we plan to use Electrically Tunable Lenses EL-10-30-C NIR to build the ThomX telescope but they need to be compatible with the powerful laser beam.

for CW regime, on the datasheet (see attached file), the optical damage threshold is 10 kW/cm².
with 70W laser power and 1mm² beam surface (which is much smaller than the real beam size), we are at 7kW/cm².

for pulsed regime, with Daniele, we can imagine that the inner material is water (n ~ 1.3 in the datasheet).
One found a paper about laser induced electric breakdown in water (see attached paper) which give a breakdown field of about 1e8 V/m (see Fig. 1 of the paper) for 7ns pulse width.
with 70W average power, 33MHz repetition rate, 10ps pulse width 1mm² beam surface, one has an intensity of ~ 2e11 W/m² (or 2.7 GW/cm²)
I = E² / 377 => E = 8.7e6 V/m which is also much smaller than the breakdown value.

from the fig. 4 of the paper, it seems the breakdown threshold increases a lot for shorter pulses from 30 GW/cm² (~10ns pulses) to ~150 GW/cm² (~10ps pulses)
so, one can expect a good behavior in pulsed regime too.

can anyone check the validity of these rough calculations ???