Measurement of the Nonlinear Refractive Index of Air Constituents at Mid-Infrared Wavelengths

We measure the nonlinear refractive index coefficients in N₂, O₂, and Ar from visible through Mid-infrared wavelengths (λ = 0.4 - 2.4 μm).    The wavelengths investigated correspond to transparency windows in the atmosphere. Good agreement is found with theoretical models of c⁽³⁾. Our results are essential for accurately simulating the propagation of ultrashort mid-infrared pulses in the atmosphere.