Experimental study on three-wavelength confocal measurement of chromatic storage

The principle of multi color storage using 3 lasers with different wavelength is introduced and the Method of Three-wavelength Confocal Adjustment (MTCA) is represented in detail. The three lasers are combined into a coaxial paralleled laser beam after passing through their own collimation system and one common light coupling system. Then they are focused in the same spot on the recording layer by an achromatic lens. The defocusing amounts' measurement bases on the knife-edge displacement method and displacement method of optoelectric detector. And then the 3 lasers can read and write confocally in recording media.