2019 Henry Moseley Medal and Prize
Dr Jonathan Breeze for his pioneering work on room-temperature solid-state masers. In particular, his breakthrough demonstration of continuous-wave room-temperature diamond masers that pave the way for a new generation of optical-microwave quantum devices.
Solid-state masers were confined to operate at liquid helium temperatures and high vacuum since the 1960s and so only found niche applications where their unparalleled low-noise performance was vital and transformative, such as radio astronomy and deep-space communications.
Jonathan Breeze’s doctoral work – on the theory of microwave absorption in metal oxides and ultra-high quality-factor microwave cavity resonators, instigated the conception and realization of the world's first room-temperature solid-state maser in 2012. This maser used photo-excited pentacene molecules as an invertible gain medium.
Breeze then miniaturised the pentacene maser using strontium titanate, reducing the optical pump power threshold by three orders of magnitude, from kilowatts to watts. With this maser he managed to observe vacuum Rabi oscillations and normal mode splitting, the hallmarks of the strong-coupling regime of quantum optics and cavity quantum electrodynamics. This was also conducted at room-temperature and was his first step in establishing masers as solid-state platforms for the exploration of many-body quantum optics and cavity quantum electrodynamics at room-temperature.
The pentacene maser was unable to operate continuously, only providing microwave maser emission briefly for a fraction of a second. Breeze turned his attention to quantum defects in inorganic materials, specifically nitrogen-vacancy colour centres in diamond. Building on the maser quantum theory he had developed, and electron spin resonance measurements on nitrogen-vacancies, he predicted that a continuous-wave diamond maser was feasible. He designed and built a high-performance sapphire microwave cavity resonator that satisfied the maser threshold conditions and then successfully demonstrated another world first: the continuous-wave room-temperature maser.
Breeze is currently the world's leading researcher in the field of solid-state room-temperature masers. His work has established a new branch in the field of solid-state quantum technology and revitalised the field of masers.