The demonstration of a terahertz wave camera that can capture 3D images of microscopic items hidden inside small objects is projected by U.K. researchers to benefit noninvasive analyses in such diverse fields as cancer screenings, security and materials research.

The terahertz wave region of the electromagnetic spectrum has frequencies ranging between microwave and infrared light. While these waves can penetrate opaque objects without causing harm, they have limited ability to discern and image view microscopic objects.

Microscopic, metallic objects distributed throughout a 3D cube were imaged using the terahertz wave camera and then combined with an artistic, rendered image. Source: Loughborough University

To overcome this limitation, the researchers engineered a time-resolved nonlinear ghost imaging approach by combining an array of advanced detection methods to manipulate light and measure its transmission through an object over time. The method effectively captured 3D images of microscopic items by probing 4 mm by 4 mm by 600 µm cubes with terahertz radiation.

The imaging technique enabled Loughborough University and University of Sussex researchers to separate and distinguish information from different depths and create detailed, 3D images of the cubes with very high accuracy, allowing observation of the chemical and physical nature of items inside them in a way that was not possible before.

The nonlinear ghost imaging method described in ACS Photonics revealed features hidden inside cubes as small as 60 µm, which is roughly the width of a human hair.