I am new in working with an optical setup. I have a small setup to mimic a 3D printer motion stage. So, it consists of a laser hitting on a cube beam splitter. The transmitted one is dumped while the reflected is focused on the target and then the backscaterred light collected via the beam splitter and focused to the CCD camera.
My problem is that on the camera image I got 2 spots (one weaker though). I think its some kind of unwanted secondary reflection from the beam splitter because:
When I cut the beam between the laser lens and the beamsplitter with a blade from any direction the spots distort and fade at the same time.
If I dump the beam hitting the target I only see the weaker spot
Can someone give some suggestion to get rid of this unwanted spot? Thanks