Tunable lasers, with the ability to continuously vary their emission wavelengths, have found widespread applications across various fields such as biomedical imaging, coherent ranging, optical communications, and spectroscopy. In these applications, a wide chirp range is advantageous for large spectral coverage and high frequency resolution. Besides, the frequency accuracy and precision also depend critically on the chirp linearity of the laser. While extensive efforts have been made on the development of many kinds of frequency-agile, widely tunable, narrow-linewidth lasers, wideband yet precise methods to characterize and linearize laser chirp dynamics are also demanded. Here we present an approach to characterize laser chirp dynamics using an optical frequency comb. The instantaneous laser frequency is tracked over terahertz bandwidth at 1 MHz intervals. Using this approach we calibrate the chirp performance of 12 tunable lasers from Toptica, Santec, New Focus, EXFO, and NKT that are commonly used in fiber optics and integrated photonics. In addition, with acquired knowledge of laser chirp dynamics, we demonstrate a simple frequency-linearization scheme that enables coherent ranging without any optical or electronic linearization unit. Our approach not only presents novel wideband, high-resolution laser spectroscopy, but is also critical for sensing applications with ever-increasing requirements on performance.

本文提出了一种基于 CMOS 0.18 μm工艺的改进型高响应度太赫兹探测器线阵，各探测像素单元由高增益片上天线、高耦合度差分自混频功率探测电路和集成电压放大器组成。其中，差分探测电路利用源极差分驱动场效应管的交叉耦合电容，将太赫兹差分信号耦合至场效应管的栅极与源极，增强场效应管沟道内自混频太赫兹信号的强度，实现高响应度。其次，该探测器配备高增益片上环形差分天线与集成电压放大器，可有效放大混频后的信号，进而提高系统信噪比，最终达到增强探测器响应度的目的。探测器1 × 3线阵系统充分利用CMOS工艺多层结构的特点，将电压放大器布置在天线地平面下方，提高了芯片面积的利用率，有效降低了制作成本，整个系统的面积为0.5 mm²。测试结果表明，当场效应管的栅极偏置为0.42 V时，该探测系统对0.3 THz辐射信号的电压响应度（Rv）最大可达到43.8 kV/W，对应的最小噪声等效功率（NEP）为20.5 pW/Hz^1/2。动态测试结果显示该探测器可对不同材质的隔挡物进行区分。

The comparison of domestic and foreign studies has been utilized to extensively employ junction termination extension (JTE) structures for power devices. However, achieving a gradual doping concentration change in the lateral direction is difficult for SiC devices since the diffusion constants of the implanted aluminum ions in SiC are much less than silicon. Many previously reported studies adopted many new structures to solve this problem. Additionally, the JTE structure is strongly sensitive to the ion implantation dose. Thus, GA-JTE, double-zone etched JTE structures, and SM-JTE with modulation spacing were reported to overcome the above shortcomings of the JTE structure and effectively increase the breakdown voltage. They provided a theoretical basis for fabricating terminal structures of 4H-SiC PiN diodes. This paper summarized the effects of different terminal structures on the electrical properties of SiC devices at home and abroad. Presently, the continuous development and breakthrough of terminal technology have significantly improved the breakdown voltage and terminal efficiency of 4H-SiC PiN power diodes.

综合实验课程以“锂离子电池”这一研究和发展热点为主题，依托新能源专业，以工程实际问题为切入点，采用固相合成法制备了锂离子电池用钛酸锂负极材料，并进行表征和电化学性能测试。教学设计围绕以学生为中心、以成果为导向的理念，与新能源材料合成与制备、材料分析测试方法等课程相结合。教学内容涉及材料制备与表征、电极制备与电池组装、性能测试与结果分析。该教学实验的设计和实践有助于学生深化理论理解，掌握基本的锂离子电池制作流程和测试方法，进一步认识所学课程在新能源领域发展中的重要作用，提高专业认同感、自主思考能力和创新意识。

铅卤化物钙钛矿作为一类新兴的光电子材料表现出了卓越的光学、电学性能，在太阳能电池、发光二极管、光电探测器以及激光等领域产生了广泛而重要的应用，引起万众瞩目。稀土是元素周期表里一类特殊材料，从57号到71号元素，具有4fⁿ和4f^n-15d电子组态。如果将稀土和钙钛矿材料以及器件相结合，会孕育出怎样的新生儿呢？本文旨在结合作者在相关领域开展的工作及取得的经验，简单梳理该领域近年来取得的进展，剖析未来所面临的问题和挑战。本文不以总结纷繁复杂的个性化现象为要扼，而以探讨具有普遍意义的共性问题为宗旨。在资料选取上，或许失之偏颇，有严重的“王婆卖瓜”之嫌，请读者慎思明辨。

针对激光超声和电磁超声两种非接触式检测方式在实验中操作复杂和灵敏度低，以及难以观察不同参数对相关物理场造成的影响等问题，文中将有限元法应用到激光声磁混合式检测当中，采用数值分析方法分析了脉冲激光与电磁超声换能器之间的匹配关系对检测灵敏度的影响，研究了激光声磁检测系统的优化设计依据。利用有限元软件建立了激光声磁检测系统的仿真模型，通过正交数值仿真分析了高斯激光脉冲激励超声的温度场和位移场特性，进而观测了电磁超声换能器参数变化对检测灵敏度的影响。结果表明：螺旋型线圈接收的电压信号能正确反应由入射激光在固体中发生热膨胀效应产生的超声位移场，当磁体的高宽比为 1.5 倍时，驱肤层处磁场强度分布最优，提离距离对换能效率的影响呈现负指数变化规律，评价了不同接收间距处电磁超声换能器的接收性能。