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Semiconducting Polymer Dots as Broadband Saturable Absorbers for Q-switched Fiber Lasers
摘要： Semiconducting polymer dots (Pdots) have attracted much attention due to their outstanding optical properties. However, Pdots potential in laser technology is rare. Here, we first report the benzobisthiadiazole (BBT)-based Pdot as a single broadband nonlinear saturable absorber (SA) for passively Q-switched fiber lasers at 1, 1.5, and 2 μm. The Pdots-SA possesses a strong saturable absorption, broadband nonlinear optical response, and large modulation depth. Once the Pdots-SA is integrated into the ytterbium-, erbium-, and thulium-doped fiber laser cavities, stable Q-switched operations are observed at the central wavelengths of 1036, 1561, and 1951 nm. Our results verify that the Pdots are promising nonlinear media for Q-switched pulses generation, and highlight the potential of Pdots for relevant nonlinear optical applications.
关键词： Saturable absorber,Semiconducting polymer dots,Q-switched fiber lasers,Broadband nonlinear optical response
更新于2025-09-23 15:19:57
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Ratiometric Fluorescent Detection of Intracellular Singlet Oxygen by Semiconducting Polymer Dots
摘要： Singlet oxygen (1O2) plays important roles in many biological processes. However, it is very difficult to detect 1O2 in the intracellular environment owing to its relatively low concentration and short lifetime. Here, we developed a ratiometric probe based on semiconducting polymer dots (Pdots) that can sensitively detect 1O2 in live cells. An organic dye, singlet oxygen sensor green (SOSG), was doped in polyfluorene Pdots, and excitation energy was efficiently transferred from the polymer to the SOSG dye. Accordingly, the Pdots showed constant blue fluorescence as a reference, and increased green fluorescence upon singlet oxygen generation. The ratiometric response of Pdots was examined in the intracellular environment by in-situ 1O2 generation with a photosensitizer and light irradiation. Both spectroscopic measurements and confocal imaging were performed to monitor intracellular 1O2 generation during photodynamic therapy using the Pdot probe. Our results indicate that the SOSG-doped Pdots are promising for intracellular 1O2 detection.
关键词： Semiconducting polymer dots,Intracellular detection,Singlet oxygen,Photodynamic therapy,Ratiometric probe
更新于2025-09-11 14:15:04