Erbium Doped Yttrium Aluminum Garnet (Er:YAG) lases at 2940 nm which is the same as hydroxyl absorption peak. Therefore the rays produced by Er:YAG can be strongly absorbed by biological tissues which make Er:YAG lasers being widely used in medical area, such as dental (hard tissues), orthopedics, etc. Er:YAG produced by WISOPTIC has high quality of good internal optical uniformity and high slope efficiency.