Determination of the absorption length of CO2 and high power diode laser radiation for a high volume alumina-based refractory material

The laser beam absorption lengths of CO2 (10.6 mm wavelength) and a high power diode laser (HPDL) (810 nm wavelength) radiation for an Al2O3/SiO2-based refractory have been determined through the application of Beer±Lambertʹs law. The ®ndings revealed marked differences in the absorption lengths despite the material having similar beam absorption coef®cients for both lasers. The absorption lengths for the Al2O3/SiO2-based refractory of CO2 and a HPDL radiation were calculated as being 345 22 and 198 15 mm, respectively. Moreover, this method of laser beam absorption length determination, which has hitherto been used predominantly with lasers operated in the pulsed mode, is shown to be valid for use with lasers operated in the continuous wave (CW) mode, depending upon the material being treated. # 2000 Elsevier Science B.V. All rights reserved