It produces photo-coagulation. This graph shows Absorption coefficient of tissue chromphores by different Lasers at different wavelengths .
The Mercury Diode Laser targets the chromophore, Hemoglobin, that shows a much higher absorption coefficient at 980nm. Thus 980nm diode laser has the ideal effects on the treatment of vascular lesions. When laser energy is being absorbed by hemoglobin, it produces thermal energy that spreads to endothelial cells in the blood vessel walls where they get damaged and vascular lesions will be treated.