The terahertz radiation detector, crafted in Russia for peering into protostellar clouds, is thinner than a human hair and must operate at temperatures near absolute zero. Acting director Andrey Khudchenko shared these details with socialbites.ca, underscoring his role at ASC FIAN’s Terahertz Devices and Technologies Laboratory.
Humanity has conquered nearly every band of the electromagnetic spectrum, from long radio waves to the incredibly energetic gamma rays. Yet for many years there was a notable gap in the terahertz range, roughly around a millimeter in wavelength, where sensitive and efficient devices were hard to build. This region, however, is ideal for examining interstellar dust and protostellar clouds. In a landmark achievement, researchers at the Institute of Physics of the Russian Academy of Sciences have developed a detector operating at 250 GHz with sensitivity close to the theoretical limit. Before the signal reaches the sensing element, it traverses a sequence of precision components that shape and guide it toward detection.
From the outside or through a controlled window, incoming radio waves pass into the cryogenic setup. A cooled cryostat employs a mirror system to focus the signal onto a horn, which then directs the radiation into a compact metal waveguide measuring 1 by 0.5 millimeters. The waveguide feeds a superconducting microcircuit housing the detector. The microcircuit, with features comparable in size to a human hair, uses microstrips to route the radiation to the sensing element. The core detection element is a superconducting tunnel junction with a barrier on the order of a micron in thickness and roughly a nanometer in width. This junction is responsible for capturing the external radiation, according to Khudchenko.
Niobium, cooled to about 4 kelvins with liquid helium, serves as the superconducting material in the detector. This frigid operating environment minimizes thermal noise because even at temperatures above absolute zero, molecular motion can produce unwanted signals. Lower temperatures reduce noise and may allow further improvements in detector performance as cooling advances continue.
The practical aim behind this detector is to enable the construction of powerful radio telescopes capable of mapping water distribution within galaxies and tracing interstellar matter. Such instruments are essential for studying molecular clouds where stars form, offering a clearer view of the processes that lead to stellar birth and the evolution of galaxies. This work complements global efforts to expand terahertz astronomy and enrich our understanding of the cosmos, with results contributing to a broader scientific dialogue about the universe’s cold, dusty regions. Citations drawn from institutional reporting and interviews with researchers involved in the project provide context for the technical achievements and their potential impact on observational astronomy.