激光加工用半导体激光器的光束变换

考虑不同的激光加工方式对激光功率密度和激光光斑尺寸的要求不同,研究了如何通过调整光路设计实现各种尺寸的聚焦光斑输出,使半导体激光器满足不同激光加工方式的需求.利用ZEMAX光学设计软件模拟半导体激光光路,包括光束整形、准直、聚焦等光束变换方式,实现了多种尺寸的光斑输出.实验中采用16个bar叠加而成的980 nm半导体激光叠阵,阈值电流为6.4A,最大工作电流为84.8A,最大输出功率为1 280 W,总的电-光转换效率为58.9％.准直后快轴的发散角小于4 mrad,慢轴的发散角小于20 mrad.通过实验对该激光叠阵进行光束整形和扩束准直、聚焦,最终实现了功率为1 031 W的激光输出,聚焦镜焦距为300 mm时的聚焦光斑尺寸达1.2 mm×1.5 mm,功率密度达3.8×104 W/cm2,可以用于金属的表面重熔、合金化、熔覆和热导型焊接.

Beam transformation of diode lasers used in laser processing

As diode laser processing for different processing technologies demands different power densities and spot sizes,this paper researched how to get focus spot outputs with different sizes by adjusting optical path design to meet the requirements of various laser applications.By using ZEMAX to simulate the diode laser optical path,including beam shaping,collimation,focus,etc.,several kinds of spot outputs with various sizes was implemented.In the experiment,a 980 nm diode laser stack with the superposition of 16 bars was used by a threshold current of 6.4 A,the maximum operating current of 84.8 A,maximum output power of 1 280 W,and the total electrical-optical conversion efficiency of 58.9%.After collimation,the divergence angles for the fast axis and slow axis are less than 4 mrad and 20 mrad,respectively.Finally,the experiments were performed on the diode laser stack by the beam shaping,collimation and focusing,and a power output of 1 031 W is obtained.Furthermore,the focused spot size has been 1.2 mm × 1.5 mm and the laser power density is up to 3.8×104 W/cm2 when the focal length of focusing mirror is 300 nm.Results show that the laser stack can be used in remelting,alloying,cladding and thermal conductivity-type welding for metal surfaces.