We describe an experimental study of self-defocusing in Cd0.23Hg0.77Te and InSb at room temperature using a hybrid CO2 laser at 10.6 µm. The time-resolved transmitted temporal pulse profiles showed the effects of refractive-index changes of up to Δn ~ 0.1 caused by the electronically induced optical nonlinearity. Thermally induced contributions due to dn/dT ~ -1 × 10-3 K-1 in CdHgTe were also measured.
D. Craig, A. Miller, and M. J. Soileau, "Time-resolved self-defocusing in Cd0.23Hg0.77Te and InSb," Opt. Lett. 11, 794-796 (1986)