Complex wavefront reconstruction from multiple-image planes produced by a focus tunable lens

Mosso, Fabian; Peters, Eduardo; Pérez, Darı́o G.

doi:10.1364/ol.40.004623

Cited by 31 publications

(6 citation statements)

References 17 publications

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“…Figure 6 shows these images decoded correctly following the procedure described above and depicted in figure 2. This verification validates the feasibility of our proposal to encode digitalized complex data, as phase and amplitude information like a ciphertext holographically recorded or by phase retrieval means [23,24]. By considering that the CZT can be implemented optically as well as electronically, for example in field programmable gate arrays, this proposal would contribute to strengthening the technological transfer of hybrid optical and digital encryption of images and signals for optics communications.…”

Section: Resultssupporting

confidence: 72%

Dynamic multiple-image encryption based on chirp z-transform

Mosso

Bolognini

2019

J. Opt.

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A dynamic encryption scheme is demonstrated based on chirp z-transform (CZT). The novel design of this setup allows us to protect multiple images in a multiplexed format and fully recover them without the influence of crosstalk and sample noise. The encoding stage is implemented using the 2D CZT and a Fourier lens. The CZT works with proper frequency parameters to control the position and size of the input frequency spectrum. The accurate positioning leads to an efficient packing of the multiplexed images and a remarkable improvement of the signal-to-noise ratio of the decrypted pictures. The introduction of the CZT in the field of encryption is significant, since it can expand the functionality to a dynamic regime of optical and digital architectures for static encoding. We validated the feasibility of our proposal with the encryption and decryption of a color image sequence and a set of binary images.

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Section: Resultssupporting

confidence: 72%

Dynamic multiple-image encryption based on chirp z-transform

Mosso

Bolognini

2019

J. Opt.

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“…A rough surface illuminated with coherent light produces a chaotic signal called speckle [18]. Phase retrieval based on FBPA employing intensity of axial speckle patterns allows wavefront reconstruction [19][20][21]. However, slight variations in recording lengths and the number of used axial patterns strongly impact the phase convergence success, yielding a non-stable phase between propagations.…”

Section: The Keystream Synthesizer: Stochastic Procedures For Rpms Ge...mentioning

confidence: 99%

An optical-cryptographic encryption scheme using a keystream synthesizer based on chaotic speckle nature

Mosso

2022

J. Opt.

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We propose a comprehensive and efficient optical-cryptographic encryption scheme to improve the security of vulnerable optical encryption systems. Based on cryptography theory, we increase data protection using diffusion-confusion processes acting in the input and output of the optical encryption scheme. The new enhanced ciphertext has attributes of a one-way function that is easy to achieve but almost impossible to revert without the correct random phase masks used for diffusion-confusion operations. Despite the straightforward design, combining optical, cryptographic, and chaos methods increases the number of encryption-decryption keys raising two significant concerns. First, the management and transmission of several keys carry a high storage footprint, and second, it impairs the optical high-speed information processing capability. We overcome these two drawbacks by applying a new optical keystream synthesizer based on the stochastic speckle nature and a maximum entropy constraint in a forward-backward propagation algorithm. This new approach quickly replicates the necessary keystream in the encryption-decryption stations offering higher security and efficiency than other reported systems. We validate the feasibility of this proposal by synthesizing an experimental keystream and performing 24-bit data encryption-decryption. Then, we verify the security improvement of two vulnerable cryptosystems and their robustness against cryptanalysis attacks. Finally, we perform experimental encryption-decryption.

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“…New phase retrieval techniques have been introduced to improve the acquisition speed, reducing the system size and eliminating any potential mechanical error. 7,8 Some years ago, an experimental application of a dynamic complex field reconstruction technique was successfully implemented. 9 The reconstruction is carried out using the intensity measurements-at a fixed distance-of the field modulated by random amplitude masks.…”

Section: Introductionmentioning

confidence: 99%

High-speed complex phase retrieval of a Gaussian beam propagating through controlled optical turbulence

Peters

Sepúlveda²,

Scherz³

et al. 2022

Environmental Effects on Light Propagation and Adaptive Systems V

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Optical turbulence induces distortions in amplitude and phase in any beam propagating through it, resulting in beam spreading, beam wandering, and irradiance fluctuations among other effects. Due to the dynamic nature of these effects, the complex field reconstruction of a perturbed beam presents a great experimental challenge. Interferometric wavefront reconstruction techniques require very sophisticated assemblies prone to alignment errors due to their high sensitivity to environmental disturbances. This hinders its experimental implementation. New complex phase retrieval methods overcome most of the limitations of interferometric methods: they are suitable for amplitude or phase objects (or both) and their reconstruction algorithms-based on propagation equations-make unnecessary any a-priori knowledge of the beam to be reconstructed. We propose an experimental implementation of a complex phase retrieval technique for the characterization of Gaussian beams propagating through turbulence. This technique is based on binary amplitude modulation using a digital micro-mirror device (DMD) which has proven to be suitable for dynamic applications. To our knowledge, this is the first experimental high-speed complex wavefront reconstruction of optical beams-by binary amplitude modulation-through controlled real turbulence. This experiment represents the first step in our research focused on understanding optical turbulence from an experimental point of view.

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Complex wavefront reconstruction from multiple-image planes produced by a focus tunable lens

Cited by 31 publications

References 17 publications

Dynamic multiple-image encryption based on chirp z-transform

Dynamic multiple-image encryption based on chirp z-transform

An optical-cryptographic encryption scheme using a keystream synthesizer based on chaotic speckle nature

High-speed complex phase retrieval of a Gaussian beam propagating through controlled optical turbulence

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