Double-pulsed laser ablation with two targets and lasers in a background gas is a method to form nanoparticle complex. Effects of pulse delay between two lasers on plume expansion dynamics are discussed. The germanium and silicon targets were set parallel to each other and irradiated by two YAG lasers. The germanium target was irradiated followed by irradiation of the silicon target with delay time, t d . We found that the expansion distance of delayed silicon plume is enhanced for 2 µs ≤ t d ≤ 50 µs, compared to that when only the silicon target is irradiated. For t d = 200 µs, the expansion distance of delayed silicon plume is similar to that when only the silicon target is irradiated. We discuss the expansion dynamics of the delayed silicon plume based on the effect of the density distribution induced by the primary germanium plume. Our results indicate that the effect of primary germanium plume remains up to about t d = 50 µs, and it disappears by t d = 200 µs.

中文翻译：

---

反激波通过背景气体后激光诱导羽流的膨胀

在背景气体中使用两个目标和激光的双脉冲激光烧蚀是一种形成纳米颗粒复合物的方法。讨论了两个激光器之间的脉冲延迟对羽流膨胀动力学的影响。锗靶和硅靶相互平行，并由两个 YAG 激光器照射。辐照锗靶，然后用延迟时间 td 辐照硅靶。我们发现，与仅辐照硅靶时相比，延迟硅羽流的膨胀距离在 2 µs ≤ td ≤ 50 µs 时有所增强。对于 td = 200 µs，延迟硅羽流的扩展距离与仅照射硅靶时的扩展距离相似。我们根据初级锗羽流引起的密度分布的影响讨论延迟硅羽流的膨胀动力学。