How it works
The physics here is selective photothermolysis, the principle Anderson and Parrish described in 1983: match the wavelength to the target chromophore, keep the pulse shorter than the target's thermal relaxation time, and you destroy the target while sparing what's around it. A Q-switch releases the stored laser energy in a nanosecond burst with very high peak power. That burst is absorbed by ink or melanin far faster than heat can spread.
The result isn't gentle warming. It's a photoacoustic blast. Pigment particles shatter into fragments; some are expelled through the skin surface, and the rest break into pieces small enough for phagocytes to engulf and the lymphatic system to clear over the following weeks. Because the pulse is so brief, surrounding skin structures see very little of that energy.
Why two wavelengths? Penetration depth grows with wavelength, a point our skin-science training notes make plainly. So 1064 nm reaches pigment lodged deep in the dermis and is only weakly absorbed by epidermal melanin, which helps when treating clients with more melanin-rich skin. The 532 nm output, generated through a KTP crystal selected for a clean green beam, is absorbed strongly by red and superficial pigment, which is exactly where 1064 nm alone falls short.
