Multispectral imaging of mineral samples by infrared quantum dot focal plane array sensors

•Proposed a system using QDIP FPAs for rapid direct mineral in-situ measurements.•Different components in rocks were successfully distinguished by the system.•Emittances of dolomite were successfully evaluated with a precision of 1–2%.•QDIP has potential to fill the application blank in a wavelength range of 5–7 µm. Infrared (IR) spectral imaging is a powerful tool for component analysis and identification in the geological field. In this report, we originally use quantum dot infrared photodetector (QDIP) focal plane arrays (FPAs) with different peak-responsivity wavelengths to analyze the mineral composition of rock samples by IR spectral imaging and show the QDIP’s potential as a solution for some geological problems. After clarifying fundamental characteristics such as the blackbody responsivity, current noise density, and spectral responsivity of QDIPs, we present qualitative and quantitative analyses of mineral samples including conglomerate, sandstone, marble, and dolomite. In the qualitative analysis, we distinguish two different compositions in each rock. In the quantitative analysis, we measure the emittance of dolomite and show the emittance errors. Finally, we discuss which experimental factor determines the quantitative precision most dominantly.