LASERS OF LOVE: Born Problem-Solver Leads World-Class Research in Quantum Physics

(PUSHING THE ENVELOPE: Ten years ago this week, anthrax-laced letters addressed to two United States senators and believed to have been mailed from a box on the Princeton University campus resulted in five deaths and dozens of cases of inhalation infection, not to mention a second wave of nationwide hysteria in the wake of 9/11. Texas A&M University quantum physicist Marlan Scully led the joint Texas A&M-Princeton team that developed a technique to instantly detect anthrax spores in the mail using lasers. He is now applying those lessons to his current research, dubbed “ghost lasers in the sky” — a laser system capable of detecting threats, from poisonous gas to pollutants, in the upper atmosphere without ever opening an envelope or even leaving the ground.)

COLLEGE STATION — Dr. Marlan O. Scully knows that his son Jim, an American Airlines pilot, has to expect the unexpected on any of his flights. A frequent flier in his own right as a distinguished professor of physics and internationally renowned researcher at Texas A&M University, Scully is well aware of the myriad possible scenarios his son and fellow pilots face, whether in the air or on the ground.

However, as a father and a scientist, he knew that back in 2001, things were drastically different.

That entire fall had been a tumultuous time for the United States, which was still reeling from the terrorist attacks of 9/11. Exacerbating matters were several inexplicable anthrax attacks that unleashed a whole new wave of national paranoia and uncertainty — seven mysterious letters containing the hazardous substance sent to various media headquarters and two U.S. senators that caused many Americans to wonder if their nation was under yet another terroristic siege.

Against this backdrop while piloting an otherwise routine November flight to Chicago, Jim received a gut-wrenching phone call from the flight crew. A passenger had been checking her mail when she discovered a suspicious powder in one of the envelopes, they said, sending the passengers into a panic. After several days of testing, officials determined it was a hoax, but for Jim, whose passengers’ safety was first priority, that was several days too long.

The pilot did the only thing he knew to do: He challenged his pioneering-physicist father to find a faster way to detect potential bioterrorism agents. Never one to back down from a challenge, Scully set out to do just that.

Answering the Scientific Call

Scully says he approached the situation the same way he always did, using the same method that solves most problems — applying existing knowledge. Based on his extensive experience with lasers, Scully felt that finding a faster method of Bacillus anthracites (anthrax) identification indeed was possible. After putting together a team of top physicists from both Texas A&M and Princeton University, where Scully had begun teaching as a visiting professor, he established labs at both universities so the teams could simultaneously test several aspects of their idea and hopefully reach a conclusion more swiftly.

“Anthrax was a big problem then, and we found we couldn’t get an immediate response when testing [the substance] for identification,” Scully recalls. “Texas A&M is the place where we finally broke the problem, and we nicely developed it at Princeton. Now, we could get an immediate answer.”

Key to this immediacy was a light-scattering technique known as Raman scattering, named for pioneering Indian physicist Chandrasekhara Venkata Raman, in which packets of light called photons bounce back after exiting the material with another laser pulse. The molecular bonds are probed, thereby creating a unique “signature” dependent on and specific to that material.

In this particular case, because the signal it produced for anthrax proved to be very weak, Scully and his team went one pioneering step further, developing coherent anti-Stokes Raman scattering, or CARS, as a way to measure the scattering of photons that occurs when a molecule is hit with light. Their investigations proved that an appropriate sequence of three lasers targeting that molecule could result in a light pattern unique to a particular substance.

Unfortunately, Scully says his team also found that other molecules present in the medium containing the anthrax spores could sometimes interfere in the anthrax molecules’ CARS signatures. But by using the same concept, they came up with a revolutionary new technique that emitted a more powerful signal known as femtosecond adaptive spectroscopic techniques via coherent anti-stokes Raman scattering, or FAST CARS. First, two lasers are aimed at the object, causing a molecular vibration. A third laser pulse is sent in on a time-delay, just long enough for “false-alarm” molecules with a smaller oscillation to cease their movement, allowing molecules that are still vibrating to become the true target which amplifies the signature. Scully likens the laser beam to music: The steady rhythm of the beam disrupts molecules by creating a molecular “melody” specific to that material.

“I got into this business in the ’60s when the laser was brand new and not very well understood,” Scully notes. “In trying to understand the purity of light, you could say that light from the sun is like a radio with a lot of static, but a laser, a laser is one beat; it’s like perfect music.”

The entire process takes only a fraction of a second, putting to bed the older, slower methods of anthrax detection and opening new doors for laser technology. Lasers, Scully explains, have evolved into useful tools with far more implications than just anthrax detection. For instance, they can be used to identify numerous other materials, such as glucose in blood which could one day be beneficial to diabetics, or to determine moisture levels in crops, taking the guesswork out of when and how much to water for farmers.

A Lifetime of Lasers

Improving anthrax detection methods is but one accomplishment in a long list of Scully’s breakthrough findings involving lasers and light made while at the various universities and laboratories where he has spent time during his decorated science career. He says problem solving is something that comes naturally — a skill honed early on in his childhood in Casper, Wyo., when his parents gave him a toy microscope set. Little did they know they were instilling a keen interest that eventually would culminate in an illustrious career in quantum physics which ultimately would count him among the most distinguished players in laser research.

One of his earliest achievements occurred while he was an instructor at Yale University in 1967. Scully, along with 1955 Nobel Prize in Physics winner Dr. Willis E. Lamb Jr., came up with what is perhaps his most noteworthy achievement — the first quantum theory of the laser which is still influential in today’s laser science technology.

Then in 1982, after accepting a joint position at the Max Planck Institute für Quantenoptik in West Germany and the University of New Mexico as a distinguished professor, Scully played a key role in another innovative experiment, the quantum eraser, in which he was able to show how “erasing” information in a photon at one location can have a drastic effect on a photon at another location.

Scully’s years of work are summed up in the more than 700 articles and two standard textbooks in laser physics and quantum electronics he has written. However, he says one of his favorite publications is a book he co-authored in 2007 with another of his sons, Robert, entitled The Demon and the Quantum: From the Pythagorean Mystics to Maxwell’s Demon and Quantum Mystery, which details the correlation between thermodynamics and quantum mechanics.

It’s an impressive career by any standards. Yet at age 72, Scully has no interest in slowing down his research or curbing his appetite for new knowledge. He has since turned his attention toward solar cells, devices that convert sunlight into electricity. Citing plants and photosynthesis as an example of natural conversion efficiency, Scully says he hopes to better understand the chemical and electrochemical power of solar-cell operation to enable new methods of harnessing the solar spectrum in order to exceed the Schockley-Queisser single-band-gap limit to solar-cell efficiency.

“In solar cells, we are interested in the basic physics,” Scully says. “We need to study the fundamentals so we can ask questions that aren’t normally asked.”

True to form, Scully plans to approach the obstacle like he does any other — one step at a time. If the past is any indication, perhaps another revolutionary finding will emerge.

“Much of what we do is drawn out by curiosity,” he explains. “I start working on a problem, and it leads to another problem. That only increases the likelihood of its practicality.”

Texas A&M, IQSE and Beyond

Curiosity about the open dean position in the College of Science was what initially brought Scully to Texas A&M in the early 1990s. At that point, he already was highly regarded in quantum physics and, although the late Dr. Richard E. Ewing ultimately was hired as the college’s eighth dean, Scully joined him in Aggieland as another tremendous acquisition for the expanding College of Science. Nearly 20 years later, he continues to hold the Hershel E. Burgess ’29 Chair in Physics as well as a distinguished research chair with the Texas Engineering Experiment Station (TEES). Elected as a member of the National Academy of Sciences in 2001 and as a fellow of the American Academy of Arts and Sciences in 2008, he has received a plethora of prestigious awards, including the Charles Townes Award and Herbert Walther Award of the Optical Society of America (OSA) and the Quantum Electronics Award of the Institute of Electrical and Electronics Engineers (IEEE).

After several years as a visiting professor at Princeton, Scully accepted a joint professorial appointment in 2005, and he continues to teach classes and conduct experiments at both Texas A&M and Princeton.

In February 2011 he earned his most recent honorary doctorate from the University of Ulm in Germany. The gesture is a sentimental one for Scully, who spent several years working in Germany. Moreover, Ulm is the birthplace of one of the most famous physicists in the world, Albert Einstein, the father of many of the concepts Scully is working to advance today.

“It’s a nice thing that my friends put together,” he says. “One of my favorite students, Wolfgang Schleich, is now the dean of quantum physics at Ulm. It’s a great university.”

Although he’s received an ample amount of praise during his entire career, Scully says he is most excited to be working with a group of colleagues in Texas A&M’s Institute for Quantum Science and Engineering (IQSE) who personify the fact that it’s the sum of each part which makes for such a greater whole. As director of the IQSE, Scully leads a research-based effort that spans the gamut of quantum physics and engineering and focuses on the study of new lasers, quantum computing, nonlinear optics and more — technologies that will impact any number of fields, from national security and bioscience to navigation and refinery safety.

It’s no great surprise that Scully sees a bright future, both for Texas A&M and for IQSE research and development, considering the team he has helped put together. Currently, the IQSE boasts a who’s who of top scientists, including Nobel Prize winners Dr. Dudley Herschbach and Dr. David Lee, and a variety of excellent early and mid-career researchers. In addition to working diligently with laser technology, IQSE faculty are equally driven to develop the next generation of scholars — a job Scully views as both an innate responsibility and a unique point of Aggie pride. Together with his colleagues, he is helping to groom young post-doctorate students for lead professorships at top universities across the nation. As but one example, he cites Dr. Mikhail Lukin, who was promoted to full professor of physics at Harvard in 2004 at the age of 32 after earning his doctorate from Texas A&M in 1998 under Scully.

“These guys are the measure of what’s going on in the IQSE,” Scully adds. “Now, we are taking advantage of leadership. We’ve traditionally had great optics at Texas A&M with people like Distinguished Professor Dr. Edward Fry and 2011 Texas Distinguished Scientist of the Year Dr. George Kattawar, but when you add this caliber of a supporting cast, you really get things done.”

In anticipation of additional people and progress, the IQSE hopes to enhance its current workspace, which is located on the fifth floor of the George P. Mitchell ’40 Physics Building, as well as its campus collaborations and connectivity via an eventual bridge linking the institute and their laboratories in the adjacent Jack E. Brown Building. To Scully, it’s a necessary step to accommodate the level of research the IQSE is conducting — a move that will epitomize to other universities the rapid advances Texas A&M is making in a very important science, including a recent breakthrough involving the creation of “lasers out of thin air” that can break down air and make it lase. The interdisciplinary work, dubbed “ghost lasers in the sky” by attendees at the 2011 American Physical Society (APS) Annual Meeting in Dallas, was championed by IQSE-affiliated rising research stars Dr. Simon North, a chemist, and Dr. Alexei Sokolov, a physicist.

“One kilogram of anthrax in an airplane applied upwind could do a lot of damage,” Scully notes. “One hundred kilograms could kill more people than an atomic bomb. Our sky laser technique can detect poison gas in the atmosphere at very low levels tens of kilometers away. Right now we have techniques for measuring pollution, gases and other formerly untraceable substances. While LIDAR [Light Detection And Ranging] looks at backscattered light, we’re getting much bigger results with the sky laser.

“Because of quantum physics, we have the potential for computers that are exponentially faster, microscopes that are more precise and lasers that produce results almost without limits,” Scully says. “That Texas A&M is doing world-class research in quantum physics is already understood everywhere, for sure.”

-aTm-

Contact: Chris Jarvis, (979) 845-7246 or cjarvis@science.tamu.edu or Dr. Marlan O. Scully, (979) 862-2333 or scully@physics.tamu.edu