Nd:Yag laser is named after the laser medium, Neodymium: yytrium-alumunium-garnet. This laser was specifically designed to help with pigmentation, roughness and also can help removing old tattoos.
The Q-switched ND YAG laser takes specific wavelengths light in high energy, which are absorbed by the pigment and shatters the pigment into particles, breaking them into very small fragments , some parts will consequently bounce out of the skin and the other parts will spilt even further into minute particles which eventually will be engulfed by the phagocytes and ultimately gets eliminated by the lymphatic system.