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I'm thinking of a project that would send a laser beam through a powell lens to create a horizontal laser line. But I also want the line to have a certain vertical viewing angle. So just as an example say 20 degrees at 1000m. I don't mean bend the laser to 20 degrees, more like anyone at an angle of -20 to 20 degrees could view it. Is there some type of lens I could put after the powell or a way I could have the powell made that would achieve this?

Thank you

edit: Adding a picture for clarity. enter image description here

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    $\begingroup$ I’m unclear what you mean by “viewing angle”. Clarify, please? $\endgroup$
    – Gilbert
    Commented Oct 19, 2020 at 16:02
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    $\begingroup$ Let me try. If you had a laser and you aimed it at me and I was 1000m away if you aimed it in my face I would definitely see it. But what if I then climbed up a ladder? I'd like to be able to still see the beam up until I had climbed past the angle of 20 degrees. Let me try to draw something and see if I can edit my question. $\endgroup$
    – confused
    Commented Oct 19, 2020 at 17:14

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You could accomplish this with two lenses. The first, a spherical lens, would be selected to give you the large horizintal angular spread that you want. The second, a cylindrical lens, would be oriented with its axis horizontal and could be placed either before ir after the spherical lens. Adjusting the distance between the two lenses would adjust the vertical spread of the beam.

A Powell lens will give you a more uniform horizontal distribution of light, but no control of the vertical spread. A pair of cylindrical lenses downstream from the Powell lens should provide adjustment of vertical spread. Locate the first one close to the Powell lens and the second one about two focal lengths beyond the first. Adjust the vertical spread by moving the second cylindrical lens closer or farther away.

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