High-fidelity temporally-corrected transmission through dynamic smoke via pixel-to-plane data encoding

Securing 2D information carriers over dynamic and turbulent media in a free-space optical channel

In this Letter, a new, to the best of our knowledge, scheme is proposed to realize high-fidelity secured free-space optical information transmission through dynamic and turbulent media by encoding 2D information carriers. The data are transformed into a series of 2D patterns as information carriers. A novel differential method is developed to suppress noise, and a series of random keys are also generated. A different number of absorptive filters are arbitrarily combined to be placed in the optical channel to generate ciphertext with high randomness. It is experimentally demonstrated that the plaintext can be retrieved only when correct security keys are applied. Experimental results demonstrate that the proposed method is feasible and effective. The proposed method provides an avenue for securing high-fidelity optical information transmission over dynamic and turbulent media in a free-space optical channel.

Optical analog-signal transmission system in a dynamic and complex scattering environment using binary encoding with a modified differential method

High-fidelity optical transmission through dynamic scattering media is challenging, since transmission errors are induced due to dynamic scattering media. In this paper, a new scheme is proposed to realize high-fidelity free-space optical analog-signal transmission in dynamic and complex scattering environments using binary encoding with a modified differential method. Each pixel of an analog signal to be transmitted is first divided into two values, and each of them is encoded into a random matrix. Then, a modified error diffusion algorithm is utilized to transform the random matrix into a 2D binary array. Each pixel of the analog signal to be transmitted is eventually encoded into only two 2D binary arrays, and transmission errors and dynamic scaling factors induced by dynamic and complex scattering media can be temporally corrected. Dynamic smoke and non-line-of-sight (NLOS) are created as a dynamic and complex scattering environment to verify the proposed method. It is experimentally demonstrated that analog signals retrieved at the receiving end are always of high fidelity using the proposed method, when average path loss (APL) is less than 29.0 dB. Only the half number of measurements is used compared to that in conventional methods. The proposed method could open up a novel research perspective for high-fidelity free-space optical analog-signal transmission through dynamic and complex scattering media.

Optical data transmission through highly dynamic and turbid water using dynamic scaling factors and single-pixel detector

Free-space optical data transmission through non-static scattering media, e.g., dynamic and turbid water, is challenging. In this paper, we propose a new method to realize high-fidelity and high-robustness free-space optical data transmission through highly dynamic and turbid water using a series of dynamic scaling factors to correct light intensities recorded by a single-pixel bucket detector. A fixed reference pattern is utilized to obtain the series of dynamic scaling factors during optical data transmission in free space. To verify the proposed method, different turbidity levels, different strengths of water-flow-induced turbulence and a laser with different wavelengths are studied in optical experiments. It is demonstrated that the proposed scheme is robust against water-flow-induced turbulence and turbid water, and high-fidelity free-space optical information transmission is realized at wavelengths of 658.0 nm and 520.0 nm. The proposed method could shed light on the development of high-fidelity and high-robustness free-space optical data transmission through highly dynamic and turbid water.