Here is the report of the installation and alignment of the EOM in the cristallin cavity experiment. The EOM has been installed after the a telescope in order to adapt the beam diameter to the aperture of the EOM. The measurement and the characterization of the beam parameter befor the first lens of the telscope can be found in this logbook : 

The telescope has been design using jamMt the optical parameters are : 3999

f1 = 200mm

f2 = -100mm

d = 18cm

The expected beam radius after the telecope form the simulation of jamMt is presented on the figure 1. in reality, it was necessary to place the second lens a little bit further away, maybe because our estimation of the optical beam parameter berfore the first lens was not really precise.

We measured the profile at the output of this telescope to check if the beam radius was effectively under 1mm of diameter. The result of this measurement is presented on the figure 2. The 0 position is the one of the first lens of the telescope.

The output surface of the cristal is expected to be wedged and separate the beam into two distinct polarization states. we effectively observed two beam far away from the EOM, we added an half weavelate and a quarter waveplate between the two lens for the telescope in order to fully control the polarization states injected inside the EOM. With this method, we were able to recover a single beam i n transmission

Then we tried to align the EOM and reach the maximum power in transmission. the alignment was performed with 16.4mW at the entrance of the EOM but for now we could not get more than 11.3mW in transmission corresponding to 68.9% of the total injected power. Further work is maybe needed to obtain higher power in transmission.

We also observed that the crystal of the EOM was very dirty and maybe a damage. the figure 3 show the crystal inside the EOM. The replacement of this EOM by another (Maybe at another frequency) is currently under discussion.