Time resolved self-defocusing in InSb at room temperature

We report a detailed study of time resolved self-defocusing in InSb at room temperature, using 3 μs long CO
2
laser pulses. We have determined that the intensity dependence of the refractive index varies as intensity to the two-thirds power. The measured values correspond to an equivalent
dn/dI
of -0.11 cm
²
/MW at an incident intensity of 210 kW/cm
²
.