What this application demands
Airborne and spaceborne optics face the widest combination of stressors in this industry: ultraviolet exposure that darkens some glasses over time, thermal vacuum cycling through large temperature ranges, mechanical shock during launch, and in some cases radiation that alters transmission. The specification problem is that these effects are cumulative, so the optic has to be qualified not only for the day it is installed but for the end of its service life.
Multi-band operation adds a second layer of difficulty. A single aperture frequently has to serve visible, near-infrared and sometimes mid-infrared channels, which constrains the substrate to materials transparent across all of them and forces the coating to be designed as a multi-band function rather than a single pass band.
Specifications we recommend
| Component | Typical specification | Why |
|---|---|---|
| Sensor windows | Sapphire for hardness and broad transmission, or fused silica for UV paths | Survives sand, rain and thermal cycling while passing the required bands |
| Multi-band filters | Hard dielectric stacks with defined blocking between pass bands | Separates channels across a shared aperture |
| Protective domes and covers | Hard-coated, sealed, specified against shock and thermal vacuum | First surface in the path usually takes the environmental load |
| Guidance and tracking optics | Mid-IR transmitting windows with AR coatings | Preserves signal in low-contrast thermal scenes |
Failure modes we design against
UV-induced transmission loss is a slow, cumulative effect that is easily missed in short-term testing. It is mitigated by selecting materials with known UV stability and by qualifying the coating under representative exposure rather than by assumption. Thermal vacuum exposure is the second risk, particularly for coatings with organic content, which is one reason hard dielectric designs are preferred where outgassing matters.
Shock and vibration usually damage the mounting rather than the optic, but the optic's edge quality matters: chips and subsurface cracks become crack initiation sites under sustained vibration. Controlled chamfers and specified edge-chip limits are a practical mitigation.
Frequently asked questions
Do you have flight heritage?
We supply optical components to aerospace and defence programmes. Qualification and flight approval rest with the prime contractor; we supply measured data and test evidence to support it.
Which substrate for a multi-band aperture?
Sapphire where the path extends into the mid-infrared; fused silica where ultraviolet performance dominates and hardness is not the limiting factor.