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# see around corners with lasers

make road shimmer with warming laser; aim imaging laser at new mirror; see around corners
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I wondered if you could use a two laser system to see around corners. If you have seen road shimmer you know it looks like a mirror. Use one laser to heat a section of air (or two) then aim the imaging second beam at the custom mirrors to get otherwise unavailable views.

Imagine getting a 90 degree corner with light at a distance.

spectacularly powerful lasers could turn two corners with another shimmer generation.

 — beanangel, Jan 25 2018

Some prior art from Heriot-Watt University https://www.google....t-watt+laser+corner
They use multiple reflections off of natural surfaces, followed by deconvolution, rather than creating a lens or mirror by heating. Pick an article or video yourself [notexactly, Feb 03 2018]

You are trying to use the mirage effect, except that the angle light gets bent via that effect is quite shallow. To make light bend 90 degrees is likely to require a huge amount of distance-traversal during the bending process.
 — Vernon, Jan 25 2018

 To what wavelength(s) is air not transparent?

And, assuming that your laser is producing such a wavelength, why won't it heat the air immediately in front of itself? Doesn't this idea require the beam to pass through the firsr few metres of air without absorbtion, then suddenly to start getting absorbed by the next bit of air, near where the corner is? Why would the beam behave like that?
 — pertinax, Jan 25 2018

 [pertinax] You could use an array of lasers that cofocalize at a distance to warm air at one point. Then you could scan the area ahead to create different densities of air. I saw an image at wikipedia of three stacked fluids of different refractive indices, so you could make sideways rather than up and down heat layers.

[Ian] I like your idea about hearing around corners with a laser listener!
 — beanangel, Jan 25 2018

Thank you. But ... but ... focus implies convergence. I thought the rays that made up laser beams were approximately parallel, neither diverging nor converging (maybe diverging a bit over very long distances). Am I imagining that wrong?
 — pertinax, Jan 26 2018

Yes. You are imagining a collimated laser beam. If you take a laser diode out of an optical drive or a laser pointer, and operate it with no lens, it will send light all over the place. Some laser types (like the original ruby rod laser), I think, naturally generate collimated beams, but they don't all. And a collimated beam can be expanded and refocused using lenses, just like any other beam of light can.
 — notexactly, Feb 03 2018

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