Data encryption with chaotic light in the long wavelength infrared atmospheric window

In environments where traditional fiber optic cables are impractical, free-space optical communications offer a promising solution for transmitting large amounts of data, especially in the mid-infrared wavelength range. Despite the advantages of minimal atmospheric interference and stable signals, the vulnerability of wireless optical communications to eavesdropping poses a significant challenge. This study addresses this challenge by demonstrating a method for privately transmitting optical data using photonic chaos from distributed feedback quantum cascade lasers operating at 9.3 µm. Signal processing techniques are applied to enhance the quality of the transmission over distances exceeding 30 m, accompanied by a comprehensive analysis of the photonic chaos complexity to ensure data confidentiality. These findings mark a significant advancement in developing private communications systems within the thermal atmospheric window, with a substantially reduced risk of interception by adversaries. The research not only contributes to secure communications but also has potential implications for enhancing security of data transmission in challenging environments, impacting various industries and applications.