Real-time beam shaping without additional optical elements

查看全文 作　　者：Felix [1]Fries;Markus [1]Fröbel;Pen Yiao [1]Ang;Simone [1]Lenk;Sebastian [1]Reineke 机构地区：[1]Dresden Integrated Center for Applied Physics and Photonic Materials(IAPP),Technische Universität Dresden,Nöthnitzer Straße 61,Dresden 01187,Germany 出　　处：《Light(Science & Applications)》索引2018年第7卷第1期,共11页 基　　金：the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation programme(grant agreement No 679213). 摘　　要：Providing artificial light and enhancing the quality of the respective light sources is of continued interest in the fields of solid state,condensed matter,and semiconductor physics.Much research has been carried out to increase the luminous efficiency,lifetime and colour stability of such devices.However,the emission characteristics of a given light source do not necessarily comply with today’s often sophisticated applications.Here,beam shaping addresses the transformation of a given light distribution into a customized form.This is typically achieved by secondary optical elements often sporting elaborate designs,where the actual light source takes up only a small fraction of the system’s volume.Such designs limit the final light source to a single permanent operation mode,which can only be overcome by employing mechanically adjustable optical elements.Here we show that organic light-emitting diodes(OLEDs)can enable real-time regulation of a beam shape without relying on secondary optical elements and without using any mechanical adjustment.For a red light-emitting two-unit OLED architecture,we demonstrate the ability to continuously tune between strongly forward and strongly sideward emission,where the device efficiency is maintained at an application-relevant level ranging between 6 and 8%of external quantum efficiency for any chosen setting.In combination with additional optical elements,customizable and tuneable systems are possible,whereby the tuning stems from the light source itself rather than from the use of secondary optics. 关 键 词：tuning BEAM ELEMENTS