Masers – the microwave analogues of lasers – have not seen the degree of use one might expect because they have long required cryogenics and high-vacuum systems. The development of room-temperature solid-state masers based on pentacene molecules in a p-terphenyl host in 2012 was a breakthrough, but the poor mechanical and thermal properties of p-terphenyl have restricted these masers to pulsed mode. Now, Jonathan Breeze of Imperial College London and colleagues have demonstrated the first continuous-wave room-temperature maser oscillator using optically pumped nitrogen-vacancy defect centres in diamond at 9.2 GHz. Immediate applications include radio astronomy and deep-space communications.

Further reading

J D Breeze et al. 2018 Nature 555 493.