Niek Doelman

Research area

The Control of Optical Wavefields – my research has a focus on novel technologies in modeling, control, sensing and correction of Optical Wavefields in Free Space. I aim at improving the imaging resolution of optical telescopes (ground & space), increasing the data rate of Free Space Optical communication links, improving the contrast in the direct imaging and characterization of exo-planets, enhancing the secret key-rate in QKD over Free Space Optical channels and improving the ground resolution of Earth-observation satellites.

Specific Topics:

• Active and Adaptive Wavefield correction,
• Adaptive Optics, High-performance MIMO Control,
• Non-stationary disturbances,
• Adaptive control,
• Deformable mirrors,
• Wavefront sensing,
• Optical turbulence modeling,
• Scintillation and fading in Free Space Optical channels
• Wavefield propagation through turbulent media.

The research connects well to the TNO roadmaps of:

• Industry/ Space: Laser Satellite Communication, Space Science, Astronomy and Earth Observation and Industry/Semiconductor Equipment
• Defence, Safety and Security: Information and Sensor systems
• ICT: Digital Infrastructure and Quantum-safe Technologies

Recent results

• Adaptive wavefield correction strategy to reduce phase and amplitude errors in optical beams for free space data communication.
• Anisoplanatic effects in Adaptive Optics systems; detailed analysis of temporal, spatial and angular sources and optimized approaches to maximize the AO performance under anisoplanatism.
• Direct Contrast control by Adaptive Optics in exoplanet imaging systems.
• Robust and adaptive control for adaptive optics under non-stationary turbulence and time-varying observation conditions.
• NWO program ‘Optical Wireless Superhighways’ granted (started December 2021), 2 research positions at Leiden University on Adaptive Wavefield Correction of Fading FSO Channels.

PhD supervision

• Maaike van Kooten; funding: ELT-Metis, NOVA Instrument Steering Committee, Sterrewacht Leiden and TNO.
• Vikram Radhakrishnan; funding: Sterrewacht Leiden and TNO.
• Minttu Seppälä; funding NWO.

Recent publications

• Niek Doelman, “The minimum of the time-delay wavefront error in Adaptive Optics”, Monthly Notices of the Royal Astronomical Society, Volume 491, Issue 4, February 2020, Pages 4719–4723.
• Maaike van Kooten, Niek Doelman and Matthew Kenworthy, “Impact of time-variant turbulence behavior on prediction for adaptive optics systems”, Journal of the Optical Society of America A 36 (5), 731-740, 2019.
• Niek Doelman and James Osborn, “Modelling and prediction of non-stationary optical turbulence behaviour”, Proc. SPIE 9909, Adaptive Optics Systems V, 99091M (2016).
• Wimar Klop, Rudolf Saathof, Niek Doelman et al., “QKD optical ground terminal developments”, International Conference on Space Optics, 2021.