The scientists created the mirrors by utilizing chemical vapor deposition to grow membrane mirrors on a rotating liquid inside a vacuum chamber. This allowed them to form parabolic thin membrane that can be utilized as the main mirror of a telescope when coated with a reflecting surface such as aluminum. Credit: Sebastian Rabien, Max Planck Institute for Extraterrestrial Physics
In the Optica Publishing Group journal Applied Optics, Rabien reports the successful fabrication of parabolic membrane mirror prototypes approximately 30 cm in size. These mirrors, which might be scaled as much as the sizes needed in space telescopes, were developed by utilizing chemical vapor deposition to grow membrane mirrors on a rotating liquid inside a vacuum chamber. He also established a method that utilizes heat to adaptively correct flaws that may happen after the mirror is unfolded.
” Although this work only demonstrated the feasibility of the techniques, it prepares for larger packable mirror systems that are more economical,” stated Rabien. “It could make lightweight mirrors that are 15 or 20 meters in diameter a reality, enabling space-based telescopes that are orders of magnitude more delicate than ones presently deployed or being prepared.”
Using an old procedure in a brand-new way
The brand-new technique was developed throughout the COVID-19 pandemic, which Rabien says provided him some additional time to believe and attempt out brand-new principles. “In a long series of tests, we looked into many liquids to learn their use for the process, investigated how the polymer growth can be carried out homogeneously, and worked to enhance the procedure,” he stated.
For chemical vapor deposition, a precursor material is vaporized and thermally split into monomeric particles. Those molecules deposit on the surface areas in a vacuum chamber and after that integrate to form a polymer. This procedure is commonly used to apply coverings such as the ones that make electronics water-resistant, however this is the very first time it has been used to produce parabolic membrane mirrors with the optical qualities needed for use in telescopes.
Membrane mirrors used the new method are flexible enough to be rolled up. This might be handy for saving the mirrors within a launch vehicle. Credit: Sebastian Rabien, Max Planck Institute for Extraterrestrial Physics
To produce the accurate shape needed for a telescope mirror, the scientists added a rotating container filled with a small quantity of liquid to the inside of the vacuum chamber. The liquid forms a perfect parabolic shape onto which the polymer can grow, forming the mirror base. When the polymer is thick enough, a reflective metal layer is applied to the top via evaporation and the liquid is gotten rid of.
” It has long been known that turning liquids that are lined up with the local gravitational axis will naturally form a paraboloid surface area shape,” said Rabien. “Utilizing this standard physics phenomenon, we transferred a polymer onto this perfect optical surface, which formed a parabolic thin membrane that can be used as the main mirror of a telescope once covered with a reflecting surface such as aluminum.”
Other groups have produced thin membranes for comparable purposes, these mirrors are generally shaped using a high-quality optical mold. Using a liquid to form the shape is much more affordable and can be more easily scaled approximately plus sizes.
Improving a folded mirror
The thin and light-weight mirror produced using this method can easily be folded or rolled up throughout the trip to area. However, it would be almost impossible to get it back to the best parabolic shape after unpacking. To improve the membrane mirror, the scientists developed a thermal technique that utilizes a localized temperature level modification developed with light to allow adaptive shape control that can bring the thin membrane into the preferred optical shape.
The scientists checked their method by creating 30-cm diameter membrane mirrors in a vacuum deposition chamber. After much experimentation, they had the ability to produce premium mirrors with a surface shape ideal for telescopes. They also showed that their thermal radiative adaptive shaping method worked well, as shown with a selection of radiators and illumination from a digital light projector.
The brand-new membrane-based mirrors might likewise be utilized in adaptive optics systems. Adaptive optics can improve the performance of optical systems by using a deformable mirror to compensate for distortion in inbound light. Due to the fact that the surface area of the new membrane mirrors is deformable, these mirrors might be shaped with electrostatic actuators to create deformable mirrors that are less costly to make than those created with traditional approaches.
Next, the researchers prepare to apply more advanced adaptive control to study how well the last surface area can be shaped and how much of an initial distortion can be endured. They likewise plan to develop a meter-sized deposition chamber to better research study the surface area structure and product packaging and unfolding procedures for a large-scale main mirror.
Referral: “Adaptive parabolic membrane mirrors for big deployable space telescopes” by Sebastian Rabien, 4 April 2023, Applied Optics.DOI: 10.1364/ AO.487262.
The scientists created the mirrors by utilizing chemical vapor deposition to grow membrane mirrors on a rotating liquid inside a vacuum chamber. These mirrors, which might be scaled up to the sizes needed in area telescopes, were created by utilizing chemical vapor deposition to grow membrane mirrors on a rotating liquid inside a vacuum chamber. To produce the precise shape essential for a telescope mirror, the scientists included a turning container filled with a small amount of liquid to the inside of the vacuum chamber. After much trial and error, they were able to produce top quality mirrors with a surface area shape ideal for telescopes. Due to the fact that the surface area of the brand-new membrane mirrors is deformable, these mirrors could be shaped with electrostatic actuators to develop deformable mirrors that are less pricey to make than those created with standard techniques.
Scientists have actually established a brand-new way to make telescope mirrors that could make it possible for much larger, and thus more delicate, telescopes to be placed in orbit. Credit: Sebastian Rabien, Max Planck Institute for Extraterrestrial Physics
Mirrors that are both versatile and lightweight might be compactly rolled up for the launch, and then precisely improved once they are released.
Researchers have established a brand-new approach to produce and form big, premium mirrors, considerably thinner than the main mirrors typically used in area telescopes. These resultant mirrors possess enough flexibility to be rolled up and loaded efficiently within a spacecraft during launch.
” Launching and releasing area telescopes is a expensive and complicated procedure,” stated Sebastian Rabien from Max Planck Institute for Extraterrestrial Physics in Germany. “This new method– which is extremely different from typical mirror production and polishing procedures– might assist fix weight and packaging problems for telescope mirrors, making it possible for much bigger, and hence more delicate, telescopes to be put in orbit.”