A computer controlled laser beam recording technique using the CO2 laser radiation at 10.6 micrometers is demonstrated. Multimode lightguide patterns with dimensions in the range of 100 micrometers to 1000 micrometers may be recorded in polymer films or polymer substrates. In the adequate exposure range smooth patterns may be obtained. A model for the etching of PMMA by CO2 laser radiation is presented.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.