Flat visible beam from a laser pointer

I'm Rodrigo and I'm writing from Madeira island, Portugal. I've been in the composting toilet business and research of my own for 4 years. I'm willing to find in this forum a solution for a challenge that I have in hands.

It goes like this: since a composting toilet doesn't use water to flush human waste, there is a need for a vertical fall of the waste into a tank. With this the user when in need to use a composting toilet, will have a visual contact with others people waste inside the tank. From my questions to the users this is the most unpleasant side of using a composting toilet.



So my idea is to create a visible flat laser beam just right bellow the toilet lid, so the users cannot see inside the tank and the waste will still have a free vertical fall. Do you think that this is possible to make? I was thinking of using a laser pointer, pointed at some kind of amplifying glass that would transform a visible laser beam into a visible flat wide beam. The color of the beam isn't important for me. The goal is to "hide" the waste inside the tank for a human eye.

Tell me if you guys need more information or drawing about this idea. Thank you!

The only issue I see with this is that the beam would not have any thing to reflect off of. If there was fog in the air it sould work. If not all you would have is a line on the other side of the lid and no visiable beam in between.

But isn't it true that there is visible and non-visible laser light/beam? If it is I'm looking for a visible laser beam.

There is but without particulate in the air you wont see the "beam" of the laser. Just its termination point.

Well.. There is some amount of humidity and darkness in the tank. Could this help?

It may. But I doubt it will be enough to block the view. You would need a good deal of fog or an extremeley overpowered laser.

By your diagram, it should be pitch black in there. Are your users using a flashlight? If so, tell them to knock it off.