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Several recent business reports have described the global growth in demand for optical and photonic components, paralleled by technical reports on the growing shortage of skilled manufacturing staff to meet this demand. It is remarkable that producing ultraprecision surfaces remains so dependent on people, in contrast to other sectors of the economy, e.g., car manufacturing. Clearly, training can play some role, but ultimately, only process automation can provide the solution. This paper explores why automation is a challenge and summarizes multidisciplinary work aiming to assemble the building blocks required to realize automation.Highlights: Capturing polishing craft-expertise was academically successful, but commercially unviable due to personal privacy issues. Automating software communication between optical-design and manufacturing can minimise manufacturing cost and risk. Computational fluid dynamics of abrasive-slurries, plus real-time process-sensing, promises improved rocessconvergence. [ABSTRACT FROM AUTHOR]

Optics means a general area of physics that covers a broad range of topics relevant to the study of light. Optics has subfields they are quantum optics, geometrical optics, and physical optics. Photonics refers to a subset of the optics discipline. The simplicity, high efficiency, reliability, transparency, and robust feature of PID controllers were few factors behind the reasons for its acceptance and more popularity for control in processing industries globally. All the conventional techniques for PID controller design and tuning offer early workable values for reaching favorable performances. The manual tuning of the PID controller variables becomes a difficult role that needs comprehensive knowledge and expertise in that field. Certain meta-heuristic techniques are explored to design PID controllers with the main aims of attaining minimum overshoot in lesser settling time and steady state response. For accomplishing enhanced robustness, minimization of disturbance elimination, operating, and physical restraints are treated as multi-optics functions. Therefore, this article presents a modified honey badger optimization (MoHBO) algorithm-based parameter tuning of the PID controller for optics and photonics. The tuning of the PID controller with constraints on the relative delay margin was considered an optimum disturbance rejection issue and summarized the tuning process. The presented MoHBO algorithm is derived by the inclusion of oppositional based learning (OBL) with standard HBO algorithm. In addition, the MoHBO algorithm is tested using the Magnetic Levitation System (MLS) and Phase Locked Loop system (PLL) to assure the enhanced robust nature of the PID controller. A wide ranging comparison study with other metaheuristic optimization algorithms demonstrates the better performance of the MoHBO algorithm over recent algorithms. [ABSTRACT FROM AUTHOR]

Neuromorphic photonics has relied so far either solely on coherent or Wavelength-Division-Multiplexing (WDM) designs for enabling dot-product or vector-by-matrix multiplication, which has led to an impressive variety of architectures. Here, we go a step further and employ WDM for enriching the layout with parallelization capabilities across fan-in and/or weighting stages instead of serving the computational purpose and present, for the first time, a neuron architecture that combines coherent optics with WDM towards a multifunctional programmable neural network platform. Our reconfigurable platform accommodates four different operational modes over the same photonic hardware, supporting multi-layer, convolutional, fully-connected and power-saving layers. We validate mathematically the successful performance along all four operational modes, taking into account crosstalk, channel spacing and spectral dependence of the critical optical elements, concluding to a reliable operation with MAC relative error < 2 % . [ABSTRACT FROM AUTHOR]

Symmetry underpins our understanding of physical law. Open systems, those in contact with their environment, can provide a platform to explore parity-time symmetry. While classical parity-time symmetric systems have received a lot of attention, especially because of the associated advances in the generation and control of light, there is much more to be discovered about their quantum counterparts. Here we provide a quantum theory which describes the non-Hermitian physics of chains of coupled modes, which has applications across optics and photonics. We elucidate the origin of the exceptional points which govern the parity-time symmetry, survey their signatures in quantum transport, study their influence for correlations, and account for long-range interactions. We also find how the locations of the exceptional points evolve as a function of the chain length and chain parity, capturing how an arbitrary oligomer chain transitions from its unbroken to broken symmetric phase. Our general results provide perspectives for the experimental detection of parity-time symmetric phases in one-dimensional arrays of quantum objects, with consequences for light transport and its degree of coherence. Open quantum systems governed by non-Hermitian dynamics provide a platform to explore PT symmetric phases. Here, a general theory is derived to describe the location of exceptional points in a 1D oligomer chain of arbitrary length. [ABSTRACT FROM AUTHOR]

Much of the progress in astronomy has been driven by instrumental developments, from the first telescopes to fiber fed spectrographs. In this review, we describe the field of astrophotonics, a combination of photonics and astronomical instrumentation that is gaining importance in the development of current and future instrumentation. We begin with the science cases that have been identified as possibly benefiting from astrophotonic devices. We then discuss devices, methods and developments in the field along with the advantages they provide. We conclude by describing possible future perspectives in the field and their influence on astronomy. [ABSTRACT FROM AUTHOR]

The controllability of photonic setups is strongly related to how coherently their outputs react to changes in their inputs; such a generic concept is treated in the case of films comprising multilayers of tilted optical axes, under visible light. The optimized designs incorporate ordinary metals or semiconductors while being able to achieve practically all the combinations of reflected, transmitted and absorbed power within the passivity limits. Importantly, most of the proposed structures exhibit substantial robustness to manufacturing defects and are fabricable with various methods. Therefore, they can make indispensable pieces of integrated photonic systems by improving their light-controlling operation for applications ranging from steering and electrodynamic switching to filtering and optical signal processing. [ABSTRACT FROM AUTHOR]

The study and applications of in vivo skin optics have been openly documented as early as the year 1954, or possibly earlier. To date, challenges in analyzing the complexities of this field remain, with wide scopes requiring more scrutiny. Recent advances in spectroscopic research and multivariate analytics allow a closer look into applications potentially for detecting or monitoring diseases. One of the challenges in this field is in establishing a reference for applications which correspond to certain bandwidths. This article reviews the scope on past research on skin spectroscopy, and the clinical aspects which have or may have applications on disease detection or enhancing diagnostics. A summary is supplied on the technicalities surrounding the measurements reported in literature, focused towards the wavelength-dependent applications in themes central to the respective research. Analytics on the topology of the papers' data cited in this work is also provided for a statistical perspective. In short, this paper strives to immediately inform the reader with possible applications via the spectroscopic devices at hand. Graphical Abstract . [ABSTRACT FROM AUTHOR]

Acknowledgements The authors extend their appreciation to the Deputyship for Research & Innovation, Ministry of Education in Saudi Arabia for funding this research work through the project number IF 2020 NBU 463. The online version of the original article can be found at https://doi.org/10.1007/s11082-022-04139-z. [Extracted from the article]

A different silicon photonic wire waveguide is proposed, which uses multiple thin cladding layers in order to reduce the index contrast between core and cladding interface. The reduced index contrast in the proposed waveguide has led to reduction in the scattering losses by 37% as compared to silicon wire waveguide for 400 nm × 220 nm waveguide dimension. The proposed waveguide has shown significant reduction in bending losses. It offers the bending loss of 0.0118 dB at the radius of 1 μm and 0.0063 dB for a radius of 2 μm at 1.55 μm wavelength as compared to 0.086 and 0.013 dB at the radius of 1 and 2 μm, respectively, offered by silicon photonic wire waveguide at 1.5 μm wavelength. The use of polymer material as top cladding layer resulted in decreasing the sensitivity of effective index against temperature for the designed waveguide by a factor of 2 as compared to silicon wire waveguide. [ABSTRACT FROM AUTHOR]

Hybrid organic-inorganic integrated photonics integrate the organic material, as a part of active layer, with inorganic structure, and it is the organic component that extends the functionalities as compared to inorganic photonics. This paper presents the results of fabrication and characterization of inorganic and organic layers, as well as of hybrid organic-inorganic structures. Inorganic oxide and nitride materials and structures were grown using plasma enhanced chemical vapor deposition. As a substrate for tested organic layers and for preparation of multilayer structures, commercially available SiO created by thermal oxidation on Si was used. The hybrid organic-inorganic structures were prepared by spin coating of organic materials on SiO/Si inorganic structures. As the basic photonics devices, the testing strip inorganic and organic waveguides were fabricated using reactive ion etching. The shape of fabricated testing waveguides was trapezoidal and etched structures were able to guide the radiation. The presented technology enabled to prepare hybrid organic-inorganic structures of comparable dimensions and shape. The fabricated waveguides dimensions and shape will be used for optimisation and design of new lithographic mask to prepare photonic components with required characteristics. [ABSTRACT FROM AUTHOR]

Quantum superposition is the quantum-mechanical property of a particle whereby it inhabits several of its possible quantum states simultaneously. Ideally, this permissible coexistence of quantum states, as defined on any degree of freedom, whether spin, frequency or spatial, can be used to fully exploit the information capacity of the associated physical system. In quantum optics, single photons are the quanta of light, and their coherence properties allow them to establish entangled superpositions between a large number of channels, making them favourable for realizations of quantum information processing schemes. In particular, single-photon W-states (that is, states exhibiting a uniform distribution of the photons across multiple modes) represent a class of multipartite maximally-entangled quantum states that are highly robust to dissipation. Here, we report on the generation and verification of single-photon W-states involving up to 16 spatial modes, and exploit their underlying multi-mode superposition for the on-chip generation of genuine random numbers. [ABSTRACT FROM AUTHOR]

In this paper, we will review research done by the Large-Scale Integrated Photonics group at HP Laboratories, and in particular we will discuss applications of optical resonances in dielectric microstructures and nanostructures to future classical and quantum information technologies. Our goal is to scale photonic technologies over the next decade in much the same way as electronics over the past five, thereby establishing a Moore's Law for optics. [ABSTRACT FROM AUTHOR]

The optical transfer functions of underwater imaging systems that use narrow beams modulated by a complex high-frequency signal to form an image are studied. Images of simple objects observed with the use of such systems are calculated. The image distortions caused by the interference of modulation waves are estimated, and a method for eliminating these distortions is proposed. The potential for improving the image quality through the application of complexly modulated illumination beams is demonstrated using explicit calculations. [ABSTRACT FROM AUTHOR]