ErYAG

Er:YAG stands for erbium-doped yttrium aluminum garnet, a synthetic crystalline laser medium with the chemical composition Y3Al5O12 doped with Er3+ ions. The crystal is grown by the Czochralski process and used as a solid-state laser medium in medical and industrial systems.

In operation, Er:YAG lasers emit at a wavelength of approximately 2.94 micrometers (2940 nanometers) from the Er3+ ion transition, typically the ^4I11/2 → ^4I13/2 transition. The laser is usually pumped by near-infrared diode lasers around 940–970 nm or by flashlamps; emission is typically produced in pulsed or quasi-continuous modes, with pulse durations ranging from microseconds to milliseconds in many medical applications.

The 2940 nm wavelength is strongly absorbed by water and by hydroxyapatite, resulting in precise, shallow ablation with minimal thermal damage. This makes Er:YAG lasers well suited to medical procedures where tissue preservation is important, including delicate tissue ablation with controlled depth and smooth surfaces.

Applications include dentistry, where Er:YAG lasers are used for hard-tissue (enamel and dentin) ablation, caries removal, and periodontal procedures, as well as implant site preparation. In dermatology and general surgery, they are used for skin resurfacing, soft-tissue ablation, and minor surgical incisions. In dental use, pulsed operation with microsecond to millisecond-scale durations helps minimize heat diffusion and charring.

Compared with CO2 lasers, which also target water-rich tissues, Er:YAG offers finer control and less thermal necrosis but typically shallower penetration and lower ablation efficiency per unit power. Compared with Nd:YAG lasers at 1064 nm, the Er:YAG operates at a wavelength with much higher water absorption, yielding more superficial but cleaner ablation.