Check the infrared beam with CCD

I checked the infrared beam with the CCD camera.

The first picture is set to check the beam in front of the dichoric mirror, and the second picture is what I got. It seems a really normal beam.

The third picture is set to check before the cavity, since I tried many different ways but cannot put another mirror in the middle of the dichoric mirror and the cavity without moving them, so I used the filter to reflect the beam. The fourth is what I got, it does not look like a round one.

So I change the mirror in first picture to filter to see if it is the reason of beam shape change, and I got the fifth picture.After checking the infrared beam many many times, I think the strange green beam probably not caused by the infrared beam.