Resonant four wave mixing in n-type silicon

We observe a strong resonance in the third order nonlinear optical susceptibility of n-type silicon corresponding to the valley orbit splitting of the 1s-states of phoshorous and antimony donors. Cross-sections for valley orbit Raman scattering near 10 μm obtained from our data agree with calculations based on an intraband model. The expression for the cross-section resulting from this model is equivalent to that of Jain et al.