A new on-chip sensor using twisted moiré photonic crystals can precisely tune light properties in real time. This could replace bulky optical systems with one compact, powerful chip.
Twisted moiré photonic crystals — a cutting-edge type of optical metamaterial — hold significant promise for building smaller, more powerful, and more versatile optical systems. But how exactly do they work?
Think of two sheets of fabric with simple repeating patterns, like stripes or checks. When you place them directly on top of each other, each pattern remains visible. But if you slightly twist or shift one layer, new, more complex patterns appear — patterns that aren’t present in either sheet alone.
Fine-Tuning Light with Twists and Layers
The same principle applies to twisted moiré photonic crystals. When the layers are rotated or spaced differently, the way they interact with light changes. By carefully adjusting the twist angle and the distance between layers, researchers can fine-tune the material to control multiple properties of light at once — such as phase, polarization, and wavelength. This opens the door to replacing multiple bulky optical components with a single, compact device.
However, researchers have been unable to integrate twisted moiré photonic crystals into devices that can actively control the twist and distance between layers in real time, severely limiting their application.
A Breakthrough in On-Chip Design
Now, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), in collaboration with Stanford University and the University of California – Berkeley, have developed an on-chip twisted moiré photonic crystal sensor that uses MEMS technology to control the gap and angle between the crystal layers in real-time. The sensor can detect and collect detailed polarization and wavelength information simultaneously.
The research was published on April 3 in Nature Photonics and funded by the National Science Foundation, DARPA, the U.S. Air Force Office of Scientific Research, and the U.S. Office of Naval Research. The sample fabrication was performed at Harvard University Center for Nanoscale Systems, which is a member of the National Nanotechnology Coordinated Infrastructure Network and is supported by the National Science Foundation.
Compact, Tunable, and Powerful
“Twisted moiré photonic crystals are promising for engineering smaller, more powerful optical systems because they offer highly tunable optical properties, precise light control, compact and scalable design, and broad application potential across various advanced photonic technologies,” said Eric Mazur, the Balkanski Professor of Physics and Applied Physics at SEAS and senior author of the paper.
“Our research demonstrates how powerful these materials can be when we have precise control and establishes a scalable path towards creating comprehensive flat-optics devices suitable for versatile light manipulation and information processing tasks,” said Haoning Tang, a postdoctoral fellow at SEAS and first author of the study.
Built for Scalability
In the Harvard device, the layers of photonic crystals sit on vertical and rotary actuators, connected to an electrode. The whole device is only a few millimeters in scale and can be fabricated using CMOS-compatible processes, meaning it can be mass-fabricated using standard foundry nanofabrication processes.
The researchers demonstrated that by using the actuators to change the distance and rotational position of the layers of photonic crystals, they could perform simultaneous hyperspectral and hyperpolarimetric imaging — meaning every pixel captured by the sensor contained information from across the electromagnetic spectrum and detailed information about the polarization state. It is the first device with active tuning to demonstrate such detailed information about multiple properties of light.
Potential Across Industries
“These devices could be used for a range of applications including quantum computing, data communications, satellites or medical scans, where getting a clear image and detailed information about light and color is really important,” said Tang.
In the future, these devices would be made with even more complex tuning capabilities, including actuators with even more degrees of freedom.
Reference: “An adaptive moiré sensor for spectro-polarimetric hyperimaging” by Haoning Tang, Beicheng Lou, Fan Du, Guangqi Gao, Mingjie Zhang, Xueqi Ni, Evelyn Hu, Amir Yacoby, Yuan Cao, Shanhui Fan and Eric Mazur, 3 April 2025, Nature Photonics.
DOI: 10.1038/s41566-025-01650-z
This research was co-authored by Beicheng Lou, Fan Du, Guangqi Gao, Mingjie Zhang, Xueqi Ni, Evelyn Hu, Amir Yacoby, Yuan Cao and Shanhui Fan.
Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.
1 Comment
This might help improve the efficiency of a vortex cooler.