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Ashwin Ramasubramaniam Obtains Collaborative Grant to Develop Superior, Ultracompact, On-chip Spectrometers

Ashwin Ramasubramaniam

Ashwin Ramasubramaniam

Traditional spectrometers – used for key applications such as gas sensing, thermal imaging, microbial detection, and surveillance – are bulky, expensive, and usually consist of mechanically moving parts. To transform the current technology, Professor Ashwin Ramasubramaniam of the Mechanical and Industrial Engineering Department is the co-principal investigator on an international research team that seeks to develop an ultracompact, on-chip spectrometer in the critical, but less-explored, mid-infrared wavelength range.

The research team from UMass Amherst, Yale, and Bar Ilan University of Israel has received grants from the National Science Foundation and the U.S.-Israel Binational Science Foundation totaling nearly $720,000 to develop the miniaturized new spectrometers.

One key to this team’s research is a class of materials called van der Waals materials, which consist of stacks of atomically thin layers bonded to each other via weak so-called van der Waals forces – similar to how a sticky tape attaches to a flat surface.

As Ramasubramaniam explains, “In this program, mid-infrared spectrometers based on a single, on-chip, tunable sensor will be developed, leveraging van der Waals heterostructures and advanced mathematical algorithms. The proposed research involves investigations of the optical properties of emerging materials, device fabrication, and numerical analysis.”

According to the research team, although significant progress has been made in the miniaturization of spectrometers, most current compact spectrometers still consist of an array of on-chip components to capture the different spectral components of the light, leading to a footprint much larger than the operational wavelength.

Moreover, current research on developing compact spectrometers focuses on the visible and near-infrared wavelength range, and the effort to develop integrated, on-chip, mid-infrared spectrometers is very limited despite their technical significance in such important applications as environmental monitoring and medical science.

“The goal of this program,” says Ramasubramaniam, “is to develop a highly compact, mid-infrared spectrometer based on a single, tunable van der Waals heterostructure photodetector.”

As Ramasubramaniam and his team members explain, “The proposed heterostructure spectrometer will build upon the novel, tunable, single-element, photodetector scheme and further leverage the promising physical properties of emerging van der Waals heterostructures to advance the frontiers of on-chip infrared spectroscopy.”

This new spectrometer aims to overcome the resolution limitations of traditional on-chip spectrometers and enable spectroscopic functionality within a footprint comparable to the wavelength of the operation. In addition, the pioneering spectrometer will be vastly miniaturized and much less expensive compared to today’s state-of-the-art technology.

As Ramasubramaniam and his team conclude, “The program is highly interdisciplinary and leverages latest developments in material sciences, condensed matter physics, and electrical engineering to deliver much-anticipated, transformative applications with van der Waals materials.”

(October 2022)