The technology
How a picosecond laser works
Tattoo ink and pigment sit in the dermis as particles too large for the body's macrophages to carry away. A laser pulse absorbed by the particle heats and expands it faster than the surrounding tissue can respond, and the particle fractures. The shorter the pulse, the more of that energy goes into the mechanical fracture (the photoacoustic effect) and the less into heating the surrounding skin. Nanosecond Q-switched lasers (pulses of 5 to 20 billionths of a second) established the service; picosecond lasers (pulses of hundreds of trillionths of a second) fracture particles into smaller fragments with less collateral heat, which is the basis for the claims of fewer sessions and less risk of scarring and pigment change.
The four wavelengths
- 1064 nm: black and dark blue inks; weakly absorbed by melanin, so the safest wavelength on darker skin and the one used for pigment toning.
- 532 nm: red, orange and yellow inks and superficial pigmented lesions; strongly absorbed by melanin, so used with care.
- 755 nm: green and blue inks and some pigmented lesions; the wavelength that distinguishes a full-color platform.
- 1320 nm: a longer wavelength used as the carbon peel tip (a carbon lotion is applied, the laser vaporizes it and exfoliates the surface) and for skin texture sessions.
Spot size and energy
Larger spots (up to 10 mm on every model here) penetrate deeper and cover ground faster for large tattoos; small spots (down to 2 mm) concentrate energy for detail and resistant ink. The useful comparison is energy at the spot size you will use: the EL400, for example, ranges from 50 mJ at 532 nm to 1,200 mJ at 755 and 1064 nm. The EL900 and Picoking II run 3,000 W power supplies.