Hyperspectral fluorescence Imaging

The hyperspectral microscopy setup makes use of an Inverted, infinity-corrected, epifluorescence microscope (Nikon Ti-U Eclipse) equipped with a brightfield, oil-immersion objective with a magnification of 60 and numerical aperture of 1.4 (CFI Plan Apo Lambda 60x Oil, Nikon). Excitation can be provided by small solid-state lasers, with a wavelength of 568 nm, 655 nm or 808 nm. The setup is equipped with two, two-dimensional detectors covering different wavelength ranges.  A Si CCD camera (Pylon:400BR_eXcelon, Princeton Instruments, 20µm pixel size) is sensitive up to about 1100nm, while a 2D NIR camera (Photonic Science, Snake SWIR 640x512, 15 μm pixel size) covers wavelengths up to 1600 nm. Hyperspectral imaging can be performed by filtering the images with a wavelength-tunable liquid crystal tunable filter (LCTF, VariSpec NIR, 850-1800nm) with varying bandwidth (7-25nm).

The setup was originally developed for hyperspectral imaging of carbon nanotubes. A convolutional network was developed to automatically recognize pixels belonging to in-focus SWCNT images and analyze their emission spectra through detailed fitting and statistical analysis. The full description of the setup can be found in the reference below.

Reference of setup: M. Erkens et al, ACS Nano, 18, 14532-14545 (2024), https://doi.org/10.1021/acsnano.4c02226