本所吴育任教授指导黄隽宇博士生荣获「国际电机电子工程师学会中华民国分会2023年博士论文奖」，特此恭贺！

Simple Architecture for Highly Collimated Backlight

Professor Chung-Chih Wu

Graduate Institute of Photonics and Optoelectronics, National Taiwan University

台湾大学光电所 吴忠帜教授

Highly collimated and directional backlights are essential for realizing advanced display technologies such as autostereoscopic 3D displays. Previously reported collimated backlights, either edge-lit or direct-lit, in general still suffer unsatisfactory form factors, directivity, uniformity, or crosstalk etc. In our study, we devise a simple stacking architecture for the highly collimated and uniform backlights, by combining linear light source arrays and carefully designed cylindrical lens arrays. Experiments were conducted to validate the design and simulation, using the conventional edge-lit backlight or the direct-lit mini-LED (mLED) arrays as light sources, the barrier sheets, and cylindrical lens arrays fabricated by molding. Highly collimated backlights with small angular divergence of ±1.45°~±2.61°, decent uniformity of 93-96%, and minimal larger-angle sidelobes in emission patterns were achieved with controlled divergence of the light source and optimization of lens designs. Such an architecture provides a convenient way to convert available backlight sources into a highly collimated backlight, and the use of optically reflective barrier also helps recycle light energy and enhance the luminance, providing a facile approach for display technologies requiring highly collimated backlights.

— 资料提供：影像显示科技知识平台 (DTKP, Display Technology Knowledge Platform) —

— 整理：林晃岩教授、黄茂恺 —

多传感器的光频梳

光学感测技术又向前迈进了一步！消息指出，一种芯片级电光频梳能够同时检测芯片上的温度传感器和芯片外的微制造光机械加速度计，分别达到5 μK Hz^–1/2和130 μm s^–2 Hz^–1/2的顶尖灵敏度 (K. Han, et al. Optica 11, 392–398; 2024) （如图一(a)(b)所示）。

Kyunghun Han及其来自美国国家标准暨技术研究院、马里兰大学和Theiss Research的合作团队开发了一种芯片上的频梳光谱仪，该光谱仪由一个马赫-曾德尔(Mach–Zehnder)干涉仪组成，每个臂上都有一个电光相位调制器（如图一(c)所示）。

一个波长接近1,550 nm的二极管激光被耦合至输入波导，该波导由一个宽度为2.5 μm的Si₃N₄脊形波导和垂直间隔100 nm的LiNbO₃板层组成。下臂的电光调制器由一个展频啁啾波形驱动，以生成电光频梳，而上臂的调制器则接收锯齿波调制，以生成用于外差检测的频移本地振荡器。

透过扫描调制频率，并测量来自光接收器的射频功率，来测量调制器的电光响应。当射频驱动功率低至25 nW时，观察到了带宽为3 GHz、重复频率为10 MHz的光频梳。下臂的频梳透过消逝波耦合与作为温度传感器的Si₃N₄赛道型微共振器相连，对应的光学腔模式的热漂移为2.5 GHz °C^–1。上臂和下臂之间的干涉图经数字化、傅立叶变换并归一化后，生成了一个光频梳光谱。

作为展示，美国科学家们对芯片上的温度传感器和安装在死循环机电振动台上的芯片级光机加速度计进行了同步测量。所得的频梳光谱显示了来自赛道型微共振器温度传感器的较宽共振峰以及光机加速度传感器产生的较窄共振峰。基于在没有外部加速度的情况下进行的重复测量的标准偏差，当使用芯片上的频梳光谱仪进行检测时，加速度计的位移灵敏度被确定为4 fm Hz^–1/2，这是目前光机械加速度计所展示的最高精度。