Patent ID: 7846151

Claim:
A medical laser apparatus for irradiating an affected tissue with a laser beam to treat the affected tissue, comprising: a laser source unit comprising an excitation light source and a Raman fiber, the laser source unit being configured to cause light from the excitation light source to enter the Raman fiber to produce a fundamental wave infrared beam having a predetermined wavelength width and emit this fundamental wave infrared beam; a wavelength demultiplexing optical system which spatially wavelength-disperses the fundamental wave infrared beam emitted from the laser source unit into a plurality of infrared beams within the predetermined wavelength width; a wavelength converting optical system, including a wavelength converting element including a single nonlinear crystal and for wavelength-converting each of the infrared beams demultiplexed by the wavelength demultiplexing optical system to second harmonic wave visible single color beams each of the infrared beams being caused to enter different portions of the nonlinear crystal and then be wavelength-converted to the visible single color beams; a wavelength multiplexing optical system which multiplexes each of the visible single color beams obtained by the wavelength conversion by the wavelength converting optical system; a beam stopper which absorbs the infrared beams not wavelength-converted by the wavelength converting optical system; and a delivery optical system which guides each of the visible single color beams multiplexed by the wavelength multiplexing optical system to the affected tissue.