Fig. 1. (a) Schematic of the alignment-free laser; (b) Zemax ray-trace model of the multi-lens retroreflector (the AoI interval between adjacent beams is 5°); and (c) the assembly drawing of the receiver lens tube.

Fig. 2. Calculated FC-induced defocusing in terms of millimeters and diopters.

Fig. 3. Power transfer of the laser at the working distances of 2 m and 5 m (AoI = 0°). The lines are a guide to the eye.

Fig. 4. Laser output power as a function of working distance L6 under an incident pump power of 16.6 W, with the receiver optimized at the working distance 5 m and with the receiver optimized at each point. The lines are a guide to the eye.

Fig. 5. Receiver FoV measured at a working distance of 2 m and 5 m (with an incident pump power of 16.6 W). The lines are a guide to the eye.