EPSRC Fellowships in Manufacturing - "Manufacturing Routes for Organic Room-Temperature MASER"

该奖学金的目的是采取最近报道的发现，即能够在室温下工作的固态微波激射器，并在此基础上开展一项工作方案，以提高两个关键应用领域的“可制造性”。背景：微波激射器，代表微波放大受激辐射，是大约60年前发明的，利用量子系统中的顺磁跃迁来放大射频/微波信号。几年后，紧接着它的激光器通过完全相同的物理机制（即受激发射）工作，但频率要高得多，利用电子跃迁来放大--从而产生--紫外线、可见光和红外光。作为一种设备，微波激射器是有用的，因为它们可以放大极其微弱（通常是珍贵的）的电磁信号，而不会通过增加随机噪声来破坏它们，否则如果使用噪声更大的传统（基于斩波器的）放大器，就会发生这种情况。激光现在无处不在，并且已经找到了大量的应用。另一方面，微波激射器仅用于特殊的、性能关键的应用，如原子钟或作为最灵敏的射频望远镜和地面站中的低噪声放大器。迄今为止，它们相对模糊的原因是，所有提供有用性能的微波激射器系统都必须包括体积庞大或消耗大量功率（通常是千瓦）的套件，或者两者兼而有之。具体来说，由NASA开发和使用的传统固态脉泽需要低温和大量施加的直流磁场才能工作，因此反过来需要庞大的耗电制冷机和磁体。原子/分子脉泽虽然能够在室温下工作（勉强），但仍然需要体积庞大的真空室和泵，同样难以组装。通过这项研究开发的新型脉泽避免了这些限制：它在空气中，在室温下，在地球的环境磁场中工作。因此，原则上，它更适合于成本敏感的便携式应用。该奖学金如何具体增加价值：导致原理验证演示器的初步工作现已发布 *，但仍存在严重抑制可制造性的问题：1原型仅在脉冲模式下工作;尽管寻求连续（CW）操作，但涉及废热的去除。1、2和3的实质性进展可以通过单独的工程解决方案来实现（而不是进一步的“突破”），同时要注意：4某些关键部件目前是由生长成本高的单晶制成的，这些单晶的形成（通过熟练的手工研磨和抛光）同样昂贵。这些建造成本需要提取。奖学金的目的是找到解决上述所有障碍的方法-特别关注最后一个障碍4，并允许它规范1，2和3中更多的工程活动。室温固态微波激射器J. D. Breeze & N. M.阿尔福德，《自然》，DOI 10.1038/nature 11339，2012年8月16日;另见阿哈龙·布兰克的《新与观点》（同上）：http://www.nature.com/nature/journal/v488/n7411/full/488285a.html

The aim of this fellowship is to take a recently reported discovery, namely a solid-state maser capable of operating at room temperature, and to carry out a programme of work based upon it that will enhance "manufacturability" for two key application areas.Background:The MASER, standing for Microwave Amplification by Stimulated Emission of Radiation, was invented some 60 years ago and exploits paramagnetic transitions in quantum systems to amplify rf/microwave signals. The LASER, which followed directly on from it a few years later, operates through exactly the same physical mechanism (namely stimulated emission) but at much higher frequencies, exploiting electronic transitions to amplify -and so generate- ultraviolet, visible, and infrared light. As devices, masers are useful because they can amplify extremely weak (often precious) electromagnetic signals without corrupting them through the addition of random noise, as would otherwise happen if noisier, conventional (semiconductor-based) amplifiers were used.Lasers are now ubiquitous and have found their way into a plethora of applications. Masers, on the other hand, are used only in specialised, performance-critical applications such as atomic clocks or as low-noise amplifiers in the most sensitive radiofrequency telescopes and ground stations. The cause of their relative obscurity to date is that all maser systems offering useful performance have necessarily included pieces of kit that are either bulky or consume substantial amounts of power (often kilowatts), or both. Specifically, conventional solid-state masers, as developed and used by NASA, require both cryogenic temperatures and substantial applied d.c. magnetic fields to work, so in turn requiring bulky, power-consuming refrigerators and magnets. Atomic/molecular masers, though capable of room-temperature operation (after a fashion), still require bulky vacuum chambers and pumps, which are equally hard to miniaturize. The novel type of maser to be developed through this fellowship avoids these limitations: it works in air, at room temperature, in the Earth's ambient magnetic field. It is thus, in principle, vastly more amenable to cost-sensitive, portable applications. How the Fellowship specifically adds value:Preliminary work leading to a proof-of-principle demonstrator has now been published*, but there remain issues that substantially inhibit manufacturability:1 The prototype works only in pulsed mode; continuous (CW) operation is sought though with thermal implications concerning the removal of waste heat.2 Wall-plug power efficiency must to be improved, aiming to get the threshold for CW masing down to a few watts.3 Physical miniaturisation is required for portable applications. Substantial progress on 1, 2 and 3 can be made through engineering solutions alone (as opposed to further "breakthroughs"), whilst being ever mindful of:4 Certain critical components are currently made out of expensive-to-grow single crystals that are equally expensive to form (by skilled hand grinding and polishing) into their required shapes. These build costs need to be extracted.The purpose of the fellowship is to find solutions to all of the above impediments -focussing especially on the last of them 4 and allowing it to regulate the more engineering activities in 1, 2 and 3.* Room temperature solid-state maser, M.O., J. D. Breeze & N. M. Alford, Nature, DOI 10.1038/nature11339, 16th August 2012; see also Aharon Blank's "New and Views" (ibid.): http://www.nature.com/nature/journal/v488/n7411/full/488285a.html