An experimental setup for measurement of optical absorption coefficients at 1.054 μm in high transparent liquids by means of the thermal lens effect was built, calibrated, and tested. The critical energy for defocusing of laser beam Ecr≅3 J and the absorption coefficient α of order 10^-6 cm^-1 were precisely measured by this device in the fluorocarbon liquids FLUORINERT FC. Obtained data were used for an optimization of the high energy Stimulated Brillouin Scattering (SBS) phase conjugated mirror and SBS compressor based on FLUORINERT FC medium.