Hf1-xSixO2 Nanocomposite Coatings Prepared by Ion-Assisted Co-Evaporation Process for Low-Loss and High-LIDT Optics

Hongfei Jiao; Xinshang Niu; Jinlong Zhang; Bin Ma; Xinbin Cheng; Zhanshan Wang

doi:10.3390/ma14102606

Hf_1-xSi_xO₂ Nanocomposite Coatings Prepared by Ion-Assisted Co-Evaporation Process for Low-Loss and High-LIDT Optics

Materials (Basel). 2021 May 17;14(10):2606. doi: 10.3390/ma14102606.

Authors

Hongfei Jiao^{1

2}, Xinshang Niu^{1

2}, Jinlong Zhang^{1

2}, Bin Ma^{1

2}, Xinbin Cheng^{1

2}, Zhanshan Wang^{1

2}

Affiliations

¹ Key Laboratory of Advanced Micro-Structured Materials, Ministry of Education, Shanghai 200092, China.
² Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China.

Abstract

Hf₁_-xSi_xO₂ nanocomposites with different SiO₂ doping ratios were synthesized using an ion-assisted co-evaporation process to achieve dense amorphous Hf₁_-xSi_xO₂ coatings with low loss and a high laser-induced damage threshold (LIDT). The results showed that the Hf₁_-xSi_xO₂ nanocomposites (x ≥ 0.20) exhibited excellent comprehensive performance with a wide band gap and a dense amorphous microstructure. High-temperature annealing was carried out to ensure better stoichiometry and lower absorption. Precipitation and regrowth of HfO₂ grains were observed from 400 °C to 600 °C during annealing of the Hf_0.80Si_0.20O₂ nanocomposites, resulting in excessive surface roughness. A phenomenological model was proposed to explain the phenomenon. The Hf₁_-xSi_xO₂ nanocomposites (x = 0.3 and 0.4) maintained a dense amorphous structure with low absorption after annealing. Finally, a 1064-nm Hf_0.70Si_0.30O₂/SiO₂ high-performance reflector was prepared and achieved low optical loss (15.1 ppm) and a high LIDT (67 J/cm²).

Keywords: Hf1−xSixO2 nanocomposites; annealing; dense amorphous structure; high LIDT; ion-assisted co-evaporation process; low optical loss.

Abstract

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