The laser useful in smear layer removal is
Erbium: Chromium: Yttrium Scandium Gallium Garnet Laser (Er:Cr:YSGG)

Etches enamel surface.
Removal smear layer.

 Erbium: Yttrium Aluminium Garnet Laser (Er:YAG)

Remove caries in enamel and dentin.
Removes dislodged GIC and Composite. 
Desensitize the hypersensitivity dentin.

 Neodymium - Yttrium Aluminum Garnet Laser (Ne: YAG)  

Good hemostasis.
Used in non-surgical sulcular debridement.

 Argon Laser 

Yield high intensity visible blue light. 
Curing of dental restorations.
It also changes the surface chemistry of both enamel and root surfaces dentin, which reduces the probability of recurrent caries. 
Removes extrinsic and intrinsic stains.
Bleaching of teeth.
Er:Cr:YSGG
Er:YAG
Ne:YAG
Argon Laser