Light Analysis

Near-Infrared (NIR) and Short Wave Infrared (SWIR) Spectroscopy for Light Investigation and Spectral Analysis

Linear arrays and 2 dimensional focal plane arrays (FPAs) are widely used in the realm of spectroscopy. Two dimensional FPAs can acquire both spectral and spatial information at the same time. Linear arrays are used to produce spectrographs capable of measuring many wavelength bands simultaneously. Sensors Unlimited produces FPAs that are sensitive from 0.4 µm to 1.7 µm, as well as FPAs that are sensitive from 0.9 µm to 1.7 µm using Indium Gallium Arsenide (InGaAs). Through the manipulation of the epitaxial growth process, the wavelength range can be extended up to 2.6 µm for the linear array products.

The image below shows that short wave infrared spectroscopy can help with light analysis in wavelengths from 900 to 1700 nanometers.

Most minerals contain distinct absorption features in the SWIR/NIR, making this region of the spectrum the best candidate for spectroscopic analysis in many applications. Hydroxyl bearing minerals, sulfates, and carbonate materials produced naturally on Earth are easily identified through SWIR spectroscopy. Clays in general, like Kaolinite and Alunite, have strong absorption near 1.4 µm and 2.2 µm. Many Earth orbiting satellites utilize the SWIR spectrum to image and map mineral concentrations through spectroscopic techniques.

See Below - A spectrometer uses mirrors and diffractors to direct light into a device, for example a Sensors Unlimited linear array detector, that analyzes the light and provides the user with information on the sample.

NIR Fluorescence Spectroscopy is also a strong source of material identification and analysis. Countless applications from the identification and analysis of organic matter and fungal biomass concentrations to in vivo Nitrous Oxide (NO) concentration mapping are possible in the NIR/SWIR. In vivo measurements are possible due to the tissue penetrating capabilities of longer wavelengths, a clear advantage over visible light.