Tunable terahertz source on a chip with decade-long stability using layered-superconductor elliptical microcavities

Abstract

Chip-scale, electrically tunable, continuous-wave, coherent terahertz (THz) radiation sources are critical for emerging applications in sensing, imaging, spectroscopy, communications, space, and quantum technologies. Here, we demonstrate a robust source-on-a-chip THz emitter based on a layered high-temperature superconductor, engineered with an elliptical microcavity and capable of sustained coherent emission over an unprecedented operational lifetime exceeding 11 years. This compact THz source operates up to 60 K (with Tc ≈ 90 K), delivering stable radiation in the 0.7–0.8 THz range, with on-chip electrical tunability from 100 GHz to 1 THz. Coherence arises from the phase-locked oscillation of intrinsic Josephson junction arrays, resonantly coupled to transverse electromagnetic modes within the cavity, analogous to a laser cavity, yielding collective macroscopic oscillations. THz emission remains detectable across an approximately 0.5-m free-space open-air link at room temperature. We analyse the cavity-mode structure and extract THz photon generation rates up to approximately 503 photons fs−1 in cryogenic conditions and 50–260 photons ps−1 over the air. These results demonstrate, for the first time, sustained and electrically tunable coherent THz emission from superconductors over multiyear timescales, defining another class of robust, chip-integrated THz lasers with applications in scalable THz and quantum technologies.

Source-reported materials — not catalogue approval

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