Pulsed multicolor digital holography using hydrogen Raman shifter
For the first time, a hydrogen Raman shifter is used as a light source for pulsed multicolor digital holography. To generate a pulsed white light laser source, the Raman shifter (200 psi) is pumped by a 355 nm Nd:YAG pulsed laser. The multiple wavelength Raman output beam is initially dispersed by a prism and the Stokes lines: 415.9nm (blue), 502.9nm (green), and 635.9nm (red), are selected. Each of the RGB lines is passed through a beam conditioning system to improve beam quality and to equalize the RGB intensities. The RGB lines are then recombined to become the new nanosecond holographic white light source. As a demonstration of the technique, a negative resolution target with color filters is illuminated by the Raman shifter. Three holograms generated by the RGB lines are recorded on a charge-coupled device (CCD) camera, reconstructed in the computer and unified to achieve full-color final image.