红外光谱有着广泛的应用。合肥红外自由电子激光装置能够为用户提供高亮度的中/远红外辐射，为高水平的红外研究提供基础条件。自由电子激光和实验站之间需要用光束线连接起来，以便在完成红外辐射高效输送的同时进行聚焦、诊断等。本文介绍了合肥红外自由电子激光装置红外光束线的设计与性能，主要包括光束线的总体要求、设计方案和布局、光学设计、光斑演化、光束传输、激光的分束取样、激光宏脉冲的在线同步测量、激光光谱的在线同步测量等。调试结果表明，设计达到了预期指标，整个光束线可以稳定运行。

中国工程物理研究院红外太赫兹自由电子激光装置是一台用于材料、光谱、生物、医学等领域前沿研究的多功能用户装置，在实验室现有的太赫兹自由电子激光装置（CTFEL）基础上，拟新增两套2×9-cell超导加速单元和两台波荡器，将电子能量提升至最大50 MeV，输出频率覆盖范围拓展至0.1~125 THz，最大宏脉冲功率大于100 W。同时，采用跑道型束线设计，拟建设一台小型能量回收型直线加速器实验研究平台。本文主要介绍了中国工程物理研究院红外太赫兹自由电子激光装置的总体设计、工作模式以及用户实验站布局。

Diamond anvil cell (DAC) experimental technique is widely employed in the fields of physics, chemistry and materials for scientific research. Since Bridgman carried out metal anvil device and later development of DAC technique, novel design of DAC and applied pressure technique have been developed. This paper introduces the piezoelectric driving DAC device for achieving high pressure at low temperature of 20 K by in situ continuous tuning pressure. A tuning range is about 2—4 GPa. The DAC device can be easily embedded in a cryostat due to its small size and convenient operation.

Different from most flare studies based on observations in the optical band, this paper focuses on the elementary units of solar activity——flaring loops and physical parameters that vary in time and space, as observed by radio microwave (cm band) spectra and images. In particular, this paper will be an important reference for studies on the data collected by a new radio heliograph (MUSER) built in China, which has the highest time, space, and frequency resolutions to date. In addition, X-ray, EUV, and optical studies related to microwave emission are included, in accordance with the trend of multiple wavelength research in all the various fields of astrophysics, including solar physics. Only the most representative studies, the ideas, main conclusions and typical figures are mentioned; for detailed data analysis and theoretical derivations, readers can look up the original references.

Weak magnetic field detection has played an increasingly important role in the field of scientific research, industrial manufacture, and people's daily lives. In recent years, a new kind of magnetic sensor has been proposed, composed of a superconducting flux-to-field transformer and a high-sensitivity magnetoresistive sensor. This kind of sensor is expected to be widely used because of its excellent sensitivity (femtotesla), stability, band characteristics, and low cost. In this paper, its structure and principle of operation will first be reviewed. We then describe and compare the development and applications of giant magnetoresistance sensors and the tunnel magnetoresistance/superconductor based mixed sensors fabricated in our lab.

Surface plasmon polaritons (SPPs) have extensive application prospects in high-sensitivity biosensing because of their extraordinary optical properties. However, the large size and cost of prism-based plasmonic sensors limit their commercial applications. Fortunately, the emergence of metallic nanostructured sensors has provided an effective approach to realize low-cost and highly integrated plasmonic sensors. In this review, we first assess the current status and advantages of plasmonic nanostructured sensors, then focus on our group's recent research on their miniaturization, integration, and fabrication cost reduction. Our work is of significance for the development of both plasmonic sensing theory and nanostructured sensing technology.

Photonic integration is one of the most important issues in scientific research. Silicon-on-insulator (SOI) and other materials play an important role in photonic integration, but their losses are large and affect the integration, so it is very important to find new waveguide materials. As a consequence, Si3N4 came into being and is now a hot area of research. Its crystal structure is stable, with a wide energy band of Eg~5.1 eV, so it is transparent in the whole optical range from ultraviolet to infrared. Also, its optical loss in this range is very low, α~0.045±0.04 dB/m, which is lower than that of SOI waveguides by 3—4 orders of magnitude. Its refractive index at 1550 nm is ~2, so combined with Si and SiO2, high-performance dielectric waveguide structures can be designed. Its thermal expansion coefficient is ~2.35×10-6/℃, smaller than that of Si, so its growth on Si will introduce a larger tensile stress and may produce cracks. Thus, growing thick films of large area is very difficult. By using low-pressure or plasma-enhanced chemical vapor deposition, Si3N4 films can be deposited on low refractive index SiO2 to form Si3N4-SiO2 waveguides, which are smaller in size and allow better integration. Current research progress in this field is reviewed, and future application prospects are reviewed.

Ion migration in solid materials is the basis of many applications, including lithium ion batteries, memory devices, catalysis, and so on. The dynamics and kinetics of ion migration are the core of solid state ionics. Microscopically, the behavior of ion migration depends on the local barrier characteristics determined by the microstructure of the material. Therefore, it is very important to study the relationship between ion migration and microstructure. In this paper, we describe the present status and development trends of research on ion migration behavior in solid materials such as lithium ion batteries and resistive random-access memory materials by in situ transmission electron microscopy.