Shakhno Elena A, Nguyen Quang D, Sinev Dmitry A, Matvienko Elizaveta V, Zakoldaev Roman A, Veiko Vadim P
Faculty of Laser Photonics and Optoelectronics, ITMO University, 197101 Saint Petersburg, Russia.
Institute of Automation and Electrometry of the Siberian Branch of the Russian Academy of Sciences IA&E SB RAS, 1 Academician Koptyug ave., 630090 Novosibirsk, Russia.
Nanomaterials (Basel). 2020 Dec 30;11(1):67. doi: 10.3390/nano11010067.
Laser-induced thermochemical recording of nano- and microsized structures on thin films has attracted intense interest over the last few decades due to essential applications in the photonics industry. Nevertheless, the relationship between the laser parameters and the properties of the formed oxide structures, both geometrical and optical, is still implicit. In this work, direct laser interference patterning of the titanium (Ti) film in the oxidative regime was applied to form submicron periodical structures. Depending on the number of laser pulses, the regime of high contrast structures recording was observed with the maximum achievable thickness of the oxide layer. The investigation revealed high transmittance of the formed oxide layers, i.e., the contrast of recorded structures reached up to 90% in the visible range. To analyze the experimental results obtained, a theoretical model was developed based on calculations of the oxide formation dynamics. The model operates on Wagner oxidation law and the corresponding optical properties of the oxide-metal-glass substrate system changing nonlinearly after each pulse. A good agreement of the experimental results with the modeling estimations allowed us to extend the model application to other metals, specifically to those with optically transparent oxides, such as zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), and tantalum (Ta). The performed analysis highlighted the importance of choosing the correct laser parameters due to the complexity and nonlinearity of optical, thermal, and chemical processes in the metal film during its laser-induced oxidation in the air. The developed model allowed selecting the suitable temporal-energetic regimes and predicting the optical characteristics of the structures formed with an accuracy of 10%. The results are promising in terms of their implementation in the photonics industry for the production of optical converters.
在过去几十年中，由于在光子学工业中的重要应用，激光诱导薄膜上的纳米和微米级结构的热化学记录引起了广泛关注。然而，激光参数与所形成的氧化物结构的几何和光学性质之间的关系仍然不明确。在这项工作中，采用在氧化环境下对钛（Ti）薄膜进行直接激光干涉图案化的方法来形成亚微米级周期性结构。根据激光脉冲的数量，观察到了高对比度结构记录模式以及氧化层的最大可实现厚度。研究发现所形成的氧化层具有高透过率，即在可见光范围内记录结构的对比度高达90%。为了分析所获得的实验结果，基于氧化物形成动力学的计算开发了一个理论模型。该模型基于瓦格纳氧化定律以及氧化物 - 金属 - 玻璃基板系统在每个脉冲后非线性变化的相应光学性质运行。实验结果与建模估计的良好一致性使我们能够将模型应用扩展到其他金属，特别是那些具有光学透明氧化物的金属，如锆（Zr）、铪（Hf）、钒（V）、铌（Nb）和钽（Ta）。所进行的分析强调了由于金属薄膜在空气中激光诱导氧化过程中光学、热学和化学过程的复杂性和非线性，选择正确激光参数的重要性。所开发的模型允许选择合适的时间 - 能量模式，并以10%的精度预测所形成结构的光学特性。这些结果在光子学工业中用于生产光学转换器方面具有广阔的应用前景。
