Interferometric sensing for measuring the complex amplitudes of a 3-D object by R, G and B tunable lasers

摘要

A color digital Fresnel hologram has been recorded those complex amplitudes can be measured by six-step phase-shifting interferometry with the wavelength shifts of R, G and B tunable lasers. A six-step calculation is insensitive to the power change in tunable lasers. The wavelengths can be tuned by a current change of a red laser diode (LD), a cavity-length change of a green laser and an angle change in a grating of a Littman-type blue LD. Three monochromatic images are reconstructed from the numerical Fresnel diffraction integral and combined into a full-color image with CIE chromaticity. The experimental result of a full-color image reconstruction based on digital holography is shown.