A coherent tetryon beam was a powerful type of scan used by the alien being known only as the Caretaker in the 24th century, in an attempt to locate lifeforms genetically compatible with himself. In 2371, the Caretaker used this technology to scan a Maquis vessel commanded by Chakotay in the Badlands before utilizing a powerful displacement wave to transport the ship to the Delta Quadrant. Later, the Caretaker used the same technique to scan the USS Voyager, which had been searching for Chakotay's ship in the Badlands, before bringing it to the Delta Quadrant as well. (VOY: "Caretaker")