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

在调查与该项目相关的领域的趋势时，我们注意到，到目前为止，多次光散射和球形共振（形态依赖共振; MDR）的有效性已经相互独立地讨论。本计画结合多重光散射与多重共振特性，探讨高增益随机介质中单一微滴光学特性的基本动力学，并进行实验研究，以揭示其输出、空间与光谱特性。根据实验方法的不同，将它们分为两类。第一种是Lawandy等人[N. M. Lawandyetal. Nature，p.436，1994]提出的，基于光泵染料混合体溶液和强散射的固体纳米TiO_2散射体。第二种方法 关于我们 最初依赖于染料掺杂的液体球形微滴（微球），其中透明介质产生具有高Q值的光学腔，使得可以通过用强激光束激发来容易地观察激光作用[P. W. Barber和R. K. Chang，Eds.，“与小粒子有关的光学效应“，世界科学，新加坡，1988年]。1）首次报道了将聚甲基丙烯酸甲酯（PMMA）固体纳米粒子取代到罗丹明6 G（RH 6 G）染料微滴中，激光发射得到了显著增强，并具有明确的阈值[H.Taniguchi et al.Opt.Lett.p.263，1996]。2)使用与某些激光染料[Appl.Phys.Lett.p.719，1996; Appl.Opt.in Press]和3）新的生物化学材料（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[www.example.com，1996; CLEO/Pacific Rim '97，P6，p.156，1997; Electron.Lett.p.1797，1997]混合的球形微滴中的高散射脂肪乳剂Intralidid-10%进行后续实验。Electron.Lett.p.1484 5)我们还证实了在这些染料-高散射纳米颗粒混合物中，由于球形腔的MDR而导致的模式结构的消失取决于散射体的取代含量;即，表明多重光散射在微滴内部建立激光的主导作用。该项目的主要目的通过该项目在世界上领先足够地完成。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