Semiclassical and Quantum Theory of Open and Complex Lasers

该奖项支持凝聚态物理、量子光学和光子学领域的理论研究和教育。PI及其同事开发了一种新颖的自洽激光理论，该理论发现了具有任意复杂性和开放性腔的激光器的稳态，而无需进行时间相关的模拟。该理论用一个单一的、合理的近似准确地处理了空腔的开度和空腔中所有阶的非线性相互作用。最近与精确的随时间变化的激光方程数值模拟的比较证实了该方法的准确性和有效性。PI已经将该理论应用于处理扩散随机激光器，这种系统由于其极端的开放性而抵制传统方法。将研究该理论在介质腔激光器的形状设计、增益介质中的散斑相关测量和可调谐随机激光器中的应用。此外，将发展一个完整的随机激光器的统计理论，以表征它们的频率分布，激光模式的数量，它们的频率和模态强度在泵浦和杂质结构变化下的稳定性。最后，该理论将扩展到超出半经典极限的范围，包括决定激光线宽和噪声特性的场量化效应。长期目标是根据这项工作开发的理论模型开发一个现实的激光仿真代码，这可能会产生非常广泛的技术影响。该奖项支持对量子光学和光子学领域有潜在影响的理论研究和教育。该奖项支持的研究有可能改变我们对激光的基本认识，激光广泛应用于包括CD播放机和一些手术工具在内的各种技术中。与灯泡不同的是，激光产生的光波中每一波都是同步的。这种相干性使器件技术能够利用干扰现象进行操作。这个研究项目发展了一种新型激光器的理论，随机激光器，像其他激光器一样，发射相干光，但不像其他激光器，在随机方向。普通激光器使用精确放置的反射镜将激光捕获在增益材料中以放大光。相比之下，随机激光器中的光被捕获在增益材料中，因为激光从该材料中随机定位的散射中心散射。光局域化的概念类似于电子被困在不完美材料中的局域量子力学状态？凝聚态物理中研究的一种现象，它的某些方面使该问题处于该领域的前沿。π吗?S的研究对新开发的激光有潜在的影响，这种激光的尺寸约为千万分之一英寸，有许多潜在的实际应用，包括检测人体组织的损伤，揭示水中的化学杂质，以及确定文件的真实性。PI的目标是基于该理论模型开发一个现实的激光仿真代码，这将具有广泛的技术影响，然后将代码用于激光设计和优化。这项研究处于科学和光学工程的前沿，并将有可能在现实世界中应用，从而造福社会。

TECHNICAL SUMMARYThis award supports theoretical research and education at the interface of condensed matter physics, quantum optics, and photonics. The PI and coworkers have developed a novel self-consistent laser theory, which finds the steady-state of a laser with a cavity of arbitrary complexity and openness without doing time-dependent simulations. The theory treats the openness of the cavity exactly and the non-linear interactions in the cavity to all orders with a single, well-justified approximation. Recent comparisons to exact time-dependent numerical simulations of the lasing equations confirm the accuracy and validity of the approach. The PI has applied the theory to treat diffusive random lasers, a system which resisted conventional approaches because of its extreme openness. Applications of the theory to shape design of dielectric cavity lasers, to speckle correlation measurements in media with gain and to tunable random lasers will be studied. In addition, a full statistical theory of random lasers will be developed, to characterize their frequency distribution, number of lasing modes, the stability of their frequencies and modal intensities under changes in pump and impurity configuration. Finally, the theory will be extended beyond the semiclassical limit to include field quantization effects, which determine the laser linewidth and noise properties. A long-term goal is to develop a realistic laser simulation code based on the theoretical model developed by this work, which could have very wide technological impact.NONTECHNICAL SUMMARYThis award supports theoretical research and education with potential impacts on the fields of quantum optics and photonics. The research supported by this award has the potential to change our basic understanding of lasers, which are used in a wide range of technologies including CD players and some surgical tools. Unlike a light bulb, lasers generate light waves in which each wave is in lock-step with another. This property of coherence enables device technologies that exploit the phenomenon of interference for their operation. This research project develops a theory for a new kind of laser, random lasers which, like other lasers, emits coherent light, but unlike other lasers, in random directions. Ordinary lasers use strategically placed precision mirrors to trap laser light in a gain material to amplify the light. In contrast, light in random lasers is trapped in the gain material by the laser light being scattered from randomly positioned scattering centers in that material. This notion of localizing light has analogies to electrons being trapped in localized quantum mechanical states in imperfect materials ? a phenomenon studied in condensed matter physics with aspects that keep the problem at the frontiers of the field. The PI?s research has potential impact on newly developed lasers that are about a ten-millionth of an inch in size and has many potential practical applications, including detecting injuries in human tissues, revealing chemical impurities in water, and determining the authenticity of documents. The PI aims to develop a realistic laser simulation code based on this theoretical model, which would have wide technological impact, with the code then used for laser design and optimization. This research lies at the cutting edge of science and optical engineering, and will possible real world applications that would benefit society.