New ultrathin lens enables optical needle for deeper imaging in medicine

Researchers at Sun Yat-sen University in China have developed a groundbreaking ultrathin lens that focuses light into an optical needle, enhancing imaging capabilities in medical applications. This innovation, detailed in a paper accepted for publication in Optics Letters, promises to significantly improve optical coherence tomography (OCT) imaging by allowing deeper penetration into tissue while maintaining clarity. The findings were published on July 7, 2026.

Advancements in Optical Technology

The newly designed lens measures approximately 7 microns in thickness and employs a multi-level diffractive structure to create a narrow, focused beam of light. This optical needle can achieve a depth-to-width ratio of 1100:1, allowing for high-resolution imaging of both the surface and deeper layers of tissue simultaneously. According to Haowen Liang, the research team leader, "With the optical needle, it's possible to get clear, high-resolution images both across the tissue surface and deep inside it at the same time."

This innovative lens replaces conventional focusing lenses in OCT systems, resulting in an impressive nine-fold increase in imaging depth without requiring complex optical redesigns. The optical needle can focus light in the wavelength range of 800–900 nm with an average lateral focal width of 2.4 μm and a longitudinal focal depth of 2,640 μm.

Implications for Medical Imaging

The integration of this lens into spectral-domain OCT (SD-OCT) systems marks a significant advancement in medical imaging technology. By enhancing the ability to visualize details within the eye, this technology could lead to earlier disease detection and improved diagnostic capabilities. Liang noted, "The new lens could help doctors see deeper and more clearly inside the eye, leading to earlier disease detection and better diagnosis."

Current OCT systems often struggle with capturing fine details, particularly on the surface of tissues. This lens addresses that limitation, potentially transforming how conditions are diagnosed and monitored.

Future Applications and Developments

The research team is not only focused on improving OCT performance but is also exploring the lens's potential for everyday devices, such as smartphone cameras. The goal is to create smaller, simpler, and lower-cost imaging systems without sacrificing performance. Liang emphasized, "With a straightforward lens replacement, we were able to image much deeper into tissue while still maintaining high resolution. That's very difficult to achieve with conventional optical designs."

The researchers are working on making the optical needle dynamically tunable, allowing adjustments to the shape and intensity profile for various imaging conditions. This adaptability could lead to simpler optical architectures for high-performance imaging in consumer electronics.