Portable maser oscillator at room temperature with reduced magnetic field requirements through spatial orientation

Masers could transform medical sensing and boost qubit readout detection due to their superb low-noise amplification. The negatively charged nitrogen-vacancy diamond maser is the only continuous-wave solid-state maser operable at room temperature; however, it requires cumbersome magnets, which prevent its widespread use. We present a significant size reduction of the diamond maser oscillator using a much lighter electromagnet with a small footprint, reducing the weight from 2000 kg to a more portable 30 kg. We achieve a maximum oscillator output power near <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mo>−</a:mo><a:mn>80</a:mn></a:math> dBm, ten times higher than the first implementation, and discover techniques to reduce the magnetic field strength required for masing by 30 mT through precise manipulation of spin orientation. With the diamond maser now shrunk to a size that can fit on a benchtop, we move continuous-wave room-temperature masers away from the confines of research laboratories and closer to transforming readouts in quantum computing, frequency standards, and quantum-limited medical sensing.