title: Highly efficient continuous-wave operation of a Nd:YAG rod laser that is side pumped by p-polarized diode laser bars.
abstract: We report on the performance of highly efficient, high-power continuous-wave (CW) Nd:YAG lasers that are side pumped by p-polarized diode laser beams. In this configuration pump light is directly coupled into the Nd:YAG rod through a threefold symmetric gold-coated flow tube. The polarization direction of our pump diode bars is perpendicular to the rod's axis (p-polarized). In a closed coupled resonator, a maximum output power of 195 W in multimode operation is obtained for a pump power of 423 W, which corresponds to an optical-to-optical efficiency of 46% and an electrical-to-optical efficiency of 23%. This is, to the best of our knowledge, the highest electrical-to-optical efficiency reported for a CW diode side-pumped Nd:YAG laser. By the pump-power leakage analysis method, we measured the pumping efficiency to be approximately 94%. The high efficiency of the system can be attributed to wing pumping, which results in uniform pump-light distribution and better pumping efficiency because of the use of p-polarized pump beams.
authors.affiliation: Solid-State Laser Division, Centre for Advanced Technology, Indore-452 013 Madhya Pradesh, India. ranga@cat.ernet.in
authors.forename: Ranganathan
authors.initials: R
authors.lastname: Kandasamy
authors.forename: Sundar
authors.initials: S
authors.lastname: Raghavachari
authors.forename: Puskar
authors.initials: P
authors.lastname: Misra
authors.forename: Sthanu T P
authors.initials: ST
authors.lastname: Nathan