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NASA’s laser mount technology introduces a unique flexible crystal mount to accommodate the dynamics of thermal expansion to eliminate unsymmetrical thermally induced mechanical stresses on the crystal. In addition, while the mount accommodates thermal expansion, it also offers fixed placement of the crystal to maintain alignment and provides continuous and uniform surface contact between the mount and crystal for rapid dissipation of heat. The mount is compatible with any heat sink reservoir. The mount design allows unrestrained thermal expansion of the crystal in two dimensions (i.e. a- and c- axes) because of the design shown in the figure below. The L-shape blocks also deliver cooling to the crystal by providing a path to the heat sink reservoir. The L-shape blocks are manufactured with a high thermal conductivity material such as copper. A softer material with high thermal conductivity such as indium is used to buffer the interface between the crystal and the L-shape blocks surfaces. A coolant medium acts to transfer the heat from the crystal to the cooled mount. Cooling can be provided in different ways – for example by water or by heat pipes with radiator (for use in space). The springs used to hold the laser crystal also provide the adjustment method to align the beam, and once aligned, the crystal mount is very stable. The related patent is now available to license. Please note that NASA does not manufacture products itself for commercial sale.

The ALD-Enhanced Far-to-Mid IR Camera Coating is fabricated by first applying a conductively loaded epoxy binder ~500 microns thick onto a conductive metal substrate (e.g., Cu, Al). This serves to provide high absorptance and low reflectance at the longest wavelength of interest, as well as to provide a mechanical buffer layer to reduce coating stress. Borosilicate glass microspheres are coated with a thin film metal via ALD, essentially turning the microspheres into resonators. That film is optically thin in the far infrared and approximates a resistive (~200 ohms per square) coating. Light trapped in the borosilicate glass microspheres is reflected back and forth within the glass–at each contact point, the light is attenuated by 50%. A monolayer of thin metal film-coated borosilicate glass microspheres is applied to the epoxy binder and cured, forming a robust mechanical structure that can be grounded to prevent deep dielectric charging by ionizing radiation in space. Once cured, the far-to-mid IR absorber structure can be coated with a traditional ~20-to-50 microns “black” absorptive paint to enhance the absorption band at short wavelengths, or a “white” diffusive paint to reject optical radiation. At this thickness and broad tolerance, the longwave response of the coating is preserved. Tailoring the electromagnetic properties of the coating layers and geometry enables realization of a broad band absorption response where the mass required per unit area has been minimized. While NASA originally developed the ALD-Enhanced Far-to-Mid IR Camera Coating for the Stratospheric Observatory for Infrared Astronomy mission, its robustness, absorptive qualities, and optical performance make it a significant addition to IR and terahertz imaging systems. The IR camera coating is at Technology Readiness Level (TRL) 3 (experimental proof-of-concept) and is available for patent licensing.