2940 nm Er:YAG Laser: The Water-Absorption Champion Among Ablative Lasers

The Er:YAG laser uses an erbium-doped yttrium aluminum garnet crystal, emitting at 2940 nm — one of water’s absorption peaks, with an absorption coefficient roughly 10-20 times that of CO2. Nearly all pulse energy is absorbed by surface water, giving exceptionally sharp vaporization boundaries and a very narrow zone of residual thermal damage.

• Thermal damage: Er:YAG’s residual thermal zone is only microns to tens of microns versus dozens to ~200 for CO2 — erbium is “colder”, while CO2’s heat adds collagen contraction and hemostasis.
• Ablation efficiency: erbium converts energy into precise, controllable vaporization per pulse, ideal for fine superficial passes.
• Hemostasis: CO2 seals small vessels for a cleaner field; erbium bleeds more.
• Recovery: erbium produces lighter, shorter erythema, though insufficient dermal heating can mean less collagen remodeling than CO2.

• Superficial pigmented lesions, seborrheic keratoses
• Fine wrinkles and shallow acne scars
• Fine resurfacing on face and body
• Mid-to-deep fractional rebuilding in long-pulse/thermal modes

Choose erbium for minimal thermal injury and fast recovery; choose CO2 when stronger dermal heating, contraction and hemostasis are wanted. Premium platforms offer dual 2940+10600 nm with per-zone switching.

Is Er:YAG suitable for darker skin?

Its minimal thermal spread carries relatively lower PIH risk, making it a gentler ablative option for darker skin — still fractional, low-density first and strict photoprotection.

How long is recovery after fractional Er:YAG?

At superficial settings, crusting resolves in 3-5 days and erythema in 1-2 weeks — clearly shorter than CO2 at comparable depth.

• CO2 Fractional Laser
• Fractional Photothermolysis
• Ablative vs Non-Ablative