title: Stretchable Random Lasers with Tunable Coherent Loops.
abstract: Stretchability represents a key feature for the emerging world of realistic applications in areas, including wearable gadgets, health monitors, and robotic skins. Many optical and electronic technologies that can respond to large strain deformations have been developed. Laser plays a very important role in our daily life since it was discovered, which is highly desirable for the development of stretchable devices. Herein, stretchable random lasers with tunable coherent loops are designed, fabricated, and demonstrated. To illustrate our working principle, the stretchable random laser is made possible by transferring unique ZnO nanobrushes on top of polydimethylsiloxane (PDMS) elastomer substrate. Apart from the traditional gain material of ZnO nanorods, ZnO nanobrushes were used as optical gain materials so they can serve as scattering centers and provide the Fabry-Perot cavity to enhance laser action. The stretchable PDMS substrate gives the degree of freedom to mechanically tune the coherent loops of the random laser action by changing the density of ZnO nanobrushes. It is found that the number of laser modes increases with increasing external strain applied on the PDMS substrate due to the enhanced possibility for the formation of coherent loops. The device can be stretched by up to 30% strain and subjected to more than 100 cycles without loss in laser action. The result shows a major advance for the further development of man-made smart stretchable devices.
authors.affiliation: Department of Physics, National Taiwan University , Taipei 106, Taiwan.
authors.forename: Tzu-Min
authors.initials: TM
authors.lastname: Sun
authors.affiliation: Department of Physics, National Taiwan University , Taipei 106, Taiwan.
authors.forename: Cih-Su
authors.initials: CS
authors.lastname: Wang
authors.affiliation: Department of Physics, National Taiwan University , Taipei 106, Taiwan.
authors.forename: Chi-Shiun
authors.initials: CS
authors.lastname: Liao
authors.affiliation: Department of Physics, National Taiwan University , Taipei 106, Taiwan.
authors.forename: Shih-Yao
authors.initials: SY
authors.lastname: Lin
authors.affiliation: Department of Physics, National Taiwan University , Taipei 106, Taiwan.
authors.forename: Packiyaraj
authors.initials: P
authors.lastname: Perumal
authors.affiliation: Department of Physics, National Taiwan University , Taipei 106, Taiwan.
authors.forename: Chia-Wei
authors.initials: CW
authors.lastname: Chiang
authors.affiliation: Department of Physics, National Taiwan University , Taipei 106, Taiwan.
authors.forename: Yang-Fang
authors.initials: YF
authors.lastname: Chen
mesh_terms: D004548:Elasticity; D007834:Lasers; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D015034:Zinc Oxide / Q000737:chemistry
chemical_list: D015034:Zinc Oxide
keywords: Fabry−Perot resonance; ZnO nanostructure; coherent loop; random laser; stretchable; tunable