Optical reconstruction of digital holograms recorded at 10.6 μm: route for 3D imaging at long infrared

“We demonstrate the optical reconstruction in the visible range (0.532μm) of digital holograms recorded at long IR wavelengths (10.6μm) by means of a spatial light modulator. By using an integrated recording-reconstruction system, it is, in fact, feasible to achieve direct imaging of holograms acquired outside the visible range, i.e., in the IR spectrum. By choosing a Fourier recording configuration, the reconstructed image, obtained at about a 20 times shorter wavelength than the acquisition image, exhibits minor aberrations, which do not significantly affect the optical reconstruction. The high NA achievable at a long IR wavelength allows us to image large objects at reasonable distances.”