title: Robust Whispering-Gallery-Mode Microbubble Lasers from Colloidal Quantum Dots.
abstract: Microlasers hold great promise for the development of photonics and optoelectronics. Among the discovered optical gain materials, colloidal quantum dots (CQDs) have been recognized as the most appealing candidate due to the facile emission tunability and solution processability. However, to date, it is still challenging to develop CQD-based microlasers with low cost yet high performance. Moreover, the poor long-term stability of CQDs remains to be the most critical issue, which may block their laser aspirations. Herein, we developed a unique but generic approach to forming a novel type of a whispering-gallery-mode (WGM) microbubble laser from the hybrid CQD/poly(methyl methacrylate) (PMMA) nanocomposites. The formation mechanism of the microbubbles was unraveled by recording the drying process of the nanocomposite droplets. Interestingly, these microbubbles naturally serve as the high-quality WGM laser resonators. By simply changing the CQDs, the lasing emission can be tuned across the whole visible spectral range. Importantly, these microbubble lasers exhibit unprecedented long-term stability (over one year), sufficient for practical applications. As a proof-of-concept, the potential of water vapor sensing was demonstrated. Our results represent a significant advance in microlasers based on the advantageous CQDs and may offer new possibilities for photonics and optoelectronics.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Physics, King's College London , Strand, London, WC2R 2LS, United Kingdom.
authors.forename: Van Duong
authors.initials: VD
authors.lastname: Ta
authors.affiliation: School of Electrical and Electronic Engineering, Luminous! Center of Excellence for Semiconductor Lighting and Displays, Nanyang Technological University , Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Kheng Swee
authors.initials: KS
authors.lastname: Leck
authors.forename: Beng Hau Ian
authors.initials: BH
authors.lastname: Tan
authors.forename: Zeng
authors.initials: Z
authors.lastname: Wang
authors.affiliation: College of Physics Science and Technology, Shenzhen University , Shenzhen 518060, China.
authors.forename: Tingchao
authors.initials: T
authors.lastname: He
authors.forename: Claus-Dieter
authors.initials: CD
authors.lastname: Ohl
authors.affiliation: School of Electrical and Electronic Engineering, Luminous! Center of Excellence for Semiconductor Lighting and Displays, Nanyang Technological University , Nanyang Avenue, Singapore 639798, Singapore.|Department of Electrical and Electronics Engineering, Department of Physics, and UNAM-National Nanotechnology Research Center, Bilkent University , Bilkent, Ankara 06800, Turkey.
authors.forename: Hilmi Volkan
authors.identifier: 0000-0003-1793-112X
authors.initials: HV
authors.lastname: Demir
authors.forename: Handong
authors.identifier: 0000-0002-2261-7103
authors.initials: H
authors.lastname: Sun
keywords: Microlaser; microbubble; nanocomposites; quantum dot; whispering-gallery-mode