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Multiplexing holography with metasurfaces using different degrees of freedom of light has enabled recent applications in display and information processing. In terms of polarization‐multiplexed holograms, the most general form is an arbitrary Jones matrix profile in storing the maximum amount of information. It requires a relaxation to bianisotropic metasurfaces from a conventional single‐layer implementation of nanostructures, but it will also complicate both the inverse design of the nanostructures and the hologram generation algorithm. Here, an integrated neural network approach, being extended from the recent DeepCGH algorithm, is developed to obtain metasurface structural profiles directly from independent holograms from an arbitrary set of polarizations to another, with maximally four different co‐ and cross‐polarization conversion channels. Such an information‐driven approach enables designing complex polarization holograms directly from an existing metamaterial library without detailed physical knowledge on the constraints, and can be extended to other multiplexing holograms to further facilitate an efficient usage of the information stored on a metasurface. [ABSTRACT FROM AUTHOR]

This article, titled "Deep-Learning Assisted Polarization Holograms," discusses a new method for designing metasurfaces that can generate complex polarization holograms. The researchers have developed an integrated deep neural network that encodes target holograms directly to the design parameters of a metasurface. This method allows for the generation of metasurface designs without the need for detailed physical knowledge on the nanostructure constraints. The article provides further details on this innovative approach. [Extracted from the article]

In recent years, owing to the continuous development of polymer nanofiber manufacturing technology, various nanofibers with different structural characteristics have emerged, allowing their application in the field of sensing to continually expand. Integrating polymer nanofibers with optical sensors takes advantage of the high sensitivity, fast response, and strong immunity to electromagnetic interference of optical sensors, enabling widespread use in biomedical science, environmental monitoring, food safety, and other fields. This paper summarizes the research progress of polymer nanofibers in optical sensors, classifies and analyzes polymer nanofiber optical sensors according to different functions (fluorescence, Raman, polarization, surface plasmon resonance, and photoelectrochemistry), and introduces the principles, structures, and properties of each type of sensor and application examples in different fields. This paper also looks forward to the future development directions and challenges of polymer nanofiber optical sensors, and provides a reference for in-depth research of sensors and industrial applications of polymer nanofibers. [ABSTRACT FROM AUTHOR]

As an emerging battery, solid-state battery has broad development and application prospects. The safety and stability of the battery cannot be monitored in real-time during the work process. In this work, we fabricated solid electrolytes, assembled solid-state battery and proposed a method to monitor internal real-time temperature and strain information by embedding short fiber Bragg gratings in the battery. The experimental results show that the maximum temperature change is 0.42 °C and the maximum strain change is 11.5 με during the charging and discharging processes of the battery, and the formation of lithium dendrites is observed. This method enables real-time online in-situ monitoring of temperature and strain in solid-state battery and explains the causes of strain at the microscopic level, which is critical for the safe use of the battery. [Display omitted] • Optical fiber sensors embedded in solid-battery for in-situ measurements. • Real-time monitoring of temperature and strain. • To explain the formation of strain at the microscopic level. • To optimise of battery designs and to promote solid-battery safety improvement. [ABSTRACT FROM AUTHOR]

A novel photonic crystal fiber (PCF) sensor for refractive index detection based on polydimethylsiloxane (PDMS) is presented in this research, as well as designs for single-channel and dual-channel structures for this PDMS-PCF sensor. The proposed structures can be used to develop sensors with biocompatible polymers. The performance of the single-channel PDMS-PCF sensor was studied, and it was found that adjusting parameters such as pore diameter, lattice constant, distance between the D-shaped structure and the fiber core, and the radius of gold nanoparticles can optimize the sensor's performance. The findings indicate that the detection range of the single-channel photonic crystal is 1.21–1.27. The maximum wavelength sensitivity is 10,000 nm/RIU with a resolution of 1 × 10 − 5 RIU, which is gained when the refractive index is set to 1.27. Based on the results of the single-channel PCF, a dual-channel PDMS-PCF sensor is designed. The refractive index detection range of the proposed sensor is 1.2–1.28. The proposed sensor has a maximum wavelength sensitivity of 13,000 nm/RIU and a maximum resolution of 7.69 × 10 − 6 RIU at a refractive index of 1.28. The designed PDMS-PCF holds tremendous potential for applications in the analysis and detection of substances in the human body in the future. [ABSTRACT FROM AUTHOR]

With the in-depth study of solid-state batteries (SSBs), various in situ and ex situ characterization technologies have been widely used to study them. The performance and reliability of SSBs are limited by the formation and evolution of lithium dendrites at the interfaces between solid electrodes and solid electrolytes. We propose a new method based on optical coherence tomography (OCT) for in situ characterization of the internal state of solid-state batteries. OCT is a low-loss, high-resolution, non-invasive imaging technique that can provide real-time monitoring of cross-sectional images of internal structures of SSBs. The morphology, growth, and evolution of lithium dendrites at different stages of cycling under various conditions can be visualized and quantified by OCT. Furthermore, we validate and correlate the OCT results with scanning electron microscopy (SEM) and XPS, proving the accuracy and effectiveness of the OCT characterization method. We reveal the interfacial phenomena and challenges in SSBs and demonstrate the feasibility and advantages of OCT as a powerful tool for in situ and operando imaging of battery interfaces. This study provides new insights into the mechanisms and factors that affect SSB performance, safety, and lifetime, and suggests possible solutions for improvement and application in the field of applied energy. [ABSTRACT FROM AUTHOR]

• A fast-manufactured optical fiber temperature and humidity sensor with compact size was proposed. • The temperature and humidity sensitivities of the proposed sensor were −0.02539 dB/%RH and 11.14 pm/℃. • The measurement humidity sensitivity increased by nearly four times after the addition of nano-ZnO particles to the PVA. [Display omitted] A peanut-shaped optical fiber sensor cascaded with a fiber Bragg grating (FBG) was designed to measure temperature and humidity. A mixed polyvinyl alcohol/nano-zinc oxide (PVA/nano-ZnO) solution was electrospinning into nanofibers, and these nanofibers were then attached to the peanut-shaped structure surface to form a nanofiber film. Humidity changes caused changes in both the refractive index and the thickness of the PVA/nano-ZnO composite nanofiber film that subsequently caused changes in the transmitted light loss. Temperature changes caused a shift in the center wavelength of the FBG. Experimental results showed that the humidity and temperature sensitivities of the proposed sensor coated with the PVA/nano-ZnO composite film were −0.02539 dB/%RH and 11.14 pm/℃, respectively. Compared with an optical fiber sensor using a PVA film alone, the humidity sensitivity of the proposed sensor was increased by nearly four times after the addition of nano-ZnO. [ABSTRACT FROM AUTHOR]

A highly sensitive, reversible, and linear sensor, exhibiting excellent stability in response to temperature and humidity, has been successfully proposed and demonstrated for the first time. This sensor is achieved by wrapping a polyvinyl alcohol/graphene nanofiber film onto a chiral long-period fiber grating (CLPG), which is fabricated by periodically twisting single mode fiber. In the experiment, the CLPG sensor demonstrates a temperature sensitivity of 74 pm/°C , which is approximately twice as high as that of conventional fiber grating sensors. Note that, by wrapping the graphene nanofiber film on CLPG, the temperature sensitivity of the sensor is up to 115.23 pm/°C in the range of 30°C to 75°C. In addition, CLPG using for humidity sensing is first demonstrated. The humidity sensitivity measures −9.92 pm/%RH with linearity of 0.995 during a change from 40%RH to 80%RH. In comparison to other humidity sensors, the sensitivity of the CLPG is comparable, whereas its sensing linearity stands out notably above the rest. The results show that CLPG has the characteristics of simple fabrication, easy combination with materials, stable performance, and high sensitivity and holds significant development potential in optical fiber sensing application fields. [ABSTRACT FROM AUTHOR]

A fiber-optic humidity sensor based on excessively tilted fiber grating (Ex-TFG) wrapped with tin dioxide (SnO 2)/polyvinyl alcohol (PVA) hybrid nanofibers is presented. Relative humidity (RH) rise causes the changes both in refractive index (RI) and geometry size of the film. The transmitted spectrum of the Ex-TFG changes as a result, owing to the strong interaction of the excited forward propagating cladding modes to the surface coating. Experimental results demonstrate the maximum intensity sensitivity of 0.43 dB/%RH in RH range of 35%−75%. Compared with pure PVA film coated ones, the RH sensitivity of the SnO 2 /PVA wrapped grating is vastly enhanced by one order of magnitude. The reticular morphology of electrospun SnO 2 /PVA film around the Ex-TFG promises the unimpeded permeation of water molecules, and then the sensor exhibits an ultrafast response of ∼67 ms and recovery times of ∼83 ms, by monitoring the human breathing with different rhythms. Lastly, the negligible spectral deformation to temperature perturbations verifies the temperature de-correlation of the designed RH sensor. This work indicates that the proposed SnO 2 /PVA nanofibers wrapped Ex-TFG can provide a simple, robust and high-sensitive optic device for healthcare monitoring, environmental and biochemical sensing applications. • Wrapping SnO 2 /PVA nanofibers on an excessively tilted fiber grating. • High intensity sensitivity up to 0.43 dB/%RH with negligible temperature crosstalk. • Monitoring human breathing with ultrafast response speed of 67 ms. • Performing the merits of long-term stability, reliability, and easy fabrication. [ABSTRACT FROM AUTHOR]