Liquid crystal devices for compact optical space instruments

Abstract

Our group in the Space Optics Department at INTA has been working during more than 20 years in the development of devices based on liquid crystals for optical payloads onboard space missions. Currently, there are three of our devices successfully in operation in the PHI and METIS instruments of the Solar Orbiter ESA/NASA mission. Therefore, they have the highest technology maturity level, TRL9 (Technology Readiness Level). To the best of our knowledge, we are pioneers of the use of polarization modulators based on liquid crystals in a telescope or a camera in a space platform.Liquid crystal devices avoid using standard solutions that involve mechanisms with rotatory polarization optical parts. Instead, we use this technology that minimizes the size, mass and power consumption of the device while maximizing its useful aperture and performance. These new capabilities open up new possibilities for small satellites that were previously only attainable by larger satellites. Liquid crystal-based polarization modulator technology is highly versatile and can be configured in multiple ways to suit diverse applications. It is based on the ability of liquid crystal variable retarders to control, modify and measure the polarization state of light, be it in an image or in a spot beam.The application fields are numerous, from Astrophysics to Earth Observation. This work will introduce some of the main instruments that we are working on: from the Vigil ESA mission for Space Weather to Quantum Communication Space Systems, and including the Miniature Absolute Magnetometer for the NanoMagSat mission of ESA's SCOUT Program. Also, we will show the development status of other liquid-crystal devices for compact space instrumentation that we are developing as Liquid Crystal Tunable Filters (LCTFs) and Spatial Light Modulators (SLMs).In October 2023, the INTA spinoff Eye4Sky was established to the exploitation and commercialization of this optical technology of liquid crystal devices for space applications. This deep-tech startup has been selected for the prestigious European Space Agency Business Incubation Centre (ESA BIC) program.