Researchers are developing powerful, efficient, field-deployable lasers that have many applications including laser weapons, defense against heat-seeking missiles, the detection of harmful gases, and the detection of air turbulence that might interfere with the flight of civilian or military aircraft.
Research at risk: Advancing ultrafast lasers for national defense
By James Dean, Cornell Chronicle
After more than five years of work supported by the Office of Naval Research (ONR), Jeffrey Moses, Ph.D. ’07, felt his team was on the cusp of significant progress developing an advanced laser that could be useful for national defense and a host of civilian applications.
So-called ultrashort laser pulses, or ultrafast lasers, are nearly instantaneous bursts of light that can emit power equal to or greater than the entire power supply of the U.S. electrical grid – for a few millionths of a billionth of a second.
Beyond potential relevance to futuristic laser weapons, improvements in that technology could bolster defense against heat-seeking missiles and aid the detection of harmful gases, as well as of turbulence that could endanger aircraft. Additional nondefense applications could benefit greenhouse gas detection; brain imaging; medical therapies; and the study of physics, biology, chemistry and materials science.
Early this year, the research team led by Moses, an associate professor, and Frank Wise, the Samuel B. Eckert Professor of Engineering, both in Cornell Engineering’s School of Applied and Engineering Physics, planned to conduct culminating experiments that Moses said would be most valuable to the Department of Defense. But a stop-work order prevented those experiments from proceeding, and the grant – totaling more than $1 million since 2019 – is set to expire.
“We were hoping to verify predictions we made based on fundamental physics understanding we had developed, as well as computational tools we used to predict what can happen in the real world,” Moses said. “These pointed us to the conclusion that we can be successful in very efficiently converting powerful near-infrared laser light from a good commercial laser source to the mid-infrared range vital for defense applications. And to do this with an efficiency several times what is currently achievable, and in a way that’s particularly simple and not too cumbersome, so something that might be eventually field deployable.”
Doctoral students Amir Amhaz, left, and Connor Davis work in the Ultrafast Phenomena, Ultrafast Technologies and Nonlinear Optics laboratory led by Jeffrey Moses, Ph.D. ’07, associate professor in Cornell Engineering’s School of Applied and Engineering Physics.
Laser technology has come a long way since the 1960s, Moses said, but current lasers only work well at certain frequencies. The ONR-funded research sought to extend the best and most powerful lasers’ capability by changing the light’s color, or frequency. The team’s approach utilized nonlinear optics, which investigates how intense light modifies a material’s normal properties – in this case, the properties that are relevant to ultrafast laser light.
“We figure out just the right way of sending a bright laser into, often it’s a crystal, that can efficiently change the frequency of the laser to something that’s useful for another application,” Moses said.
The Navy’s investment laid the foundation for research unlikely to be pursued outside a small number of university laboratories, Moses said. His Ultrafast Phenomena, Ultrafast Technologies and Nonlinear Optics lab set up costly infrastructure including commercial laser systems, optics and custom-built components. The team investigated technical challenges, narrowed concepts, performed experiments and published preliminary findings.
The work also supported the development of graduate students whose laser expertise promises to contribute to both science and national security.
“One of the things we’ve learned over the years of working in this program,” Moses said, “is how much value there is for the Department of Defense in seeing through the education of bright graduate students who could later become part of the workforce, especially in this highly technical area of laser research and development.”
Now, unless the stop-work order is lifted, the team’s focus will be redirected and the military research’s primary goal will go unfulfilled.
“We’ve done some great work over the last five years,” Moses said. “But to see it through, to actually demonstrate this efficient near-infrared to mid-infrared conversion that was the ultimate aim of the program, we were cut off before we got there, so that’s a shame.”
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