Rubicon Technology Develops World’s Largest Sapphire Crystal

In August 2012, Rubicon Technology announced a ground-breaking project to produce large-area sapphire windows of optical quality for military sensing applications. Dubbed Large-Area Net-shape Crystal Extraction (LANCE), the project was supported by a contract from the United States Air Force Research Laboratory (AFRL) Electronic & Sensors Branch, Materials & Manufacturing Directorate, totaling $4.7 million over three years.

Fast forward to today.

Rubicon announced it has reached a key project milestone — successfully producing the first-ever synthetic sapphire crystal of its size and thickness, coming in at an incredible 36 x 18 x 2 inches.

Sapphire Slab

Previous sapphire production methods were incapable of supporting the growth of quality sapphire at the size and thickness needed by the AFRL, so Rubicon developed a new growth platform to achieve the production of very large sapphire windows up to 2 inches thick. The process of creating sapphire of this size was incredibly complex and time-intensive, but Rubicon was determined to deliver a product unlike anything the market had ever seen before.

The military and other high-performance Industries desire sapphire at this size due to a variety of its qualities, including:

  • Strength
  • Optical clarity in the visible and infrared spectra
  • Hardness
  • Abrasion resistance
  • Thermal conductivity

Once thoroughly tested, the sapphire slab produced by Rubicon will be evaluated for use as infrared windows in extreme environments, such as space or the deep sea, where both durability and optical clarity are essential.  The potential uses are almost limitless.  Large-format sapphire will serve demanding applications in defense along with future commercial and industrial applications.

While the project is not yet complete, this is an encouraging breakthrough.

For more information on the LANCE project, visit http://www.rubicontechnology.com/research-development/project-lance-very-large-sapphire-windows.

Case number 88ABW-2015-0182

How Large Can You Go? Sapphire Windows Grow Up and Across

 

Dr. Jonathan Levine, Director of Technical Business Development, Rubicon Technology, at SPIE Defense, Security and Sensing 2013

SPIE Defense, Security and Sensing 2013 was held last week in Baltimore, MD.  There was a very interesting paper on large sapphire optical windows.  Rubicon Technology’s Dr.  Jonathan Levine, Director of Technical Business Development, talked about recent advances in making very large sapphire optical windows from his paper, “Synthesis and Characterization of Large Optical-Grade Sapphire Windows Produced from a Horizontal Growth Process,” that he presented at the conference.

As sensor technology and applications, in defense and aerospace in particular, have evolved, the size requirements for sapphire sensor windows have grown substantially. Dr. Levine detailed how Rubicon successfully produced very large sapphire blanks using a highly modified horizontal directional solidification process. This new method, named the Large‐Area Netshape Crystal Extraction (LANCE) system is currently able to produce crystals of several different orientations weighing up to 50 kg with plans to expand the process to larger 100 kg sapphire crystals.

Based on a different technique than Rubicon’s ES-2 method, Levine’s team used the LANCE method because it produces plates or slabs of sapphire instead of cylindrical boules.  Using LANCE is advantageous since the near-net shape dramatically reduces machining and associated fabrication costs.  Further, since the melt is horizontal, capillary forces play a minimal role during growth and the crystal is not limited in size or thickness as compared to edge‐defined film-fed growth (EFG) crystals.

According to Levine, Rubicon has been able to synthesize several prototypes up to 1.75 inches thick, 14 inches wide and 20 inches long. The research sets the standard for high quality monolithic sapphire sheets large enough for use as seamless integrated optical windows in both military and civilian applications.

Sapphire is very good for defense and aerospace applications due to its excellent transmission in the UV through IR spectrum, high impact durability, and corrosion resistance in harsh environments.  Sapphire applications include missile domes, transparent armor systems, FLIR and enhanced vision systems for aircraft, and shaped optics for land, air and sea vehicles.

For Further Reading

Rubicon Technology, Rubicon Technology Develops New Sapphire Crystal Growth Platform to Manufacture Large Optical-Grade Windows for Military and Industrial Applications, http://phx.corporate-ir.net/phoenix.zhtml?c=215281&p=irol-newsArticle&ID=1724966&highlight=

SPIE Defense, Sensing and Security 2013, http://spie.org/x6765.xml?WT.svl=mddce7