12-03, 11:40–12:00 (Europe/Luxembourg), Banquet Room
The quest for interstellar travel presents one of the most formidable challenges in modern science and engineering, primarily due to the need for propulsion systems capable of achieving relativistic speeds. Traditional chemical and nuclear propulsion methods are inadequate for these requirements, prompting exploration into alternative technologies such as laser propulsion. This approach leverages photon pressure to accelerate spacecraft to significant fractions of the speed of light, necessitating the development of ultra-lightweight, highly reflective structures. Due to required radiation pressure, achieving levitation at macro scale poses important challenges in the fields of optomechanics and nanofabrication, as these structures have to be optimized both for their mass and optical properties, generally resulting in designs with extreme aspect ratios with almost perfect reflectivity. Here, we demonstrate our initial results and roadmap for achieving macroscopic scale optical levitation as a critical step towards the realization of laser-propelled spacecraft for interstellar travel. The focus is on the development, optimization and characterization of high aspect ratio photonic crystal membranes designed for stability and efficiency under high-intensity laser illumination. Using cutting-edge nanofabrication techniques, we fabricate SiN photonic crystal lightsail membranes with extreme aspect ratios (1 cm / 200 nm) optimized via neural network algorithms. Our novel fabrication-measurement scheme ensures these membranes are released and measured within an Inductively Coupled Plasma - Reactive Ion Etching (ICP-RIE) system, avoiding exposure to atmospheric pressure and external forces that could compromise their integrity. The photonic crystal lightsail membranes are subsequently subjected to continuous strong radiation pressure (400 W - 1070 nm) to assess their mechanical integrity and dynamic stability. We present our progress on achieving and characterizing the macroscale optical levitation and share our future plans with the goal of demonstrating the feasibility of stable levitation of macroscopic structures using a single laser, paving the path for this previously unexplored regime of optomechanics. These results will be essential for realizing the dream of interstellar travel, providing a feasible pathway to propel spacecraft beyond our solar system within human lifetimes.
Richard Alexander Norte is a faculty member at Delft University of Technology (TU Delft) in the Netherlands. His research group develops cutting-edge nanotechnologies for quantum hardware, focusing on optical metasurfaces and nanomechanics. Richard holds dual BSc degrees in Physics and Mathematics from Stanford University and a Ph.D. in Physics from Caltech.
Since joining TU Delft, his work has been featured in Nature, Nature Photonics, Science, Physical Review Letters, and on the cover of Scientific American. He was recently awarded a €2.5 million ERC Starting Grant—one of Europe’s most prestigious personal grants—to advance next-generation laser sails for interstellar exploration.
His team has achieved significant breakthroughs in laser sail nano-manufacturing, reducing fabrication times from 15 years to a single day by integrating nanophotonics, fabrication techniques, and economic considerations of the Starshot mission. These innovations and expertise position his lab as a global leader in the pursuit of practical materials for laser-based interstellar travel.