Statistical properties of the Strehl ratio as a function of pupil diameter and level of adaptive optics correction following atmospheric propagation.

The propagation of an optical beam through atmospheric turbulence produces wave-front aberrations that can reduce the power incident on an illuminated target or degrade the image of a distant target. The purpose of the work described here was to determine by computer simulation the statistical properties of the normalized on-axis intensity--defined as (D/r0)2 SR--as a function of D/r0 and the level of adaptive optics (AO) correction, where D is the telescope diameter, r0 is the Fried coherence diameter, and SR is the Strehl ratio. Plots were generated of (D/r0)2 (SR) and sigmaSR/(SR), where (SR) and sigma(SR) are the mean and standard deviation, respectively, of the SR versus D/r0 for a wide range of both modal and zonal AO correction.

Multiplexed holographic Fabry-Perot étalons.

We discuss a multiplexed holographic Fabry-Perot étalon that includes a multiplexed hologram in a novel holographic Fabry-Perot étalon. Two unique advantages can be achieved by using the multiplexed holographic Fabry-Perot étalon: coherently coupled fabrication of holographic Fabry-Perot mirrors significantly reduces the need to have the nearly flat surfaces typically required in conventional Fabry-Perot etalons, and the angular-wavelength multiplexing capability of a multiplexed hologram can be added to the tunable narrow-band filtering capability of Fabry-Perot étalons. Several types of multiplexed holographic Fabry-Perot étalon are experimentally demonstrated.

Calculation of the near field phase in unstable resonators with mirror misfigures.

A method is presented for finding the output phase front psi(r,phi) of a large Fresnel number unstable resonator with mirror misfigures and misalignments. The technique, which is based on geometric optics, can also be used to analyze the effects of index of refraction variations. The near-field phase is then used to find the far-field on-axis intensity.

Adaptive mirror effects on the performance of annular resonators.

Computer studies have shown that azimuthal static mirror misfigures as small as lambda/20 can lead to severe degradation in the far field on axis intensity for resonators with an annular gain region. This poor far-field pattern can, however, be dramatically improved by the use of adaptive elements within the resonator. A rear cone in the resonator had a static misfigure applied to it, and an adaptive ring axicon located in the front of the resonator was deformed in such a way as to compensate for the misfigure of the rear element of the resonator.

Transverse Bragg-reflector injection lasers.

A GaAs-GaAlAs injection laser has been tested that confines light in the lateral dimension (normal to junction plane) by a multilayer Bragg reflector. In the past, light has been confined as a result of the higher-index guiding region and resulting evanescent fields.