Lasing Characteristics and Ultra High-Speed Optical Dynamics from Single Microdroplets Containing Gain-Highly Scattering Turbid Media

在调查与本项目相关的领域的趋势时，我们注意到，到目前为止，多重光散射和球面共振(形态相关共振；MDR)的有效性一直被相互独立地讨论。该项目将多重光散射和具有高品质因数共振的MDR相结合，探索含有增益-高散射混浊介质中单个微滴的光学性质的基本动力学。光学增益随机介质中的激光行为最近引起了人们的极大兴趣，并进行了实验研究，以揭示发射的输出、空间和光谱特性。根据实验方法，将其分为两类。第一个是由Lawandy的小组[N.M.Lawandy等人]发起的。自然，P.436,1994]，是基于光学泵浦的染料溶液与强散射固体纳米二氧化钛散射体混合而成的。第二种方法…更多的依赖于染料掺杂的液体球形微滴(微球)，透明介质在其中产生具有高Q值的光学空腔，从而可以通过强激光光束的激发容易地观察到激光作用[P.W.Barber和R.K.Chang编辑，“与小粒子相关的光学效应，”世界科学，新加坡，1988]。1)通过将聚甲基丙烯酸甲酯(PMMA)固体纳米粒子替换到罗丹明6G(RH6G)染料微滴中，我们首次报道了伴随着明确定义的阈值的激光发射显著增强[H.Taniguchi等人，Opt.Lett.263,1996]。2)随后的实验使用高分散脂肪乳剂Intralipid-10%在球形微滴中与一些激光染料混合[Appl.Phys.Lett.p.719,1996；Appl.Opt.in Press]和，3)一种新的生化材料(Ribo-Flavin)[CLEO/Pacific Rim‘97，P7，p.157,1997]，4)与直接从生物组织中提取的色素[Electron.Lett.1484,1996；CLEO/Pacific Rim’97，P6，P.156,1997；Electron.Lett.p.1797,1997]作为激光。5)我们还证实了在这些染料-高散射纳米粒子混合物中，由于MDR导致的模式结构的消失取决于被取代的散射体的含量，即表明多重光散射在微滴内部建立激光的主导作用。本项目的主要目的充分地提前于世界。较少

In surveying a trend of the field related to this Project, we notice that the effectiveness of multiple light scattering and of spherical resonance (morphology-dependent resonance ; MDR) has been discussed independently each other, up to the present. This Project pursued probing the fundamental dynamics of optical properties in single microdroplets containing gain-highly scattering turbid media, combining the multiple light scattering and the MDR with high quality-factor of resonances.Lasing action in optical gain random media has attracted recently a great deal of interest and experimental studies were performed to reveal the output, spatial, and spectral characteristics of the emission. They are divided into two categories according to the experimental methods. The first one, initiated by Lawandy's group [N.M.Lawandy et al. Nature, p.436,1994], is based on optically pumped bulk solution of dye mixed with strongly scattering solid-nanoparticles of TiO_2 scatterers. The second approach … More relies originally on dye-doped liquid spherical microdroplets (microspheres) in which transparent medium produces optical cavities with high-Q values so that laser action can be readily Observed by excitation with intense laser beams [P.W.Barber and R.K.Chang, Eds., "Optical effects associated with small particles, "World Scientific, Singapore, 1988]. The results obtained from this Project are as follows :1) By substituting the poly (methyl methacrylate) (PMMA) solid-nanoparticles into Rhodamine 6G (RH6G) dye microdroplet, we have first reported significantly enhanced laser emission accompanying with the well-defined thresholds [H.Taniguchi et al.Opt.Lett.p.263,1996]. 2) Succeeding experiments were performed using highly scattering fat emulsion Intralipid-10% in spherical microdroplets mixed with some laser dyes [Appl.Phys.Lett.p.719,1996 ; Appl.Opt.in Press] and, 3) a new biochemical material (Ribo-Flavin) [CLEO/Pacific Rim '97, P7, p.157,1997], 4) together with pigments extracted directly from biological tissues [Electron.Lett.p.1484,1996 ; CLEO/Pacific Rim '97, P6, p.156,1997 ; Electron.Lett.p.1797,1997] as lasants. 5) We have also confirmed in these dye-highly scattering nanoparticle mixtures, the disappearance of the mode structures due to MDR's of spherical cavities depending on the substituted contents of the scatteres ; i.e., indicative of dominant role of multiple light scattering to establish lasing inside the microdroplet.The main aim of this Project was accomplished sufficiently in advance of the world by this Project. Less