本所吳育任教授指導黃雋宇博士生榮獲「國際電機電子工程師學會中華民國分會112年博士論文獎」，特此恭賀！

Simple Architecture for Highly Collimated Backlight

Professor Chung-Chih Wu

Graduate Institute of Photonics and Optoelectronics, National Taiwan University

臺灣大學光電所 吳忠幟教授

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.

— 資料提供：影像顯示科技知識平台 (DTKP, Display Technology Knowledge Platform) —

— 整理：林晃巖教授、黃茂愷 —

多感測器的光頻梳

光學感測技術又向前邁進了一步！消息指出，一種晶片級電光頻梳能夠同時檢測晶片上的溫度感測器和晶片外的微製造光機械加速度計，分別達到5 μK Hz^–1/2和130 μm s^–2 Hz^–1/2的頂尖靈敏度 (K. Han, et al. Optica 11, 392–398; 2024) （如圖一(a)(b)所示）。

Kyunghun Han及其來自美國國家標準暨技術研究院、馬里蘭大學和Theiss Research的合作團隊開發了一種晶片上的頻梳光譜儀，該光譜儀由一個馬赫-曾德爾(Mach–Zehnder)干涉儀組成，每個臂上都有一個電光相位調制器（如圖一(c)所示）。

一個波長接近1,550 nm的二極體雷射被耦合至輸入波導，該波導由一個寬度為2.5 μm的Si₃N₄脊形波導和垂直間隔100 nm的LiNbO₃板層組成。下臂的電光調制器由一個展頻啁啾波形驅動，以生成電光頻梳，而上臂的調制器則接收鋸齒波調制，以生成用於外差檢測的頻移本地振盪器。

透過掃描調制頻率，並測量來自光接收器的射頻功率，來測量調制器的電光響應。當射頻驅動功率低至25 nW時，觀察到了帶寬為3 GHz、重複頻率為10 MHz的光頻梳。下臂的頻梳透過消逝波耦合與作為溫度感測器的Si₃N₄賽道型微共振器相連，對應的光學腔模式的熱漂移為2.5 GHz °C^–1。上臂和下臂之間的干涉圖經數位化、傅立葉變換並歸一化後，生成了一個光頻梳光譜。

作為展示，美國科學家們對晶片上的溫度感測器和安裝在閉環機電振動台上的晶片級光機加速度計進行了同步測量。所得的頻梳光譜顯示了來自賽道型微共振器溫度感測器的較寬共振峰以及光機加速度感測器產生的較窄共振峰。基於在沒有外部加速度的情況下進行的重複測量的標準偏差，當使用晶片上的頻梳光譜儀進行檢測時，加速度計的位移靈敏度被確定為4 fm Hz^–1/2，這是目前光機械加速度計所展示的最高精度。