Abstract:Flat optics have become capable of achieving unprecedented functionalities through electromagnetic (EM) wave manipulation by employing the metasurfaces. The most crucial part in the design of metasurface is the selection the constitutive component i.e. the meta-atom's material and structure so that it exhibits the precise operation as per the desired application. The unit-cell design calls for an iterative loop of simulations in order to explore the EM responses for intended operation. In this work, we have st… Show more
“…For non-invasively evaluating blood flow in these wounds, laser speckle contrast imaging (LSCI) has shown to be an invaluable tool that can support risk assessment, therapy monitoring, and diagnosis. Artificial Intelligence has been employed in engineering sciences for the study of optical devices [23][24][25]. Two interesting techniques have emerged because of LSCI's capabilities being further enhanced by the incorporation of artificial intelligence (AI):…”
Section: Artificial Intelligence-based Lsci Study Of Dfumentioning
Diabetic foot ulcers (DFU) are open sores or wounds that develop on the feet of people with diabetes. They are a serious complication and often occur on the bottom of the foot. DFU treatment in the field of medical sciences is an advanced field of study. Patients with DFU have a five-year death rate of approximately 40%. Age, gender, medical history, vascular diseases, and renal illness are major risk factors for mortality. While 90% of people with diabetes worldwide have type 2 diabetes mellitus, accounting for 463 million cases of the disease. DFU diagnosis and treatment has been performed with Laser Speckle Contrast Imaging (LSCI) which is a non-invasive imaging technology. LSCI is becoming widely recognized as a vital technique for evaluating the impacts and implications of this disease. Major types of LSCI has been studied for the application of laser speckle technology in medical diagnosis. Region of Interest (ROI) and Multi exposure based LSCI applications and implementations has been reviewed in this study. Along with the application of conventional LSCI, Artificial Intelligence (AI) tools has been studied for robust results to combat issues associated with diabetes.
“…For non-invasively evaluating blood flow in these wounds, laser speckle contrast imaging (LSCI) has shown to be an invaluable tool that can support risk assessment, therapy monitoring, and diagnosis. Artificial Intelligence has been employed in engineering sciences for the study of optical devices [23][24][25]. Two interesting techniques have emerged because of LSCI's capabilities being further enhanced by the incorporation of artificial intelligence (AI):…”
Section: Artificial Intelligence-based Lsci Study Of Dfumentioning
Diabetic foot ulcers (DFU) are open sores or wounds that develop on the feet of people with diabetes. They are a serious complication and often occur on the bottom of the foot. DFU treatment in the field of medical sciences is an advanced field of study. Patients with DFU have a five-year death rate of approximately 40%. Age, gender, medical history, vascular diseases, and renal illness are major risk factors for mortality. While 90% of people with diabetes worldwide have type 2 diabetes mellitus, accounting for 463 million cases of the disease. DFU diagnosis and treatment has been performed with Laser Speckle Contrast Imaging (LSCI) which is a non-invasive imaging technology. LSCI is becoming widely recognized as a vital technique for evaluating the impacts and implications of this disease. Major types of LSCI has been studied for the application of laser speckle technology in medical diagnosis. Region of Interest (ROI) and Multi exposure based LSCI applications and implementations has been reviewed in this study. Along with the application of conventional LSCI, Artificial Intelligence (AI) tools has been studied for robust results to combat issues associated with diabetes.
“…Using polarization-insensitive, efficient, and straightforward design strategies is highly desirable to realize all-dielectric multifunctional metastructures spanning various applications. Apart from these improvements, deep learning techniques revolutionized the design procedure of ultrathin structures and opened new avenues for the implementation of many phenomena [58]- [60].…”
Generating structured light beams has become a research hotspot to target many emerging practical applications like optical sensing, super-resolution imaging, and optical communication. Ingenious tailoring of spatial structures of light helps to manifest several intriguing beams like Bessel beams, Airy beams, vortex beams, etc. Among them, optical vortices (OVs) hold distinctive promise to meet the anticipated demands for optical communication, optical trapping, microscopy, quantum information processing, and many more. Due to their spatial dimensions, traditional methods of generating OVs are not viable to fit with the cutting-edge on-chip optical systems. In contrast, subwavelength structured devices enormously aggravate the capability to realize chip-integrated devices via abrupt phase discontinuity. Besides the many exotic features of optical metasurfaces, their fixed functionality limits the realization of breakthroughs in many real-life applications. Here, we present an exquisite design that enables multifunctional metastructures to develop multichannel focused optical vortices of like or distinct topological charges on the same focal plane regardless of the input polarization state. Our design is based on a symmetric array of nanocylinders where the index waveguide theory concept is utilized effectively to accumulate the desired phase in the direction of propagation. Moreover, zinc sulfide, as a prime material used in device prototyping, enables a highly transmissive structure. Our work regarding the multidimensional generation of optical vortices has far-reaching effects on multifunctional optical devices.
“…Metasurface-based devices such as metalenses [12]- [15], structured light generators [16]- [21], multifunctional metadevices [22]- [28], meta-absorbers [29]- [33], holograms [34]- [39], reconfigurable intelligent surfaces [40]- [42] are previously reported. Recently, metasurface design methodology has been revolutionized by machine learning techniques [43]- [46]. By utilizing arrays of meta-atoms having subwavelength physical parameters, metasurfaces can control light wavefront, as opposed to typical optical components that perform wavefront engineering by phase accumulation [47]- [49].…”
In recent years, metasurfaces, a flat version of three-dimensional metamaterials, have become a versatile nanophotonics platform for unprecedented light manipulation. Amongst the numerous realizations of exotic optical phenomena through metasurfaces such as meta-lensing, meta-holography, and structured beams, Bessel beam generation caught significant attention due to its non-diffracting and self-healing nature. Bessel beams can be produced using various conventional methods, including spatial light modulators, composite holograms, and diffractive optical elements. These methods, however, are unfit to integrate with cutting-edge on-chip devices due to low throughput, polarization dependence, excessive bulkiness, and limited numerical aperture. In the method of generating Bessel beams through flat optics, the selection of suitable material is a crucial factor. Thus, due to constraints of inherent material properties, broadband operation with high efficiency remains challenging. Here, we demonstrated highly efficient broadband Bessel beams generating meta-devices in the visible domain using single-layer all-dielectric transmissive metasurfaces. The constituent nanoresonators of zinc sulfide (ZnS) are optimized for high-resolution phase modulation. ZnS offers the best-suited optical properties that ensure high transmission efficiency throughout the visible spectrum. To verify the proposed design technique, we realized single-element-driven meta-devices to generate Bessel beams with higher numerical apertures and different topological charges, illustrating their exceptional non-diffraction properties. For real-life applications like optical communication, the proposed design strategy could speed up consumer-level device implementation.
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