Tractor Beam?

shreve912 writes: "No captured Romulan Birds of Prey just yet, but the beam consisting of a helix of twisting laser light is able to seize hold of objects as small as a protein molecule. Scientists believe it will be an invaluable tool for manipulating parts of living cells or components of micro-machines. Holodecks and Borg implants can't be far off! Check out the article."

Comments

Re:Tell us what we want to know!

[caffeinated_bunsen]

Well, the principle of operation of this (which only rotates objects) and optical tweezers (which move objects but can't rotate them) requires that the object refract light. Strictly speaking, there is no upper bound. But in order to produce a noticable force on a macroscopic object, you'd need far more light (several orders of magnitude) than would be necessary to incinerate said object.

The force results from the object changing the direction of propagation of photons, and thus changing their momentum. The recoil from this change is what moves the particle. The force is on the same order of magnitutde as the radiation pressure on an opaque object.