We wish to add polarization camera in the readout section on the PCI. We don't have a lot of space but do require a beam of divergence less than 2deg for camera and less than 3mm in diameter. 

For this we used the initial beam characteristics and chose a lens which could fit itself alongwith the camera in the readout.

At 2 cm after box The beam characteristics looks like shown here. 

At 0.5 cm after box  beam characteristics looks like shown here. 

so, we can probably add the F=100mm lens 2cm after the box starts. The farther we go the beam divergence and beam diameter incident on the camera will increase, which is not desirable in our case.