Angle of Minimum Deviation: As shown to the right, when α=β, the refractive light ray is parallel to the base surface, there will be a minimum value of the deviation (γ).
Please note that such formula could only work for the material with refractive index < 2.0, when the n is >2.0, total internal reflection will occur at angle C shown as above. Thus for ZnSe dispersive prisms listed below, they will have a beam exiting from the bottom face, and that’s why the 3rd surface should be polished for those prisms.
| Material： See details in the list | Bevel：<0.25mm × 45° |
| Diameter Tolerance： See details in the list | Clear Aperture：70% |
| Mounting Surface： Commercial polished | Surface Quality：40/20 |
| All Other Surfaces：Fine ground | Coating：See detail in the list |
