Photorefractive Properties of Molybdenum and Hafnium Co-Doped LiNbO3 Crystals

• Main Authors: Ling Zhu, Dahuai Zheng, Shahzad Saeed, Shuolin Wang, Hongde Liu, Yongfa Kong, Shiguo Liu, Shaolin Chen, Ling Zhang, Jingjun Xu
• Format: Article
• Language: English
• Published: MDPI AG 2018-08-01
• Series: Crystals
• Subjects: LiNbO3 crystal; molybdenum and hafnium co-doping; photorefractive properties
• Online Access: http://www.mdpi.com/2073-4352/8/8/322

A series of LiNbO3: Mo, Hf crystals with 0.5 mol % fixed MoO3 and various HfO2 concentrations (0.0, 2.0, and 3.5 mol %) were grown by the Czochralski technique. The photorefractive properties of the LiNbO3: Mo, Hf crystals were investigated by two-wave coupling measurements and the beam distortion method was employed to obtain the optical damage resistance ability. The UV-visible and OH− absorption spectra were also studied. The experimental results imply that the photorefractive properties of LiNbO3: Mo crystals at laser wavelengths of 532, 488, and 442 nm can be greatly enhanced by doping HfO2 over the threshold concentration. At 442 nm especially, the response time of LN: Mo, Hf3.5 can be shortened to 0.9 s with a diffraction efficiency of 46.07% and a photorefractive sensitivity reaching 6.28 cm/J. Besides this, the optical damage resistance at 532 nm is 3 orders of magnitude higher than that of the mono-doped LiNbO3: Mo crystal, which is beneficial for applying it in the field of high-intensity lasers.