N152-107        TITLE:  Manufacturing of Visibly Transparent Large Conformal Windows TECHNOLOGY AREAS:  Air Platform, Materials/Processes, Sensors

ACQUISITION PROGRAM:  UCLASS, The Carrier Unmanned Aviation Program Office PMA-268

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals

(FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 5.4.c.(8) of the solicitation. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. 

OBJECTIVE:  Develop methods to grind and polish freeform conformal sensor windows with dimensions up to 24x24 inches with a sag height of approximately 8 inches and an optical precision of 0.5 micron or better. The purpose of this topic is to demonstrate manufacturing methods for optics from glass. A related topic NSMA-152-257 will address the production of near-net-shape spinel blanks for future manufacturing of optics.

DESCRIPTION:  Conformal electro-optic sensor windows are desirable for future air platforms as they maintain the shape of the aircraft moldline and allow for a large sensor angle of regard. Such windows may have little to no symmetry depending upon their location. Spinel is an excellent candidate window material as it is both durable and multi-spectral (ultraviolet through mid-wave infrared). Spinel is more erosion resistant than multispectral zinc sulfide, which is another logical candidate for a large conformal window. The objective for this project is to create methods to grind and polish freeform conformal sensor windows with dimensions up to 24x24 inches with a sag height of approximately 8 inches and an optical precision of 0.5 micron or better. It is expected that methods will be developed with glass or fused silica and that a full sized window will be made from glass or fused silica. It is also possible that a full sized spinel blank may be available from the government during this project. 

PHASE I:  Demonstrate the feasibility of grinding and polishing a glass or fused silica conformal window with dimensions of 12x12 inches. The contractor shall propose a shape with a window sag height of approximately four inches and lacking rotational symmetry. The precise shape of the conformal window will be selected by mutual agreement with the government. The root-mean-square precision of the optical figure shall be 0.5 micron or less with a clear aperture extending within half an inch from the edge.

PHASE II:  Based on Phase I effort, scale up window fabrication with glass or fused silica to lateral dimensions of 24x24 inches with a sag of approximately eight inches. The shape shall be proposed by the contractor with mutual agreement from the government. A root-mean-square precision of the optical figure of 0.5 micron or less with a clear aperture extending within half an inch from the edge is desired. There is a possibility that a spinel blank will be made available by the government for Phase II.

PHASE III:  Implement commercial manufacturing capabilities for large conformal windows made of durable ceramics such as spinel. Manufacture an instrument for sale to optics manufacturers to make large, aggressively aspheric optics. Alternatively, provide a commercial service to manufacture such optics.

REFERENCES:  

1.                S. DeFisher, E. Fess, and F. Wolfs, “Freeform and Conformal Optical Manufacturing,” Proc. SPIE 2013, Volume 8708 paper 870813. (http://www.spie.org/x1848.xml)

2.                J. DeGroote Nelson, A. Gould, N. Smith, K. Medicus, and M. Mandina, “Advances in freeform optics fabrication for conformal window and dome applications,” Proc. SPIE 2013, Volume 8708 paper 870815. (http://www.spie.org/x1848.xml)

3.                J. Taylor, R. Boland, E. Gowac, P. Stupik, and M. Tricard, “Recent advances in high-performance window fabrication,” Proc. SPIE 2013, Volume 8708 paper 870816. (http://www.spie.org/x1848.xml)

KEYWORDS:  Optical fabrication; conformal windows; large optics; aspheric optics; sensor window; infrared window

** TOPIC AUTHOR (TPOC) **

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