Undoped YAG is a substrate and window crystal that can be used for both UV and IR optic.It is particularly useful for high temperature and high energy applications.The mechanical stability of YAG is similar to Sapphire,but YAG is not birefringent and is available with high optical homogeneity.
Advantages of Undoped YAG Crystals
● Non-birefringent
● High bulk damage threshold
● High index of refraction,facilitating low aberration lens design
● High thermal conductivity
● Stable mechanical and chemical properties
● Low stress and high optical quality
| Crystal Symmetry Hexagonal | System |
| Lattice constant | a =4.75 ; c =12.97 |
| Transparence range | 250-5000nm |
| Density | 4.5g/cm3 |
| Mohs hardness | 8.5 |
| Melting point | 1970℃ |
| Thermal conductivity | 14W/m/K |
| Expansion coefficien | 6.9X10 -6/K |
| Refractive Index | 1.8197@1064nm |
Typical finished part specifications and tolerances are listed below.
Material……………………………………….. ………………………………………YAG
Diameter Tolerance……………………………………………………. ……………+0,-0.025mm
Length Tolerance………………………………………………………….. ………. +/-0.5mm
Parallelism……………………………………………………………………………. <10 arc seconds
Perpendicularity……………………………………………………………………. ..<5 arc minutes
Chamfer……………………………………………………………………………….. 0.13±0.08mm at 45°
Barrel Finish……………………………………. …… ……….. …………………. 50-80 micro-inch(RMS)
Wavefront Distortion Rod……………………………… ……………….. …. …. <λ/8 per inch @632.8nm
Extinction Ratio…………………………………………………………………… >30dB
Surface Flatness………………………………………………. ………………….<λ/10 @632.8nm
Surface Quality……………………………………………………………………… 10/5
Clear Aperture……………………………………………………………………….. >95%
Anti-Reflection Coating………………………………………………………………R<0.15%@1064nm per surface
High-Reflection Coating…………………………………….Standard HR coating with R>99.8%@1064nm and R<5%@808nm
