Sapphire Materials:
Sapphire is grown using various different methods, each with its
advantages. By offering Sapphire grown by Stepanov, Czochralski,
Kryopolus and HDSM methods, Roditi ensure that the specification is
met with the best production time and cost in mind.
Boules, Ingots and Blanks
Unprocessed, single crystal Sapphire takes the form of a boule
before being cut and polished into the required forms.
The boule is a large, cylindrical-like piece of Sapphire with no
ground, polished or flat faces and offers any crystallographic
orientation of components, such as c, m, r and a-cut. Because of
Sapphire's tremendous hardness, the cutting and processing is done
with diamond tools.
Boules such as this are processed into blanks and ingots ready for
further processing and polishing. Such blanks and ingots are
uniformly shaped, usually as cylinders, and have ground surfaces.
Properties of Single Crystal Sapphire
| Chemical formula | Al₂O₃ |
| Purity | 99.999% |
| Crystal structure | Hexagonal |
| Hardness Mohs | 9 |
| Fusion point | 2045℃ |
| Boiling point | 2980℃ |
| Coefficient of Thermal Expansion | 5.8×10 -6 /K |
| Specific heat | 0.418W.s/g/k |
| Thermal conduction | 25.12W/m/k(@100°C) |
| Refractive index | no=1.768 ne=1.760 |
| dn/dt | 13×10-6/K(@633nm) |
| Transmission | T≈80%(0.3-5μm) |
| Permittivity | 11.5(//c), 9.3(⊥c) |
Sapphire Components
Sapphire's range of superior qualities make it ideal for optical
and non-optical components. From the forward-facing optics of
imaging systems to the thermal insulators in plasma systems,
Sapphire's performance at extreme physical conditions often make it
the preferred choice for the following:
Lightguides
Sapphire offers higher working temperatures in applications such as
temperature thermometry and IPL systems, with a broad transmission.
Lenses
High optical quality Sapphire is used for lenses in systems that
require durability and ruggedness where standard materials suffer
from grit, impact and temperature damage. Sapphire lenses also
offer high performance in laser devices, offering high thermal
conductivity.
The broad transmission of Sapphire, across visible and NIR
spectrums, make it ideal for FLIR imaging systems in hazardous
environments, or where the reduced thickness of Sapphire lenses
lead to reduced system footprint.
Tubes
Sapphire tubes, made using the Stepanov growth method, replace
glass and quartz tubes in high temperature and pressure systems
such as plasma applications and insulators.
Pins and Rods
As well as the optical proporties offered by Sapphire rods for
fibre optcal and light-guide applications, the physical strength
and inert nature of Sapphire make it ideal for engineering and
structural uses.
