人工晶体学报2026，Vol.55Issue(3)：331-339,9.DOI:10.16553/j.cnki.issn1000-985x.2025.0235
卤化亚汞晶体及其在红外偏光/声光与核辐射探测器件中的应用
Mercurous Halide Crystals and Their Applications as Infrared Polarization/Acousto-Optic and Nuclear Radiation Detectors
摘要
Abstract
The detection of electromagnetic waves—including infrared rays,visible light,ultraviolet rays,X-rays,gamma rays—is one of the most essential approaches for humankind to understand the world.In the ultraviolet-visible light band,detection technologies are relatively mature due to the well-developed materials such as crystalline silicon.However,numerous challenges still persist in the detection of extremely short-wave X-rays and gamma rays as well as long-wave infrared rays.In the field of infrared detection,HgCdTe(MCT)focal plane array detectors are capable of capturing thermal imaging that is invisible to the naked eye.Nevertheless,they are unable to provide spectral information due to the lack of infrared spectroscopic devices at the front end.Therefore,developing optical crystals for infrared polarizing prisms and infrared tunable filter devices forms the foundation for advancing infrared multispectral and hyperspectral detection.In addition,for the detection of highly penetrating X-rays and gamma rays,semiconductor-based detection and scintillator-based detection are the most extensively studied approaches.However,the commercial semiconductors CdTe and CdZnTe(CZT)suffer from non-uniform defect distribution and high production costs,while traditional halide and oxide scintillators are hygroscopic,costly,or have insufficient energy resolution. Hg2X2(X=Cl,Br,I)crystals have emerged as a promising multifunctional alternative,combining exceptional infrared polarizing optical properties,strong acousto-optic performance,and high-performance radiation detection capabilities.Hg2X2 crystals crystallize in the I4/mmm space group,featuring one-dimensional X-Hg-Hg-X chains stabilized by intra-chain covalent bonding and inter-chain van der Waals interactions.Halogen substitution from Cl to Br and I enables systematic tuning of key material parameters:lattice constants increase,band gaps decrease(from 2.9 to 2.1 eV),infrared transparency extends up to 40 μm(in Hg2I2),and both birefringence and the acousto-optic figure of merit improve significantly(2 600×1.5×10-18 and 3 200×1.5×10-18 s3/g for Hg2Br2 and Hg2I2,respectively).Notably,researchers at Shandong University have successfully grown high-quality and large-sized Hg2Cl2 and Hg2Br2 crystals with diameters up to 54 mm via physical vapor transport(PVT)method by optimizing temperature gradient,growth rate,and cooling profile to suppress defects such as impurities and cloud-like inclusions. Hg2Cl2 crystals have been employed for fabricating various polarizing devices such as Glan-Taylor prisms and Wollaston prism,which are operable within the spectral range of 3 μm to 20 μm.They exhibit an extinction ratio of 30 000∶1 and a laser-induced damage threshold(LIDT)of 8.06 J/cm2 at 3.5 μm.Moreover,the anti-reflection-coated polarization beam combiner(PBC)achieves combination efficiencies of 93.5%at 4.6 μm and 92.4%at 9.2 μm,with excellent beam quality(M2=1.23/1.17).For acousto-optic applications,Hg2Br2-based acousto-optic tunable filter(AOTF)represents the only viable solution for MWIR/LWIR operation,demonstrating internal diffraction angles greater than 7° and a peak diffraction efficiency of 97.35%,achieved through engineered acoustic absorption layers.In radiation detection,Hg2X2-based detectors achieve an energy resolution of 1.35%for 662 keV γ-rays from 137Cs.Furthermore,Hg2Br2 enables dual-mode detection of γ-rays and thermal neutrons due to the high neutron capture cross-section of 199Hg,and has been applied in wearable α-particle detectors for real-time monitoring of water contamination.This review highlights the pivotal role of Hg2X2 crystals in the fields of infrared and nuclear radiation detection,and offers perspectives on the challenges associated with their crystal growth and device fabrication.关键词
Hg2X2/晶体生长/物理气相传输法/声光器件/偏光器件/核辐射探测Key words
Hg2X2/crystal growth/physical vapor transport method/acousto-optic device/polarization device/nuclear radiation detection分类
数理科学引用本文复制引用
宋剑,岳中杰,乔晓杰,翟仲军,张国栋,陶绪堂..卤化亚汞晶体及其在红外偏光/声光与核辐射探测器件中的应用[J].人工晶体学报,2026,55(3):331-339,9.基金项目
国家自然科学基金(U25A20521,51972194,62274103) （U25A20521,51972194,62274103）
