回音壁模式是光子在一个准二维平面内运动,并不断地在微腔边界发生全反射而不折射出腔的一种光学模式,具有高的Q值和小的模式体积,对外部环境的变化极其敏感。利用回音壁模式可以使宽带荧光实现窄光谱的激光输出。利用掺杂DG(dragon green)荧光染料的聚苯乙烯微球作为回音壁模式光学微腔,通过细胞的吞噬功能,使荧光微球到达细胞内部,利用纳秒脉冲激光进行泵浦,实现了细胞内的回音壁模式激光输出。与在纯水环境中的激光输出相比,细胞内荧光微球回音壁模式的谐振峰发生了红移,且红移量与细胞类型有关,说明可以用回音壁模式实现细胞种类的无标记识别。

Whispering gallery mode is a type of optical mode where photons move in a quasi-two-dimensional plane, and the total reflection occurs at the boundary of the microcavity without reflecting out of the cavity. This mode has a high Q value and small mode volume, and it is extremely sensitive to changes in the surrounding environment. A broadband fluorescence can be transformed into narrow-spectrum laser output by using the whispering gallery mode. In this paper, polystyrene microspheres doped with the dragon green fluorescent dye are used as whispering gallery mode optical microcavity. Through the phagocytosis of cells, the fluorescent microspheres reach inside cells and then are pumped by nanosecond pulsed laser to achieve the output of whispering gallery mode laser in cells. In comparison with the laser output in the pure-water environment, a redshift of the intracellular fluorescent microsphere whispering gallery mode resonance emission can be observed, and the redshift is related to cell type; therefore, it can be used for unlabeled identification of cell type.