用于制作衍射变色图形的激光干涉打标系统

A Laser Interference Marking System for Making Diffractive Optical Variable Patterns

研制出一种用于在光滑表面制作衍射变色图形的双光束干涉打标系统。采用分束器将高功率脉冲激光分成两束,并聚焦成双光束干涉光场,直接对工件表面进行单脉冲刻蚀,形成周期性微光栅结构。改变干涉光场的取向和干涉光之间的夹角,实现下一次刻蚀,最终实现大面积打标不同取向和不同空频的微光栅构成的衍射变色图形。在不同角度入射光照射下,衍射变色图形产生不同亮度的衍射变色效果。激光波长527nm,单脉冲能量1.0mJ@20ns,打标材料有不锈钢、氧化铬薄膜等,给出了激光干涉打标的实验结果。

A novel two-beam laser interference marking system has been fabricated for making diffractive optical variable patterns on the smooth surface of materials. A laser beam with high-power is split into two beams with equal energy,which are focused to form a spot composed of interference field with bright and dark fringes on the surface of the material. Periodic micro-grating structures are marked with a single shot of laser ablation using interfered two beams. The marks, which are composed of micro-grating structures with different directions and different periods, have diffractive chromatic dispersion effects under the illumination of white light. The wavelength of the laser is 527nm. The energy of the single-pulse laser is 1.0mJ@ 20ns. The materials can be the stainless steel, the chromium and other metals. The experimental results have been given.