Pressure-induced shift and broadening of 1510–1540-nm acetylene wavelength calibration lines

Abstract

We have measured the pressure-induced shift for 15 lines of the ${\nu }_1+{\nu }_3$ rotational–vibrational band of acetylene ${ }^{12}{\mathrm{C}}_2{\mathrm{H}}_2.$ These lines are useful as wavelength references in the 1510–1540-nm region. We find that the pressure shift varies from +0.008(2) pm/kPa for line $R1$ to +0.043(2) pm/kPa for line $R27,$ with many of the lines exhibiting a shift near +0.017 pm/kPa (or, equivalently, $+2.3\times {10}^{-3} \mathrm{pm}/\mathrm{Torr}$ or -0.29 MHz/Torr). In addition, we have measured the pressure broadening of these lines and find that it also varies with line number and is typically ∼0.7 pm/kPa (∼12 MHz/Torr). We also evaluate the line sensitivity to temperature changes and electromagnetic fields.