A broadban-tunable photonic bandgap and thermally convertible laser with an ultra-low lasing threshold from a refilled chiral polymer templateElectronic supplementary information (ESI) available: Pictures and plots to show the improvement via thermally reverse diffusion and rapid annealing processes; plots to show energy thresholds of the refined DDNLC-refilled gradient-pitched template; and characteristics of the unrefined laser sample. See DOI: 10.1039/c9tc00194h

• Main Authors: Lin, Jia-De, Lin, Hsin-Yu, Wei, Guan-Jhong, Chuang, Yu-Chou, Chen, Lin-Jer, Mo, Ting-Shan, Lee, Chia-Rong
• Format: Article
• Language: English
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c9tc00194h

This study demonstrates a broadband-tunable photonic bandgap (PBG) and thermally convertible laser with an ultra-low lasing threshold based on a gradient-pitched cholesteric liquid crystal (CLC) polymer template. The lowest energy threshold of the laser is 16 nJ per pulse under a pumped diameter of ca. 250 μm ( i.e. , 0.33 μJ per pulse per mm 2 ), a value that is superior to those of other band-edge lasers based on most dye/quantum-dot-doped CLC systems. Owing to its multiple advantages, such as high stability, ultra-low lasing threshold, wide-band and linear spatial PBG-tunability, and lasing-mode convertibility, the CLC template device can be potentially used for photonics and display applications. This study reports broadband-tunable photonic bandgap and thermally-convertible lasers with ultra-low lasing thresholds based on refilled chiral polymer templates.