Optical system maps multiple infrared fields onto one small detector

Researchers from the Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, have created an optical system that directs light from multiple areas onto a single small detector. By examining the shape of the spot on the detector, the system determines the originating subfield of an infrared target.

In tests, it correctly identified the field 89% of the time. Traditional wide-field infrared imaging requires large arrays of detectors, increasing costs and complexity. This new system recycles the same detector space for various viewing regions, reducing hardware demands for sparse targets. However, this approach introduces a challenge as overlapping fields can cause targets to appear at the same detector location.

To solve this, the researchers encode subfield information in the point spread function, the small image formed by a point-like source. By altering the spot's orientation, width, and elongation, the system can differentiate between subfields. The optical system employs a reflective folding module and a cylindrical modulation element to create these field-dependent patterns.

A codebook stores the unique spot patterns for each field, allowing the system to match measured spot characteristics to the correct field. The researchers tested the design using simulated trajectories and confirmed that the encoding method can effectively differentiate subfields under certain conditions. While promising, the method's effectiveness depends on factors like calibration, detector noise, and alignment errors.

Further research is needed to improve its capabilities and expand the number of distinguishable subfields.