Femtosecond laser ionization and damage mechanisms in transparent materials

透明材料中的飞秒激光电离和损伤机制

• 批准号: 9988123
• 负责人: Eric Mazur
• 金额: $ 34.42万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-15 至 2003-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9988123&HistoricalAwards=false
• 关键词: Femtosecond; laser; ionization; damage; mechanisms

This project focuses on studying plasma formation and material damage produced by nonlinear absorption of laser pulses in transparent materials. By tightly focusing ultrashort laser pulses, preliminary evidence of material damage with as little as five nanoJoule of laser energy has been observed. Because of the low pulse energy and tight focusing used in the experiments, intensities producing permanent damage can be achieved with minimal self-focusing, allowing the field intensity at the focus to be accurately determined. Measuring the threshold intensity for various laser and material parameters affords the group an opportunity to identify the relative role of multiphoton, tunneling, and avalanche ionization processes in femtosecond laser interactions with bulk media. In addition, detailed studies of the damage morphology for different laser parameters will uncover the basic damage mechanisms at work and provide useful information for applications.

本项目主要研究激光脉冲在透明材料中的非线性吸收引起的等离子体形成和材料损伤。 通过紧密聚焦超短激光脉冲，已经观察到材料损伤的初步证据，其激光能量低至5毫微焦耳。 由于实验中使用的低脉冲能量和紧密聚焦，可以以最小的自聚焦实现产生永久性损伤的强度，从而精确地确定焦点处的场强。 测量各种激光和材料参数的阈值强度为该小组提供了一个机会，以确定多光子，隧穿和雪崩电离过程在飞秒激光与大块介质相互作用中的相对作用。 此外，对不同激光参数下的损伤形貌进行详细的研究，将揭示激光损伤的基本机制，为激光应用提供有用的信息。