大尺寸优质CdSe单晶生长及其中红外波片制备方法研究

It is the urgent needs that the mid-infrared precision polarization observations in many areas including astronomy. Considering the needs of the infrared solar polarization measurements as object in this project, it has been planed to carry out the development of technology and research methods of large-diameter and high-precision mid-infrared wavelength plate. Due to the high infrared transmittance rate, moderate birefringence coefficient, etc., CdSe single crystals have been considered as the best materials to product infrared wave plate. However, the size and quality of the domestic grown CdSe crystals have not yet met the needs of infrared wave plate, and there has been no experience in wave plate high-precision processing at home. This project intends to adopt the international preferred vapor transport method to grow CdSe crystals. The growth parameters will be optimized by studying the thermal dynamic mechanism during growth. A homogeneous and high-quality CdSe single crystal larger than Φ40 × 40mm in size will be grown. The high-precision machining process is researched for the CdSe single crystals to obtain a wave plate with high precision in phase delay and high infrared transmittance. In this project, some process has been made, and it is hoped to get hold of the preparation methods of large, high-quality CdSe crystals and mid-infrared wavelength plate through further work, providing the necessary technical support for the construction of future large infrared telescope. The project belongs to the cross field of the material physics and measured solar physics, whose expected results have important academic value, which would fill the blank of the domestic technology.

中红外波段高精度偏振观测，是包括天文在内的诸多领域的迫切需求。本项目以中红外太阳偏振测量的需求为研究对象，开展大口径、高精度的中红外波片研制的技术与方法研究。由于具有红外透过率高、双折射系数适中等优点，CdSe单晶体成为制作中红外波片的首选材料。然而国内生长的CdSe晶体尺寸和质量还未达到中红外波片需求，也无高精度波片加工的研究经验。本项目拟采用国际首选的气相提拉法，通过研究生长的热动机制，优化生长参数，制备出尺寸达Φ40×40mm的优质CdSe单晶；探索CdSe单晶的高精度加工（定轴切割、研抛、退火、镀膜等）工艺方法，获得高相位延迟精度和高红外透过率的波片。本项目有一定的工作基础，期望通过进一步的工作能全面掌握大尺寸CdSe晶体及波片制备方法，为未来大型红外望远镜建设提供技术支持。本项目属于人工晶体与红外偏振测量的交叉领域，填补国内技术空白，预期成果具有重要的学术价值。

中红外波段高精度偏振观测，是包括天文在内的诸多领域的迫切需求。本项目以中红外太阳偏振测量的需求为研究对象，开展大口径、高精度的中红外波片研制的技术与方法研究。由于具有红外透过率高、双折射系数适中等优点，CdSe单晶体成为制作中红外波片的首选材料。然而之前国内生长的CdSe晶体尺寸和质量还未达到中红外波片需求，也无高精度波片加工的研究经验。本项目拟采用国际首选的气相提拉法，通过研究生长的热动机制，优化生长参数，制备出尺寸达Φ37×45 mm的优质CdSe单晶；探索出CdSe单晶的高精度加工（定轴切割、研抛、退火、镀膜等）工艺方法，获得高相位延迟精度（小于0.7°）和高红外透过率（大于90%）的波片。通过项目的研究，全面掌握大尺寸CdSe晶体及波片制备方法，为国内大型红外望远镜建设提供了技术支持。本项目属于人工晶体与红外偏振测量的交叉领域，填补了国内技术空白，研究成果具有重要的学术价值。