Etalon mounts for tunable Fabry-Perot interferometers can now be fabricated from reaction-bonded silicon carbide structural components. These mounts are rigid, lightweight, and thermally stable. The fabrication of these mounts involves the exploitation of post-casting capabilities that (1) enable creation of monolithic structures having reduced (in comparison with prior such structures) degrees of material inhomogeneity and (2) reduce the need for fastening hardware and accommodations. Such silicon carbide mounts could be used to make lightweight Fabry-Perot interferometers or could be modified for use as general lightweight optical mounts.
Heretofore, tunable Fabry-Perot interferometer structures, including mounting hardware, have been made from the low-thermal-expansion material Invar (a nickel/iron alloy) in order to obtain the thermal stability required for spectroscopic applications for which such interferometers are typically designed. However, the high mass density of Invar structures is disadvantageous in applications in which there are requirements to minimize mass.
Silicon carbide etalon mounts have been incorporated into a tunable Fabry-Perot interferometer of a prior design that originally called for Invar structural components. The strength, thermal stability, and survivability of the interferometer as thus modified are similar to those of the interferometer as originally designed, but the mass of the modified interferometer is significantly less than the mass of the original version.
This work was done by Scott Lindemann of Michigan Aerospace Corp. for Goddard Space Flight Center. GSC-14957-1