Novel metamaterial optical filters may help researchers learn more about Earth’s atmosphere

Colors of the Southern Crab Nebula

Spectroscopy allows researchers to detect specific chemicals by measuring the kinds of light those chemicals emit. ESTO’s novel metamaterial optical filter will make it easier for scientists to build compact, lightweight spectrometers for Earth observation. (Image Credit: NASA, ESA, and J. DePasquele)

11/2/2023 – A NASA-funded metamaterial optical filter could become the cornerstone of new sensors and spectral cameras for observing atmospheric composition, which are critical tools for improving weather, air quality, and climate models.

Igor Bendoym, Lead Design Engineer at Phoebus Optoelectronics and Principal Investigator for this project, explained that he and his team created a novel metamaterial that can detect multiple light signatures reflected by atmospheric aerosols and gasses.

It’s an ideal component for compact, cost-efficient spectrometers, and those instruments are key to characterizing trace gases, aerosols, water vapor, and industrial pollutants on a global scale.

Traditional spectrometers rely on complex optical subsystems to target specific wavelengths of light for observation. Bendoym’s metamaterial optical filter, which is thinner than a grain of sand, allows researchers to eliminate those bulky subsystems without compromising the quality of gathered data.

“Using the metamaterial, we can remove most of the optics within the spectrometer, measuring only the spectral channels needed and miniaturize the entire system because we can eliminate most pre-processing of the light signal. The metamaterial allows the direct filtering of the collected, focused light, eliminating the need for bulky collimating and dispersing optics,” said Bendoym.

Metamaterials are synthetic materials specifically engineered to exhibit electromagnetic qualities and properties that are hard to find in naturally occurring materials. They are a promising technology for solving a host of scientific problems, from remote sensing to laser communications.

“What metamaterials provide for us scientists, engineers, and humanity, is really what I’d like to describe as a chest of light-controlling tools that we can deploy in whatever way an application requires,” said David Crouse, founder of Phoebus Optoelectronics and Professor of Electrical and Computer Engineering at Clarkson University.

Bendoym and his team created a metamaterial design that includes carefully engineered arrays of resonators located within stacks of thin semiconductor layers. The exact geometry and configuration of the resonators can be changed across the chip so that only the targeted gases and aerosols are observed.

“We wanted to design metamaterial structures that can be made using conventional fabrication techniques such that the path to high volume manufacturing and commercialization is easier.” said Crouse.

Having developed and demonstrated the utility of their metamaterial for airborne and spaceborne spectroscopy with a grant from NASA’s Advanced Component Technology program, Bendoym and his team are currently working with NASA’s Instrument Incubator Program, along with researchers at Atmospheric & Environmental Research, Inc. (AER) and Ball Aerospace, to develop a complete miniaturized spectrometer prototype for the measurement of boundary layer temperature and water vapor profiles.

From there, Bendoym and his team hope to work with NASA and private companies to incorporate their miniaturized spectrometer onboard spaceborne and airborne platforms. These might include CubeSats situated in low-Earth orbit or small, unmanned aerial vehicles flying through Earth’s atmosphere.

Their metamaterial optical filter could even find its way into applications beyond planet Earth. Bendoym and his team are collaborating with AER and Ball Aerospace to see whether their metamaterial might help researchers gather better images of distant stars, planets, and other interstellar objects.

“We want to work with our industry and government partners to make products that, at the end of the day, will benefit humanity to the widest extent possible,” said Crouse.

The Advanced Component Technology (ACT) program and Instrument Incubation Program (IIP) are both part of NASA’s Earth Science Technology Office (ESTO).

The Cornell University Nanoscale Science and Technology Facility, the Harvard University Center for Nanoscale Systems, and the Clarkson University Center for Advanced Materials Processing helped Bendoym’s research team fabricate and test its metamaterials.

Gage TaylorNASA Earth Science Technology Office