Correction of static and non-common path aberrations in an adaptive optics system using inherent calibration data.

For low-order adaptive optics systems, a method that is able to correct for system aberrations in the final focal plane is presented. The paper presents a novel figure of merit, corresponding to the integrated non-normalized tip-tilt-free optical transfer function. The inherent singular value decomposition modal content of the interaction matrix is used to optimize this figure of merit.

Neural networks for image-based wavefront sensing for astronomy.

We study the possibility of using convolutional neural networks for wavefront sensing from a guide star image in astronomical telescopes. We generated a large number of artificial atmospheric wavefront screens and determined associated best-fit Zernike polynomials. We also generated in-focus and out-of-focus point-spread functions.

Concept, modeling, and performance prediction of a low-cost, large deformable mirror.

While it is attractive to integrate a deformable mirror (DM) for adaptive optics (AO) into the telescope itself rather than using relay optics within an instrument, the resulting large DM can be expensive, particularly for extremely large telescopes. A low-cost approach for building a large DM is to use voice-coil actuators connected to the back of the DM through suction cups. Use of such inexpensive voice-coil actuators leads to a poorly damped system with many structural modes within the desired bandwidth.

Noninvasive imaging of human foveal capillary network using dual-conjugate adaptive optics.

Purpose: To demonstrate noninvasive imaging of human foveal capillary networks with a high-resolution, wide-field, dual-conjugate adaptive optics (DCAO) imaging instrument.

Methods: The foveal capillary networks of five healthy subjects with no previous history of ocular or neurologic disease or surgery were imaged with a novel high-resolution, wide-field DCAO instrument. The foveal avascular zone (FAZ) in each image was defined using a manual procedure.

Comparison of wavefront sensor models for simulation of adaptive optics.

The new generation of extremely large telescopes will have adaptive optics. Due to the complexity and cost of such systems, it is important to simulate their performance before construction. Most systems planned will have Shack-Hartmann wavefront sensors.

Dual-conjugate adaptive optics for wide-field high-resolution retinal imaging.

We present analysis and preliminary laboratory testing of a real-time dual-conjugate adaptive optics (DCAO) instrument for ophthalmology that will enable wide-field high resolution imaging of the retina in vivo. The setup comprises five retinal guide stars (GS) and two deformable mirrors (DM), one conjugate to the pupil and one conjugate to a plane close to the retina. The DCAO instrument has a closed-loop wavefront sensing wavelength of 834 nm and an imaging wavelength of 575 nm.

Very high-resolution spectroscopy for extremely large telescopes using pupil slicing and adaptive optics.

Under seeing limited conditions very high resolution spectroscopy becomes very difficult for extremely large telescopes (ELTs). Using adaptive optics (AO) the stellar image size decreases proportional with the telescope diameter. This makes the spectrograph optics and hence its resolution independent of the telescope diameter.

Extended object wavefront sensing based on the correlation spectrum phase.

In this paper we investigate the performance of a Fourier based algorithm for fast subpixel shift determination of two mutually shifted images subjected to noise. The algorithm will be used for Shack-Hartmann based adaptive optics correction of images of an extended object subjected to dynamical atmospheric fluctuations. The performance of the algorithm is investigated both analytically and by Monte Carlo simulations.

High-order laser guide star performance for the Euro50 telescope.

High-order laser guide star performance for the Euro50 telescope is analyzed. Focus anisoplanatism residual errors using multiple LGSs are obtained by numerical simulations. Results calculated for annual mean conditions at the La Palma site show that, considering only focus anisoplanatism, it will be possible to obtain a Strehl ratio of 0.

Emulation of dual-conjugate adaptive optics on an 8-m class telescope.

In this article we present a downscaled laboratory setup emulating five natural guide stars, a layered static atmosphere and a 7.5-m aperture telescope equipped with dual-conjugate adaptive optics at a wavelength of 2.2 microm.

Multiconjugate adaptive optics for large telescopes: analytical control of the mirror shapes.

We present an analytical algorithm for deriving the shapes of the deformable mirrors to be used for multiconjugate adaptive correction on a large telescope. The algorithm is optimal in the limit where the overlap of the wave-front contributions from relevant atmospheric layers probed by the guide stars is close to the size of the pupil. The fundamental principle for correction is based on a minimization of the sum of the residual power spectra of the phase fluctuations seen by the guide stars after correction.