The paper by Gibson et al. demonstrates the use of orbital angular momentum (OAM) states of light beams for secure information transfer in free-space optical communication. The system employs spatial light modulators to prepare and measure OAM states, encoding data into one of eight pure OAM states. The security of this method is enhanced because any attempt to intercept the beam away from its axis introduces angular restrictions and lateral offsets, leading to inherent uncertainty in the measurement. This uncertainty is demonstrated through experiments where the beam is apertured and misaligned, showing that the OAM content of the beam becomes difficult to infer. The authors also discuss the implications of atmospheric turbulence and other environmental factors on the system's performance and suggest that adaptive optics could be used to mitigate these effects. The paper concludes by highlighting the potential of OAM encoding for secure and reliable free-space optical communication, emphasizing its compatibility with current FSO techniques and the need for further research to address remaining challenges.The paper by Gibson et al. demonstrates the use of orbital angular momentum (OAM) states of light beams for secure information transfer in free-space optical communication. The system employs spatial light modulators to prepare and measure OAM states, encoding data into one of eight pure OAM states. The security of this method is enhanced because any attempt to intercept the beam away from its axis introduces angular restrictions and lateral offsets, leading to inherent uncertainty in the measurement. This uncertainty is demonstrated through experiments where the beam is apertured and misaligned, showing that the OAM content of the beam becomes difficult to infer. The authors also discuss the implications of atmospheric turbulence and other environmental factors on the system's performance and suggest that adaptive optics could be used to mitigate these effects. The paper concludes by highlighting the potential of OAM encoding for secure and reliable free-space optical communication, emphasizing its compatibility with current FSO techniques and the need for further research to address remaining challenges.