Selective etching of fs-laser written structures in Y3Al5O12

Summary form only given. We present a detailed study on selective chemical etching of fs-laser modified single crystalline Y
₃
Al
₅
O
₁₂
(YAG) toward the fabrication of microchannels for micro- and optofluidic as well as photonic applications. The precise knowledge of parameters such as the etching rate, selectivity and roughness of the etched surfaces is essential for this purpose. In particular their dependence on structuring parameters, such as pulse energy and translation velocity as well as etching parameters, such as agent and temperature needs to be determined. The irradiation of dielectric materials such as YAG or sapphire with strongly focused fs-laser pulses causes a material modification in the focal volume. The modified material shows a significantly increased etching rate in suitable etching agents as reported e.g. for YAG in phosphoric acid (H
₃
PO
₄
) [1, 2] or various glasses and sapphire in hydrofluoric acid (HF) [3, 4]. This enables the fabrication of three-dimensional hollow microstructures in the material.