Abstract

The observation of large nonlinear refraction near the fundamental absorption edge in InSb (Ref. 1) has brought considerable interest in the possible application of narrow-band-gap semiconductors in all-optical signal processing. The mechanism of the nonlinear refraction has been studied by a number of authors.² The different approaches that have been taken in explaining the effect have put varying emphasis on electron-hole correlation effects, band-gap renormalization, and T₂ broadening of conduction-band states. So far comparison between theory and experiment has been limited by the dearth of experimental data. Qualitative agreement with theory has been demonstrated in InSb (Ref. 3) and HgCdTe.^4,6 What is needed is a quantitative comparison using well-characterized samples with all free parameters known (e.g., carrier lifetime). InAs offers an excellent opportunity to do this. Its band parameters are all well known, and its band gap happens to match the HF laser.

© 1984 Optical Society of America