SBIR-STTR Award

Sapphire possesses a number of physical properties, including high strength, high melting point, chemical inertness, and excellent transparency in the visible and IR spectrum, which make it an attractive window material for military applications. Until recently, the largest detrimental factor has been the small size of available crystals. However, crystal growth capabilities have advanced to where large, single crystal sapphire windows are now realizable. During Phase I, Rubicon Technology, with their extensive experience in bulk sapphire crystal growth, will investigate the feasibility of producing optical grade sapphire blanks for use as IR windows. Research efforts will focus on designing and demonstrating a horizontal furnace capable of producing sapphire windows with minimum post-processing dimensions of 14” x 20” x 1”.

Benefit:
The ability to provide c-plane sapphire will address new markets where application are currently not serviceable by current sapphire products due to limitations in window size and thickness and/or concerns over strength or optical quality of the material. Some specific target markets include commercial aircraft and commercial shipping which will benefit from the enhanced optical qualities as well as enhanced strength of the c-plane material. In addition, many applications for clear armor currently rely on less effective materials that could be improved by utilizing sapphire windows.

Keywords:
Rubicon Technology, Sapphire, Crystal Growth, Ir Windows, Leds

Sapphire possesses a number of physical properties, including high strength, high melting point, chemical inertness, and excellent transparency in the visible and IR spectrum, which make it an attractive window material for military applications. For Phase I, Rubicon Technology demonstrated a sapphire crystal growth process to MRL 5 capable of growing slabs 20” x 14”. During Phase II the process will be scaled up and finalized to produce polished sapphire windows 36” x 18” x 0.8”. All aspects of the process, starting from growth and progressing through slicing, surface grinding, polishing, and characterization will be performed and finalized in order to reach MRL 7. The needs of the end user, Lockheed Martin, will be considered to ultimately provide a drop-in replacement for the current sapphire windows used in the Joint Strike Fighter Electro-Optical Targeting System.

Benefit:
The ability to provide large scale sapphire windows will address new markets where application are currently not serviceable by current products due to limitations in window size and thickness and/or concerns over strength and optical quality of the material. Some specific target markets include commercial aircraft and commercial shipping which will benefit from the enhanced optical qualities as well as enhanced strength of sapphire over conventional materials. In addition, such windows can be used to protect onboard imaging and targeting systems for the Joint Strike Fighter and RC-135 Cobra Ball. Furthermore, large sapphire windows can fulfill the need for transparent armor in Army vehicles requiring maximum situational awareness that opaque materials cannot supply.

Keywords:
sapphire, crystal growth, IR Windows, index homogeneity, transparent armor, electro-optical targeting system, Joint Strike Fighter, DDG-1000