Edge Bonding of Infrared Windows

Onyx Optics, Inc. proposes to apply its patented AFB® (Adhesive-Free Bond) composites process that has been developed for solid state laser components to the edge bonding fabrication of IR windows. The key process step is to obtain optical contact between the components to be bonded, followed by heat treatment. There are a number of techniques of establishing this optical contact but they all result in an interface that is bonded mainly through Van der Waals forces after at least moderate heat treatment and out-diffusion of volatile species. Van der Waals forces consist of three types: fixed dipole/fixed dipole interactions, fixed dipole/induced dipole interaction, and induced dipole/ induced dipole interactions, respectively. They become prominent when the separation distance between two adjacent solid bodies becomes much smaller than any wavelength of the random dipole field. Lifshitz quantum field theory will be applied to the specific case of composite infrared windows and linked to experimental results. AFB® composites will be characterized and compared with non-composite controls in terms of: Mechanical properties: tensile fracture strength, fracture toughness, elastic modulus, stress birefringence. Optical properties: Transmitted wavefront as function of angle of incidence, refractive index, transmission between visible to far IR.