RGB source based on simultaneous quasi-phasematched second and third harmonic generation in periodically poled lithium niobate.

We present a pulsed RGB source based on cascaded nonlinear processes that occur inside a single crystal of PPLN with two poling periodicities placed in tandem. The first periodicity produces a ~1.43 mum signal through optical parametric generation and the last section simultaneously produces the second (near - IR) and third harmonic (blue). The green is produced by second harmonic generation of the pump and the red is produced by non-phase-matched sum-frequency generation between the signal and pump beam.