Abstract

The MASER, acronym for Microwave Amplification by Stimulated Emission of Radiation, was invented around 60 years ago and exploits paramagnetic transitions in quantum systems to amplify radio frequency/microwave signals. Potential applications include more sensitive variants of Electron Paramagnetic Resonance (EPR) spectroscopy, magnetic resonance body scanners, deep-space telecommunications, read-out schemes for spin-based quantum computers, and embodiments of “quantum optics” at microwave and radio frequencies. Recent improvements on masers have demonstrated room-temperature operation in both pulsed and continuous waves using solid-state materials and solid-state laser pumping [1, 2]. A crucial research challenge is to replace the pump laser by a more rugged and low-cost system. LED-pumped luminescent concentrators [3-5] are ideal for this purpose, because they are low-cost with simple fabrication and low maintenance.

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