用于激光除草的高功率蓝光半导体模块研制

Development of High-Power Blue Light Semiconductor Module for Laser Weed Control

摘要: 针对激光除草对高功率蓝光激光光源的应用需求，本文设计并研制了一种波长为450 nm的高功率光纤耦合半导体激光模块。基于单管激光器，采用阶梯式空间合束和偏振合束方法实现多路蓝光半导体激光的功率叠加，利用Zemax软件进行光路设计与光纤耦合仿真，结合SolidWorks实现机械结构设计及样机搭建。仿真结果表明，合束光束经聚焦后功率约为120 W，耦合进入芯径100 μm、NA为0.22的光纤后的输出功率为115 W，理论耦合效率约为95.8%；样机实测输出功率达到100.2 W。在此基础上搭建蓝光激光除草实验平台，对麦瓶草和稗草幼苗开展50.9~509.3 J/cm²不同激光剂量的辐照试验。结果表明，两种杂草生长点及茎秆的热损伤程度和处理7天后的死亡数量均随激光剂量增加而提高。在本试验剂量梯度下，麦瓶草在254.7 J/cm²时死亡率达到100%，稗草在305.6 J/cm²时死亡率达到100%，继续提高剂量后死亡率均维持在100%。研究结果验证了所研制百瓦级450 nm光纤耦合蓝光激光用于激光除草的可行性，为高功率蓝光激光器在精准激光除草中的应用及剂量优化提供参考。

Abstract: Addressing the application needs of high-power blue laser sources for laser weed control, this paper designs and develops a high-power fiber-coupled semiconductor laser module with a wavelength of 450 nm. Based on a single-tube laser, the power superposition of multiple blue semiconductor lasers is achieved through stepwise spatial beam combining and polarization beam combining methods. Optical path design and fiber coupling simulation are carried out using Zemax software, and mechanical structure design and prototype construction are implemented using SolidWorks. Simulation results show that the power of the combined beam is approximately 120 W after focusing, and the output power after coupling into a fiber with a core diameter of 100 μm and a numerical aperture (NA) of 0.22 is 115 W, with a theoretical coupling efficiency of approximately 95.8%. The measured output power of the prototype reaches 100.2 W. Based on this, a blue laser weed control experimental platform is established, and irradiation experiments are conducted on seedlings of weeds such as Silene conoidea L. and barnyard grass at different laser doses ranging from 50.9 to 509.3 J/cm². The results indicate that the thermal damage degree to the growth points and stems of the two weeds, as well as the number of dead plants after 7 days of treatment, increases with the increase of laser dose. At the dose gradient tested in this experiment, the mortality rate of Silene conoidea L. reaches 100% at 254.7 J/cm², and that of barnyard grass reaches 100% at 305.6 J/cm². Further increasing the dose maintains the mortality rate at 100% for both weeds. The research results verify the feasibility of using the developed hundred-watt-level 450 nm fiber-coupled blue laser for laser weed control, providing a reference for the application and dose optimization of high-power blue lasers in precision laser weed control.