Diffraction efficiency and noise analysis of hidden image holograms

The simplified approach for analysis of hidden image holograms is discussed in this paper. Diffraction efficiency and signal to noise ratio of reconstructed images were investigated using direct measurements technique and digitized image analysis employing “ImageJ” software. All holograms were recorded in a photoresist layer spin-coated on glass substrates applying laser interference lithography technique. Both analogue and digital analysis approaches showed the similar results thus confirming the appropriateness of the used analysis methods. It was found that holograms recorded at higher laser energy densities demonstrated improved diffraction efficiency and reduced signal to noise ratio of the reconstructed image. The best diffraction efficiency at sufficient signal to noise ratio was obtained using exposure energy density in the range from 150 to 200 J/m2 during the hologram writing process.