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.

钒酸铋是最具有光电催化应用潜力的水分解光电阳极之一, 但由于表面缓慢的动力学反应速率, 其光电催化效率仍不理想。本研究通过浸渍法在BiVO₄薄膜光阳极上负载纳米RhO₂助催化剂, 研究RhO₂负载量对BiVO₄光阳极光电催化性能的影响规律及其机理。晶粒尺寸10~25 nm的RhO₂均匀负载在颗粒尺寸100~250 nm、厚度约为400 nm的BiVO₄光阳极薄膜表面。考虑到贵金属铑的昂贵成本, RhO₂的最佳负载量为质量分数1.65%, 在偏压1.23 V (vs. RHE)、1.0 mol/L Na₂SO₃溶液中(pH8.5)AM 1.5模拟可见光照射下, 光电流密度达3.81 mA·cm^-2, 相较纯BiVO₄提升了10.58倍。在没有有机牺牲剂的条件下, 光阳极同时析出了氢气和氧气, 两者比例接近2 : 1, 产氧速率为8.22 μmol/(h·cm²)。负载RhO₂有效改善了光阳极的表面水氧化动力学, 使光生空穴更快与电解质溶液进行水氧化反应, 抑制光生载流子复合, 从而显著提升光电催化性能。另外, 负载RhO₂后, 空穴更容易从光阳极表面被有效提取到电解质溶液中, 减少其在光阳极表面积累, 从而使BiVO₄/RhO₂(1.65%)光阳极可持续稳定工作10 h以上。

Structural color from artificial structures, due to its environmental friendliness and excellent durability, represents a route for color printing applications. Among various physical mechanisms, the Fabry–Perot (F–P) cavity effect provides a powerful way to generate vivid colors in either the reflection or transmission direction. Most of the previous F–P type color printing works rely on electron beam grayscale lithography, however, with this technique it is challenging to make large-area and low-cost devices. To circumvent this constraint, we propose to fabricate the F–P type color printing device by the laser grayscale lithography process. The F–P cavity consists of two thin silver films as mirrors and a photoresist film with a spatially variant thickness as the spacer layer. By controlling the laser exposure dose pixel by pixel, a centimeter-scale full-color printing device with a spatial resolution up to 5 μm × 5 μm is demonstrated. The proposed large area color printing device may have great potential in practical application areas such as color displays, hyperspectral imaging, advanced painting, and so on.

对二能级原子与饱和铁氧体材料板之间的Casimir-Polder量子真空扭矩进行了研究。利用格林张量推导求得二能级原子与饱和铁氧体之间Casimir-Polder扭矩的表达式。结合不同的原子偶极矩和铁氧体特殊的电磁特性，从原子频率、原子位置、外磁场和圆极化偶极矩极化平面所受微扰等方面对Casimir-Polder扭矩进行分析。结果表明，原子位置和跃迁频率会影响Casimir-Polder扭矩的强度，而扭矩随铁氧体所处外磁场强度的变化特性在不同的原子位置和频率下会呈现非单调的拐点。此外，原子圆极化偶极矩在受到一定的角度微扰下，其扭矩具有回归原旋转平面趋势的平衡稳定性。因此，通过改变铁氧体所处的外磁场环境，可以调控原子的Casimir-Polder扭矩，这为二能级系统旋转态的加速或冷却至量子基态的控制提供一种新方法。

制备了平面结构2D/3D混合钙钛矿（PEA）_0.15FA_0.85SnI₃/SnO₂异质结光探测器。研究发现，SnO₂薄膜的引入可以调控（PEA）_0.15FA_0.85SnI₃薄膜的晶体生长过程，有助于获得致密的连续薄膜。在520 nm单色光辐照下，器件的响应度高达3.19×10⁵ A/W，相应的探测率为6.39×10¹⁵ Jones。在808 nm单色光辐照下，器件的响应度和探测器率也可分别达到1.70×10⁴ A/W和7.28×10¹³ Jones。相关性能明显高于（PEA）_0.15FA_0.85SnI₃单层薄膜光探测器。器件性能的提高一方面是由于钙钛矿薄膜表面形貌的改善，提高了器件的吸收效率和载流子收集效率；另一方面是由于（PEA）_0.15FA_0.85SnI₃和SnO₂之间形成了p?n结结构，从而有效提高了钙钛矿薄膜中的光生电子?空穴对的分离效率，降低了电子和空穴的复合几率。同时，（PEA）_0.15FA_0.85SnI₃/SnO₂界面处特殊的能级结构也可诱导器件产生光电导增益。

随着长波红外探测器技术的进步，通过选用宇航级大阵列长波红外探测器，天基红外遥感卫星技术得到快速发展。长波红外探器响应强非线性导致传统的基于线性模型的非均匀性校正算法校正误差大，从而影响卫星在轨使用效能。针对该问题，结合大量实验室数据和卫星在轨数据的统计分析结果，建立了一种新的长波红外探测器非线性响应模型，据此提出了一种基于改进伽马曲线的非均匀性校正算法，以有效克服探测器响应强非线性对校正精度的影响。该算法首先建立基于改进伽马曲线的探测器非线性响应模型，依据此模型对获取图像进行非线性压缩映射，实现探测器响应的线性化，然后利用星载基于定标技术的线性化算法实施非均匀性校正，同时，定标温度点根据所建立模型参数动态更新，最后通过逆非线性化压缩映射还原出实际的非均匀校正后的图像。基于人造黑体和在轨实景红外图像的实验结果表明，该算法有效解决了探测器响应强非线性对校正精度的影响，校正后图像的视觉效果和定量化指标均优于传统的星载非均匀校正算法。

印刷钙钛矿太阳能电池采用无机介孔骨架包覆有机无机杂化钙钛矿材料的器件结构, 制备工艺简单, 原材料成本低廉, 且稳定性优异。然而, 在介孔骨架中均匀沉积高质量的钙钛矿材料存在一定困难。本研究通过在典型钙钛矿材料甲胺铅碘(MAPbI₃)前驱液中引入醋酸铅(Pb(Ac)₂)作为添加剂, 加快钙钛矿晶体的成核从而改善其在介孔骨架中的生长和填充。同时, Ac^-与MA⁺所形成的MAAc在热退火过程中逃逸可使得所沉积的钙钛矿光活性层中PbI₂略微过量, 达到钝化晶界的作用。添加摩尔分数1% Pb(Ac)₂的钙钛矿前驱液所制备的印刷钙钛矿太阳能电池的光电转换效率达到15.42%, 表明引入添加剂调控钙钛矿光活性层结晶质量是提升印刷钙钛矿太阳能电池性能的有效途径。