Miguel Levy
Miguel Levy
Miguel Levy Figure 1
Figure 1: A photonic crystal prototype for slow-light studies consists of vertical and tilted holes of about 200 nanometers in diameter each.
Miguel Levy Figure 2
Figure 2: The wider (central) region is where the photons get trapped.
Miguel Levy Figure 3
Figure 3: Data collected in Levy’s lab showing spectral regions where light is rejected or trapped in magnetic photonic crystal films.

For more information on Miguel Levy's research:

phy.mtu.edu/~mlevy

He Works in Light

by Dennis Walikainen

Miguel Levy is breathing rarified air: he is bending, distorting, and ultimately slowing down light, changing this energy source for myriad uses, including some not yet dreamed of.

In quiet tones, the physics and materials science and engineering professor gives a lesson on subjects not visible, about research seemingly undoable.

He focuses on human-made photonic crystals, which catch and manipulate light, and he changes their patterns to "mold the flow of light in new ways," he says. The amazing part is "you can change the speed of light or create regions, on the order of a few microns, where light is trapped within or bounced back out." By engineering the hole-array distribution (Figure 1), structures can be created where the speed of light may be slowed down by a factor of one thousand or more. This has implications for optical memory storage in computers, although, Levy points out, there is much work to be done before commercialization.

Levy also works to create gaps in the optical spectrum—band gaps (where light cannot penetrate into the material at those wavelengths)—and it is here that he has his "most exciting news," he says. "With postdoctoral researcher Amir Jalali and my colleagues in Russia, we discovered a new way of creating a band gap in photonic crystals. It is a magnetically controlled band gap."

According to Levy, the best thing about this discovery is "the science: a new way of coupling photonic states—altering the way light exists—to produce optical regions that can be switched on and off by applying a magnetic field."

Working with this new effect, Levy controls the passage of light through the photonic crystal. "We are still playing around with how we fabricate the crystals," he says. This can be done by delicately controlling the magnetic films (Figure 2).

Levy’s work, which earned him the 2007 Michigan Tech Research Award, also has implications for optical switches, which could be used in data processing, optical filtering, and on-chip optical interconnections. The latter would allow the computer chips we all use to get even smaller without overheating, which is a current problem.

And optical switches can be used to open or close a gate for light, like turning a light on and off, but doing so on computer chips at a microscopic scale. Trapping or rejecting light through on-chip light conduits (Figure 3) can serve for data processing in telecommunication systems or cinema projectors.

The optical filtering of light, via one-way filters (called optical isolators) offers another application. Photon traps in magnetic films can be used to make very tiny on-chip optical isolators to help lasers
produce a clear signal by protecting them from backscattered radiation.

Of all this work, Jalali adds: "Light is the most amazing phenomenon in nature. We have just worked hard to make a step toward better understanding of the interaction of light with matter."

And there’s more magic to come.