It has been widely known for centuries that photons carry the capacity to impart force onto whatever they collide into. Taking this into account with Newton’s second law of motion, we can assume that when these photons collide with matter, that their individual inertia is transferred into that mass. The challenge of Tractor Beams is to take this concept, produce it on an infinitely larger scale, and then do it backward.
Modern Tractor Beams are usable to tow ships of the same weight class, or to hold a ship of a smaller class in place so it cannot escape a battle. This is done by firing two laser beams across the ship that intersects at the center of the ship’s mass. This intersection of the two beams creates a reverse polarity that excites the photons while also creating a negative value to their inertia. By doing this, instead of pushing, the photons begin to pull the ship. To the onlooker it appears as one beam, but this is only an optical illusion that results from the ship using the beam being larger than the target ship. The focus point is so small in comparison that the beams appear as one.