The material response of Borofloat, BK7, and B270 glass targets to 34 fs pulses of 800 nm central wavelength is analyzed in the 1–30 J/cm2 fluence domain. The contours of the craters change with the fluence very much the same for all three glasses up to approximately 20 J/cm2, above which the Borofloat and BK7 continue behaving similarly, while bump formation sets on for the B270 glass. Analyzing the contours single-shot ablation thresholds are determined by applying both the conventional diameter regression technique and a multiphoton absorption-based fit to depth data. The ablation threshold values are equal within the 6.1 ± 0.55 J/cm2 domain for the three glasses as well as the three-photon absorption coefficients, which lie in the same magnitude (10–25 cm3/W2). Above the ablation threshold, the diameter values follow logarithmic dependence in the fluence range investigated, reaching similar values around 45 µm at 30 J/cm2 with 51 ± 1 µm 1/e2 beam diameter on the target surface as derived from the diameter regression technique. The onset of plasma formation derived from the changes in the energy reflected from the processed surface is also found to be similar for the three glasses (9.5, 10, and 8.0 J/cm2) in good correlation with the ablation threshold values.

中文翻译：

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在强场电离域中通过单个 34 fs 脉冲处理光学玻璃：烧蚀特性和陨石坑形态

在 1–30 J/cm2 通量域中分析了 Borofloat、BK7 和 B270 玻璃靶材对 800 nm 中心波长的 34 fs 脉冲的材料响应。陨石坑的轮廓随着注量的变化而变化，对于所有三种玻璃，高达约 20 J/cm2 的注量都非常相同，高于此值时，Borofloat 和 BK7 继续表现相似，而 B270 玻璃则开始形成凸起。分析轮廓单次烧蚀阈值是通过应用传统的直径回归技术和基于多光子吸收的深度数据拟合来确定的。三种玻璃的消融阈值在 6.1 ± 0.55 J/cm2 域内相等，三光子吸收系数也处于相同的量级 (10–25 cm3/W2)。高于消融阈值，直径值在所研究的注量范围内遵循对数依赖性，在 30 J/cm2 下达到类似值约 45 µm，目标表面上的光束直径为 51 ± 1 µm 1/e2，源自直径回归技术。还发现，三种玻璃（9.5、10 和 8.0 J/cm2）从加工表面反射的能量变化产生的等离子体形成的开始是相似的，与烧蚀阈值具有良好的相关性。