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带来了一场革命：从重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，这是由基质材料中的掺杂剂决定的，并且通常与之相关。我们的目标是取消一些限制，通过使用量子点(QD)形式的工程化“原子”来执行三项功能：放大、激光和激光的逆功能：用激光进行固态冷却。QD的主要优势不是找到与掺杂剂的吸收光谱相匹配的激光，而是通过改变其大小，它可以在几乎任何波长下表现出吸收，使其与任何激光波长相匹配。这对于创建用于激光的新光源、打开用于放大的新波长区域(例如，在1200 nm波长区域，高增益主要是通过拉曼散射才能实现)以及最终用于激光诱导冷却具有许多优点，而激光诱导冷却一直是极少数材料系统的保留，对样品的纯度和质量要求极高。我们的理论和模型表明，使用超辐射方案和量子点，有可能将这一过程开放给更多的玻璃和晶体，使它们对非辐射过程(如俄歇复合)具有显著的耐受性，并可用于高声子能量材料。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.