For any inspection application, the choice of illumination is crucial to achieve repeatability, consistency, accuracy, and effectiveness. Because Short Wavelength Infrared (SWIR) light is reflected or absorbed by an object it provides the strong contrast needed for high resolution inspection tasks. Many inspection tasks that are difficult to perform using visible light are possible at SWIR wavelengths (0.9 to 1.7 microns). For instance, colours that appear almost identical in the visible may be routinely differentiated using SWIR making it highly effective for material inspection.
Learn more: https://www.resolveoptics.com/uv-ir-and-swir-lenses/