Colored object recognition by digital holography and a hydrogen Raman shifter

Multi-wavelength holography is demonstrated with a H(2) Raman shifter that is pumped with an elliptically-polarized pulsed 532 nm beam to produce temporally coherent, intense, polarized output lines. Digital holograms of two-dimensional colored objects are recorded using Raman output lines at 630.4 nm (S(05), Red), 532 nm (Rayleigh, Green) and 435.7 nm (aS(10), Blue). Object reconstruction is done numerically via the convolution method and colored object recognition is achieved by multi-channel correlation of the Red, Green, and Blue reconstructions of the reference and the target object.