RUI: Unilateral Lasing in Underwater Animals

非技术描述：自然界中一些最鲜艳的颜色不是由吸收光线的染料或颜料造成的，而是由物体的非常微观的结构造成的。许多热带鱼通过被称为虹膜载体的特殊细胞内的小平面结构反射的光波的干扰，显示出美丽的虹彩颜色。这些反射结构与现代显微激光技术有相似之处。虹膜载体细胞可以被注入荧光分子并发光，而不是反射光线。虹膜基团内部的结构导致光线在很长一段时间内反弹，从而在微观尺度上产生激光发射所需的反馈。该项目的目标是更好地了解来自虹彩生物结构的激光散射和发射，并将这些信息作为一种工具，以获得围绕在一些专门细胞中发现的微观结构的新见解。为此，将使用基于光的实验方法以及原子尺度的倾斜悬臂和电子束来探索在两种不同鱼类中发现的虹膜基团发出的激光的基本物理。将开发模型以更深入地了解观察到的现象。了解生物介质中的激光发射可能会对生物学、激光物理、材料科学和医学等领域产生潜在影响。通过这项提议，将专门为本科生和高中生创造研究机会，这对培养未来的科学家和工程师至关重要。技术描述：入侵夏威夷珊瑚礁的淡水鱼Paracheirodon inniti和海鱼Cephalopholis Argus都有特殊的色团细胞，称为虹膜细胞，由于反射光的干扰而显示出虹彩颜色。科学验证的多层鸟嘌呤/细胞质结构导致了多彩的外观，可以作为多层分布式反馈激光结构。Gain将通过具有高量子产率的荧光发色团的扩散引入细胞质层，这些荧光发色团通过各种方法穿过脂质双层膜。激光阈值行为和斜率效率将在这两个物种的虹膜中进行研究，以及由于光子晶体结构中诱导的物理变化而产生的激光发射的可调性。鸟嘌呤小片的尺寸将决定单个鸟嘌呤晶体小片的结构，而透射电子显微镜技术将成像光子晶体结构的横截面。基于物理的现象学模型将从物理、电子束、线性光学和激光测量中发展出来。激光发射的结果将与使用原子力显微镜和透射电子显微镜研究获得的腔体信息的有限差分时间域模拟进行比较。这两种鱼的发射特性将与无机、有机和生物激光的既定结果进行比较。从根本上讲，通过对复杂生物结构中激光的研究，可以产生用于可调谐激光器的新的激光结构。从系统的角度来看，这项研究将进一步加深我们对动物中相干光的产生和操纵的理解。从工程角度来看，将实现用于显微激光的新的生物兼容性和/或生物原生设计。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical Description:Some of the most brilliant colors in nature are not caused by light-absorbing dyes or pigments, but rather from the very microscopic structure of objects. Many tropical fish display beautiful iridescent colors through the interference of reflected light waves from small planar structures inside specialized cells called iridophores. These reflective structures have similarities to modern microscopic laser technologies. Instead of reflecting light, iridophore cells can be infused with fluorescent molecules and emit light. The structures inside the iridophores cause light to bounce around for long periods of time which causes the feedback necessary for laser emission at the microscopic scale. The project’s goals are to better understand laser light scattering and emission from iridescent biological structures and use this information as a tool to gain new insights surrounding the microscopic structures found in some specialized cells. To this end, the underlying physics of laser light emitted from the iridophores found in two different fish species will be probed using light-based experimental methods as well as atom-scale tipped cantilevers and beams of electrons. Models will be developed to gain a deeper understanding of the observed phenomena. Understanding laser emission from biological media can potentially impact the fields of biology, laser physics, materials science, and medicine. Research opportunities, critical to training future scientists and engineers, will be created specifically for undergraduate and high school students through this proposal. Technical Description:The freshwater fish, Paracheirodon innesi, and the marine fish invasive to Hawaiian reefs, Cephalopholis argus, have specialized chromatophore cells called iridophores that exhibit iridescent colors caused by the interference of reflected light. The scientifically verified multilayer guanine/cytoplasm structures in Paracheirodon innesi that cause the colorful appearance can act as a multilayer distributed feedback laser architecture. Gain will be introduced into the cytoplasm layers through diffusion of fluorescent chromophores with high quantum yields that are passed across the lipid bilayer membrane through various methods. The laser threshold behavior and slope efficiencies will be studied in the iridophores of both species as well as the laser emission’s tunability from induced physical changes in the photonic crystal structures. The guanine platelet dimensions will determine the structure of individual guanine crystal platelets, and transmission electron microscopy techniques will image cross sections of the photonic crystal structures. Physics-based phenomenological models will be developed from physical, electron beam, linear optical, and laser measurements. The laser emission results will be tested against finite-difference time-domain simulations using cavity information gained from atomic force microscopy and transmission electron microscopy studies. The emission characteristics in both fish species will be compared with established results for inorganic, organic, and biological lasers. From a fundamental perspective, new laser architectures for tunable lasers could result from this study of lasing in complex biological architectures. From a systems perspective, the investigation will further our understanding of the production and manipulation of coherent light in animals. From an engineering perspective, new biocompatible and/or biogenic designs for microscopic lasers will be realized.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.