Large-scale array of resonant-tunneling-diode terahertz oscillators for high output power at 1 THz

TLDR

The study proposes and fabricates large‑scale arrays of resonant tunneling diode oscillators to achieve high‑output‑power terahertz sources. The arrays consist of RTD elements integrated with slot resonators and dipole array antennas on a dielectric stack, designed to radiate upward without a silicon lens and to maximize average output power through size variation. Experiments show output power scales with array size, reaching 0.73 mW for an 89‑element array at ~1 THz, but the per‑element power (9 µW) is lower than isolated oscillators (21 µW), with multiple spectral peaks attributed to unintentional coupling.

Abstract

We proposed and fabricated large-scale arrays of resonant tunneling diode (RTD) oscillators for high-output-power terahertz (THz) sources. The array element is composed of an RTD, a slot resonator, and a dipole array antenna on a dielectric layer stacked on the RTD. In this structure, the output power is radiated in the upward direction of the substrate without a hemispherical silicon lens. The dipole array antenna was designed so that the average output power determined by the variation in the size of the RTD in the array was maximized. The experimental output power was proportional to the element number, and its value was 0.73 mW for an 89-element array at ∼1 THz in a pulsed mode with a repetition rate of 300 Hz and a duty ratio of 10%. Multiple peaks were observed in the oscillation spectra, because the elements were not intentionally coupled with each other. The average output power per element was 9 μW in the array, which was lower than that of the separated single oscillators (21 μW). Possible causes of this difference are discussed.