Study of techniques for efficient nonlinear frequency conversion of fibre lasers to the visible wavelength band

在可见波段缩放激光功率仍然是激光科学家面临的最重大挑战之一，这是由于材料和医学激光加工等领域越来越多的应用需求所驱动的。使用这种波长的传统方法与高功率水平下的操作不兼容，因此需要一种不同的方法。本项目将结合包层泵浦光纤激光器在近红外波段的功率缩放优势和新颖的非线性频率转换方案，研究在可见光波段产生千瓦级激光功率的新策略。该方法提供了在整个可见波段以高功率水平和高整体效率实现前所未有的波长覆盖的前景。该项目将包括对频率转换光纤激光器的物理学进行详细研究，以建立功率缩放策略并确定基本限制。预计开发抑制光纤激光器中不必要的非线性过程和减轻由于光学元件中残余热量而产生的热效应的策略将是该项目的重要方面。该项目的总体目标是开发新一代可见光激光器，其性能水平远远超过目前工业激光加工中使用的最先进技术。

Scaling laser power in the visible band remains as one of the most significant challenges facing laser scientists, motivated by the needs of a growing number of applications in areas such laser processing of materials and medicine. Traditional methods for accessing this wavelength regime are not compatible with operation at high power levels and so a different approach is needed. This project will investigate a new strategy for generating kilowatt-class laser power in the visible band by combining the power-scaling advantages of cladding-pumped fibre lasers in the near-infrared band with novel nonlinear frequency conversion schemes. The approach offers the prospect of unprecedented wavelength coverage across the entire visible wavelength band at high power levels and with high overall efficiency. The project will involve a detailed study into the physics of frequency-converted fibre lasers to establish a power scaling strategy and to determine the fundamental limits. It is anticipated that development of strategies to suppress unwanted nonlinear processes in the fibre laser and to mitigate thermal effects due to residual heating in optical components will be important aspects of the project. The overall ambition of the project will be a new generation of visible lasers boasting levels of performance well beyond the current state-of-the-art for use in industrial laser processing.