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Purpose of this work is the comparative analysis of two approaches to the synthesis of two-dimensional binary identifiers of nucleotide sequences obtained using DNA sequencing of biological objects. Methods. One of the approaches is based on modeling the polarization-dependent diffraction of a coherent readout beam on a two-dimensional phase-modulating structure (phase screen) associated with the symbolic sequence obtained as a result of DNA sequencing. Another approach uses a two-dimensional representation of the symbolic sequence using a chaos game representation (CGR). To obtain a finite-element CGR mapping, it is fragmented into a given number of cells, ensuring acceptable sensitivity of the synthesized binary identifier to structural changes in the displayed sequence. Results. The comparative analysis was carried out using fragments of symbol sequences corresponding to various strains (Wuhan, Delta, Omicron) of the SarSCoV2 virus. In the course of the analysis, the correlation coefficients between the binary identifiers corresponding to various strains were obtained and compared with each other. Conclusion. It has been established that binary identifiers synthesized using the polarization encoding technique are characterized by significantly higher sensitivity to structural changes in the analyzed sequences and smaller sizes compared to CGR binary identifiers.

We report a theoretical analysis of a photonic quantum interface, which makes it possible to deterministically convert photonic qubits from subcarrier wave to polarization encoding. The interface provides unambiguous conversion of an arbitrary phase of the input signal into the corresponding polarization of the converted radiation. Possibilities of implementing this interface in an integrated optical design and its use in constructing a hybrid quantum network are discussed. [ABSTRACT FROM AUTHOR]

Two approaches to the synthesis of 2D binary identifiers (“fingerprints”) of DNA-associated symbol sequences are considered in this paper. One of these approaches is based on the simulation of polarization-dependent diffraction patterns formed by reading the modeled DNA-associated 2D phase-modulating structures with a coherent light beam. In this case, 2D binarized distributions of close-to-circular extreme polarization states are applied as fingerprints of analyzed nucleotide sequences. The second approach is based on the transformation of the DNA-associated chaos game representation (CGR) maps into finite-dimensional binary matrices. In both cases, the differences between the structures of the analyzed and reference symbol sequences are quantified by calculating the correlation coefficient of the synthesized binary matrices. A comparison of the approaches under consideration is carried out using symbol sequences corresponding to nucleotide sequences of the hly gene from the vaccine and wild-type strains of Listeria monocytogenes as the analyzed objects. These strains differ in terms of the number of substituted nucleotides in relation to the vaccine strain selected as a reference. The results of the performed analysis allow us to conclude that the identification of structural differences in the DNA-associated symbolic sequences is significantly more efficient when using the binary distributions of close-to-circular extreme polarization states. The approach given can be applicable for genetic differentiation immunized from vaccinated animals (DIVA).

Results of computational analysis and visualization of differences in gene structures using polarization coding are presented. A two-dimensional phase screen, where each element of which corresponds to a specific basic nucleotide (adenine, cytosine, guanine, or thymine), displays the analyzed nucleotide sequence. Readout of the screen with a coherent beam characterized by a given polarization state forms a diffracted light field with a local polarization structure that is unique for the analyzed nucleotide sequence. This unique structure is described by spatial distributions of local values of the Stokes vector components. Analysis of these distributions allows the comparison of nucleotide sequences for different strains of pathogenic microorganisms and frequency analysis of the sequences. The possibilities of this polarization-based technique are illustrated by the model data obtained from a comparative analysis of the spike protein gene sequences for three different model variants (Wuhan, Delta, and Omicron) of the SARS-CoV-2 virus. Various modifications of polarization encoding and analysis of gene structures and a possibility for instrumental implementation of the proposed method are discussed.

Optics has strong potentiality in data processing. Here, quantum Fredkin gate is implemented with the help of switching property of optical nonlinear material and polarization-based encoding and decoding technique of optical signal. The gate is very much useful for quantum computing and communications. [ABSTRACT FROM AUTHOR]

Design and performance of all optical ternary NOT & XOR gate using the Dual semiconductor optical amplifier (SOA)-based technology is investigated. The basic principal behind the operation of these logic gates is nonlinear cross-polarization modulation (XPolM) effect in SOA. Optical NOT gate is universal logic gate, and optical XOR gates are very useful in designing higher order optical devices like flip-flops, parity checker and generator circuits, etc. The Q-value of the design is greater than 50 dB maintaining high operational speed (~ 100Gbit/s) ensures negligible bit error rate. Numerical simulation using MATLAB ensures CR values more than 55 dB and ER values more than 50 dB. These high values ensure practical feasibility of the proposed devices. The large relative eye opening(> 94%) ensures clear transmissions of the information. [ABSTRACT FROM AUTHOR]

Metasurface provides subwavelength structures for manipulating wavefronts of light. The benefits of subwavelength components offer a continuous modulation of amplitude, phase, and polarization, thus eliminating the production of higher-order images and improving the utilization of light intensity. Despite the rapid progress in this field, multiparameter control of light using single layer metasurface is rarely reported. In fact, multiparameter control of light helps to improve information storage capacity and image fidelity. With simultaneous manipulation of polarization and amplitude at each pixel, it is possible to encode two separate images into one metasurface and reconstruct them under proper conditions. In a proof of concept experiment, we demonstrate an independent display of two binary images at the same position with polarization de-multiplexing from a single metasurface. This unique technology of encoding two images through amplitude and polarization manipulation provides a new opportunity for various applications in, such as encryption, information storage, polarization holograms, optical communications and fundamental physics.

In this communication, a new all-optical quaternary Galois field adder is designed, the nonlinear cross-polarization modulation (XPolM) effect is implemented in semiconductor optical amplifier (SOA), and polarization encoding scheme is proposed and analyzed. Soliton pulses are used to improve the quality of operation (Q ~ 30 dB) even for long-range communication, maintaining high speed (~ 100 Gbit/s). Some theoretical simulative work has been done to establish the quality of operation of the proposed design. The SOA is very important device because of its small size (~ 800 µm) and low energy than the other complex optical devices (< 1 mW). A comparison with related work has also been included which shows improvement over related works. [ABSTRACT FROM AUTHOR]

Two approaches to the synthesis of 2D binary identifiers ("fingerprints") of DNA-associated symbol sequences are considered in this paper. One of these approaches is based on the simulation of polarization-dependent diffraction patterns formed by reading the modeled DNA-associated 2D phase-modulating structures with a coherent light beam. In this case, 2D binarized distributions of close-to-circular extreme polarization states are applied as fingerprints of analyzed nucleotide sequences. The second approach is based on the transformation of the DNA-associated chaos game representation (CGR) maps into finite-dimensional binary matrices. In both cases, the differences between the structures of the analyzed and reference symbol sequences are quantified by calculating the correlation coefficient of the synthesized binary matrices. A comparison of the approaches under consideration is carried out using symbol sequences corresponding to nucleotide sequences of the hly gene from the vaccine and wild-type strains of Listeria monocytogenes as the analyzed objects. These strains differ in terms of the number of substituted nucleotides in relation to the vaccine strain selected as a reference. The results of the performed analysis allow us to conclude that the identification of structural differences in the DNA-associated symbolic sequences is significantly more efficient when using the binary distributions of close-to-circular extreme polarization states. The approach given can be applicable for genetic differentiation immunized from vaccinated animals (DIVA).

Quantum key distribution (QKD), ensuring the unconditional security of information, attracts a significant deal of interest. An important task is to design QKD systems as a platform for education as well as for research and development applications and fast prototyping new QKD protocols. Here, we present a modular QKD setup driven by National Instruments (NI) cards with open source LabView code, open source Python code for post-processing procedures, and open source protocol for external applications. An important feature of the apparatus developed is its flexibility offering the possibility to modify optical schemes, as well as prototype, and verify novel QKD protocols. The other distinctive feature of the setup developed is the implementation of the decoy-state protocol, which is a standard tool for secure long-distance quantum communications. By testing the plug-and-play scheme realizing BB84 and decoy-state BB84 QKD protocols, we show that the developed QKD setup shows a high degree of robustness beyond laboratory conditions. We demonstrate the results of the use of the developed modular setup for QKD experiments in the urban environment. [ABSTRACT FROM AUTHOR]

Optics plays an important role in data processing. In this context, optical nonlinear material is very useful for superfast switching operations. Again polarization-based encoding and decoding technique plays a convenient way for data processing. In this paper, a new method to implement a quantum Toffoli gate with the active use of optical nonlinear material and polarization-based encoding technique is reported. [ABSTRACT FROM AUTHOR]

Highilights • Optical image authentication scheme using dual polarization decoding is purposed and validated. • We examine a sparse encoding method based on image division to process the original image. • The proposed scheme resolves the alignment problem of previous polarization encoding methods. • Our verification system exhibits high robustness and flexibility against attacks and interference. • Results might be useful for polarization-encoding based optical verification. Abstract We report on an optical image authentication scheme using dual polarization decoding configuration. We examine a sparse encoding method based on image division to process the original image. Next, the sparse original image is separated into two noise-like structure images with random polarization parameters which are digitally encoded. During the decoding stage, the encoded images are sent into a dual polarization decoding configuration where a pixelated polarizer with sparse distribution of transmission angle is employed for image recovering. The proposed scheme avoids complicated recording of complex information and resolves the alignment problem of previous polarization encoding methods. Then we examine numerical simulations to show that the proposed scheme is well suited to recover the original image when decryption keys are correctly used. We find evidence that the verification system exhibits high robustness and flexibility against attacks and interference. We expect that these results might be useful for polarization-encoding based optical verification. [ABSTRACT FROM AUTHOR]

Quantum key distribution (QKD) provides theoretic information security in communication based on the laws of quantum physics. In this work, we report an implementation of quantum-secured data transmission in the infrastructure of Sberbank of Russia in standard communication lines in Moscow. The experiment is realized on the basis of already deployed urban fiber-optics communication channels with significant losses. We realize the decoy-state BB84 QKD protocol using the one-way scheme with polarization encoding for generating keys. Quantum-generated keys are then used for continuous key renewal in the hardware devices for establishing a quantum-secured VPN Tunnel between two offices of Sberbank. The hybrid approach used offers possibilities for long-term protection of the transmitted data; it is promising for integrating in the already existing information security infrastructure. [ABSTRACT FROM AUTHOR]

In recent years, dielectric and metallic nanoscale metasurfaces are attracting growing attention and are being used for variety of applications. Resulting from the ability to introduce abrupt changes in optical properties at nanoscale dimensions, metasurfaces enable unprecedented control over light's different degrees of freedom, in an essentially two-dimensional configuration. Yet, the dynamic control over metasurface properties still remains one of the ultimate goals of this field. Here, we demonstrate the optical resonant interaction between a form birefringent dielectric metasurface made of silicon and alkali atomic vapor to control and effectively tune the optical transmission pattern initially generated by the nanoscale dielectric metasurface. By doing so, we present a controllable metasurface system, the output of which may be altered by applying magnetic fields, changing input polarization, or shifting the optical frequency. Furthermore, we also demonstrate the nonlinear behavior of our system taking advantage of the saturation effect of atomic transition. The demonstrated approach paves the way for using metasurfaces in applications where dynamic tunability of the metasurface is in need, for example, for scanning systems, tunable focusing, real time displays, and more. [ABSTRACT FROM AUTHOR]

• A coding strategy based on polarization and light intensity is adopted. • The method can be easily combined into different types of phase-shifting methods. • Defocused binary fringe projection method encodes the degree of polarization. Polarized structured light is an important method to measure shiny surface. In this paper, a type of structured light encoded by polarized light is proposed. A coding strategy based on polarization and light intensity is adopted to improve the quality of the projection fringe. A type of robust phase-shift fringe is generated using the characteristics of a liquid crystal display projector by the defocus method. Compared with other polarized structured light coding methods, the proposed method requires simpler equipment and no additional custom instruments. Experiments show that the method could effectively improve the robustness of fringes. Experiments suggest that the range accuracy is improved by 2.4%. [ABSTRACT FROM AUTHOR]

Results of computational analysis and visualization of differences in gene structures using polarization coding are presented. A two-dimensional phase screen, where each element of which corresponds to a specific basic nucleotide (adenine, cytosine, guanine, or thymine), displays the analyzed nucleotide sequence. Readout of the screen with a coherent beam characterized by a given polarization state forms a diffracted light field with a local polarization structure that is unique for the analyzed nucleotide sequence. This unique structure is described by spatial distributions of local values of the Stokes vector components. Analysis of these distributions allows the comparison of nucleotide sequences for different strains of pathogenic microorganisms and frequency analysis of the sequences. The possibilities of this polarization-based technique are illustrated by the model data obtained from a comparative analysis of the spike protein gene sequences for three different model variants (Wuhan, Delta, and Omicron) of the SARS-CoV-2 virus. Various modifications of polarization encoding and analysis of gene structures and a possibility for instrumental implementation of the proposed method are discussed.

Polarization coding is a specific encoding method by using the polarization state of optical signal carrying coded information. It focuses on nonlinear effects, polarization mode dispersion and other issues in high-speed fiber-optic communications. This paper presents a measurement method for polarization state based on elastic-optic modulator. This method not only retains the original advantages of elastic-optic modulator for polarization measurement, but also overcomes the defects of existing methods including high modulation frequency and invalid collection by using array detector. Matlab simulation and experimental verification scheme are given. The feasibility of this method is verified through theoretical analysis , and simulation and experimental results are carried out. The error analysis of the measurement results shows that the method can meet the measurement requirements and provide conditions for using the polarization encoding in high-speed communication. [ABSTRACT FROM AUTHOR]

Abstract: We demonstrate experimentally an intrinsically stable polarization coding and decoding system composed of optical-fiber Sagnac interferometers with integrated phase modulators for quantum key distribution. An interference visibility of 98.35% can be kept longtime during the experiment without any efforts of active compensation for coding all four desired polarization states. [Copyright &y& Elsevier]

Abstract: We present an optical encryption method based on geometrical phase, which is originated from polarization manipulation. The decrypted picture is retrieved by measuring the polarization of the beam emerging from the encrypted element. The encrypted element is achieved by using a computer-generated space-variant subwavelength dielectric grating. Theoretical analyses of the optical concept by use of Jones and Mueller formalisms, as well as experimental results including full optical decryption process are introduced. Digital implementation and the possibility of using watermarking are also discussed. [Copyright &y& Elsevier]

• A compact optical authentication system using generator of spatially variant vector beam is proposed. • A novel sparse sampling technique of ciphertexts is developed that can simultaneously complete information removal and data compression. • Requirement for strict alignment of phase mask key is relaxed greatly. • Random polarization parameters constitute a key space with multiple dimension to resist against potential brute force attacks. An innovative image authentication scheme using spatially variant vector beam is introduced. During encoding period, the original image is converted into two angle distribution images by making use of the modified Gerchberg–Saxton algorithm (MGSA) and random polarization parameters in a digital way. By using image division and sparse sampling, two mosaic ciphertexts which retain partial encoded information are obtained. A generator of spatially variant polarized beam, combined with a sparse phase-only key, can decrypt the ciphertexts into a noise-like result that can be authenticated by a nonlinear correlator. Numerical simulation tests demonstrate the security strength and robustness of this scheme. Moreover, this scheme exhibits a higher resistance against misalignment of phase-only key, which is advantageous for practical implementation. We expect that these results might be useful for future application of polarization encoding in security application. [ABSTRACT FROM AUTHOR]