Pictures of the opened PR chamber.
3 mirrors have been added to obtain the IR and green references.
G1 is the green beam reflected by the dichroic
IR 1 is the IR beam after the Faraday Isolator and a folding mirror
GR2 and IR2 are reflected by the same mirror ( between the green folding mirror and the dichroic and between the 2 metallical structures).
They can be seen on the "PR references" picture.
I will try to upload a more precise optical scheme of this chamber