Tunable multi-color coherent light generation in single MgO: PPLN bulk crystal

We report a theoretical design analysis of domain-engineered periodically poled lithium niobate (PPLN) for wavelength conversion of near-infrared sources to generate coherent light in the visible spectral range. Our analysis on the spectral outputs show that with a proper design of the quasi phase matching (QPM) periods, tunable, multiple nonlinear optical processes can be simultaneously phase matched in a single segmented crystal. We show that a three-segment single PPLN crystal has potential to generate violet (432 nm), blue (490 nm) and orange (600 nm) wavelengths by simultaneous sum frequency and second harmonic generation processes. Such a design scheme has promising potential for a compact, robust and tunable multi-colored visible light source which can find various applications such as in biomedicine, high-density optical data storage and laser based color displays.