Digital optical phase conjugation (DOPC) emerges as a promising technique for controllable optical delivery in strongly scattering media. Notably, due to the long-standing challenges in accurate alignment of the wave-front sensor and spatial light modulator (SLM), conventional DOPC systems heavily rely on digital calibration for misalignments between these two devices, which will significantly increase the pixel crosstalk of the SLM and thus degrade the performance of DOPC systems. To circumvent this digital calibration for mitigation of the pixel crosstalk, here we propose and demonstrate a real-space alignment scheme for DOPC systems based on single-pixel imaging, which enables precise alignment of the SLM and wave-front sensor: (i) with off-plane alignment precision of submillimeter and milliradian for axial and angular positions, respectively, and (ii) with in-plane pixel match at subpixel resolution. With additional efforts on fidelity optimization of optical phase-conjugation, deformations on the phase-conjugated wave front can almost be removed and the DOPC system would exhibit ultrahigh performance, with peak-to-background ratio (PBR) approaching the theoretical limit (more than 90%) in the time-reversed optical refocusing test. It can be anticipated that all DOPC-based applications will tremendously benefit from this near-theoretical-limit performance of optical phase conjugation for improved capacity and practical utility.

In diversified optical applications, such as optical imaging and optical metrology, it is evidently significant to pursue low quantum fluctuations of light to promise the enhancement of measurement precision. Recently, it has been demonstrated that the technique of wavefront shaping provides an effective avenue to suppress the excess quantum noise of quadrature-squeezed light through a disordered medium in the presence of one-sided illumination. Nevertheless, the minimum suppressed noise is still above the initial squeezed noise level. Inspired by two-sided modulation enabling novel optical phenomena, we propose an alternative noise-reduction scheme combining two-sided illumination with wavefront shaping. It is clarified that our approach is able to further reduce the excess quantum fluctuation. The exact condition for the reduced noise to reach below the standard quantum limit is given. Intriguingly, the excess noise can be fully erased in certain case. Therefore, our scheme paves another way for elimination of the excess noise induced by multiple scattering in disordered media.

In this paper, we present an in-depth analysis for entropy source based on optical physical unclonable functions (PUFs). The randomness of speckle patterns is elaborated essentially according to its statistical characteristics. Various factors affecting the source of entropy have been analyzed in detail, including wavefront modulation, sensitivity, and universality of the optical PUF, and bit-depth settings of captured speckle patterns. In view of the above considerations, we demonstrate that the entropy source can achieve an ultra-high min-entropy (>0.985 bits/bit) while maintaining a high extraction rate of 75% and also verify its independent and identically distributed nature. These results provide an in-depth and comprehensive understanding of the developed entropy source and offer a firm foundation for its practical use.

The effects of GaN/InGaN asymmetric lower waveguide (LWG) layers on photoelectrical properties of InGaN multiple quantum well laser diodes (LDs) with an emission wavelength of around 416 nm are theoretically investigated by tuning the thickness and the indium content of InGaN insertion layer (InGaN-IL) between the GaN lower waveguide layer and the quantum wells, which is achieved with the Crosslight Device Simulation Software (PIC3D, Crosslight Software Inc.). The optimal thickness and the indium content of the InGaN-IL in lower waveguide layers are found to be 300 nm and 4%, respectively. The thickness of InGaN-IL predominantly affects the output power and the optical field distribution in comparison with the indium content, and the highest output power is achieved to be 1.25 times that of the reference structure (symmetric GaN waveguide), which is attributed to the reduced optical absorption loss as well as the concentrated optical field nearby quantum wells. Furthermore, when the thickness and indium content of InGaN-IL both reach a higher level, the performance of asymmetric quantum wells LDs will be weakened rapidly due to the obvious decrease of optical confinement factor (OCF) related to the concentrated optical field in the lower waveguide.

Physical Unclonable Function (PUF) serves as a physical security primitive that cannot be feasibly duplicated and has diversified applications in the field of hardware security. Although optical PUF is regarded as one of the most promising PUF due to high information capacity, conventional image-based optical PUF generally suffers from notorious sensitivity to mechanical alignment and difficulty in integrating with electronic circuits. Here we propose a novel silicon optical scattering PUF (SOSPUF) with its optical components integrated on Silicon on Insulator (SOI) platform, yielding easy-to-integrate and easy-to-use merits over conventional optical PUF. In the disordered scattering region, the randomly distributed holes are introduced to enhance security of SOSPUF. The uniqueness, unpredictability and reliability properties of SOSPUF are demonstrated via numerical simulations. This work provides a solid basis for the design and implementation of SOSPUF.

The volume of securely encrypted data transmission increases continuously in modern society with all things connected. Towards this end, true random numbers generated from physical sources are highly required for guaranteeing security of encryption and decryption schemes for exchanging sensitive information. However, majority of true random number generators (TRNGs) are mechanically rigid, and thus cannot be compatibly integrated with some specific flexible platforms. Herein, we present a flexible and stretchable bionic TRNG inspired by the uniqueness and randomness of biological architectures. The flexible TRNG film is molded from the surface microstructures of natural plants (e.g., ginkgo leaf) via a simple, low-cost, and environmentally friendly manufacturing process. In our proof-of-principle experiment, the TRNG exhibits a fast generation speed of up to 1.04 Gbit/s, in which random numbers are fully extracted from laser speckle patterns with a high extraction rate of 72%. Significantly, the resulting random bit streams successfully pass all randomness test suites including NIST, TestU01, and DIEHARDER. Even after 10,000 times cyclic stretching or bending tests, or during temperature shock (−25–80 °C), the bionic TRNG still reveals robust mechanical reliability and thermal stability. Such a flexible TRNG shows a promising potential in information security of emerging flexible networked electronics.

The increasing security threat is a serious challenge to the internet of things (IoT). Hardware‐based security primitive is an essential and powerful way to protect IoT devices from various attacks. But most of the current security hardwares are based on macrophysical features, which are usually produced by reproducible deterministic processes and can be copied by counterfeiters. Herein, a physical unclonable function (PUF) with high robustness based on the intrinsic random micro‐/nanostructures of the electronic packages is proposed thereby demonstrating a low‐cost and label‐free hardware security solution for IoT. Using the unique surface micropattern and the spatially coded laser scattering, the proposed PUFs can be used as anticounterfeiting labels, authentication tokens and cryptographic key generators. With the help of the proposed PUFs, the safety protection is still effective even when the attacker is able to get access to the database because the secret keys are inherently hidden in the complex microscopic stochastic physical features of the PUFs but not the database. The proposed package‐enabled PUFs provide a promising and practical physical protection solution for IoT security.

Physical unclonable function (PUF) has been proposed as a promising and trustworthy solution to a variety of cryptographic applications. Here we propose a nonimaging-based authentication scheme for optical PUFs materialized by random scattering media, in which the characteristic fingerprints of optical PUFs are extracted from stochastical fluctuations of the scattered light intensity with respect to laser challenges, which are detected by a single-pixel detector. The randomness, uniqueness, unpredictability, and robustness of the extracted fingerprints are validated to be qualified for real authentication applications. By increasing the key length and improving the signal-to-noise ratio, the false accept rate of a fake PUF can be dramatically lowered to the order of 10-28. In comparison to the conventional laser-speckle-imagingbased authentication with unique identity information obtained from textures of laser-speckle patterns, this nonimaging scheme can be implemented at small speckle size bellowing the Nyquist-Shannon sampling criterion of the commonly used CCD or CMOS cameras, offering benefits in system miniaturization and immunity against reverse engineering attacks simultaneously.

Physical unclonable function (PUF) is promising for anticounterfeiting and security applications. In this paper, a PUF concept is demonstrated based on the stochastic generation of nanodot matrix via mechanical stripping of a gold film kirigami with arrayed nanoscale split-ring cuts. The random occurrence of nanofracture of metallic nanoconnection at split-ring parts results in unpredictable remaining (labeled as "1") or peeling-off (labeled as "0") of nanodots in each unit and thus generates a unclonable binary matrix. The highest randomness, i.e., 50% nanodots remaining in binary matrix, can be achieved by tuning the width of nanoconnection. Mechanical modeling reveals that the PUF can be caused by fracture-related variations such as the effective strength of the metallic nanoconnection and nanoscale adhesion. A quick response code (QR) can be retrieved for analysis from the dark field photograph of generated nanodot matrix based on the nanofacture-enabled PUF using in-house developed solver, demonstrating excellent unclonability, repeatability, and uniformity. The encoding capacity of our PUFs can be conveniently scaled up or down depending on the demands of applications, which can be beneficial to advanced authentication and identification systems with high security.

We propose an approach for fast random number generation based on homemade optical physical unclonable functions (PUFs). The optical PUF is illuminated with input laser wavefront of continuous modulation to obtain different speckle patterns. Random numbers are fully extracted from speckle patterns through a simple post-processing algorithm. Our proof-of-principle experiment achieves total random number generation rate of 0.96 Gbit/s with verified randomness, which is far faster than previous optical-PUF-based schemes. Our results demonstrate that the presented random number generator (RNG) proposal has great potential to achieve ultrafast random number generation rate up to several hundreds of Gbit/s.

Counterfeit electronics are a growing problem for the electronic information industry worldwide, so developing unbreakable security tags is crucial to ensure the trustworthiness and traceability of electronics. Traditional anticounterfeiting and trace solutions rely on reproducible deterministic processes and additional labels, which can still be copied or faked by counterfeiters. Herein, physical unclonable functions enabled by spontaneously formed plasmonic core–shell nanoparticles on electrodes are proposed to ensure label‐free traceable electronics, giving a practical solution to fight against counterfeit electronics. Random hemispherical core–shell nanoparticles are intentionally introduced on the metal electrode of different semiconductors (Si, GaAs, and GaN) from Ni/Au bilayer heterofilms by rapid thermal annealing, which can be integrated with electronics seamlessly, with no negative effect on electrical properties. The position, size, and shape of nanoparticles are random and uncontrollable; the corresponding scattering patterns, intensity, and spectra can work as nanofingerprints of the electrode, proving multidimensional unclonable labels with large encoding capacity suitable for electrodes smaller than several micrometers. It can be further combined with machine vision and artificial intelligence to identify and track electronics automatically and efficiently. The anticounterfeiting electrodes also show good thermal robustness and mechanical stability, opening up a prospect for practical anticounterfeiting of electronics.

Information security is of great importance for modern society with all things connected. Physical unclonable function (PUF) as a promising hardware primitive has been intensively studied for information security. However, the widely investigated silicon PUF with low entropy is vulnerable to various attacks. Herein, we introduce a concept of bionic optical PUFs inspired from unique biological architectures, and fabricate four types of bionic PUFs by molding the surface micro-nano structures of natural plant tissues with a simple, low-cost, green and environmentally friendly manufacturing process. The laser speckle responses of all bionic PUFs are statistically demonstrated to be random, unique, unpredictable and robust enough for cryptographic applications, indicating the broad applicability of bionic PUFs. On this ground, the feasibility of implementing bionic PUFs as cryptographic primitives in entity authentication and encrypted communication is experimentally validated, which shows its promising potential in the application of future information security.

Quantum dots (QDs) and metasurfaces show attractive performances for security applications such as anti counterfeiting, authentication and information encryption. They are usually employed as anticounterfeiting inks or structural colors and their patterns are fabricated using reproducible deterministic process, which is clonable and can be faked by counterfeiters. Herein, fluorescence pattern and lifetime of perovskite QDs are manipulated by chaotic metasurfaces to produce unclonable fluorescent speckles at the optical diffraction limit, resulting in a spatial/temporal dual-mode physical unclonable function (PUF). Radiation-chemical reactions of polymethylmethacrylate (PMMA) under ion beam etching are employed to fabricate the chaotic metasurfaces in large areas and coupled with randomly distributed perovskite QDs, providing a low-cost way to prepare the unclonable fluorescent anticounterfeiting labels. An enormous encoding capacity of over 2(156,250) is obtained with a tiny PUF about one hundred micrometers across. A high-security mutual authentication scheme for Internet of Things (IoT) is proposed based on a pair of the PUFs, in which no private key needs to be digitally stored and more than 26 Tbit/cm(2) binary public keys are generated. Such PUF open up a new prospect for the utilization of perovskite QDs and metasurfaces as an advanced security primitive at the nanoscale.

The fluorescence intensity and spontaneous emission rate of perovskite quantum dots with different emission wavelength are enhanced by monolithic hyperbolic metamaterials, which provides a powerful way for monolithic integrated high-frequency, high-brightness perovskite multicolor photonic sources.