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I've provided a cross section from a phaser array element from DITL to aid my question:

enter image description here

The emitter is apparently the flat, horizontal part at the top. The problem is that I've never understood how the beam is directed from a phaser array. Ball turrets clearly have an opening where the phaser beam will exit, and they can swivel around to almost any angle. The arrays, however, are composed of linked segments that seem to be fixed to the hull. Sometimes in TNG and DS9, we are given close-up shots of the arrays, and there is no indication of the existence of any kind of directional controls. The segments themselves clearly don't move; oftentimes, it even looks like the phasers just shoot out of the metal panels.

If there is no mechanical method of directing/aiming the phaser beams, how is aiming accomplished?

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    Yes, exactly. This is how compact directional antennas and emitters work. Now, how this could possibly be used in the terawatt range and for such a focused beam is another matter, but <technobabble> <technobabble> Dec 20, 2022 at 18:18
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    @ThePopMachine If you assume an optical wavelength of 500 nm (reasonable since we can see the phaser), and a a 3-meter wide diffraction-limited aperture, the beam will diverge 203 nanoradians half-angle. If the beam started out 3 meters wide, after 10,000 km, your beam would be 5 meters wide, not even double. Unlike radio waves, light can remain very narrowly focused because the wavelength is so small versus the aperture.
    – user71659
    Dec 21, 2022 at 4:08
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    May I ask how this question has two close votes? Dec 21, 2022 at 15:01
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    I like how you picked pretty much the only realistic part of how the phasers work to question.
    – AndreKR
    Dec 21, 2022 at 19:12

2 Answers 2

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Note that the device is a "phaser array," not simply a phaser like the hand-held weapons used by away teams. A phased array is an arrangement of emitters that is capable of generating a steerable beam over a broad range of angles.

Schematic of a phased array antenna generating a beam at an angle to perpendicular by tuning the wavefronts from adjacent emitting elements

The simplest explanation is that a "phaser array" uses a similar constructive/destructive interference technique to generate a phaser beam at a desired angle.

(This is how a Starlink antenna generates a beam that can follow satellites moving across the sky without having to physically move.)

Starlink 2 antenna, a flat rectangular antenna

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    The TNG technical manual has a passage that talks about his. It uses that as an explanation for why a phase array discharge visibly starts beyond the point of emission on both sides and moves inward. This is clearly visible in BoBW Pt 2, around the 21 minute mark, when you see the saucer firing from Locutus' point of view. They're changing frequencies rapidly and aiming to distract, so firing multiple shots, and you can see each one starts wide in the array and narrows to the firing point.
    – T.J.L.
    Dec 21, 2022 at 13:39
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    Also see beamforming.
    – Mast
    Dec 22, 2022 at 17:49
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Here is a real life version in the animation below. The working is slightly different compared to a phasor. A phasor modifies the phases of light in a certain plane, while the setup below blocks light in a certain plane. The setup works as follows: laser light is shone onto a plate which has a certain pattern of holes in it. Each point in the hole emits light in all directions and this causes the light to constructively interfere in some places and destructively interfere in other places. By cleverly choosing which spots in the plate are opaque and which spots are holes we can do many things, like focussing the light in one spot, or in many spots, or creating a beam in a certain direction or even creating multiple beams. Of course we can't create energy so if you create multiple beams the intensity in each of the beams will be lower. The diffractive pattern below is created such that it focusses the light in a single spot that is located off-center. In the animation you see a slice of the light at a certain distance from the plate, as indicated in the drawing on the right. For the full video check out

by the channel Huygens optics.

animation of diffractive pattern focussing

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