Portable Adaptive Optics Research Articles

Adaptive threshold wavefront sensing for portable adaptive optics system driven by hybrid parallel technique

Abstract Our Portable Adaptive Optics (PAO) system designed for high-contrast imaging of exoplanets with current 2-4 meter class telescopes achieves a correction speed of nearly 1000Hz, utilizing a Shark-Hartmann Wavefront Sensor (S-H WFS) in a $9\times9$ sub-aperture configuration. As we look towards adapting the PAO system for larger telescopes, an increase in the number of sub-apertures in the WFS and enhanced precision in wavefront detection are imperative. Originally programmed in LabVIEW, our initial PAO software is based on a traditional centroid calculation module for nighttime wavefront sensing and lacks adaptive processing of background noise. To address these limitations and to boost the PAO system’s performance and accuracy in wavefront detection, we propose a compressive neural network(Th-Net) combined with a specialized hybrid parallel programming approach for wavefront detection. Our experimental results indicate that this hybrid parallel technique and Th-Net significantly enhance the PAO system’s operational speed and wavefront detection precision under uneven background noise. This work paves the way that a duplicable and low-cost PAO system can be used for direct imaging of exoplanet with large telescopes.

Portable adaptive optics for exoplanet imaging

The portable adaptive optics (PAO) device is a low-cost and compact system, designed for 4- meter class telescopes that have no adaptive optics (AO) system, because of the physical space limitation at the Nasmyth or Cassegrain focus and the historically high cost of conventional AO. The initial scientific observations of the PAO are focused on the direct imaging of exoplanets and sub-stellar companions. This paper discusses the concept of PAO and the associated high-contrast imaging performance in our recent observational runs. PAO deliver a Strehl ratio better than 60% in H band under median seeing conditions of 1″. Combined with our dedicated image rotation and subtraction (IRS) technique and the optimized IRS (O-IRS) algorithm, the averaged contrast ratio for a 5 ≤ V mag ≤ 9 primary star is 1.3 × 10−5 and 3.3 × 10−6 at angular distance of 0.36″ with exposure time of 7 minutes and 2 hours, respectively. PAO has successfully revealed the known exoplanet of κ And b in our recent observation with the 3.5-meter ARC telescope at Apache Point Observatory. We have performed the associated astrometry and photometry analysis of the recovered κ And b planet, which gives a projected separation of 0.984″ ± 0.05″, a position angle of 51.1° ± 0.5° and a mass of . These results demonstrate that PAO can be used for direct imaging of exoplanets with medium-sized telescopes.

Experimental results of a MEMS-based adaptive optics system

Adaptive optics techniques have been demonstrated in both laboratory and field tests, with a great level of scientific satisfaction, especially in astronomical and surveillance communities. Such successes have sparked the interest for these techniques in other fields, like biomedical imaging and industrial applications. However, to decrease complexity and costs, both very important issues for applications other than astronomical and surveillance, new technologies have to be brought to fruition. MEMS are becoming a very important player in this arena. We describe a portable adaptive optics (AO) system based on a MEM device that has been tested in both laboratory and field experiments. Results of these tests are discussed. Capabilities and shortcomings of this technology are discussed. A look at future applications and trends is given.