Quantum dot optical superradiance, broadband amplifiers, lasers and laser cooling: QUDOS

光的放大在人类活动的许多方面引发了一场革命：从重型工业激光应用到生物医学诊断。放大的基本原理是基于从短波长到长波长的能量转换，这取决于并且通常与主体材料中的掺杂剂有关。我们的目标是解除一些限制，通过使用量子点（QDs）形式的工程“原子”来执行三个功能：放大，激光和反向激光：用激光进行固态冷却，从而打开新的光谱窗口。量子点的主要优点是，通过改变其尺寸，它可以在几乎任何波长表现出吸收，使其与任何激光波长相匹配，而不是寻找与掺杂剂的吸收光谱相匹配的激光。这对于创建新的激光源，打开新的波长区域进行放大（例如在1200nm波长区域，高增益主要只能通过拉曼散射实现）以及最终用于激光诱导冷却有许多优点，这一直是极少数材料系统的保留，需要极高的纯度和样品质量。我们的理论和模型表明，使用超辐射方案，以及量子点，有可能将这一过程开放给更大的玻璃和晶体，通过使它们对非辐射过程（如俄歇复合）具有更大的耐受性，并且可以与高声子能量材料一起使用。最终目标是允许使用最好的玻璃系统：二氧化硅，以及其他商业材料系统，如硫族化物和ZBLAN玻璃纤维。

Amplification of light has lead to a revolution in many facets of human activities: from heavy industrial laser applications to bio-medical diagoneses. The fundamental principle of amplification is based on the energy conversion from a short wavelength to a longer wavelength, determined and usually associated with a dopant in the host material. We aim to lift some of the restrictions to open new spectral windows for gain by using engineered "atoms" in the form of quantum dots (QDs) to perform three functions: Amplification, lasing and the inverse of lasing: solid state cooling with lasers. Rather than finding a laser to match the absorption spectrum of the dopant, the principal advantage of the QD is that by modifying its size, it can exhibit absprption at virtually any wavelength, matching it to any laser wavelength. This has many advantages for creating new sources for lasing, openning new wavelength regions for amplification (for example in the 1200nm wavelength region, where high gain is principally only possible with Raman scattering), and ultimately for laser induced cooling, which has been a preserve of very few material systems, requiring extremely high purity and quality of samples. Our theory and modelling show that using the schemes of superradiance, as well as QDs, it is possible to open this process to a much larger set of glasses and crystals, by making them significantly more tolerant to non-radiative processes such as Auger recombination, and may be used with high phonon energy materials. The ultimate aim is to allow the use of the best glass system: Silica, as well as other commercially materials systems, such as chalcogenides and ZBLAN glass fibres.