Solar laser pumping approach for both simultaneous and stable multibeam operation under tracking error condition

A solar laser pumping approach to achieve both simultaneous and stable multibeam solar laser operation under solar tracking error condition is proposed here. By using a heliostat, solar radiation is firstly redirected to a parabolic mirror, secondarily concentrated by an aspheric lens, and finally absorbed by four Nd:YAG rods within a pump cavity using a homogenizer. Zemax® and LASCAD™ analysis demonstrate that four simultaneous and stable 1064-nm continuous-wave solar laser emissions with similar multimode power levels can be achieved even with azimuthal solar tracking errors up to ± 0.5 deg. The variation on the multimode solar laser power of the four rods is significantly reduced from 32.38% and 55.52% without the homogenizer to 0.00% and 0.21% with the homogenizer for ± 0.1 deg and ± 0.2 deg azimuthal solar tracking error, respectively. More importantly, simultaneous and stable TEM00 mode solar laser emissions from the four rods are also numerically attained under solar tracking error condition.