Abstract: A laser beam from a tunable solid state laser such as an alexandrite laser passes through a Raman shifter to produce a Raman-emitted beam with wavelength shifted so as to be able to activate a preselected photosensitizer for medical treatment. A combination of a laser and a Raman shifter with or without additionally a harmonic generator such as a frequency doubler may be also selected such that radiation with two different wavelengths can be obtained for treatment and detection.

Abstract: A structure and method for operating a copper-vapor laser involves splitting and polarizing the exiting beam of radiation into two beams of different polarization orientations. One beam is completely reflected back to the laser medium within a first external cavity, and the other beam is partially reflected back to the laser medium in a second external cavity and is also partially transmitted to provide an output beam of short pulse duration that is selectively shaped in response to the interaction within the laser medium of the two segregated beams.