FIELD: terahertz radiation registration. SUBSTANCE: invention can be used in the manufacture of channels for the delivery and registration of terahertz radiation in thermal imaging systems, military equipment, space technology, analytics, medicine, biotechnology, pharmaceuticals, terahertz optoelectronics and photonics. The extrusion parameters are preliminarily determined by computer simulation using the finite element method - temperature, plunger pressure on the workpiece and its speed. Single-crystal blanks are prepared based on solid solutions of bromide - silver iodide in the following ratio of ingredients, wt.%: silver bromide - 70-96; silver iodide - 30-4 and heat them at 175-185°C and a pressure of 700 - 900 MPa to move through the spinneret at a speed of 0.2-0.3 mm/min. Terahertz nanocrystalline fibers of the AgBr–AgI system obtained by extrusion have a nanocrystalline structure, are photo- and radiation-resistant, non-toxic, non-hygroscopic, and highly transparent in the terahertz range from 11 to 30 THz, and are also characterized by low losses. EFFECT: invention provides high reproducibility and manufacturability of their production. 1 cl, 2 dwg, 3 ex.