Q-Switched (Nanosecond)

A Q-switched laser uses a technique that stores energy inside the laser cavity and then releases it all at once, producing a pulse measured in nanoseconds (billionths of a second) with enormous peak power.

That speed is the secret. Pigment particles and tattoo ink are tiny, so their thermal relaxation time is extraordinarily short. A nanosecond pulse delivers its energy faster than the particle can conduct heat away, creating a photoacoustic (shockwave) effect that mechanically shatters the particle into fragments small enough for the immune system to carry off—while the surrounding skin, which heats far more slowly, is spared. This is why Q-switched Nd:YAG and the newer picosecond lasers are the workhorses of tattoo removal and pigment treatment.

Picosecond lasers push the same idea further with even shorter pulses, fragmenting ink more efficiently and often in fewer sessions.