Adaptive Optics: Technology and Applications

Dear Colleagues,

Adaptive Optics (AO) is commonly used in ground-based telescopes to restore spatial resolution in astronomical observations, which is lost due to the presence of the atmosphere. Over the last 30 years, the AO community has experienced continuous growth in technological development, mostly triggered by the Extremely Large Telescopes that will be available over the next 10 years. The very demanding requirements of these new, complex facilities have many synergies with other applications, such as Free-Space Optical Communications through the atmosphere.

Free-Space Optical Communication is a promising technology that is witnessing a tremendous expansion, especially since the 2000s. The benefits of optical links over radiofrequencies are namely the possibility to transfer information at a very high data rate, the very large available bandwidth, the security of the data transfer, and the required size, weight, and power for equipment. These benefits come at the cost of significant technical challenges that need solving. When crossing the atmosphere, optical beams suffer multiple distortions such as beam wandering, scintillation, phasefront distortion, and beam spreading. To mitigate these effects, several techniques such as adaptive optics, spatial diversity, and aperture averaging have been proven to be effective. These methods can also benefit other types of applications involving light propagation through the atmosphere, such as Space Surveillance and Tracking (SST). Indeed, globally, space debris surveillance and traffic monitoring is of increasing concern due to the sudden and fast increase in space population and is urgently calling for new technology developments. Optical sensing is a promising and versatile approach for space traffic and debris observation.

This Special Issue aims to publish selected contributions in the field of Adaptive Optics and atmospheric turbulence-related aspects with applications that demand extreme performance—from astronomy with Extremely Large Telescopes to Optical communications (e.g., LEO, MEO, GEO, deep space optical links), Quantum Key Distribution, and Space Surveillance and Tracking. Potential topics include the following:

• Innovative Adaptive Optics facilities and demonstrations;
• Monitoring of optical turbulence;
• Forecasting of optical turbulence;
• Modeling of light propagation through the atmosphere;
• Wavefront sensing methods;
• Deformable mirror concepts;
• Laser guide star concepts;
• Control methods;
• Harsh environment conditions (e.g., strong turbulence, daytime operation, urban environment, etc.).

Dr. David Alaluf
Dr. Noelia Martinez-Rey
Dr. Douglas Laidlaw
Guest Editors

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• optical communications
• quantum key distribution
• space situational awareness
• astronomy
• adaptive optics
• atmospheric turbulence
• deformable mirrors
• wavefront sensors
• laser guide stars
• monitoring and forecasting of optical turbulence