Picosecond Laser: Photoacoustic Pigment and Tattoo Removal Explained

A picosecond laser delivers pulses measured in picoseconds (trillionths of a second, 10⁻¹² s). Because the pulse is shorter than the thermal relaxation time of pigment particles, energy shatters the target through a photoacoustic — rather than a purely photothermal — effect, breaking pigment into fragments that macrophages clear away. Classic wavelengths are 1064 nm and 532 nm, with 755 nm available on many platforms. Clinics use it mainly for ephelides, solar lentigines, melasma support and tattoo removal, while long-pulse modes extend it to rejuvenation.

Nanosecond Q-switched lasers fragment pigment mostly by heat, which diffuses into surrounding tissue. A picosecond pulse arrives and departs before heat can spread, producing a photoacoustic shockwave that shatters the particle directly — higher hit accuracy with less collateral thermal injury. Using a representative super-picosecond platform (Picostar-class) as an example:

• Picosecond mode: 350-450 ps pulse width for pigment fragmentation and tattoo removal, with minimal residual heat
• Three wavelengths: 1064 nm for dermal pigment and darker phototypes, 532 nm for epidermal lesions, 755 nm in between and useful for melanin absorption
• ULP microsecond long pulse: photomodulation for sensitive-skin repair, acne support and brightening
• MLP millisecond long pulse: cool epidermis with deep heating for hair removal and tightening; 1064 long pulse bypasses epidermal melanin, making it viable for darker skin

For the underlying framework of absorption, scattering and thermal relaxation, see laser-tissue interaction.

• Epidermal pigment (freckles, sun spots): visible lightening in 1-3 sessions for most clients; aftercare sun discipline determines recurrence speed
• Dermal pigment (nevus of Ota, Hori’s naevus): long-cycle management, typically 6-12 sessions — see nevus of Ota
• Melasma: low-energy, long-interval conservative protocols combined with topicals; expectation management comes first
• Tattoo removal: wavelength matched to ink colour (1064 nm for black/blue/green, 532 nm for red/orange); multicolour tattoos need more sessions
• Texture and pores: “honeycomb”-style rejuvenation via ULP/MLP modes

Outcomes track skin phototype closely: for Fitzpatrick III and above, energies and intervals must be conservative — map clients with the Fitzpatrick scale first.

1. Assessment: pigment classification (epidermal/dermal/mixed), phototype, treatment and photosensitivity history
2. Cleansing and cooling: topical anaesthetic when indicated; document with photos
3. Treatment: wavelength and fluence per indication; full-face freckles take minutes
4. Aftercare: transient erythema for hours to a day; micro-crusts shed in 3-7 days; strict photoprotection (see post-procedure sun protection)

Reference courses: freckles/lentigines 1-3 sessions at 1-1.5 month intervals; Hori’s naevus 6-8 sessions at 45-60 day intervals; nevus of Ota about 10-12; melasma 5-8 low-fluence sessions with monthly maintenance. Dermal pigment is long-distance management — schedule follow-ups and expectations into the delivery process.

• Common transient reactions: mild erythema, pinpoint crusting, temporary dryness
• Disclosed risks: post-inflammatory hyperpigmentation (darker phototypes and sun exposure are the main triggers); rare epidermal burns or blistering
• Tattoo removal may cause hypopigmentation or texture change — disclose beforehand

Contraindications: pregnancy, lactation and menstruation; active infection or open wounds in the area; intense sun exposure or planned sun holidays within about a month; photosensitive disorders or photosensitising medication; malignant or suspicious lesions; poorly controlled systemic disease; thread lifts or fillers less than 3 months old.

These are end-market retail references only; prices vary with provider credentials, indication and wavelength mix. They describe market pricing structure, carry no price commitment, and are unrelated to LEIJEX equipment pricing.