A method and apparatus are described for photoetching organic biological matter without requiring heat as the dominant etching mechanism. Far-ultraviolet radiation of wavelengths less than 200 nm are used to selectively remove organic biological material, where the radiation has an energy fluence sufficiently great to cause ablative photodecomposition. Either continuous wave or pulse radiation can be used, a suitable ultraviolet light source being an ArF excimer laser having an output at 193 nm. The exposed biological material is ablatively photodecomposed without heating or damage to the rest of the organic material. Medical and dental applications include the removal of damaged or unhealthy tissue from bone, removal of skin lesions, cutting or sectioning healthy tissue, and the treatment of decayed teeth.