Setup 2 and no results.

As mentioned in the Setup 1 post my laser has some crazy concepts of time that I would like to eliminate. So below is the new setup I am running. We now have two detectors Ds (start) and Df (finish). So it does not matter when the beam exits the laser because our scope trigger is now just when ever it does.



And here is what that looks like.. man, I need a proper optics bench. The green line is the laser path, note the washed out mess that is the return beam to Df.

Here is my precision retro-reflector at 9 metres from the laser. Observe, a small copper tube is exactly taped to my chimney upon hangs a dimension retarded mirror via rubber band strop with disposable external hard drive for fine alignment. Well it works.

What does not work so well is the beam divergence against about A4 paper.

What does get back to Df is faint, so I'm using a lense to focus what is returned on to the detector. I'm finding though that with less light comes lower rise time so at this point I'm not able to make a measurement.

At 18 metres I'm starting to think 60ns is getting a bit beyond what I'm capable of with the equipment I have.