Description
Low noise microwave receivers – which are essential for satellite communications, radar, and radio astronomy – require first stage amplifiers to boost the received signal while adding as little noise as possible. In room temperature applications, the current best-in-class high electron mobility transistor (HEMT) based amplifiers have noise temperatures that scale poorly with frequency – Increasing from $\sim$10 K at 1 GHz to over 100 K at 35 GHz.
Room temperature diamond-based maser amplifiers [1] have the potential to operate with much lower noise temperatures, approaching the quantum limit of 1.7 K at 35 GHz. Here we present a room temperature 35 GHz maser amplifier using diamond nitrogen vacancy centres (NV$^-$) as the gain medium, with the host diamond crystal itself acting as the maser’s dielectric resonator. This architecture supports a large overlap between the microwave mode and the NV- spins, achieving a filling factor $\eta \approx 0.6$, compared to the $\eta \leq 0.2$ reported in designs placing the diamond gain medium with a tubular dielectric resonator [1-3].
We characterise the performance of the amplifier and discuss the potential for diamond-based masers to become the lowest noise room temperature amplifiers in the Q-Band.
References:
[1] T. Day et al. Room-temperature solid-state maser amplifier. Phys. Rev. X 14, 041066 (2024)
[2] J. D. Breeze et al. Continuous-wave room-temperature diamond. Nature 555, 493 (2018)
[3] C. W. Zollitsch et al. Maser threshold characterization by resonator q-factor tuning. Commun. Phys. 6, 295 (2023)
| I am the presenting author | Yes |
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