Compact diode stack end pumped Nd:YAG amplifier using core doped ceramics

We report on a compact Nd:YAG amplifier emitting a maximum pulse energy of 14 mJ. By amplifying a passively Q-switched oscillator (M2<1.2) a good beam quality of M2≈1.7 was achieved. The amplifier is diode pumped by an 8 bar diode stack of 800 W power and a nonimaging optic. This optic homogenizes the pump light and transfers it into a 5 mm diameter core doped rod with a centrally neodymium doped region of 3 mm and a samarium doped YAG cladding. We show that this cladding reduces parasitic effects in the laser rod compared to an undoped YAG cladding. Finally, we compare the compact amplifier with an amplifier, which is mode selectively pumped by a fiber coupled pump diode.