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A Tunable Optofluidic Microlaser in a Photostable Conjugated Polymer
Author(s) -
Tang ShuiJing,
Liu Zhihe,
Qian YanJun,
Shi Kebin,
Sun Yujie,
Wu Changfeng,
Gong Qihuang,
Xiao YunFeng
Publication year - 2018
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201804556
Subject(s) - materials science , conjugated system , polymer , nanotechnology , optoelectronics , composite material
Abstract The optofluidic laser has become an important platform for biological sensing and medical diagnosis. To date, fluorescent dyes and proteins have been widely utilized as gain materials for biological analysis due to their good biocompatibility, but the limited photostability restricts their reliability and sensitivity. Here, an optofluidic microlaser with an ultralow threshold down to 7.8 µJ cm −2 in the ultrahigh‐ Q whispering‐gallery microcavity, which is filled with a biocompatible conjugated polymer, is demonstrated. This conjugated polymer exhibits a significant enhancement in the lasing stability compared with a typical laser dye (Nile red). In the experiment, after 20 min of illumination with the excitation intensity of 23.2 MW cm −2 , the lasing intensity of the conjugated polymer experiences a decrease of less than 10%, while the lasing feature of Nile red completely disappears. Additionally, by mechanically stretching the resonator, the lasing frequency can be fine‐tuned with the range of about 2 nm, exceeding the free spectral range of the resonator.