Data underlying the publication: Mirror Surface Nanostructuring via Laser Direct Writing - Characterization and Physical Origins

The addition of an optically absorptive layer to otherwise standard dielectric mirrors enables a set of laser direct writing nanostructuring methods that can add functionality to such mirrors while retaining their high reflectivity. A thorough characterization of this method is given in this paper, and its physical origins are investigated. In particular, our measurements show that laser direct writing of such mirrors has a reversible and a permanent component. The reversible process originates from the thermal expansion of the surface and allows a simple yet precise way to temporarily modify the shape of the mirror. Scanning electron microscope cross-sectional images suggest that the permanent part of the nanostructuring process is due to thermally induced pore formation and enlargement in the tantalum oxide layers of the used dielectric mirror.

在标准介质镜（dielectric mirrors）中添加光学吸收层后，可实现一系列激光直写纳米加工工艺，此类工艺既能为该类介质镜赋予额外功能，又可保留其高反射率。本文对该方法开展了全面的表征分析，并对其物理起源进行了研究。具体而言，我们的测量结果显示，这类介质镜的激光直写工艺包含可逆与永久两种过程组分。可逆过程源于介质镜表面的热膨胀，借此可通过一种简便且精准的方式临时调整镜体的表面形貌。扫描电子显微镜（Scanning electron microscope）横截面成像结果表明，该纳米加工过程中的永久组分，源于所用介质镜的氧化钽（tantalum oxide）层中热诱导的孔洞形成与扩张。