Investigation of the interactions between femto-second pulse laser and ultrapure water

飞秒脉冲激光与超纯水相互作用的研究

基本信息

批准号：
20246037
负责人：
SAITO Takayuki
金额：
$ 31.62万
依托单位：
Shizuoka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2008
资助国家：
日本
起止时间：
2008 至 2010
项目状态：
已结题

项目摘要

Femtosecond-pulse lasers (fs pulses) cause very interesting phenomena due to their extremely high energy density. The effects on substances are not thermal, but multi-photon absorption. When this multi-photon absorption of fs pulses operates on water, extraordinary phenomena different from laser-induced cavitation by a usual laser such as a nano-pulse laser are induced. In the present investigation, fs pulses of 50-150fs in duration, 1kHz in repetition rate and 0.2-1.4μJ in pulse energy were focused at ultrapure water in a glass cell through several types of lens. The fs pulses split from original beams through a beam splitter were used as probe light. The femtosecond-order time-resolved optical measurement was realized by adjusting a light path length of the probe light (fs pulses). By effectively using this measurement technique, we elucidated the changes of refraction index of the water, the bubble nucleation and growth processes at an interval of femtoseconds, and the bubble properties at an interval of milliseconds. Based on these results, we have elucidated a relationship between those and fs-pulse peak intensity. In addition, we investigated the nucleation and growth processes in femtosecond- to picosecond-order. Finally, we have discovered the water molecules excited by the multi-photon absorption were decomposed into H_2 and O_2 molecules. We found out a new method of hydrogen production.Furthermore, based on the above results, the interactions between a solid transparent material (quartz) and the fs pulses were investigated. An optical fiber was microfabricated by the fs pulses, and a new type optical fiber probe was created. The excellent performances of the probe were demonstrated in micro droplet/bubble measurement (the paper received the Outstanding Paper Award from Institute of Physics, 2010).

飞秒脉冲激光器（FS脉冲）由于其极高的能量密度而引起非常有趣的现象。对物质的影响不是热的，而是多光子滥用。当这种对FS脉冲的多光子滥用在水上运行时，诱导了通常通过通常的激光（如纳米脉冲激光器）激光引起的气腔的特殊现象。在本研究中，持续时间为50-150f的FS脉冲，重复率为1kHz，脉搏能量为0.2-1.4μj，通过几种类型的镜头将玻璃电池中的超纯水集中在超纯水上。从原始梁通过梁分离器分开的FS脉冲用作探针灯。通过调节探针光的光路径长度（FS脉冲），实现了飞秒阶时时间分辨的光学测量。通过有效地使用这种测量技术，我们阐明了水的折射指数的变化，以飞秒的时间间隔和以毫秒为间隔的气泡特性，气泡成核和生长过程。基于这些结果，我们阐明了这些结果与FS-Pulse峰强度之间的关系。此外，我们研究了飞秒至皮秒级的核和生长过程。最后，我们发现，多光子滥用激发的水分子被分解为H_2和O_2分子。我们发现了一种新的氢产生方法。根据上述结果，研究了固体透明材料（QUARTZ）与FS脉冲之间的相互作用。通过FS脉冲对光纤进行了微观生殖，并创建了一种新型的光纤探针。探针的出色表现在微滴/气泡测量中得到了证明（该论文获得了物理研究所的杰出纸张奖，2010年）。