Multiwavelength Magnetic-Free Optical Isolator by Optical Pumping in Warm Atoms

Abstract

Achieving multiwavelength nonreciprocal optical devices, which can realize nonreciprocal (perfect one-way) transmission for two or more wavelengths at the same time, without magnetic materials is challenging, but is highly desirable for densely integrated multiwavelength photonic components. The authors experimentally realize multiwavelength magnetic-free optical nonreciprocity using optical pumping of warm ${}^{85}$Rb atoms, with the assistance of Doppler effect. This scheme may have advantages in decreasing the number of optical isolators, and thus can reduce the complexity of an integrated multiwavelength system.