Design of hollow duct as coupling system in solid-state laser end-pumped by LDA

A high efficient coupling system, hollow duct applied to planar laser diode array (LDA) was investigated systemically. The transmission characteristic of hollow duct was described by using a ray-tracing method and compared with the lens duct. The results show that a nearly Gaussian distribution can be obtained in near-field when incontinuous light beams in space from LDA pass through the hollow duct, and the hollow duct, which has the transmission efficiency of 93%, not only has all the characteristics of lens duct, but overcomes it's shortcomings. The hollow duct with the advantages of being easy to fabricate and install is fit for planar LDA pumping the solid laser medium with high absorption coefficient in an end-pumped configuration.