IRthrough

IRthrough refers to imaging and diagnostic techniques that rely on transmitting infrared radiation through objects to reveal internal features. Distinct from standard infrared thermography, which measures surface-emitted IR, IRthrough emphasizes transmitted IR signals to visualize subsurface structures, layer interfaces, and internal defects.

The term appears in literary and conference contexts describing research into infrared transmission in nondestructive testing, with applications across materials science, art conservation, and electronics packaging. The approach leverages transparency windows in the infrared region and advances in sensitive IR detectors.

Typical IRthrough systems use an IR source to illuminate the sample from one side and an infrared camera or photon detector from the opposite side. Wavelengths range from near- to mid-infrared (approximately 0.7 to 12 micrometers), chosen for material transmission. Data may be processed as transmission maps or spectra.

In industry, IRthrough supports inspection of polymer composites, glass and ceramics, thin films, and laminated structures. In art conservation, it aids in revealing underdrawings and repairs. In electronics, it helps inspect encapsulated components and vias where traditional IR reflection methods fail.

Penetration depth depends on material absorption and scattering; many materials are opaque in the IR. Practical systems require thin sections, special window materials, or high-sensitivity detectors. Calibration and interpretation can be complex due to multiple scattering and anisotropy.

IRthrough is an emerging concept rather than a standardized technology. Ongoing research aims to expand material windows, improve detectors, and integrate multispectral or tomographic methods to improve depth resolution and quantitative analysis.