Enhanced magnetic Purcell effect in room-temperature masers

• Published in: Nature communications Vol. 6; no. 1; p. 6215
• Main Authors: Breeze, Jonathan, Tan, Ke-Jie, Richards, Benjamin, Sathian, Juna, Oxborrow, Mark, Alford, Neil McN
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 20-02-2015; Nature Publishing Group; Nature Pub. Group
• Subjects: 119/118; 639/624/399/1097; 639/624/400/1101; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms7215

Recently, the world’s first room-temperature maser was demonstrated. The maser consisted of a sapphire ring housing a crystal of pentacene-doped
p
-terphenyl, pumped by a pulsed rhodamine-dye laser. Stimulated emission of microwaves was aided by the high quality factor and small magnetic mode volume of the maser cavity yet the peak optical pumping power was 1.4 kW. Here we report dramatic miniaturization and 2 orders of magnitude reduction in optical pumping power for a room-temperature maser by coupling a strontium titanate resonator with the spin-polarized population inversion provided by triplet states in an optically excited pentacene-doped
p
-terphenyl crystal. We observe maser emission in a thimble-sized resonator using a xenon flash lamp as an optical pump source with peak optical power of 70 W. This is a significant step towards the goal of continuous maser operation.
Masers are promising for applications that use microwave radiation. Here, the authors present a compact room-temperature maser design using a high permittivity dielectric material for the resonator to achieve low optical pumping powers. This design pushes masers closer towards their promised applications.