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Presidential Fellowship: Syed An Nazmus Saqueb

An electrical and computer engineering (ECE) doctoral student at The Ohio State University was among the recent winners of a prestigious Presidential Fellowship for his work advancing the cost and efficiency of terahertz (THz) imaging.

Student winner, Syed An Nazmus Saqueb, studies under the supervision of ECE associate professor Kubilay Sertel. Their research is focused on compressive imaging techniques for millimeter-wave and THz bands.

THz energy is a topic increasingly earning attention at Ohio State, as new grants and funding support increase each year. Much like microwave frequencies in the electromagnetic spectrum provide energy to cook food, the race is on to find a more affordable and efficient way to utilize the more untouched terahertz energy realm. 

Saqueb is developing novel and groundbreaking imaging techniques that enable a single-pixel camera to view invisible wavelengths of the electromagnetic spectrum and synthesize new information previously unachievable using low-cost sensors.

“I’ve been working to bridge the terahertz gap. It’s recently being explored, so it’s a new field. There’s not so much progress yet, but they are seeing the potential of working in this band,” he said.

Saqueb said the problems with more traditional X-ray imaging is the radiation created is hazard to human health. It provides high resolution, but the radiation also disrupts the mechanics of the molecules because it is ionizing.

“Terahertz is not ionizing and doesn’t interact with cells and tissues,” Saqueb said. “It’s completely safe within human bodies, but it gives you higher resolution than microwave. In terahertz you’re getting both higher resolution and non-ionizing advantage.”

However, he said, there are many engineering obstacles to overcome to fully utilize THz frequencies.

“The problem with developing a terahertz camera is, for a camera, you need to develop an array of sensors. A typical cell phone has millions of sensors in it. In terahertz it’s really difficult to make an array,” he said.

To tackle this issue, Saqueb said, Ohio State developed a single pixel imaging system. It uses single detectors instead of an array.

"Instead of taking a frame picture at a time, like a normal camera, we have just one detector to take serial measurements, each coded by optical light," he said.

Saqueb explained that this encoding of a THz wave is achieved via photoexcitation of Silicon. Coded patterns are generated in a computer and projected on a Silicon wafer using a commercial LCD projector. The visible light from the projector excites electrons in the Silicon, which then alters the transmission of the THz wave through it.

“We just record the intensity of these encoded measurements, one after another," he said. "It’s called compressive sensing. Using this tool, you can get the entire image using just one detector. Mathematics finishes it off."

Saqueb said they were also able to implement another technique called "Phaselift" in their THz imaging system.

"Phaselift recovers not only the intensity of the image, but also the phase of it just by using coded intensity measurements. In many scientific areas, the phase information plays a much more important role than the intensity," he said.

Ultimately, Saqueb said, the research helps to lessen the cost in the creation of THz camera technology, which could provide real-time imaging for uses in security, product integrity, and detecting neural issues in the brain for early Alzheimer’s disease diagnosis.

His doctoral work is currently being funded by his research projects, which will now be paid for by his Presidential Fellowship award until he graduates in a few more semesters. 

After graduation, Saqueb said he hopes to head into industry research and development.

“I want to go into some field where they do research on cutting edge technology,” he said.

Saqueb said his work assisting Sertel has been invaluable for his career development.

“Kubi has been very supportive. I would like to thank him for all he has done, he has been huge for my development here. It was a new track for me and there was a lot to learn,” he said.