\documentclass{article}

\begin{document}

\begin{tabular}{lrrrrrrrr}
    \hline
    Instrument & $\lambda$ (nm) & $\log_2 N_{\mathrm{G}}$ &
    \multicolumn{2}{c}{Width (mm)}& \multicolumn{2}{c}{Pitch ($\mu$)}
    & \multicolumn{2}{c}{Ratio to Disk}\\
               & & & Min & Max & Min & Max & Min & Max\\
    \hline
\end{tabular}
\end{document}

