Controlling the directionality of spontaneous emissions via the evanescent wave coupling effect in a fine truncated-cone structure

2014 Fiscal Year Final Research Report

• Project/Area Number: 24246011
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Applied materials science/Crystal engineering
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: WANG Xuelun 独立行政法人産業技術総合研究所, 電子光技術研究部門, 研究グループ長 (80356609)
• Co-Investigator(Kenkyū-buntansha): AMANO Takeru 国立研究開発法人産業技術総合研究所, 電子光技術研究部門, 主任研究員 (10392581) ; IMAMURA Hiroshi 国立研究開発法人産業技術総合研究所, スピントロニクス研究センター, 研究チーム長 (30323091)
• Project Period (FY): 2012-05-31 – 2015-03-31
• Keywords: 指向性 / 発光ダイオード / エバネッセント光 / 結合 / リッジ構造 / 錐台構造

Outline of Final Research Achievements

Spontaneous light sources with a well-defined spatial directionality are strongly desired in various applications. Despite the extensive studies devoted to controlling the radiation process of spontaneous emissions, there still lacks a reliable method which can provide a high directionality suitable for widespread applications, especially in terms of the stability of the directionality against variations in device operating conditions. In this work, we proposed a novel approach of controlling the directionality of spontaneous emissions which employs the evanescent wave coupling effect in a subwavelength-sized ridge or truncated cone structure. Strong directionalities characterized by a half-intensity angle of 43 degree are demonstrated for the first time by using a an InGaAs/GaAs light-emitting diode with fine ridges formed on its light-extraction surface. The directionality is found to be almost independent of operating conditions over a wide range of operating condition variations.

Free Research Field

化合物半導体結晶成長、光デバイス