Temperature dependence of water absorption for wavelengths at 1920 nm and 1940 nm

Abstract

In this study the absorption coefficient of water at different temperatures was investigated for wavelengths at 1920 nm and 1940 nm respectively. The laser radiation was transmitted via a quartz fibre (Ø 600 µm core) into a thermal isolated and heated water filled cuvette. At different temperatures the transmittance of water was measured for both wavelengths. According to Beer-Lambert’s law the absorption coefficient α was calculated.

Absorption coefficient α of water for 1940 nm decreases from 129.2±1.7 /cm² @ 20 °C to 118.7±1.9 /cm² @ 80 °C, while for 1920 nm α increases from 126.4±1.6 /cm² @ 20 °C to 142.5±1.6 /cm² @ 80 °C. For 35 °C the water absorption coefficient is 127.3±1.6 /cm² for 1940 nm and 132.5±1.9 /cm² for 1920 nm.

For both wavelengths in vivo investigations for ablation efficiency are planned to answer the question, if these differences are significant for laser surgery.