Abstract

The Boeing HAP (High Average Power) experiment had been reconfigured throughout 1989–1990 to incorporate a grazing incidence, 133-m round-trip ring resonator. Initial spectral, mode stability, coherence length, and interferometric wave-front quality measurements have been taken. This paper reports on the optical measurement techniques and data used to characterize the resonator optical output as 2.0 to 2.5 λ OPD. Raw data-reduction methodology and analysis supporting the subtraction of effects caused by the 7× beam reducer, fold mirrors, and the radial shear interferometer itself are included. Noteworthy observations, such as the ability to overlay interferometric fringe data over the length of a macropulse (≈180 micropulses) without destroying the fringe visibility and the occurrence of centrally localized (≈30% of the diameter) disturbances of the fringe pattern are also discussed. Coherence length measurements, made by using the interferometer, showed the spectral bandwidth to be between 64 and 120 μm. Attempts to measure the micropulse-to-micropulse mode stability were made and are discussed as well.

© 1992 Optical Society of America