UCLA’s new unidirectional imaging technology enables image formation in a single direction, preventing image capture in the reverse direction.
This novel technology, which operates effectively under partially coherent light, offers significant advancements in optical communication and visual information processing by providing selective, high-quality imaging.
Unidirectional Imaging
Traditional imaging systems are bidirectional—meaning if I can see you, you can see me too. However, researchers at UCLA have recently developed a groundbreaking imaging technology known as unidirectional imaging, which forms images in only one direction. This innovative approach enables more efficient and compact processing of visual information, allowing for new possibilities in asymmetric visual information processing and communication.
Advancements at UCLA
Unidirectional imaging creates an image from one specific field of view (FOV) to another, but it prevents image formation in the reverse direction. In other words, images are formed from FOV A to FOV B, but not from B to A.
Published on October 26 in Advanced Photonics Nexus, the work of the Ozcan Research Group at UCLA, led by Professor Aydogan Ozcan, demonstrates that these imagers excel when using partially coherent light, which has a degree of phase correlation. With partially coherent light, the imagers achieve high-quality, power-efficient imaging in the forward direction (A → B), while images in the reverse direction (B → A) appear distorted and have significantly lower power efficiency.
This selective imaging ability is achieved through specially engineered asymmetric linear diffractive layers, optimized for partially coherent illumination, making this technology both precise and directional.
Technical Details and Efficiency
Their research revealed that when the imagers are illuminated by a partially coherent beam with a phase correlation length of at least 1.5 times the wavelength of light (λ), they perform robustly, showing a clear difference in imaging quality between the forward and backward directions.
Even with a smaller correlation length, the imagers still support unidirectional image transmission, though with slightly reduced performance.
Applications and Impact
These imagers are compact, measuring less than 75 times the wavelength of light in thickness, and are independent of light polarization. They are also compatible with various types of light sources, including broadband radiation, making them versatile for different applications. This makes them particularly useful for asymmetric visual information processing and communication, where controlling the direction of image formation is crucial.
The development of unidirectional imagers marks a significant step forward in imaging technology, offering new possibilities for scientific research and practical applications in fields such as optical communication and visual information processing.
Reference: “Unidirectional imaging with partially coherent light” by Guangdong Ma, Che-Yung Shen, Jingxi Li, Luzhe Huang, Çağatay Işıl, Fazil Onuralp Ardic, Xilin Yang, Yuhang Li, Yuntian Wang, Md Sadman Sakib Rahman and Aydogan Ozcan, 26 October 2024, Advanced Photonics Nexus.
DOI: 10.1117/1.APN.3.6.066008