THz Frequency Counter based on a Semiconductor-Superlattice Harmonic Mixer with 4-Octave Measurable Bandwidth and 16-Digit Precision

We have developed a broadband and high-precision THz frequency counter based on a semiconductor-superlattice harmonic mixer. Its comprehensive characterization showed a measurement uncertainty of less than 1×10
⁻¹⁶
over a four-octave range from 120GHz to 2.8THz. This compact and easy-to-handle THz counter operating at room temperature is suitable for many THz applications requiring a wide measurement range without a bulky cryogenic apparatus.