diffraction-limited beam and quantum noise measurements in a continuous-wave laser-diode-pumped Nd:YAG MOPA system

We describe a Nd:YAG slab laser master oscillator power amplifier (MOPA) system that has been scaled to 104 W of output power at 1064 nm, single transverse mode. The amplifier system consists of rod amplifiers followed by edgeand end-pumped slab amplifiers. The MOPA output of 104 W was 89% fundamental TEM00 spatial mode with less than 3% depolarization. These results are a key milestone in the development of a high power laser system for the next generation LIGO ground-based gravitational wave detectors. We also present measurements of the power noise due to the optical amplification in a Nd:YAG free-space traveling wave amplifier as the amplifier transitions from the linear regime into the heavily saturated regime. The quantum noise behavior is demonstrated by saturating the gain of the amplifier using a high power beam and measuring the power noise detected by a single spatial mode probe beam traversing the same optical path through a zigzag slab amplifier. The experimental results are in excellent agreement with theory. OCIS codes: (140.3480) Lasers, diode pumped, (140.3280) Laser amplifier, (140.4480) Optical amplifier, (270.5290) Photon Statistics