Tiny, Low-Power Spectrometer Could Give Future Smartphones Superpowers
Scalable down to a single pixel, this novel spectrometer needs no complex optics or high-voltage power supplies to do its thing.
Researchers from North Carolina State University have developed a compact low-power spectrometer suitable for measuring wavelengths from ultraviolet to near-infrared — and it's small enough that it could be squeezed into a smartphone.
"Spectrometers are critical tools for helping us understand the chemical and physical properties of various materials based on how light changes when it interacts with those materials," explains corresponding author Brendan O'Connor of the team's work. “They are used in applications that range from manufacturing to biomedical diagnostics. However, the smallest spectrometers on the market are still fairly bulky. We've created a spectrometer that operates quickly, at low voltage, and that is sensitive to a wide spectrum of light. Our demonstration prototype is only a few square millimeters in size — it could fit on your phone. You could make it as small as a pixel, if you wanted to.”
A spectrometer works by measuring the spectral components of light — and by shining said light at or through something, can be used to figure out what it's made of. Where most off-the-shelf spectrometers are relatively bulky, though, the team's creation is considerable smaller — and can be tuned to different wavelengths by simply adjusting its supply voltage.
"If you rapidly apply a range of voltages to the photodetector, and measure all of the wavelengths of light being captured at each voltage, you have enough data that a simple computational program can recreate an accurate signature of the light that is passing through or reflecting off of the target material," O'Connor explains. "The range of voltages is less than one volt, and the entire process can take place in less than a millisecond."
The proof-of-concept device doesn't need complex optics or high voltages to operate, while its size means it could be placed into a smartphone for on-the-fly analysis — "we think this makes some exciting applications possible," O'Connor says, "[and] also paves the way for improved access to imaging spectroscopy, microscopic spectroscopy, and other applications that would be useful in the lab."
The team's work has been published under open-access terms in the journal Device.
Main article image courtesy of Brendan O'Connor.