University of Arizona synthetic wavelength imaging sees deeper into tissues

22 Oct 2025

New $2.7 million grant supports development of platform for skin cancer diagnosis.

A University of Arizona research team is set to receive $2.7 million from the NIH's Common Fund Venture Program to advance next-generation imaging technologies that allow deeper, clearer views inside the body without the need for invasive procedures.

The UA team is one of only four groups nationwide to receive funding through the NIH Advancing Non-Invasive Optical Imaging Approaches for Biological Systems initiative. The final award amount is pending successful completion of milestones and availability of funds.

Research at UA's Computational 3D Imaging and Measurement (3DIM) lab under Florian Willomitzer will study in particular routes to imaging skin cancers, to help physicians assess tumor invasion and monitor treatment response.

"This project specifically focuses on nonmelanoma skin cancers, such as basal cell carcinoma or squamous cell carcinoma," said Willomitzer. "Those skin cancers can display significantly different imaging contrast properties than melanoma, which poses a unique challenge to the development of new 'deep' imaging technologies."

Current skin cancer imaging methods, such as confocal microscopy or optical coherence tomography, use optical light with wavelengths in the visible to near-infrared spectrum. They offer superior contrast and resolution at shallow tissue depths, noted Willomitzer, but their relatively short imaging wavelengths make them susceptible to light scattering deeper inside biological tissue.

Breaking free from conventional imaging trade-offs

The answer could be synthetic wavelength imaging, SWI, a computational imaging technique in which the complex optical fields of two closely spaced wavelengths are synthesized into a third field at a much longer "beat" - a synthetic wavelength. The longer synthetic wavelength is more resistant to light scattering inside tissue, while at the same time researchers can take advantage of the higher contrast information provided by the original shorter illumination wavelengths.

This synthetic wavelength principle was demonstrated by Willomitzer while at Northwestern University in 2021 as a route to high-resolution cameras potentially able to view objects not accessible by line-of-sight-imaging. That implementation involved synthetic wavelength holography, in which the synthetic phase was used to compute a holographic representation of an obscured object.

Now UA's goal is to apply the SWI principle to imaging of nonmelanoma skin cancers, where patients often present with lesions that vary widely in size, depth and pattern of invasion.

This characteristic means that "we need tunable imaging capabilities that balance depth penetration with resolution and imaging contrast, something that current technologies cannot reliably provide," commented Clara Curiel-Lewandrowski from the UA Comprehensive Cancer Center.

If a SWI approach can be translated into clinical practice, it could allow earlier detection of invasive lesions and monitoring of therapies in real time. Interventions could then be tailored individually to each patient.

"Synthetic wavelength imaging's resilience to scattering in deep tissue while preserving high tissue contrast at the optical carrier wavelengths is a rare combination," said Willomitzer. "By pairing this property with advanced computational evaluation algorithms, our approach aims to break free from the conventional resolution-depth-contrast tradeoff."