Polycrystalline Ho:YAG transparent ceramics for eye-safe solid state laser applications

• Main Authors: Yang, Hao, Zhang, Jian, Qin, Xianpeng, Luo, Dewei, Ma, Jan, Tang, Dingyuan, Chen, Hao, Shen, De Yuan, Zhang, Qitu
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2013
• Online Access: https://hdl.handle.net/10356/95849; http://hdl.handle.net/10220/11283
• Institution: Nanyang Technological University

High optical quality holmium doped yttrium aluminum garnet (Ho:YAG) transparent ceramics that contained 0.5–2.0 at.% holmium additives were fabricated by a reactive sintering method under vacuum. Fully dense Ho:YAG ceramics with the average grain size of ~10 μm were obtained after vacuum sintered at 1780°C for 8 h. The in-line transmittances in the visible and infrared region are higher than 82% and 84%. The absorption coefficients of the 0.8, 1.0, 1.5, and 2.0 at.% Ho:YAG ceramics at 1907 nm was calculated to be 0.72, 0.89, 1.32, and 1.78 cm−1, respectively. The absorption cross-section of Ho:YAG ceramic was 0.645 × 10−20 cm2. The 1.5 and 2.0 at.% Ho:YAG ceramic slabs were in-band pumped by a Tm:fiber laser at 1907 nm. A maximum output power of 20.6 W at 2097 nm was obtained with a corresponding slope efficiency of 60.9%.