Measurement of femto-second resonant nonlinear refraction in Nd:YVO4 by degenerate pump-probe spectroscopy

Abstract

The resonant nonlinear refraction in rare-earth-doped solids is studied with femtosecond degenerate pump-probe two-beam coupling spectroscopy. The phase modulation induced by the pump pulses is shown to result in a significant contribution to the differential change of the probe transmission. An ultrafast resonant nonlinear refractive index of the order of 1×10−18 m2/W is measured in Nd:YVO4 crystals.