Knowledge Bank

The absorption of $CO2$ laser radiation in $SF6$, $WF6$ and $UF6$ has been measured for many $CO2$ laser transitions using optoacoustic detection techniques. Absolute absorption coefficients per Torr as low as $1\times 10-7$ in a 2cm active path length could be measured by taking advantage of calibration measurements performed with $SF6$. In $SF6$ the strongly absorbing $\nu 3$ fundamental absorption band and weak combination bands are measured. In $UF6$ and $WF6$ the absorption occurs only in weak combination bands with absorption coefficients per Torr ranging from $3\times 10-7$ to $1\times 10-6$ for $UF6$ and from $3\times 10-6$ to $1\times 10-4$ for $WF6$ depending on the $CO2$ laser transition.