WRIGHT-PATTERSON AFB, OHIO – Questioning the nature of things is the intrinsic nature of any scientist. Refusing to simply accept a passive answer for what they were seeing has led to a family of patents for two scientists in the Air Force Research Laboratory (AFRL) Sensors Directorate (RY).
Gary Cook, Ph.D., and his research associate Ronald Stites, Ph.D., were witnessing an experiment involving highly tunable transition metal lasers and became intrigued about the emission spectrum. Something seemed odd to them.
“I was surprised why the emission linewidth of the lasers was really broad. It was much broader than should have been possible,” Cook explained. “So, I questioned that. The wisdom in the industry at that time was a kind of shrug of the shoulders and (a response of) ‘Well, that’s just how they are.’ But to me it suggested that material had a lot of defects in it.”
The laser material in this family of four patents – the latest being U.S. Patent #11,292,967 B2: Electrically-Processed Laser and Scintillator Materials -- involves tunable transition metal lasers that are crystalline in nature. These are useful for a wide range of applications including sensing. Any defects in those crystals can greatly affect the resulting power within a given spectral range. These defects can be breaks in the optical bonds or impurities. Optical defects in materials result in a loss of power when you attempt to tune the laser to a narrow linewidth, making it highly inefficient.
After Cook and Stites discussed the experiment they had just seen, the pair began thinking about ways to reduce or irradicate these crystalline defects. What they came up with would surprise many in the field.
“We borrowed a technique from the metal working community called hot isostatic pressing (HIP). This is a method that was originally designed for metal castings. It was also used to treat early turbine blades in jet engines,” Cook said. “Essentially, it’s a process where you put your material of interest inside a heated pressure chamber and highly pressurize it. The idea is that the pressure will squeeze out all those defects.”
With help from the AFRL Materials and Manufacturing Directorate (RX), Cook and Stites were able to test this theory by putting these crystals through the HIP process. When the crystals were returned, Cook and Stites found the laser power and tuning range were unaffected, but the free-lasing linewidth was much narrower than before. The duo had discovered a technique to fix laser material that was of lesser quality and began the patent application process.
“When we first suggested HIP treatment for our laser materials, the experts in the field said laser ions (intentionally introducing defects or impurities to)– we used chromium –probably existed in the crystalline grain boundaries. So, if we put them in the HIP chamber, we would probably just purify the crystal and squeeze the chromium out,” Cook said. “But we didn’t do that. We reasoned that, if people were wrong about that aspect, they were probably wrong about other ways HIP worked.”
The process has resulted in instantaneous savings to the Department of the Air Force (DAF), Department of Defense (DoD), and the United States taxpayer. The DAF relied on industry to manufacture these crystals which would take a matter of months and cost anywhere from $2,000 to $3,000 according to Cook. They can now be made in-house at the AFRL in a matter of hours for about $100. The crystal sizes are now also greatly increased.
“The biggest we could get from industry before would be maybe a cubic centimeter. We can make coffee cup-sized diameter pieces (now),” Cook explained.
Once getting the patents approved, Cook and Stites turned to DAF Technology Transfer and Transition (DAF T3PO) Partnership Intermediary (PIA) TechLink in Bozeman, Montana to help them market this technique for licensing. They found the experience to be very encouraging.
“(The TechLink staff) is excellent; very useful and very helpful in identifying markets and helping us understand where what we do is useful in the Air Force and in wider industry. They’re also very receptive to protecting technology rights for the United States,” Cook said. “Most people think patenting is about generating income and it’s not really. It does generate an Air Force income, which is great. But the real benefit is it helps us control the marketplace because the world’s changed over the past 30 years. We can deny markets of competitors where we think that might be advantageous and allow us to keep the lead.”
Cook encourages all scientists and engineers with great ideas to go through the patenting process. This is not just to protect intellectual property but discover other benefits from said process.
“It’s also a different way of getting your work peer reviewed. Most scientists will write papers to be reviewed by other scientists. That’s not quite the same as being reviewed for inventiveness. Having someone very carefully assess your work for inventiveness is very rewarding so you can learn whether you’re on the right track of something beneficial,” Cook said.
United States Patent Office Patent: #11.292,967 B2
Patent License Agreements are offered through the Air Force Research Laboratory’s Technology Transfer and Transition (T3) program office. A comprehensive suite of T3 mechanisms for partnering with industry and academia is offered through the office. To find out how you can partner with the T3 Program, please visit https://www.aft3.af.mil. TechLink assists the Department of Defense and Veterans Affairs by actively marketing its available patented technologies to prospective companies and facilitating license agreements.