Professor takes different look at laser


While most people look at laser as a useful tool for surgery, store scanners, etc., Prof. A. Kumarakrishnan (above, with a Canada Foundation for Innovation cetificate) has a completely different interest in it. He studies the interaction of laser light with atoms, looking to establish new techniques for precision measurements related to basic and applied physics.

Kumarakrishnan, in the Department of Physics & Astronomy, Faculty of Pure & Applied Science, says an interesting feature of his ongoing experiments is that they involve the use of lasers to remove kinetic energy from atoms. The resulting laser-cooled gas consists of trapped atoms moving very slowly compared with atoms in the air around us.

“The temperature of such an atomic sample is about a million times smaller than the temperature of liquid helium. The wave nature of atoms becomes dominant and this makes it possible to carry out experiments in which the roles of matter and light are interchanged.”

Why is he so fascinated by these laser-cooled atoms of gas? Kumarakrishnan says his findings can be used to develop new and improved methods of doing precise measurements.

For example, Kumarakrishnan aims to obtain one of the best measurements of the atomic fine structure constant, as well as precise measurements of acceleration caused by gravity. The latter information would be important for oil and natural gas prospecting, correcting tidal charts and assaying mineral deposits. Other applications are related to the development of improved rotation sensors used for satellite navigation.

The acute demand for increasing memory storage on computer chips is fuelling another area of his research, Kumarakrishnan says. He manipulates atoms with lasers to form periodic structures on a scale much smaller than the wavelength of light. Techniques developed to carry out these experiments have led to applications related to high-speed, free-space optical communication using lasers.

In addition, one of Kumarakrishnan’s long-time goals is to see the development of extremely accurate atomic clocks based on cold atoms. He anticipates that such clocks will improve national primary time standards in Canada. The improved performance of these clocks is linked to greater accuracy that can be achieved with the Global Positioning System of satellites.

“This research has benefited from close ties with industry working in the area of photonics and innovative support from York University,” says Kumarakrishnan, also praising the help he has received from “an outstanding group of undergraduate and graduate students” at York.