FIELD: physics.
SUBSTANCE: infrared lightguide with a large mode field diameter contains a core and a shell consisting of rods arranged in a hexagonal order. Herewith the core with a diameter of 92.5-97.5 mcm contains a central rod with a diameter of 10.6-11.7 mcm, the shell is made with a diameter of 0.3-0.5 mm, and the rods in the shell of the same diameter as the central rod are located at the distance of 52.7-58.3 mcm between their centers, in addition, the central rod is made of crystals of solid solutions of silver chloride-bromide.
EFFECT: minimizing the aperture of the emerging laser radiation and ensuring a stable and controlled operation mode of the medical laser.