2023 Michael Faraday Medal and Prize
Room Temperature MASER Team for their discovery of the world's first room-temperature solid-state organic maser and subsequent discovery of room-temperature continuous wave masing in diamond.
The team consists of Professor Neil Alford, Professor Mark Oxborrow, Professor Chris Kay, Dr Jonathan Breeze, Dr Juna Sathian and Professor Enrico Salvadori.
The team who discovered the world’s first solid-state room-temperature masers in pentacene and then in diamond consists of Professor Mark Oxborrow and Professor Neil Alford from Imperial College London, Professor Chris Kay and Dr Jonathan Breeze from University College London, Dr Juna Sathian now at the University of Northumbria and Professor Enrico Salvadori now at Università degli Studi di Torino. This team was the first to solve a 60 year-old problem: getting a solid-state maser to work at room temperature.
The amplification of weak yet precious electromagnetic radiation without adding additional, deleterious noise to the signal, opens up many life-enhancing applications. The means for doing so still remains an engineering challenge in terms of performance, cost and convenience. One early promising low-noise technology was the maser, discovered by Charles Townes in the 1950s and a sister technology to the laser. However, the maser has had little widespread technological impact because it was inconvenient to use, only functioning in high magnetic fields, a vacuum and at cryogenic temperatures close to absolute zero. Nevertheless, masers did see continuing use where their unmatched noise properties were essential; for example, radio astronomy. Room-temperature masers offer the luxury of low noise without the debilitating constraints and costs imposed by cryogenics.
Solid-state masers are the ultimate ‘hifi’ amplifiers for weak microwave signals: they possess low residual noise temperatures, low intermodulation distortion and exhibit low 1/f noise. Certain applications in communications and measurement involve the reception of extremely weak, narrow-band signals, where the signal-to-noise ratio is perilously low (risks dropping below the threshold for detection), and which are subject to jamming/interference. Here, masers outperform semiconductor devices.
Masers could thus facilitate clearer images in a magnetic resonance imaging machine, or alternatively match current standards of resolution and contrast yet with lower acquisition times. If we chart the history of the laser and its now impressive array of ubiquitous applications, we can anticipate that a coherent source of microwaves and their subsequent detection (using so-called correlation techniques) could open up many new applications in radar, microwave computerised tomography and microwave imaging that are not possible with current incoherent sources and noisy receivers. This means that, in air- or ground-penetrating radar, the shapes of targets could be more recognizable; the possibilities of more detailed physiological medical data could be recorded and new medical imaging (and thereupon treatment) modalities invented. Quantum optical coherence tomography at microwave frequencies, for example, remains a challenge that is as alluring as it is daunting. But it is now not so far away.
Images top row left to right: Professor Neil Alford, Professor Mark Oxborrow, Professor Chris Kay. Bottom row left to right: Dr Jonathan Breeze, Dr Juna Sathian, Professor Enrico Salvadori