NONLINEAR OPTICAL-PROPERTIES OF MOLECULAR-BEAM EPITAXY GROWN BI1-XSBX

We discuss the first investigation of Bi1-xSbx as an infrared nonlinear optical material. Nondegenerate four-wave mixing experiments at CO2 laser wavelengths yield a large nonlinearity (χ(3)≊3×10-4 esu) which does not saturate at power densities up to 0.5 MW/cm2. Both the ambient and substrate interfaces of the film are highly reflective and the étalon they form is found to have a large effect on the transmission and reflectivity spectra of the as-grown films. This suggests the possibility that constructive interference of the film's internal optical fields could be used to considerably enhance the nonlinear signal.