Measurement of the nonlinear refractive index of air constituents at mid-infrared wavelengths

Measured Values of $n_2$ (“This Work”) of Major Air Constituents, Scaled to Atmospheric Pressure^a

^a Comparison is shown to values of $n_2$ calculated for our wavelengths using Eq. (3), where the coefficients $a$, $b$, and ${\gamma }_0$ were measured using the ESHG technique [33]. For long pulses, the effective nonlinearity coefficient can be written as $n_{2,\text{eff}}=n_2+n_{2,\mathrm{rot}}$.
^b $n_2$ measurements are adjusted for $\mathrm{\Delta }\alpha$ dispersion using coefficients found in [31].
^c $n_2$ measurements are not adjusted for $\mathrm{\Delta }\alpha$ dispersion. We used $\mathrm{\Delta }\alpha ({\omega }_{800\mathrm{nm}})$, measured in [22], for all wavelengths.
^d Referenced to ${\mathrm{N}}_2$ measurements.