[dekhn]

The replies already posted are quite good. Let me explain it a different way:

When light passes through the atmosphere, it undergoes a convolution known as a point spread function (think of it as convolving the signal with a 2D gaussian that spreads the intensity out to neighboring pixels). If we know that PSF specific details, we can deconvolve the image, either computationally, or by modifying the mirror in real time.

From my understanding, you can project a laser into the atmosphere, where it gets affected by the PSF. When you look at that laser projection, you can find the PSF (because you know the input shape of the laser, and what it looks like after being affected by the PSF), and therefore use that in real time to deconvolve the astronomic images you are collecting.

This process can be done so quickly it can adapt to immediate changes in the atmosphere (turbulence). "Enhance" is definitely a thing- it's widely used in both telescopes and microscopes (and if you had the right priors for a blurry photo, you could do it there too).

I think this is a relatively simple read: https://en.wikipedia.org/wiki/Laser_guide_star along with https://www.llnl.gov/article/44936/guide-star-leads-sharper-...