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
|