Vertical gradient freeze growth of ZnGeP2 crystals for nonlinear optical applications

• Published in: Journal of crystal growth Vol. 353; no. 1; pp. 158 - 161
• Main Authors: Wu, Haixin, Wang, Zhenyou, Ni, Youbao, Mao, Mingsheng, Huang, Changbao, Cheng, Xudong
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.08.2012; Elsevier
• Subjects: A1. Optical spectra; A1. X-ray diffraction; A2. Vertical gradient freeze; B2. Non-linear optic crystals; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Crystal growth; Crystallinity; Crystals; Exact sciences and technology; Growth from melts; zone melting and refining; Infrared radiation; Materials science; Methods of crystal growth; physics of crystal growth; Nonlinearity; Optical properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; Spectra; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; Thermal conductivity; A1. Optical spectra; A2. Vertical gradient freeze; A1. X-ray diffraction; B2. Non-linear optic crystals; Crystal growth; Second harmonic generation; A2 Vertical gradient freeze; Annealing; A1 Optical spectra; A1 X-ray diffraction; Crystallinity; XRD; Vertical gradient freeze method; Absorption coefficients; Germanium Zinc Phosphides Mixed; Monocrystals; Optical properties; Growth mechanism; B2 Non-linear optic crystals; Thermal conductivity; Absorption spectra; Nonlinear optics; Crystal growth from melts
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2012.04.012

ZnGeP2 crystal is the leader among nonlinear crystals for middle IR. Large sized Φ20×90mm3 ZGP single crystals have been grown successfully by the vertical gradient freeze technique. The crystallinity and optical properties of as-grown crystals were measured by XRD and transmission spectra respectively. The thermal conductivity was tested using PPMS. The absorption coefficient can be reduced to 0.08cm−1 at 2μm by post-annealing. The fabricated devices were also utilized to demonstrate SHG and OPO experiments for nonlinear optical applications. ► Large sized ZGP single crystals have been grown successfully by the vertical gradient freeze technique. ► Annealing in ZnGeP2 powders for 400h at 600°C, the transmission increases by 29.6% at 2μm. ► High power mid-IR laser is achieved by SHG and OPO using fabricated ZGP samples.