Generation and amplification of microwave signals via planar waveguides with embedded paramagnetic color centers

Year: 2026

Authors: Lagomarsino S., Agio M.

Autors Affiliation: Natl Res Council CNR, Natl Inst Opt INO, I-50019 Sesto Fiorentino, Italy; Univ Siegen, Lab Nanoopt, D-57072 Siegen, Germany.

Abstract: A concept for microwave (MW) amplification and maser generation in compact planar waveguides embedding a thin layer of paramagnetic color centers is presented. The ground state of the color centers can be optically or electrically spin-polarized, while population inversion is attained by Zeeman shifting of one spin sublevel below the populated state. A signal traveling along the waveguide, if resonant with the spin transition, can be amplified, or a self-sustained MW oscillation can be generated. A general analysis of the conditions for amplification and self-oscillation is developed for nitrogen-vacancy-rich diamond films, together with practical examples of impedance matching and resonator design. The proposed architecture combines near-unity filling factors with relatively low electromagnetic quality factors, enabling operation in strongly coupled configurations and broad frequency tunability through the external magnetic field. The same formalism naturally extends to compact lumped-element resonators operating at a few gigahertz while preserving millimeter-scale dimensions. Compared with the present state of the art of diamond masers, the approach offers reduced size, simplified integration with external electronics, and relaxed requirements on cavity quality factor.

Journal/Review: PHYSICAL REVIEW APPLIED

Volume: 26 (3)      Pages from: 34028-1  to: 34028-15

More Information: This work received funding from the European Defence Fund (EDF) under grant agreement No. 101103417 – project ADEQUADE. Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the granting authority can be held responsible for them.
KeyWords: Amplifier
DOI: 10.1103/ydkl-pjfx