Er YAG
Rod standard variable specifications
Er doping : 0.15 – 0.50 % ± 0.01 %
Diameter : 2 – 12.7 ± 0.025 mm
Lenght : 5 – 150 ± 0.5 mm
Parallelism : < 10 arc seconds
Perpendicularity : < 5 arc minute
Chamfer : 0.2 mm +0.05 / -0.1mm @45° ± 5°
Flatness : < λ/10 wave @633nm
Scratch/dig : 10 – 5
Extinct ratio : > 25 db @633 nm
Traceability : laser-marked S/N on cylindrical surface
Standard Coating : AR, R, HR, PR, etc.
Other special custom coatings are also available
PHYSICAL PROPERTIES
Er doping level : 0.10 – 50 ± 0.01 at%
Chemical formula : Er : Y3Al5O12
Molecular weight : 593.7 g/mole
Crystal structure : cubic
Lattice constants: 12.01 Å
Melting point : 1970 °C
Density : 4.56 g/cm3
Mohs hardness : 8.5 @ 20 °C
Young’s Modulus : 335 Gpa
OPTICAL PROPERTIES
Reflective index : 1.83 @632.8 nm
Lasing wavelengths (λ) : 2940 nm
Primary diode pump band:
600 – 800 nm (Er conc. 50%)
1500 nm (Er conc. 0.1 – 1.0 %)
THERMAL PROPERTIES
Thermal conductivity : 11.2 W/(cm•K)
Specific heat : 0.59 J/(g•K)
Dissipative fracture limit : W/cm
Thermal optical coefficient (dn/dT) : 7.8 × 10-6 / K
Er:YAG lasers typically emit light with a wavelength of 2940 nm, which is infrared light.
It has numerous applications in dentistry. In addition to being absorbed by water, the output of Er:YAG lasers is also absorbed by hydroxyapatite, which makes it a good laser for cutting bone as well as soft tissue. Erbium YAG dental lasers are effective for removing tooth decay atraumatically, often without the need for local anesthetic to numb the tooth. Eliminating the vibration of the dental drill removes the risk of causing microfractures in the tooth. When used initially at low power settings, the laser energy has a sedative effect on the nerve, resulting in the ability to subsequently increase the power without creating the sensation of pain in the tooth. Additional benefits are disinfection of the surface of the dentin and enamel prior to bonding the filling, and etching the surface to increase surface area for improved bonding adhesion.
