Shang Zhenzhen, Yang Mingchao, Deng Luogen
School of Physics, Beijing Institute of Technology, Beijing 100081, China.
Materials (Basel). 2016 Aug 24;9(9):725. doi: 10.3390/ma9090725.
Energy transfer is known to have a significant influence on random lasers. However, the study about the effect of energy transfer between metallic salt and dye molecules on random lasers is still lacking at present. Here, we investigate random lasing actions in Pyrromethene-597 (PM597), PM597-doped MnCl₂ (manganese (II) chloride), PM597-doped polymer-dispersed liquid crystal (PDLC) and PM597-doped PDLC with MnCl₂ capillary systems. We find that random lasing of the systems with MnCl₂ exhibits lower threshold, higher intensity, sharper peak and variable resonance wavelength in comparison with the systems without MnCl₂. This behavior is closely related to the decrease of fluorescence quenching effect and the enhancement of local field induced by energy transfer between MnCl₂ and PM597. Red-shift of wavelength is observed with increasing dosage concentration of MnCl₂ in the PM597-doped PDLC with MnCl₂ system. Through the analysis of single-shot emission spectra of PM597-doped PDLC without and with MnCl₂ systems, the role of MnCl₂ in the coupling of lasing modes is confirmed. Lengths of laser oscillation cavities of the PM597-doped PDLC without and with MnCl₂ systems are calculated by a power Fourier transform (PFT) analysis of their emission spectra. It well accounts for the effect of MnCl₂ on the variation of the oscillation cavity.
众所周知，能量转移对随机激光器有重大影响。然而，目前关于金属盐与染料分子之间的能量转移对随机激光器影响的研究仍然缺乏。在此，我们研究了5-（4-二甲氨基苯乙烯基）-3-甲基-4-异硫氰酸基吡咯（PM597）、掺杂PM597的二氯化锰（MnCl₂）、掺杂PM597的聚合物分散液晶（PDLC）以及掺杂PM597的含MnCl₂的PDLC毛细管体系中的随机激光行为。我们发现，与不含MnCl₂的体系相比，含MnCl₂的体系的随机激光表现出更低的阈值、更高的强度、更尖锐的峰值以及可变的共振波长。这种行为与荧光猝灭效应的降低以及MnCl₂与PM597之间能量转移所诱导的局部场增强密切相关。在含MnCl₂的掺杂PM597的PDLC体系中，随着MnCl₂剂量浓度的增加，观察到波长红移。通过对不含MnCl₂和含MnCl₂的掺杂PM597的PDLC体系的单次发射光谱分析，证实了MnCl₂在激光模式耦合中的作用。通过对不含MnCl₂和含MnCl₂的掺杂PM597的PDLC体系发射光谱的功率傅里叶变换（PFT）分析，计算了它们的激光振荡腔长度。这很好地解释了MnCl₂对振荡腔变化的影响。
