Physics Professor Pushes Boundaries Of Technology
Can computers operate 1,000 times faster? What if cancer cells could be identified by laser pulses to make it easier to target and destroy them?
The new Center for Nano-Optics at Georgia State University will use physics principles to answer these questions and work toward revolutionary advancements in technology and biomedical research.
Mark Stockman, a physics professor and researcher, will lead the Center for Nano-Optics. In this Q&A with Georgia State research writer LaTina Emerson, Stockman explains nano-optics, why it’s important and how it applies to our everyday lives.
Q: What is nano-optics?
A: Nano-optics is the science dealing with optical light phenomena on the nanometer scale. Our focus will be a part of nano-optics called nanoplasmonics, which is the optics of small metallic particles with sizes in the range of nanometers. A nanometer is one billionth of a meter. It is 1,000 times smaller than a micron, and a micron is about one hundredth the thickness of human hair. It’s very small. You can only see such nanoparticles in an electron microscope.
Q: Why is the study of nano-optics important?
A: It’s important because many important objects of nature and technology are of this size. Those would be biological molecules, parts of living cells, DNA and transistors, which are used in computers. The transistor is arguably the most important invention ever and the most frequently used. There are more transistors in the world than any other artificial objects combined, with more than a billion in a typical personal computer. If you remove transistors today, computers stop working, phones go silent, cars will stop, planes will fall and practically nothing will work.
Nano-optics has numerous applications in biomedical research, electronics, ultramicroscopy, the environmental industry, solar energy and solid-state lighting, the source of light for all contemporary computers and most new TVs. The goal is to enhance things with a plasmonics concept.
Q: How does nano-optics apply to everyday life?
A: Nanotechnology is used in everyday life. Brighter bicycle headlights, newer automotive headlights, magnetic hard drives and pregnancy tests are everyday life, not to mention stained glass or color windows.
You can see bicyclists biking at night. They have small, very bright headlights. This appeared about five years ago. The source of light is the semiconductor, and metal nanoparticles help to extract light from the semiconductor. They contain nanoparticles of silver.
The pregnancy test is a plasmonic test. The sensor that gives you color, the dark red color, is gold nanoparticles. It’s one of the most common tests.
Color windows have silver and gold nanoparticles. The Romans didn’t know physics, but they knew how to make colored glass. The color yellow comes from silver nanoparticles.
There are some other uses, but they’re not yet on the market. High capacity magnetic memory for hard drives is in the works by two companies. It can save about 100 times more information on the same area.
Q: Tell us about your current research.
A: I’m doing all kinds of physics. Optical physics or physics with light. Everything related to lasers – how laser light interacts with matter. I don’t know what will be important. In some cases, research is accidental. You start researching and you find out how important it is. When the first laser was reported, two journals declined to publish it because they thought there would be no practical use of it. Lasers are now one of the most commonly used devices. They are used in the most precise clocks, medical devices and many other applications.
Q: What will be the research focus at Georgia State University’s new Center for Nano-Optics?
A: We’ll be developing two things we invented at this university. One of them is the nanolaser or spaser. The spaser is a laser of a very small size. The spaser is 1,000 times smaller than the smallest laser. You can only see it under an electron microscope. It’s more than 1,000 times thinner than human hair.
The whole idea is that a light source cannot be made that small, but a plasmon source can be. A plasmon source is as good as light for nanoscale applications. It’s the source of optical energy on a nanoscale. It has the same properties of light, but it’s so much smaller.
Maybe transistors will be able to communicate with each other using spasers one day. We’ll be working on it. It is the most important technological problem today. If it can be accomplished, then the computer should be 1,000 times faster and it will be using 1,000 times less energy.
Second, we invented a way to concentrate and transfer energy to the nanoscale. It’s my work, and it’s used very widely today. Basically, it’s a metal funnel with a very thin needle at the end. There’s no hole inside, so the energy is on the outside of it. It’s very, very thin, and it’s very sharp. You scatter light onto the funnel, and the light energy propagates along the surface of the funnel. This ray follows the funnel and goes to the very end. The light ray becomes very, very thin. It becomes a plasmon ray. That’s how it allows you to deliver energy to very small spaces. They use this energy to see on a nanoscale. It can be used for ultramicroscopy to see transistors, for example.
The gold funnel has been incorporated into microscopes by many groups now. They’re not selling it yet, but they will be selling it sooner or later. The micron is the maximum you can see under the best microscope. This is about 100 times sharper.
Q: What are some of the possible applications in the future?
A: The most important technological problem is information processing. You need fast processors, in particular, for national security, where they are used for breaking codes. Breaking code is a matter of fast processors. This technology could increase the chances of breaking something encoded with longer key words. This is their (the National Security Agency’s) goal to keep us safe. They intercept a lot of communications they cannot read. If one nation can master it, they have an enormous advantage over other nations. Today, all developed nations are about the same.
Also, it’s very often important to see what is moving inside the cell, where the cell is moving or where viruses are. People use labels for that purpose. The spaser makes the brightest label in the world. They’re used in cancer research, in particular, and can be used in neuroimaging. Cancer research requires very, very bright labels. You can inject spasers into the body, and they will attach to cancer cells. The spaser is a very bright spot. You cannot confuse it with anything else. The idea is to see single cancer cells in the bloodstream. You need to see the cancer cells in the blood and kill them. For that, you need a very bright label.
Another future application is artificial intelligence. A computer is not only a computer. It will think. It will not only solve the problem. It will pose the problems. That’s what only humans do today. This could lead to computers possibly being able to invent, formulate new problems and develop science by themselves. It’s absolutely in the future. I’m not sure if it’s good, but it will happen anyway. We just have to get prepared for it.
Q: What made you decide to become a physicist?
A: It’s a strange story. I was supposed to be an engineer. Both of my parents are mechanical engineers. But then I built a prohibited item – a radio transmitter. The transmitter was so noisy that I closed the local airport [in central Ukraine]. The planes could not land. The police came to school, detained me and brought me home. They confiscated the transmitter. I was probably 15. They promised the next time I would go to jail.
Then, I went to a neighbor who was an engineer and professor to find out how it happened because it should not have interfered with the airport. He told me I needed to educate myself, to know calculus and physics to understand why I closed the airport and how to build a transmitter without disturbing it. I had other things to do, but finally I got hit by a car that broke my left leg, and I went to the hospital for a long time. I had absolutely nothing to do and started reading everything, including calculus. Finally, by the end of my period in the hospital, I knew what I had done wrong. I decided I needed to know more and became a physicist. I graduated in two years, and I went to the Physics Department at the Kiev State University in Ukraine and started studying physics.
Q: What are the career opportunities for students interested in physics?
A: Opportunities are unlimited if you finish your advanced physics degree. You will get a job immediately. There’s an extreme shortage. They go everywhere from industry, academia, high schools, the military and hospitals, where there’s a lot of medical physics. They easily find jobs. If you graduate with a degree in physics, you’ll never be without a job.
This interview has been edited and condensed. Photos of Mark Stockman by Steve Thackston.