Interferometric adaptive optics testbed for laser pointing, wave-front control and phasing.

Implementing the capability to perform fast ignition experiments, as well as, radiography experiments on the National Ignition Facility (NIF) places stringent requirements on the control of each of the beam's pointing, intra-beam phasing and overall wave-front quality. In this article experimental results are presented which were taken on an interferometric adaptive optics testbed that was designed and built to test the capabilities of such a system to control phasing, pointing and higher order beam aberrations. These measurements included quantification of the reduction in Strehl ratio incurred when using the MEMS device to correct for pointing errors in the system.

Analysis of the scalability of diffraction-limited fiber lasers and amplifiers to high average power.

We analyze the scalability of diffraction-limited fiber lasers considering thermal, non-linear, damage and pump coupling limits as well as fiber mode field diameter (MFD) restrictions. We derive new general relationships based upon practical considerations. Our analysis shows that if the fiber's MFD could be increased arbitrarily, 36 kW of power could be obtained with diffraction-limited quality from a fiber laser or amplifier.

Quasi-phase-matched second-harmonic generation by use of a total-internal-reflection phase shift in gallium arsenide and zinc selenide plates.

We fabricated a novel quasi-phase-matched frequency converter, using a zigzag optical beam path in a thin, polished parallel plate. Second-harmonic generation experiments demonstrated angle-tuned output at 4.6 to 5.

A single-shot pixellated phase-shifting interferometer utilizing a liquid-crystal spatial light modulator.

We introduce a novel phase-shifting pixellated interferometer based on a liquid-crystal spatial light modulator and simulate the expected performance. The phase-shifted frames are captured simultaneously, which reduces problems arising from vibrations and air turbulence. The liquid-crystal spatial light modulator is flexible and can be configured to provide a large number of phase-shift levels and geometries to reduce measurement error.

Differential synthetic aperture ladar.

We report a differential synthetic aperture ladar concept that relaxes platform and laser requirements compared with those for conventional synthetic aperture ladar. Line-of-sight translation-vibration constraints are reduced by several orders of magnitude, while laser frequency stability is typically relaxed by an order of magnitude. The technique is most advantageous for shorter laser wavelengths, ultraviolet to mid-infrared.