Sapphire windows are routinely being used in demanding aerospace applications due to their high strength and desirable optical and material properties. Sapphire is particularly useful in addressing the increasing need for systems that provide a wider range of capabilities in a single package. In general, refractive index homogeneity of the component materials can have a significant impact on overall optical system performance. This leads to the need for a deeper understanding of the shape and magnitude of index inhomogeneity in large sapphire windows to ensure predictable, high quality operation. Thin, sapphire slices from a sapphire crystal boule grown via the Heat Exchanger Method (HEM) have been previously evaluated for refractive index homogeneity over a 25.4cm (10.0”) aperture. The resultant transmitted wavefront error (TWE) from those measurements has now been used to model typical optical systems to quantify the effects on system-level performance attributed to representative amounts of index inhomogeneity in the sapphire window. The results of this modeling effort are presented in the following paper.
The ROBS tracking telescope was invented and developed at TTC to provide a high acceleration,k large aperture beam steering system for rapid pointing to multiple objects. The optical system consists of a fast, oversized spherical primary mirror with the 50 cm aperture stop at the center of curvature of the primary mirror (CCP). A lightweight secondary mirror selects the instantaneous field of view by scanning over the petzval image surface of the primary mirror. The secondary mirror is gimbaled about the CCP on a rigid, lightweight mast. The system's symmetry about the CCP simplifies the optical and mechanical design and provides very rapid retargeting over a 30 degree field of regard for multiple target tracking. Field corrector and pupil relay optics inside the support tube collimate the light through coude' optics to passive sensor and laser radar optics. The 2-sphere, 2-asphere aplanatic, anastigmat all-reflective design corrects the 9.1 mr of spherical aberration from the F/1 primary and provides 10 microradian resolution over a 5 mr field of view. The system incorporates near field focus adjustment to provide high resolution imaging and laser ranging over a large volume of space. Two 50 cm systems have been built and demonstrated tracking multiple targets in the field. This paper describes the opto-mechanical design and demonstrated system capabilities.
Beam agility for large aperture optical systems has proven to be a challenging engineering problem. This paper describes optical engineering issues of an agile, 1/2 meter aperture, 30 degree(s) field of regard telescope. Key system tradeoffs considered in the optical design are discussed.
The properties of a pseudodeep hologram are studied. This new term refers here to an inclined thin hologram on which a one-dimensional line object is recorded by a sagittal system of beams. In this case the reconstructed image is read out only within the line corresponding to the object. It is shown that, similar to deep 3-D hologram, the pseudodeep hologram has high angular and spectral selectivity. A simple graphic method for the construction of the images restored by the pseudodeep hologram is presented. A reference-free hologram has been recorded with the help of such a system. When reading out such a hologram for a part of the object recorded on it, the associative image of the object as a whole was reconstructed. The possibilities of using the pseudodeep hologram was performing different operations are considered, including heteroassociative readout of information by the keys associated with it, recognition of pages of information by the keys associated with it, recognition of pages of information when illuminating the hologram by the objective wave, and multiple recording of information in the same region of the photographic material. In conclusion, the associative memory scheme in which the information pages are recorded on separate stripes of the pseudodeep hologram with the use of different reference sources as the keys associated with these pages has been considered. The retrieval of the pages is performed by illuminating the entire surface of the hologram with one of the reference sources
Beam agility for large aperture optical systems has proven to be a challenging engineering problem. This paper describes optical engineering issues of an agile, 1/2 meter aperture, 30" field of regard telescope. Key system tradeoffs considered in the optical design are discussed.