One of the major goals of modern astronomy is the characterization of Earth-like exoplanets to learn about their diversity, habitability and ultimately, whether they harbor life. However, this is far from easy as Earth-like planets are extremely faint sources of light. The state-of-the-art detectors based on semiconducting technologies inherently lack the sensitivity for this. Instead, we need a new generation detectors based on superconducting technology to see the light from these planets: Optical Kinetic Inductance Detectors (OKIDs). OKIDs can detect not only the smallest possible quantities of light, single photons, but can also determine the color of the photons, something that is impossible with semiconducting detectors. Our goal at SRON is to build science instruments with OKIDs for future ground- or space-based observatories like the European Extremely Large Telescope or NASA’s Habitable Worlds Observatory.
There are a lot of challenges to solve before such a technology can be used on a telescope on Earth, let alone in space. First off, to make large arrays of these detectors requires a fabrication precision down to the single atom level, requiring some of the most advanced fabrication methods known today.
Second, we want our detectors as sensitive as possible. We do not only want to distinguish a red from a blue photon, but also a red from a slightly more red photon. This requires a fundamental understanding of the physics in order to push towards its boundaries. Third, we need to make our detector as efficient as possible. We want it it to see single-photons, but also to see all the single-photons. This requires a more complex device, fabrication and measurement setup.
These are the biggest challenges on the detector level, but once these are solved more questions await on the instrument level: Can the instrument survive a launch in a rocket? Can the instrument survive in space? It’s a good thing that at SRON we have the experts on all these areas to enable this breakthrough OKID technology for space science.
