title: Low threshold photonic crystal laser based on a Rhodamine dye doped high gain polymer.
abstract: We demonstrate low threshold lasing oscillation in a photonic crystal (PhC) laser by using tert-butyl Rhodamine B (t-Bu-RhB) doped gain media. Lactonic t-Bu-RhB is synthesized to improve doping concentration in polymethylmethacrylate (PMMA) films, and then isomerized to the zwitterion form to achieve highly fluorescent gain medium. The t-Bu-RhB doped PMMA film is sandwiched by a pair of polystyrene colloidal crystals to construct a PhC resonating cavity. Single-mode laser oscillation at 592 nm is observed when the PhC resonating cavity is pumped by a Nd:YAG laser. The lasing threshold is 0.12 MW cm(-2) utilizing 6.9 wt% t-Bu-RhB doped PMMA films, which is only 1/60 of that with 3 wt% t-Bu-RhB doped PMMA films. The concentration-dependent lasing action is attributed to different gain factors of the t-Bu-RhB doped PMMA films. Furthermore, a spatially and spectrally coherent laser beam from the PhC resonating cavity is verified by exploring the far-field image and angular dependence of the lasing emission. The approach provides a facile and efficient strategy to reduce the lasing threshold for fabricating low threshold PhC lasers.
authors.affiliation: Laboratory of Organic NanoPhotonics and Laboratory of Bio-Inspired Smart Interface Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, No. 29 Zhongguancun East Road, Beijing, 100190, P. R. China. jinfeng@mail.ipc.ac.cn xmduan@mail.ipc.ac.cn.
authors.forename: Lan-Ting
authors.initials: LT
authors.lastname: Shi
authors.forename: Feng
authors.initials: F
authors.lastname: Jin
authors.forename: Mei-Ling
authors.initials: ML
authors.lastname: Zheng
authors.forename: Xian-Zi
authors.initials: XZ
authors.lastname: Dong
authors.forename: Wei-Qiang
authors.initials: WQ
authors.lastname: Chen
authors.forename: Zhen-Sheng
authors.initials: ZS
authors.lastname: Zhao
authors.forename: Xuan-Ming
authors.initials: XM
authors.lastname: Duan