Microsphere-assisted multispectral microscopy

•Microsphere-assisted multispectral microscopy takes advantage of the imaging properties of the microsphere.•This technology enables spectral mapping through microsphere.•Relevant reflectance characterizations of materials and sub-diffracted features demonstrate the technique.•The optical setup is the combination of a microsphere and microscope objective.•This method could be further used to spectrally map nanostructures. Studies of novel nanostructures have highlighted the need for characterization methods at the nanometric level. To address this challenge, an innovative label-free microsphere-assisted multispectral microscope is presented in this paper. This spectral technique is the first, to our knowledge, to take advantage of the imaging properties of the microsphere. The multispectral acquisition is performed through a 145 µm diameter soda-lime glass microsphere to map the reflectance spectra over a surface covered by an 8 µm diameter disk and with an improved lateral resolution of a factor of 1.8. Relevant reflectance characterizations of materials and sub-diffracted features demonstrate the technique. The proposed setup can be implemented and adapted to any optical microscope.