations are restricted to enclosed environments. This project will investigate a new strategy for scaling fibre lasers to meet the needs for laser cleaning, but in a wavelength band (~1.55 -1.6 um) where the MPE limit is well over an order-of-magnitude higher than for ~1 um lasers. This will allow deployment in outdoor scenarios, without the need for an enclosure, allowing laser cleaning to be used in a much wider range of situations. If successful, this will revolutionise laser cleaning and open up the prospect of even more applications made possible due to the greatly relaxed safety considerations. In terms of laser performance, the goal will be to develop a laser power scaling technology that can deliver pulsed output with energy in the range ~10-100 mJ, duration <50 ns and average powers in the few hundred-watt to kilowatt regime, as required for the intended applications.