Open Photonics is exploring the development of a new class of lightweight, strong and inexpensive mirror substrates. By utilizing Polymer-Derived Ceramic (PDC) materials, we will provide a new pathway to lighter mirror substrate materials that can be produced in an inexpensive manner.
Until now PDCs have been limited in size to thicknesses of 300 microns or less. This has limited PDC usage to size constrained fibers and films. Our partner has developed a disruptive technology that allows for PDCs to be converted to bulk size form factors. Silicon oxycarbide (SiOC) ceramic material 4mm thick discs of 20mm and 68mm diameter have been shown through a compression molding process. The properties of this SiOC amorphous ceramic include a density range of 1.5-1.8g/cm3 as well as a high continuous operating temperature of 1100C.
Why is this needed in the marketplace?
The Missile Defense Agency (MDA) recently had an open call for SBIR proposals (MDA13-T009) requesting technology to develop the next generation airborne laser. This system will be weight constrained. Therefore the MDA is interested in investigating novel concepts to create lightweight optics and coatings while maintaining high power densities because the beam control system is projected to comprise a significant portion of the weapon system weight.
Desirable characteristics of mirrors used in the laser optical system where rapid redirection of a high power laser beam is required would be:
- Low inertial mass
- High specific stiffness
- Resistance to microyield
- Temperature resistance
High specific stiffness, temperature resistance, and low coefficient of thermal expansion (CTE) are hallmarks of ceramic materials. One of the more promising candidates has been silicon carbide (SiC). Silicon carbide has high stiffness, high strength, relatively high toughness and relatively high thermal conductivity (compared to other ceramics).