Laser-Induced Explosive Vaporization of Liquids in Contact with a Solid Surface: Fundamental Studies and Applications

CTS-9317708 Grigoropoulos这项建议涉及液体薄膜与脉冲激光加热表面接触时的快速成核和爆炸性汽化现象的新科学和重要技术应用。过热液体亚稳行为的科学只有在毫秒级的近稳态区域才能很好地建立起来。在纳秒时间尺度的快得多的区域内，过热液体可能具有不同的行为，涉及可能的过热、气泡成核和生长动力学以及表面的不均匀成核过程。由于传统的实验技术缺乏速度和灵敏度，直到最近的一项研究才对快速状态下的这种行为进行了研究。PI最近的一项研究提供了使用一种新的同时反射/散射监测方法来研究与脉冲激光加热的固体表面接触的各种液体中气泡的成核和生长的初步结果。进一步的定量实验和建模对于理解所涉及的相变现象是必要的。这些脉冲液膜爆炸汽化现象在工业上的重要应用是可能的。将继续进行实际执行，目标是展示在高科技生产环境中的制造产量和生产率。第一个应用是在“激光清洗”领域，从现代电子和数据存储设备的关键部件中去除微米和亚微米颗粒。其他有待研究的应用包括用于无损评估的光声脉冲产生、增强的激光微加工以及表面的新型图案化掺杂。

ABSTRACT -- CTS-9317708 Grigoropoulos This proposal is concerned with novel science and important technological applications of the phenomenon of rapid nucleation and explosive vaporization of a liquid film in contact with a pulsed laser-heated surface. The science of the metastability behavior of superheated liquids is well established only in the near-steady-state regime at the millisecond time scale. In the much faster regime with a nanosecond time scale, superheated liquids may have different behavior, with regard to the possible superheating, bubble nucleation and growth kinetics, and the inhomogeneous nucleation process at a surface. Such behaviors in the fast regime have not been investigated until one recent study because traditional experimental techniques lack the speed and sensitivity. A recent study by the PI provides preliminary results on the nucleation and growth of bubbles in various liquids in contact with a pulse-laser-heated solid surface using a new simultaneous reflectance/scattering monitoring approach. Further quantitative experimentation and modeling are necessary for understanding the phase change phenomena involved. Significant applications of these pulse liquid film explosive vaporization phenomena in industry are possible. Practical implementation will be pursued with the goal of demonstrating manufacturing yield and productivity in a high-technology production environment. The first application is in the area of "laser cleaning" to remove micron and sub-micron particles from critical parts of modern electronic and data-storage devices. Other applications to be investigated include photo-acoustic pulse generation for nondestructive evaluation, enhanced laser-micromachining, and novel patterned-doping of surfaces.