New chip sharpens, widens views of the universe

Chinese researchers have developed a spectroscopic chip with a novel technique that offers an unprecedented combination of exceptional resolution and a panoramic view, unlocking the potential for sharper, faster and wider scans of the universe.

While conventional high-resolution spectrometers are often bulky and heavy, the chip, named RAFAEL in English and Yuheng in Chinese, is the size of a mobile phone SIM card, researchers from Tsinghua University said. The study was published in the international journal Nature on Oct 15.

Taking the technology's application in astronomy as an example, Fang Lu, research leader and professor at Tsinghua University's Department of Electrical Engineering, said the chip is capable of capturing full spectral data with sub-angstrom resolution for about 10,000 stars per second.

"Using traditional scanning methods, compiling complete spectra for all stars in the Milky Way would take thousands of years," Fang said. "This chip could potentially reduce that time to under a decade."

Moreover, its miniaturized design also allows it to be mounted on satellites or deep-space probes, bringing hope for charting unprecedented spectral maps of the universe in the coming years, she added.

The core innovation embedded in the spectroscopic imager resolves a long-standing challenge in spectral imaging — the trade-off between resolution and field breadth, which means that extreme clarity and fine details can only be achieved at the expense of a broad field of view, and vice versa.

Fang and her team overcame this dilemma by employing advanced computational imaging methods and reconfigurable integrated photonics based on lithium niobate.

"The result is a snapshot spectroscopy with 10-megapixel-level spatial resolution and a sub-angstrom spectral resolution across visible and near-infrared wavelengths," she said.

It gives spectrometers the capability to discern light wavelengths down to ten-millionths of a millimeter and detect the slightest energy variations while simultaneously capturing wide-field scenes in high detail, according to Fang.

"This new technique significantly surpasses existing international counterparts in snapshot spectroscopy, improving the spectral resolution by two orders of magnitude," Fang said.

She added that an on-chip prototype of the technology measures 2 centimeters in length and width, with a depth of 0.5 centimeters, making it highly portable and adaptable for future space and astronomical applications.

According to the research paper, experimental results have shown the technique's promising practical applications for material identification, plant health, autonomous driving, atomic spectroscopy, astronomical observation and other fields.

Fang said operations are underway to put the technique into use on large-aperture telescopes at observatories in Xinglong county in Hebei province, Lijiang in Yunnan province and the Canary Islands of Spain.

"The study marks not an endpoint, but a beginning, showing how intelligent photonics can keep pushing the boundaries of what light can reveal," she said.