Using Nd:YAG laser (532 nm) pumped mixed-dye laser, we obtained the output of this dye laser enhanced at the wavelength interval equivalent to that given by the copper vapor laser pumped dye laser. This measure favored us with the measurement of single-color three-photon resonant ionization spectrum of atomic uranium in the range of 562-586 nm, which is otherwise not efficiently covered by Nd:YAG laser pumped dye laser with any single dye. Thus 140 UI energy levels were obtained and the peaks of interest 575.814 nm and 575.836 nm were well resolved and their relative intensity determined.