Sheeba M, Rajesh M, Mathew S, Nampoori V P N, Vallabhan C P G, Radhakrishnan P
International School of Photonics, Cochin University of Science and Technology, Cochin 682 022 India.
Appl Opt. 2008 Apr 10;47(11):1913-21. doi: 10.1364/ao.47.001913.
Two-photon excited (TPE) side illumination fluorescence studies in a Rh6G-RhB dye mixture doped polymer optical fiber (POF) and the effect of energy transfer on the attenuation coefficient is reported. The dye doped POF is pumped sideways using 800 nm, 70 fs laser pulses from a Ti:sapphire laser, and the TPE fluorescence emission is collected from the end of the fiber for different propagation distances. The fluorescence intensity of RhB doped POF is enhanced in the presence of Rh6G as a result of energy transfer from Rh6G to RhB. Because of the reabsorption and reemission process in dye molecules, an effective energy transfer is observed from the shorter wavelength part of the fluorescence spectrum to the longer wavelength part as the propagation distance is increased in dye doped POF. An energy transfer coefficient is found to be higher at shorter propagation distances compared to longer distances. A TPE fluorescence signal is used to characterize the optical attenuation coefficient in dye doped POF. The attenuation coefficient decreases at longer propagation distances due to the reabsorption and reemission process taking place within the dye doped fiber as the propagation distance is increased.
报道了在掺杂有罗丹明6G（Rh6G）-罗丹明B（RhB）染料混合物的聚合物光纤（POF）中的双光子激发（TPE）侧面照明荧光研究以及能量转移对衰减系数的影响。使用来自钛宝石激光器的800 nm、70 fs激光脉冲对掺杂染料的POF进行侧面泵浦，并在不同传播距离下从光纤末端收集TPE荧光发射。由于能量从Rh6G转移到RhB，在存在Rh6G的情况下，掺杂RhB的POF的荧光强度增强。由于染料分子中的再吸收和再发射过程，随着掺杂染料的POF中传播距离的增加，观察到从荧光光谱的较短波长部分到较长波长部分的有效能量转移。发现能量转移系数在较短传播距离下比在较长距离下更高。TPE荧光信号用于表征掺杂染料的POF中的光学衰减系数。随着传播距离增加，由于在掺杂染料的光纤内发生再吸收和再发射过程，衰减系数在较长传播距离处降低。
