We describe a new, improved approach for sodium guide-star lasers for the correction of atmospheric aberrations in telescopes, which satisfies all current requirements for advanced pulse burst waveforms. It makes use of sum frequency generation (SFG) of two pulsed, Q-switched, injection mode-locked Nd:YAG lasers, resulting in a macro-micro pulse-burst output, optimized in power and bandwidth to maximize the fluorescence from the high altitude sodium layer. The approach is robust and power scalable and satisfies the requirements for Multi Conjugate Adaptive Optics (MCAO) for current and future telescopes, including extremely large ground telescopes (ELTs). It is also adaptable for advanced design options. Here we describe the approach in detail, the results from critical design verification experiments, the current status and plans for further work required to demonstrate a complete sodium guide-star laser.