Hyperspectral imaging of rare-earth doped nanoparticles emitting in near- and short-wave infrared regions

Comparing to other optical imaging techniques, hyperspectral imaging (HSI) possesses a unique feature, being capable of not only obtaining a spatial information about a specimen, but also providing a spectral information in every image pixel. Being employed in biomedical applications, similarly to other optical bioimaging techniques, HSI struggles with limited light penetration depth, caused by high absorption and scattering of light by biological tissues. Overcoming the limitations of imaging in visible spectral range, optical bioimaging in near-infrared (NIR) and short wave infrared (SWIR) spectral ranges (∼700 -1700 nm) has being actively advanced in recent years, as due to the strongly reduced tissue absorption and scattering, NIR-SWIR imaging systems can achieve deeper tissue imaging with higher resolution. With the aim to combine both the advantages of SWIR imaging and HSI, we have built a hyperspectral imaging system operating in NIR-SWIR spectral region (900 - 1700 nm). The constructed HSI system is based on a wavelengths scanning method, with a liquid crystal tunable filter (LCTF) as a dispersion element. The spectral unmixing software has been developed to map the regions of the specified spectral features. Finally, an application of the developed method towards spatial differentiation of rare-earth doped nanoparticles emitting in NIR-SWIR range has been demonstrated.