Prototyping Blue Phase Wavefront Correctors for Astronomical Adaptive Optics

Adaptive optics is a technique developed in the field of astronomy for the correction of aberrations introduced by the atmosphere when observing stars, planets and deep sky objects using telescopes based on Earth. This correction is usually applied with deformable mirrors, which have the benefit of being polarisation and wavelength insensitive, while also matching the submillisecond rate at which the turbulence changes. This work provides an alternative solution, by using blue phase liquid crystals as the correcting medium, which also comes with the same benefits of polarisation insensitivity and speed. By using correctors made with blue phases, the cost of manufacturing is reduced, requiring much less precision during fabrication. Techniques to apply this specifically to the field of astronomical adaptive optics are demonstrated, and a streamlined process is developed, in which prototypes of blue phase correctors are achieved. These meet an expected rise and fall time of trise = 130 μs and tfall = 125 μs, respectively. They achieve a phase modulation of 1.23 radians, corresponding to 0.39π, at an applied field of 7.73 V/μm, in a transmissive topology. For reflective devices, which are further compatible with existing adaptive optics systems, a tip/tilt mode is successfully applied with a root mean square of the wavefront of 76.05 radians across a 1 cm x 1 cm area at an applied field of 14.3 V/μm. This is a milestone achievement for blue phases in the first ever demonstration of them being used for astronomical adaptive optics. Moreover, these devices were built on a PCB substrate with no intermediary layer, furthermore forming the first demonstration of blue phases grown on PCB. All the steps and architectures described throughout the work are optimised to achieve a low-cost, approachable alternative suitable for prototyping blue phase devices for adaptive optics

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2026

Author dc:creator

• Niculescu, Oana

Advisor dc:contributor.advisor

• Wilkinson, Timothy

• adaptive optics
• blue phase
• liquid crystal
• wavefront corrector
• aberration correction
• astronomy instrumentation

Licence

• https://www.repository.cam.ac.uk/bitstreams/5c53d9f1-e0da-405d-8b75-92fbfadf2e26/download
• http://purl.org/NET/rdflicense/allrightsreserved

Language dc:language

eng

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.131859

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/405728