清華大學

研究概況以GaN基LED為核心的半導體照明技術，在我國已形成年產值數千億元戰略性新興產業。本課題組針對LED光源的特點，在國內率先開展基于非成像光學的三維自由曲面照明光學系統設計研究，原創了采用三維自由光學曲面高效、均勻調控LED光線到被照明區域的系列技術，突破了制約半導體照明實際應用的瓶頸。相關研究成果已經實現產業化，產品廣泛應用于國內27個省市的眾多照明工程中，并出口至美國、日本等國家，展示了較傳統照明和同類產品優異的照明和節能效果。相關研究獲得2010年廣東省科學技術一等獎、2014年國家技術發明二等獎。

目前的研究興趣包括，半導體照明和顯示技術；新型光信息處理、成像、探測、三維顯示器件和系統，柔性光電子器件，生物光學/光子學器件和系統等。

本人先后承擔國家自然科學基金青年基金、國家自然科學基金國際合作基金、國家“863”計劃子課題、國家科技支撐計劃子課題、國家實驗室開放基金、國家重點實驗室開放基金、部委專項等項目。

獎勵與榮譽2014年國家技術發明二等獎（排名第5）。

學術成果迄今為止發表SCI論文40余篇，主要代表性論文：

[1]. Luo Yi, Bai Yiming, Han Yanjun Han, Li Hongtao Li, et. al, “Light extraction efficiency enhancement of GaN-based blue LEDs based on ITO/ InxO ohmic contacts with microstructure formed by annealing in oxygen,” OPTICS EXPRESS 24, A797-A809 (2016).
[2]. Mao Xianglong, Li Hongtao*, Han Yanjun, Luo Yi, “Polar-grids based source-target mapping construction method for designing freeform illumination system for a lighting target with arbitrary shape,” OPTICS EXPRESS 23, 4313-4328(2015).
[3]. Mao Xianglong, Li Hongtao*, Han Yanjun, Luo Yi, “Two-step design method for highly compact three-dimensional freeform optical system for LED surface light source,” OPTICS EXPRESS 22, A1491-A1506(2014).
[4]. Mao Xianglong, Li Hongtao*, Han Yanjun, Luo Yi, “A two-step design method for high compact rotationally symmetric optical system for LED surface light source,” OPTICS EXPRESS 22, A233-A247(2014).
[5]. Xu Bin, Li Hongtao*, Mao Xianglong, Han Yanjun, Luo Yi, “A Design Method of Freeform Optical Surface Using the Mapping Obtained from Supporting Ellipsoids Algorithm[C],” Asia Communications and Photonics Conference. Optical Society of America ATh1J.2(2014).
[6]. Li Hongtao*, Mao Xianglong, Han Yanjun, Luo Yi, “Wavelength Dependence of Colorimetric Properties of Lighting Sources Based on Multi-Color LEDs,” OPTICS EXPRESS 21, 3775-3783(2013).
[7]. Li Hongtao*, Chen Shichao, Han Yanjun, Luo Yi, “A Fast Feedback Method to Design Easy-Molding Freeform Optical System with Uniform Illuminance and High Light Control Efficiency,” OPTICS EXPRESS 21, 1258-1269(2013).
[8]. Wang Kun, Han Yanjun, Li Hongtao, Luo Yi, “Overlapping-based optical freeform surface construction for extended lighting source,” OPTICS EXPRESS 21, 19750-19761(2013).
[9]. Situ Wenchang, Han Yanjun, Li Hongtao and Luo Yi, “Combined feedback method for designing a free-form optical system with complicated illumination patterns for an extended LED source," OPTICS EXPRESS 19 (105), A1022-A1030 (2011).
[10]. Luo Yi, Feng Zexin, Han Yanjun and Li Hongtao, “Design of compact and smooth free-form optical system with uniform illuminance for LED source,” OPTICS EXPRESS 18(9), 9055-9063 (2010).
[11]. Li Hongtao, Luo Yi, et al., “Determination of the twist angle of GaN film by high resolution X-ray diffraction,” Applied physics express 1(4), 045004 (2008).
[12]. Li Hongtao, Luo Yi, et al., “Thickness measurement of GaN films by X-ray diffraction,” ACTA PHYSICA SINICA 57(11), 7119-7125 (2008).