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Weed_O_Whirler t1_j4xgk6q wrote

Reply to comment by Fair-Ad3639 in Whats stopping us from sending a probe into a black hole if we haven't already? by stealth941

But over long distances, it re-becomes inverse square again. After the waist of a laser beam, it spreads out like an inverse square law again, and when you're dealing with lightyears, most of the spread will be after the waist.

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Fair-Ad3639 t1_j4xitxi wrote

Yep! Turns out you're correct (says Google). Lasers do follow the inverse square law. https://www.quora.com/Is-the-light-from-lasers-reduced-by-the-inverse-square-law-as-distance-grows-similar-to-other-light-sources

How powerful the transmitter will need to be is also a function of the gain of the antenna. In this case, the spread angle of the laser

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dumb_password_loser t1_j4zja46 wrote

But the spread angle is inversely proportionate to the aperture.
If you send multiple probes that spread out a bit and couple them optically, they can transmit coherently with a huge effective aperture. (like the reverse of a telescope array)

And if the black hole is big enough, you can maybe use its gravitational field to increase the aperture using some mathematical sorcery.

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