Efficient 946-nm Laser Operation of a Composite Nd:YAG Rod With Undoped Ends

We present comparative studies on laser performance of diode end-pumped, composite Nd:YAG rods with undoped ends at 946 nm. Efficient heat removal in a composite rod can reduce the peak of rise in temperature in the active segment to 61% by theoretical calculation. The maximum, continuous-wave output power of 1.5 W, which is three times higher than a conventional noncomposite rod, was obtained at an absorbed pump power of 8 W because of the 55 deg reduction in temperature rise that was estimated experimentally. The performance and characteristics of composite rods in quasi-three-level laser operation are analyzed and discussed in detail, taking into account the reduction in reabsorption loss, which is strongly temperature dependent.