We measured the beam profile and wavefront of tripler (see the right figure). M2(X)= 1.58, M2(Y)=1.56; Beam width(X)= 3.3 mm, Beam width(Y)= 2.9 mm.
After the first beam expander, the beam size was enlarged about 10 times. In order to measure the whole beam, we used a lens to concentrated the beam into the CCD camera. The beam profile is shown in the below. Only the beam size was changed to bigger, the other beam characteristics were similar to the tripler one(see the bottom figure).
M2(X)=1.89, M2(Y)=1.72; Beam width(X)=20.5 mm, Beam width (Y) = 23.4 mm.