SLM experiment - Laser characterisation

# Beam profile characterization for SLM experiment

We use the 2nd lightwave laser, serie 126-1064-700, serial 225 (Nov. 1996).

The general datasheet (*) mentions waist (horiz/vertic) ~ 250/180 um at 5 cm from the laser front panel
(*) https://resource.lumentum.com/s3fs-public/technical-library-items/npro125126-ds-cl-ae.pdf?VersionId=null

we check the beam profile after a 15 cm focal length lens (Thorlabs LA133-C) located @ 0.54 m from the laser front panel.
-> see figure 1, Weird behavior, M^2 ~ 1.75 along the vertical direction
we deduce the upstream waist (horiz/vertic) ~ 151/168 um at 0.1 m from the laser front panel.

Rem.:
- the beam at the output of the laser is quite shifted to the right (when looking to the laser) and let think it could be clipped by the shutter. However this is the vertical direction which features weird profile and the worst M^2 parameter. We found the same feature for the laser used by Shalika on EOM's experiment.
- figure 2, non-TEM00 feature at some distance from the waist

# Laser P vs I characterization for SLM experiment
Polarisation set to S (vertical)
I (A) P1(mW) P2 (mW)
1.38 3.69 97
1.50 6.18 168
1.60 9.7 280
1.70 14.5 380
1.80 18.2 480
2.0 28.8 764 (Rem_2)

P2: read at the laser output (after a L/2), meas. with the integrating sphere
P1: is after L/2 (Polar set to vertic), + BeamSampler (AOI ~ 25 deg) + Rmax + Lens

Rem_2: P1/P2 = 3.8% compatible with the Beam sampler R (R = 4.1% for 22 deg AOI and S polar)