Imaging and spectroscopy at terahertz frequencies have great potential for healthcare, plasma diagnostics, and homeland security applications. Terahertz frequencies correspond to energy level transitions of important molecules in biology and astrophysics. Because of its shorter wavelength, terahertz radiation also offers higher spatial resolution than microwaves or millimeter waves. We are developing hot electron bolometer (HEB) mixer receivers for heterodyne detection at terahertz frequencies. HEB detectors provide unprecedented sensitivity and spectral resolution at terahertz frequencies. Terahertz imagers based on HEB technology have sufficient sensitivity to operate in a passive imaging mode, thus eliminating the need for active illumination. HEB mixers have, therefore, become the detectors of choice for applications requiring low noise temperatures at frequencies from 0.5 THz up to 10 THz. We have developed receivers and focal plane arrays operating near the quantum noise limit for astrophysical applications. We have demonstrated a low-noise heterodyne two-element focal plane array (FPA) operating at 0.85 THz. The integrated mixer block consists of NbN hot electron bolometric (HEB) detectors and state-of-the-art MMIC low-noise amplifiers in a compact design. HEB technology is becoming the basis for advanced terahertz imaging and spectroscopic technologies for the study of biological and chemical agents over the entire terahertz spectrum.
The Joint International Conference on Infrared and Millimeter Waves and International Conference on Terahertz Electronics