Room Temperature Continuous-Wave Inorganic Maser

直到最近，微波激射器还只能用于非常专业的应用，如射电天文学。这样做的原因是，低温冷却和较小程度的高磁场都以复杂性和成本为由阻止了大规模生产。尽管脉泽是在激光之前被发现的，但这些问题意味着后者，不需要施加磁场或冷却，在从条形码阅读器、激光光盘到激光眼科手术的广泛应用中得到了广泛应用。2013年，帝国理工学院和伦敦大学学院获得了EPSRC资助的研究项目，以生产室温脉泽。尽管我们初步观察到室温磁化是可能的，但我们还没有在不同的实验室环境中验证这一点，我们也不清楚磁化分子如何与光相互作用，以及哪些晶体取向或掺杂浓度将是最佳的。这次合作非常成功地实现了我们设定的所有目标。现在，在另一个世界，该团队建造了一台能够在室温下连续工作的钻石微波激射器。我们以前的研究只集中在有机材料作为介质。在这项提议中，我们将探索在室温下在无机材料中进行磁化的潜力。在这样做的过程中，我们将避免遇到与有机物有关的两个关键问题。问题1-衰减率：阻止有机物连续运行的主要障碍是最低三重态亚能级的相对较长的寿命，减少了可用于光学泵浦(瓶颈)的并五苯的数量并破坏了布居反转。问题2-加热：有机增益介质，对三联苯中的并五苯，我们首先用来证明室温微波激射器不能承受激光的连续照射，因为三联苯主体的温度高于其熔点。解决这两个问题：一个激进但令人兴奋的出发点将同时解决这两个问题，那就是探索具有高熔化/分解温度和良好导热系数(T.C.)的无机材料中的高自旋态：如钻石(M.P.3550C；T.C.2000 W/MK)和碳化硅(2730C；T.C.120 W/MK)。最近，我们在利用NV中心的钻石中观察到了室温下的磁化。这意味着我们可以在英国和其他地方关于钻石NV中心的大量研究基础上再接再厉。同样，有很多研究探索碳化硅中的缺陷，我们可以在此基础上进行改进。我们已经开始与维尔茨堡集团的Vladimir Dyakonov教授团队合作，他们目前正在探索SIC。裁判Https://arxiv.org/pdf/1709.00052.pdf实现了这一点，无疑将进一步确立英国作为开展室温脉泽主题基础研究的关键地点。

Until very recently the MASER could only be used in very specialist applications such as radio astronomy. The reason for this is that cryogenic cooling and to a lesser extent, high applied magnetic fields, prohibited mass production on the grounds of both complexity and cost. Despite the fact that the MASER was discovered before the LASER these issues meant that the latter, which does not need applied magnetic fields or cooling, saw widespread adoption in a huge range of applications from bar-code readers, laser discs to laser eye surgery.In 2013 Imperial and UCL were awarded an EPSRC funded research project to produce a room temperature MASER. Although we had preliminary observations that room temperature masing was possible we had not verified this in a different laboratory setting, nor did we have a clear idea of how the masing molecule interacted with light and which crystal orientations or dopant concentrations would be optimal. This collaboration was remarkably successful achieving all the objectives we set.Now, in what is another world first, the team has constructed a diamond MASER capable of continuous-wave operation at room temperature. Our previous research has concentrated solely on organic materials as the masing medium. In this proposal we will explore the potential of masing in inorganic materials at room temperature. In doing so we will obviate two key problems encountered with organics.Problem 1 - Decay rates: The primary obstacle that prevents continuous operation in organics is the relatively long lifetime of the lowest triplet sub-level, reducing the number of pentacenes available for optical pumping (bottleneck) and destroying the population inversion.Problem 2 - Heating: The organic gain medium, pentacene in p-terphenyl we first used to demonstrate a room temperature MASER cannot withstand a continuous illumination by a laser because the temperature of the terphenyl host rises above its melting point. Solution to both problems: a radical but exciting departure which will address both problems simultaneously is to explore high spin states in inorganic materials with high melting/decomposition temperature and favourable thermal conductivities (T.C.): such as diamond (M.P. 3550C; T.C. 2000 W/mK) and silicon carbide (2730C; T.C. 120 W/mK).Very recently we observed masing at room temperature in diamond exploiting NV centres. This means we can build upon a huge wealth of research in the UK and elsewhere on diamond NV centres. Again there is much research exploring defects in SiC that we can build on. We have initiated a collaboration with the group of Prof. Dr. Vladimir Dyakonov at Würzburg group who are currently exploring SiC. REF. https://arxiv.org/pdf/1709.00052.pdf Achieving this would further establish without doubt the UK as the key place to carry out fundamental research on the topic of room temperature MASERs.