Physicists at the Max Planck Institute of Quantum Optics (MPQ) have engineered the lightest optical mirror imaginable. The novel metamaterial is made of a single structured layer that consists only of a few hundred identical atoms. The atoms are arranged in the two dimensional array of an optical lattice formed by interfering laser beams. The research results are the first experimental observations of their kind in an only recently emerging new field of subwavelength quantum optics with ordered atoms. So far, the mirror is the only one of its kind. The results are today published in Nature.

Usually, mirrors utilize highly polished metal surfaces or specially coated optical glasses to improve performance in smaller weights. But physicists at MPQ now demonstrated for the very first time that even a single structured layer of a few hundred atoms could already form an optical mirror, making it the lightest one imaginable. The new mirror is only several tens of nanometers thin, which is a thousand times thinner than the width of a human hair. The reflection, however, is so strong it could even be perceived with the pure human eye.