WO2024023844A1

WO2024023844A1 - A system and method for ultrasonic far-field super resolution imaging using hyperlens and waveguide

Info

Publication number: WO2024023844A1
Application number: PCT/IN2023/050719
Authority: WO
Inventors: Prabhu Rajagopal; Mohamed Subair Syed Akbar Ali
Original assignee: INDIAN INSTITUTE OF TECHNOLOGY MADRAS (IIT Madras)
Priority date: 2022-07-29
Filing date: 2023-07-27
Publication date: 2024-02-01

Abstract

The present disclosure relates to a system (100) for providing ultrasonic far-field super resolution imaging. The system (100) includes a transmitter (102), a hyperlens (110), a waveguide (112), and a receiver (114). The transmitter (102) is configured to transmit a wavefield towards an object (106) under observation. The transmitted wavefield is scattered through the object (106). The hyperlens (110) is configured to receive the scattered wavefield from the object (106). The hyperlens (110) is configured to transform the scattered wavefield into a plurality of propagating waves. The waveguide (112) is configured to receive and transmit the plurality of the propagating waves in a predefined direction. The receiver (114) is operatively coupled to the waveguide (112). The receiver (114) is configured to receive the plurality of the propagating waves transmitted from the waveguide (112).

Description

“A SYSTEM AND METHOD FOR ULTRASONIC FAR-FIELD SUPER RESOLUTION IMAGING USING HYPERLENS AND WAVEGUIDE”

TECHNICAL FIELD

[001] The present disclosure relates to the field of an ultrasonic far-field super resolution imaging, and in particular relates to the field of subwavelength imaging and super resolution imaging, utilizing a hyperlens and a waveguide receiver system to compress and convert evanescent waves, transfer sub-wavelength information, and capture waves past the hyperlens discretely for enhanced imaging capabilities.

BACKGROUND OF INVENTION

[002] The following description includes information that may be useful in understanding the present disclosure. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

[003] The resolution of classical imaging systems is fundamentally limited by diffraction, restricting their ability to resolve fine features to half the operating wavelength. This limitation is particularly significant for evanescent scattered waves, which carry crucial information about subwavelength details but decay rapidly within the near field. Achieving imaging beyond the diffraction limit requires successfully extracting information from these evanescent waves, which may be challenging and complex.

[004] One approach to overcome this limitation is imaging within the near field. However, this approach is affected by poor signal-to-noise ratios and complicated post-processing, making it less practical for certain applications. Another alternative approach is to transfer the information carried by the evanescent waves to the far-field, which has garnered interest in recent years with concepts such as negative indexed media, super-lenses, and metamaterials in the electromagnetic and acoustic domains have been explored to achieve this goal. [005] The authors of the invention have previously demonstrated the use of periodic and nonperiodic holey metamaterials for super-resolution imaging in the ultrasonic domain. However, many metamaterial concepts require the acquisition of wavefields transmitted through their subwavelength geometric features, which demands sophisticated equipment and makes practical implementation challenging, especially for miniaturized lenses aiming for deeper subwavelength resolution.

[006] To address these challenges, the invention introduces a mechanism for achieving super resolution along with magnification capabilities using "hyperlenses." Hyperlenses are devices that may convert evanescent waves into propagating waves, enabling the transfer of subwavelength information to the far-field. While the term "hyperlens" is initially associated with an ideal indefinite medium with hyperbolic dispersion, it is also applicable to lenses with elliptical dispersion, as long as dispersion remains flat for a wide range of wavevectors.

[007] Among various proposed concepts, the invention focuses on the design and experimental demonstration of cylindrical hyperlens in the acoustic domain. The cylindrical hyperlens employs radially spreading metal fins, arranged alternately in the angular direction. These fins have subwavelength dimensions with respect to the operating frequency, allowing for effective medium approaches to describe the lens's dispersion. For example, the dispersion of cylindrical hyperlenses can be expressed as, k² k_g a>² Pr Po where, k_r, k_g and p_r, p_g are the wavevectors and effective densities along the radial and angular directions respectively, B is the effective bulk modulus and a> is the operating frequency. The large density difference between the metal and air causes the effective density in the angular direction to be much higher than in the radial direction. This results in a flat dispersion that encompasses high angular wavevectors, contributing to the hyperlens's effectiveness in converting evanescent components into propagating waves as they pass through the structure. The magnification factor of the hyperlens depends on the ratio of its outer and inner radii.

[008] While hyperlenses have been demonstrated in the electromagnetic and acoustic domains, their extension to the ultrasonic regime has been limited. The authors of the invention have conducted studies on cylindrical hyperlenses in the ultrasonic domain, yet their application for imaging defects in ultrasonic nondestructive evaluation (NDE) and non-invasive diagnostics remains unexplored. This is primarily due to two challenges: understanding the performance of hyperlenses in the ultrasonic regime and developing an effective approach for receiving waves transmitted by the hyperlens, especially in an underwater immersion setting where higher frequencies are employed. Overcoming these challenges is critical to enable practical experiments and further the use of hyperlenses in ultrasonic imaging applications.

[009] Moreover, an effective approach for the reception of waves transmitted by the hyperlens is essential. Given the higher frequencies employed in ultrasonics (as compared to acoustics), the transmitted wavefield would need to be picked up carefully using sophisticated instrumentation, and doing this under water immersion is a significant further challenge.

SUMMARY OF INVENTION

[0010] The present disclosure overcomes one or more shortcomings of the prior art and provides additional advantages discussed throughout the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

[0011] In one non-limiting embodiment of the present disclosure, a system for providing ultrasonic far-field super resolution imaging is disclosed. The system comprises a transmitter, a hyperlens, a waveguide, and a receiver. The transmitter is configured to transmit a wavefield towards an object under observation. The transmitted wavefield is scattered through the object. The hyperlens is configured to receive the scattered wavefield from the object. The hyperlens is configured to transform the scattered wavefield into a plurality of propagating waves. The waveguide is configured to receive and transmit the plurality of the propagating waves in a predefined direction. The receiver is operatively coupled to the waveguide. The receiver is configured to receive the plurality of the propagating waves transmitted from the waveguide.

[0012] In another embodiment of the present disclosure, the receiver is further coupled to a processing unit. The processing unit is configured to process the plurality of the propagating waves received from the receiver, to generate a subwavelength image of the object.

[0013] In yet another embodiment of the present disclosure, the hyperlens is selected at least from a group of cylindrical hyperlens, flat face hyperlens, or spherical hyperlens. The hyperlens comprises a plurality of fins. Each of the plurality of the fins is configured to transform the scattered wavefield into the plurality of the propagating waves. The hyperlens comprises an input side and an output side. Further, the hyperlens is configured to receiver the scattered wavefield from the object on the input side via the plurality of the fins. Furthermore, the hyperlens is configured to transform the scattered wavefield into the plurality of the propagating waves. The plurality of the propagating waves carries subwavelength information of the object. Moreover, the hyperlens is configured to exit the plurality of the propagating waves from the output side via the plurality of the fins.

[0014] In yet another embodiment of the present disclosure, the waveguide has a shape selected from a group consisting of circular strip, cylindrical strip, tubular strip, elliptical strip, square strip, or rectangular strip. The waveguide is provided in a form selected from at least one of a wire, a rod, a sheet, a plate, or a fiber.

[0015] In yet another embodiment of the present disclosure, the receiver is configured to receive the plurality of the propagating waves exiting from each of the plurality of the fins of the hyperlens, separately. [0016] In another non-limiting embodiment of the present disclosure, a method for providing ultrasonic far-field super resolution imaging is disclosed. The method comprises transmitting, by the transmitter, the wavefield towards the object under observation. The transmitted wavefield is scattered through the object. Further, the method comprises receiving, by the hyperlens, the scattered wavefield from the object. Furthermore, the method comprises transforming, by the hyperlens, the scattered wavefield into the plurality of the propagating waves. Moreover, the method comprises receiving and transmitting, by the waveguide, the plurality of the propagating waves in the predefined direction. Also, the method comprises receiving, by the receiver, the plurality of the propagating waves transmitted from the waveguide. The receiver is operatively coupled to the waveguide.

[0017] In yet another embodiment of the present disclosure, the method further comprises processing the plurality of the propagating waves received from the receiver to generate the subwavelength image of the object.

[0018] In yet another embodiment of the present disclosure, the method further comprises transforming the scattered wavefield into the plurality of the propagating waves via the plurality of the fins of the hyperlens.

[0019] In yet another embodiment of the present disclosure, the method further comprises receiving the scattered wavefield from the object on the input side of the hyperlens via the plurality of the fins. Further, the method comprises transforming the scattered wavefield into the plurality of the propagating waves. The plurality of the propagating waves carries subwavelength information of the object. Furthermore, the method comprises exiting the plurality of the propagating waves from the output side of the hyperlens via the plurality of the fins.

[0020] In yet another embodiment of the present disclosure, the method comprises receiving the plurality of the propagating waves exiting from each of the plurality of the fins of the hyperlens, separately. [0021] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF DRAWINGS

[0022] Further aspects and advantages of the present disclosure will be readily understood from the following detailed description with reference to the accompanying drawings, where like reference numerals refer to identical or functionally similar elements throughout the separate views. The figures together with the detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the aspects and explain various principles and advantages, in accordance with the present disclosure wherein:

[0023] Figure 1 illustrates a system for providing ultrasonic far-field super resolution imaging using a hyper lens, in accordance with an embodiment of the present disclosure;

[0024] Figure 2a illustrates an exemplary system for providing ultrasonic far-field super resolution imaging using a cylindrical hyperlens, in accordance with an embodiment of the present disclosure.

[0025] Figure 2b illustrates the cylindrical hyperlens of Figure 2a, in accordance with an embodiment of the present disclosure.

[0026] Figure 3 illustrates an exemplary system for providing ultrasonic far-field super resolution imaging using the cylindrical hyperlens of figure 2a immersed under water, in accordance with an embodiment of the present disclosure.

[0027] Figure 4 illustrates geometric parameters for constructing the cylindrical hyperlens of Figure 2b, in accordance with an embodiment of the present disclosure. [0028] Figure 5a illustrates an exemplary 2D Finite Element (FE) model of the cylindrical hyperlens of figure 2b for imaging defects in an ultrasonic domain, in accordance with an embodiment of the present disclosure.

[0029] Figure 5b illustrates normalized pressure amplitudes obtained at an outer side of the cylindrical hyper lens of figure 2b, in accordance with an embodiment of the present disclosure.

[0030] Figure 6a illustrates an exemplary Finite Element (FE) model considered for studying of wave transmission passing a single water-filled fin, in accordance with an embodiment of the present disclosure.

[0031] Figure 6b illustrates a frequency spectrum of a wave captured at an exit of the fin shown in figure 6a, in accordance with an embodiment of the present disclosure.

[0032] Figure 6c illustrates spectral ratio obtained for various cases of entry width (wi) of the fin shown in figure 6a, in accordance with an embodiment of the present disclosure.

[0033] Figure 7a and 7b illustrate dispersion curves of the cylindrical hyperlens of figure 2b, composed of water and stainless steel fins with various filling fractions, in accordance with an embodiment of the present disclosure.

[0034] Figure 8a illustrates a schematic illustration of constant period flat face hyperlens, in accordance with an embodiment of the present disclosure.

[0035] Figure 8b illustrate numerical results from 10X magnifying flat face hyperlens showing magnified image for defects separated by a subwavelength distance of 2 mm (A/3), in accordance with an embodiment of the present disclosure. [0036] Figure 9 illustrate exemplary experimental results showing comparison of frequency spectrums received with and without waveguide attachment to a transducer, in accordance with an embodiment of the present disclosure.

[0037] Figure 10 illustrate experimental results from 5X hyperlens showing the magnified image for defects separated by a subwavelength distance of 5 mm (X/3), with and without defects, in accordance with an embodiment of the present disclosure.

[0038] Figure 11 illustrates comparison of experimental results obtained using exemplary waveguide receiver and exemplary commercial transducer, in accordance with an embodiment of the present disclosure.

[0039] Figure 12 depicts a flowchart describing a method for providing ultrasonic far-field super resolution imaging, in accordance with an embodiment of the present disclosure.

[0040] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the scope of the present disclosure.

DETAILED DESCRIPTION

[0041] The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure.

[0042] In the present disclosure, the term “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment or implementation of the present subject matter described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0043] The terms “comprise”, “comprising”, “include”, “including”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a device that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such setup or device. In other words, one or more elements in a system or apparatus proceeded by “comprises... a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.

[0044] The terms like “fins”, “plurality of fins”, “plurality of metallic fins” may be used interchangeably or in combination throughout the description.

[0045] The terms like “Finite Element” and “FE” may be used interchangeably or in combination throughout the description.

[0046] The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure.

[0047] The novel features which are believed to be characteristic of the disclosure, both as to its system and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying Figures. It is to be expressly understood, however, that each of the Figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure. [0048] The present disclosure aims to overcome the drawbacks related to ultrasonic imaging techniques that have limited ability to achieve higher resolution due to certain constraints. The use of hyperlenses, which may magnify subwavelength features and achieve superresolution in the far-field, has not been widely explored in non-destructive evaluation and non-invasive diagnostics. This limitation may be attributed to the lack of comprehensive understanding of hyperlens performance in the ultrasonic domain and challenges associated with receiving the elastic wavefield past fine features.

[0049] To overcome these limitations, the present disclosure introduces a novel approach to address these challenges and unlock the potential of hyperlenses for ultrasonic imaging. By conducting thorough numerical simulations, the present disclosure gains valuable insights into the construction and performance of hyperlenses in an ultrasonic regime. Further, the present disclosure presents a groundbreaking waveguide-based reception technique, which utilizes conventional ultrasonic transducers to separately capture transmitted waves from the hyperlens. This novel approach eliminates the need for sophisticated and costly equipment, making hyperlenses more feasible for practical implementation. The disclosure further extends the concept from cylindrical hyper lens to flat face hyperlens, enhancing versatility and broadening the potential applications of the technology. To demonstrate the practicality of the invention, a custom-fabricated metallic hyperlens is utilized to showcase, a super-resolved image with magnification in the ultrasonic domain. By overcoming the limitations of existing ultrasonic imaging techniques, the present disclosure offers significant implications for achieving higher resolution imaging in industrial and biomedical applications, revolutionizing the field of ultrasonic diagnostics and evaluation.

[0050] Figure 1 illustrates a system 100 for providing ultrasonic far-field super resolution imaging using a hyperlens, in accordance with an embodiment of the present disclosure. As will be apparent in the description that follows, the system 100 may be generally configured to utilize a waveguide-based reception technique utilizing an ultrasonic transducer as a receiver to separately capture waves emanating from the hyperlens. By way of example, the hyperlens may be a custom-fabricated metallic hyperlens may demonstrate a super- resolved image with at least 5X magnification in an ultrasonic domain. The system 100 may include, but not limited to, a transmitter 102, an object 106 which is under observation, a hyperlens 110, a waveguide 112, a receiver 114, and a processing unit 116.

[0051] In one non-limiting embodiment of the present disclosure, transmitter 102 is configured to emit a wavefield 104 directed towards the object 106 under observation. Further, the wavefield 104 may include ultrasonic waves. It should be noted that those skilled in the art will appreciate the possibility of utilizing any available ultrasonic transducer as the transmitter 102 for transmitting ultrasonic waves in accordance with the present disclosure. By way of example, the object 106 may include at least two circular defects 108 separated by a subwavelength distance. In one non-limiting embodiment of the present disclosure, the wavefield 104 is scattered though the object 106 and transmitted towards the hyperlens 110.

[0052] Referring to figure 1, the hyperlens 110 may receive the scattered wavefield from the object 106. In one non-limiting embodiment of the present disclosure, the hyperlens 110 may be selected at least from a group of various hyperlens types such as, cylindrical hyperlens, flat face hyperlens, or spherical hyperlens. The selection of the hyperlens type is not limited to these options but rather encompasses a range of possibilities to suit specific application requirements and desired imaging outcome. In one non-limiting embodiment of the present disclosure, the hyperlens 110 may include a plurality of fins. Each of the plurality of the fins is configured to transform the scattered wavefield into the plurality of the propagating waves. In an exemplary embodiment of the present disclosure, the plurality of the fins is configured to facilitate the transformation of the scattered wavefield encountered during its operation. Further, the plurality of the fins effectively converts the scattered wavefield into the plurality of the propagating waves through coordinated efforts to enhance the imaging and resolution capabilities of the hyperlens 110.

[0053] In one non-limiting embodiment of the present disclosure, the hyperlens 110 may include an input side and an output side. In one non-limiting embodiment of the present disclosure, the input side may include precise arrangement of the plurality of the fins. The plurality of the fins is positioned to efficiently receive the scattered wavefield emitting from the object 106 under observation. Through this arrangement, the hyperlens 110 may capture the scattered wavefield for further transformation and imaging processes. It must be understood to a person skilled in art that the present disclosure may also be implemented using wide range of objects, other than the object 106, shown in Figure 1. In second nonlimiting embodiment of the present disclosure, the hyperlens 110 may transform the received scattered wavefield into the plurality of the propagating waves. By way of example, the transformative operation is carried out to ensure that the resulting propagating waves contain subwavelength information of the object 106. As a result, the hyperlens 110 may significantly improve the ability to detect and understand micro details and structures of the object 106.

[0054] Further, the hyperlens 110 may include the output side, where the plurality of the fins ensures smooth and efficient transmission of the plurality of the propagating waves from the hyperlens 110. In an exemplary embodiment of the present disclosure, the plurality of the fins guides the plurality of the propagating waves for further analysis or visualization. A person skilled in the art may appreciate that smooth and seamless exit of the plurality of the propagating waves ensures an uninterrupted flow of subwavelength information of the object 106, contributing to the hyperlens' overall improved performance and accuracy.

[0055] Referring to figure 1, the system 100 may include the waveguide 112. In one non-limiting embodiment of the present disclosure, the waveguide 112 has a shape selected from a group consisting of circular strip, cylindrical strip, tubular strip, elliptical strip, square strip, or rectangular strip. In another non-limiting embodiment of the present disclosure, the waveguide 112 is provided in a form selected from at least one of a wire, a rod, a sheet, a plate, or a fiber. It must be understood to a person skilled in art that the present disclosure may also be implemented using wide range of waveguides, other than the waveguide 112, shown in Figure 1. In one non-limiting embodiment of the present disclosure, the waveguide 112 may receive and transmit the plurality of the propagating waves in a predefined direction. A person skilled in the art may appreciate that the waveguide may ensure precise wave manipulation, facilitating optimal results in various applications, thereby improving the overall system's performance and enabling targeted wave propagation.

[0056] Referring to figure 1, the system 100 may include the receiver 114. In an embodiment of the present disclosure, the receiver 114 is operatively coupled to the waveguide 112. In another embodiment of the present disclosure, also not restricted to specific instances, the receiver 114 may function independently of direct coupling to the waveguide 112. It should be noted that those skilled in the art will appreciate the possibility of utilizing an ultrasonic transducer as the receiver 114 for receiving the plurality of the propagating waves, in accordance with the present disclosure. In one non-limiting embodiment of the present disclosure, the receiver 114 may receive the plurality of the propagating waves exiting from each of the plurality of the fins of the hyperlens 110, separately or discretely. By way of this arrangement, the receiver 114 may be capable to accurately analyze and extract information from the plurality of the propagated waves. This capability significantly enhances the system's imaging and data retrieval capabilities, leading to optimized system performance in various applications.

[0057] Referring to figure 1, the receiver 114 may be further coupled to the processing unit 116. In one non-limiting embodiment of the present disclosure, the processing unit 116 may process the plurality of the propagating waves received from the receiver, to generate the subwavelength image of the object 106. Thus, the ability of the receiver 114 in conjunction with the processing unit 116 to capture subwavelength details and structures, surpasses the resolution limits set by wavelength of imaging waves. The processing unit's 116 functionality significantly enhances imaging resolution, resulting in generation of spatial magnified subwavelength images. These images offer valuable insights and information regarding the object 106 under observation, facilitating an understanding of its intricate features and characteristics.

[0058] By way of example, the processing unit 116 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions for performing various operations of the system. Among other capabilities, the processing unit 116 is configured to fetch and execute computer-readable instructions stored in a memory (not shown). It must be understood to a person skilled in art that the processing unit 116 may process the plurality of the propagating waves received from the receiver 114 according to various embodiments of the present disclosure.

[0059] Figure 2a illustrates an exemplary system 200 for providing ultrasonic far-field super resolution imaging using a cylindrical hyperlens, in accordance with an embodiment of the present disclosure. Figure 2b illustrates the cylindrical hyperlens of Figure 2a, in accordance with an embodiment of the present disclosure. Figure 2a and figure 2b is explained in conjunction with figure 1. Referring to figure 2a, the exemplary system 200 may include, but not limited to, a transmitter 202, a wavefield 204, an object 206 with defects 208, a cylindrical hyperlens 210, a waveguide 212, a receiver 214, and a processing unit 216. The exemplary system 200 may employ the cylindrical hyperlens 210 to achieve the subwavelength imaging capability. Further, the components of the exemplary system 200 closely resemble to those of the system 100, depicted in figure 1. Due to their substantial similarities, a detailed description of these common components is not reiterated here for the sake of brevity.

[0060] In one non limiting of the present disclosure, the cylindrical hyperlens 210 may contain radially enlarging fins of subwavelength dimensions to conserve angular momentum, which effectively preserves high frequency evanescent waves. Further, the radially enlarging fins of the cylindrical hyperlens 210 efficiently compresses and converts the high-frequency evanescent waves into the plurality of the propagating waves as described in figure 1. To produce the plurality of the propagating waves, the cylindrical hyperlens 210 without relying on resonance, performs effectively across a broad range of frequencies. This allows the cylindrical hyperlens 210 to work optimally, preserving and utilizing evanescent waves without being limited to specific frequency ranges. [0061] Figure 3 illustrates an exemplary system 300 for providing ultrasonic far-field super resolution imaging using the cylindrical hyperlens of figure 2a immersed under water, in accordance with an embodiment of the present disclosure. Figure 3 is explained in conjunction with figures 1, and 2a-2b. The exemplary system 300 may include, but not limited to, a transmitter 302, a wavefield 304, supporting means 306, an object 308 with defects 310, water 312, a cylindrical hyperlens 314, a waveguide 316, a receiver 318, a motion controller 320, a computer 322, a DAQ card 324, and a pulse generator 326. Further, the components of the exemplary system 300 closely resemble those of the system 100 depicted in figure 1 and the exemplary system 200 depicted in figure 2a. Due to their substantial similarities, a detailed description of these common components is not reiterated here for the sake of brevity.

[0062] By way of example, the exemplary system 300 employs water immersion ultrasound imaging with a 'through-transmission' configuration. To facilitate this process, the cylindrical hyperlens 314 with a radially symmetric structure is employed. The cylindrical hyperlens 314 may include a plurality of metallic fins arranged periodically in the radial direction, and water 312 fills the channels formed between the plurality of the metallic fins for imaging defects under water immersion.

Finite Element (FE) Simulations

[0063] In an exemplary embodiment of the present disclosure, subwavelength imaging with magnification is demonstrated by addressing the problem of resolving two circular defects 310 separated by a subwavelength distance, as commonly encountered in practical NonDestructive Evaluation (NDE) scenarios. The defects 310 considered in this embodiment are spaced subwavelength apart, approximately X/2.5, relative to the operating frequency of 250 kHz. For this application, a water immersion ultrasound imaging setup employing a 'through-transmission' configuration is utilized.

[0064] To achieve superior imaging capabilities, the cylindrical hyperlens 314 with a radially symmetric structure may be adopted. This cylindrical hyperlens 314 may include metallic fins arranged periodically in a radial direction, with the channels filled with water during the inspection process. By way of example, the unique design of the cylindrical hyperlens 314 allows to overcome the limitations of conventional imaging techniques, enabling the visualization of subwavelength defects with remarkable magnification.

[0065] To optimize the cylindrical hyperlens for practical realization, extensive Finite Element (FE) simulations may be carried out using a validated modeling approach. These 2D FE simulations provide a comprehensive study of the hyperlens's performance, analyzing the impact of various geometric and other parameters on defect imaging in the high-frequency ultrasonic domain under water immersion conditions.

[0066] To accurately simulate wave propagation within the cylindrical hyperlens, a state-of-the- art commercial FE software package may be employed. Further, a numerical model assumes 2D plane strain conditions, utilizing linear quadrilateral acoustic elements for accurate representation. To mimic the hyperlens's alternating structure, the model assumes the cylindrical hyperlens to be composed of alternating layers of water and metal fins. Further, water properties may be assigned to the model, and rigid boundary conditions are set on the respective fin boundaries, ensuring a realistic representation of the metallic fins.

[0067] For the simulations, the circular defects 310 may be modeled as circular holes within the setup. By way of example, a Hannnig pulse excitation is applied to a specific node located at a sufficient distance from the defects and the cylindrical hyperlens to ensure plane wave incidence. To minimize unwanted reflections and ensure reliable results, non-reflective boundary conditions may be assigned to the outer boundaries of the model.

[0068] The mesh size and incremental time step are carefully chosen to satisfy the established convergence and stability criteria. This meticulous selection of parameters ensures that the simulations produce accurate and meaningful insights into the hyperlens's performance and its suitability for subwavelength imaging under water immersion conditions.

[0069] Moreover, the exemplary embodiment demonstrates an application of the cylindrical hyperlens for subwavelength imaging with magnification in the high-frequency ultrasonic domain under water immersion. The hyperlens's innovative design, coupled with thorough FE simulations and optimization, makes it practical for NDE (Non-Destructive Evaluation) applications, offering significant advancements in defect detection and visualization capabilities.

Experimental demonstration

[0070] In an exemplary embodiment of the present disclosure, the plurality of metallic fins may be fabricated to demonstrate the super-resolution imaging capabilities in the ultrasonic domain. The cylindrical hyperlens 314 may be designed with radially alternating fins composed of Stainless Steel (SS) and water. In one exemplary embodiment, to achieve a 5X magnification at 100 kHz, the plurality of metallic fins may be designed with an entry width of 0.5 mm and an exit width of 2.5 mm, ensuring that the geometrical parameters may be of subwavelength dimensions.

[0071] By way of example, the defects 310 may correspond to scatterers in a form of metallic wires placed near an inner region of the cylindrical hyperlens, separated by a center-to- center distance of 35 mm (X/3) to serve as imaging targets.

[0072] In one exemplary embodiment of the present disclosure, the plurality of metallic fins may be fabricated on a 12.5 mm thick SS plate using Electric Discharge Machining (EDM) to a depth of 10 mm, resulting in a substrate thickness of 2.5 mm. Further, another 2.5 mm thick SS plate may be added to enclose the cylindrical hyperlens and confine wave propagation within the plurality of metallic fins. The metallic hyperlens, thus assembled, may be capable of providing enhanced imaging resolution in water immersion setups.

[0073] In one exemplary embodiment of the present disclosure, a commercial transducer, in the experimental setup, with a center frequency of 100 kHz (e.g., 05L007, Valpey Fisher) may be utilized as the transmitter 302. By way of example, a 3-cycle Hanning-windowed toneburst centered at 100 kHz may be generated using a RITEC 4000 Pulser-Receiver (Ritec Inc., USA) and may be applied to the transmitter 302 to excite wave propagation in water. The defects or scatterers 310 may be precisely positioned near the inner region of the cylindrical hyperlens to allow coupling of their scattered wavefield into the cylindrical hyperlens. In one exemplary embodiment of the present disclosure, a custom-designed transducer holder, equipped with both the receiving transducer and the waveguide receiver, may be attached to a raster scanning system to capture the scattered wavefield on an output region of the cylindrical hyper lens.

[0074] A person skilled in the art may appreciate that the exemplary embodiment showcased the practical implementation of a metallic hyperlens or cylindrical hyperlens for superresolution ultrasonic imaging, offering significant advancements in ultrasonic diagnostics and non-invasive evaluation techniques.

[0075] Referring to figure 3, the receiver 318 is coupled to the motion controller 320 may control a motion of the system 300 during imaging procedure. Further, the computer 322 serves as the central processing unit, managing and analyzing data acquired during imaging process. Furthermore, the DAQ card 324, which stands for Data Acquisition card, may gather and process data from various sensors and instruments. The DAQ card 324 may be coupled to the pulse generator 326. Moreover, the pulse generator 326 may be operatively coupled to the transmitter 302. In an exemplary embodiment of the present disclosure, the pulse generator 326 may be configured to provide an excitation signal to the transmitter 302. This excitation signal may initiate and propagate waves within the water 312. A person skilled in the art may appreciate that the excitation signal may facilitate accurate and targeted imaging data collection.

Essential geometric parameters for the design of a cylindrical hyperlens

[0076] Figure 4 illustrates geometric parameters for designing the cylindrical hyperlens of Figure 2b, in accordance with an embodiment of the present disclosure. In an exemplary embodiment of the present disclosure, the design of the cylindrical hyperlens involves one or more parameters denoted as M, Ri, R_o, Wi, w₀, and L. Here, M represents the magnification factor, while Ri and R_o signify an inner and outer radius of a semicircle forming the cylindrical hyperlens, respectively. Additionally, Wi and w₀ correspond to an entry and exit width of the plurality of metallic fins, while L represents a length of the plurality of the metallic fins.

[0077] For the cylindrical hyperlens, a magnification factor M may be calculated as a ratio of R_o to Ri. Thus, the magnification facture M may be expressed as

M = R₀/Ri.

[0078] Utilizing this relationship and the cylindrical geometry of the hyper lens, the specific values for Ro and wo may be determined as M times Ri and wi, respectively. Similarly, the length of the fin L may be defined as:

L=(M-1) x Ri

[0079] As a result, in designing the cylindrical hyper lens with M times magnification, the critical geometric parameters may be simplified to Ri and Wi. These parameters may configure the cylindrical hyperlens to achieve the desired magnification factor, ensuring accurate and efficient imaging capabilities.

Optimal inner radius of hyperlens

[0080] Figure 5a illustrates an exemplary 2D FE model of the cylindrical hyperlens of figure 2b for imaging defects in an ultrasonic domain, in accordance with an embodiment of the present disclosure. Figure 5b illustrates normalized pressure amplitudes obtained at an outer side of the cylindrical hyperlens of figure 2b, in accordance with an embodiment of the present disclosure.

[0081] By way of example, to study the impact of the inner radius (Ri) of the cylindrical hyperlens as illustrated in figure 4, on subwavelength spaced defect imaging, considering three different scenarios: Ri < A, R, = X, and Ri > X, where Ri represents the radius of the inner semicircle forming the cylindrical hyperlens, and X is a wavelength at an operating frequency. The outer radius R_o of the cylindrical hyperlens as illustrated in figure 4, set at 10 times Ri to achieve a 10X magnification at an outer region of the cylindrical hyper lens.

[0082] In figure 5a, the Finite Element (FE) model's schematic demonstrates use of a Hanning windowed pulse, excited at 250 kHz, to image defects represented by circular holes positioned in front of the cylindrical hyperlens. By way of example, the radially extending fins of the cylindrical hyperlens may be modeled with entry and exit widths of 100 pm and 1 mm, respectively, which are both considered subwavelength for the operating frequency (X/60 and X/6, respectively). The defects analyzed may be of 1 mm diameter and spaced at a center-to-center distance of 2.5 mm, which is subwavelength (X/2.5) concerning the operating frequency.

[0083] In figure 5b, envelopes of a maximum signal amplitude outside the cylindrical hyperlens are shown. The results indicate that an optimal performance of the cylindrical hyperlens is achieved when the inner radius of the cylindrical hyperlens (Ri) is > X. This phenomenon may be attributed to elliptical dispersion characteristics and cylindrical symmetry of the cylindrical hyperlens, which conserves angular momentum. Due to this conservation, radial wavevector (k_r) tends to zero at any given point as the angular wavevector (k_0) increases towards the origin and decays elsewhere. The dispersion relation may establish a lower limit of Ri, which may be found by setting k_r to zero.

[0084] For any hyperlens with an elliptical dispersion, a lower limit of Ri has to be smaller than X due to large major axis. This value of Ri mainly depends on material properties of the plurality of metallic fins. In general, the inner radius may be considered comparable to X, as it may satisfy the lower limit for all the dispersion relations. This analysis allow to understand optimal conditions for designing and operating the cylindrical hyperlens to achieve effective and accurate imaging of defects in the ultrasonic domain.

Optimal fin entry width

[0085] Figure 6a illustrates an exemplary Finite Element (FE) model considered for studying of wave transmission passing a single water-filled fin. Figure 6b illustrates a normalized frequency spectrum of a wave captured at an exit of the fin as shown in figure 6a. The normalized frequency spectrum of the wave received without hyperlens may be shown as a dotted curve to indicate the signal's bandwidth. Figure 6c illustrates spectral ratio obtained for various cases of entry width (wi) of the fin as shown in figure 6a.

[0086] By way of example, the FE model may be utilized to optimize the entry width of fins by conducting spectral analysis on waves passing the fins and captured at the exit of the hyperlens. To conduct the spectral analysis, a single fin model and various cases of the entry width of the fin (wi) may be considered relative to X (wavelength). Further, the exit width (w₀) may be set at 10 times Wi, assuming a 10X magnifying hyperlens. Furthermore, a length of the fin (E) may be fixed at 9k (i.e., Ro - Ri), with the hyperlens inner radius (Ri) assumed to be X. Moreover, the spectral ratios for the different cases of Wi may be calculated by comparing frequency spectrum of the wave captured with the fin and without the fin, and the results are presented in figure 6c. The results demonstrate that the magnitude in the transmitted spectrum is directly proportional to Wi, and there is no spectral loss associated with Wi while the fin length E remains constant.

[0087] Additionally, the spectral ratio may increase with an increase in frequency for all cases of Wi. Further, the waves propagating inside each fin are of the fundamental plane wave mode, and no other higher-order modes exist since the size of each fin is much smaller than the wavelength. The observed decrease in the magnitude of the spectrum with decreasing entry width is attributed to the fact that energy of the wave propagating inside each fin is directly proportional to the size of each fin.

[0088] In an exemplary embodiment of the present disclosure, each fin width may alter maximum resonance frequency, but this effect is not significant in the context of the cylindrical hyperlens, as its working principle does not involve any resonance. As a result, the fin entry width does not significantly affect performance of the hyperlens. However, for the effective medium description to be valid, the fin entry and exit width dimensions must be smaller than the wavelength of the operating frequency. Filling Fraction

[0089] Figure 7a and 7b illustrate dispersion curves of the cylindrical hyperlens of figure 2b, composed of water and stainless-steel fins with various filling fractions, in accordance with an embodiment of the present disclosure. By way of example, in addition to the geometrical parameters of the fins, the filling fraction of the fins may be important in optimizing the hyperlens' performance. Unlike the fin entry width and inner radius, the filling fraction is a material-related parameter, and its impact on the hyperlens performance may be studied using the dispersion curves discussed herein. By analyzing the dispersion characteristics of the hyperlens using effective medium approximations, the optimal filling fraction may be determined to enable higher angular wavevector k_0, which typically carries the evanescent wave components.

[0090] To calculate the effective material properties, such as effective bulk modulus, radial, and angular densities, the following equations (l)-(3) are used, where f represents the filling fraction, and the variables with subscripts 1 and 2 denote the material properties of water and metal, respectively,

Pe = f Pi + (1 -/) Pz . (2)

- = — + . (3)

B Bi B₂ ^{v 7}

[0091] Based on above calculations, the elliptical dispersion curve of the hyperlens using water and Stainless Steel (SS) as materials for various filling fractions of the fin is shown in figure 7a. The dispersion curve with the largest k_0 may be obtained for a filling fraction of 0.6. However, in this study, a filling fraction of 0.5 may be considered due to limitations in the fabrication process when machining the minimum fin entry width (wi). [0092] To emphasize that the filling fraction is a material-dependent parameter, dispersion curves may also be computed for the hyperlens composed of air and SS fins, shown in figure 7b for comparison. The dispersion curves for the air-filled hyperlens exhibit a flatter profile and cover a larger angular wavevector k_0 compared to the water-filled hyperlens. This difference is attributed to the higher density difference achieved between air and SS as compared to water and SS material. Additionally, it is observed that, for this case, the largest k_0 obtained for a filling fraction is of 0.5 value.

Planar Hyperlens

[0093] Figure 8a illustrates a schematic illustration of constant period flat face hyperlens, in accordance with an embodiment of the present disclosure. Figure 8b illustrate numerical results from 10X magnifying flat face hyperlens showing magnified image for defects separated by a subwavelength distance of 2 mm (A/3), in accordance with an embodiment of the present disclosure. The dotted lines show the expected locations of the defects in the magnified image.

[0094] While demonstrating super resolving capability, the practical implementation of the cylindrical hyperlens is limited by its curved form, which requires objects to be placed inside the lens's inner semi-circle. To address this limitation, the flat face hyperlens may be used.

[0095] By way of example, design of the flat hyperlens may be derived from the cylindrical hyperlens design, assuming both the inner and outer radii (Ri and R_o) to be much greater than the wavelength (X). Consequently, constant periodicities of the fins (Pi and P_o) at the inner and outer flat faces of the hyperlens may also considered. Under these assumptions, a constant angle of the fin (e) is maintained for all fins of the flat face hyperlens. However, due to the finite width of the lens (H) and fixed periodicities on both faces, the angle (e) varies from fin to fin across the lens, resulting in varying lengths of the fins.

[0096] To demonstrate the flat face hyperlens, a numerical model is developed by adopting the same modeling configuration used in the studies to optimize the inner radius of the cylindrical hyperlens. In one example implementation, the hyperlens operated at a frequency of 250 kHz, with a width of 48 mm and designed for a 10X magnification. Each fin in the hyperlens may include an entry width of 100 pm and an exit width of 1 mm. The periodicities of the fins at the inner and outer faces may also considered as 100 pm and 1 mm, respectively.

[0097] The numerical simulation focused on studying defects with a diameter of 1 mm, separated by a center-to-center distance of 2 mm, which is subwavelength (X/3) relative to the operating frequency. The results from the simulation, shown in figure 8b, demonstrated an agreement with an expected 10X magnified super-resolved image of the defects. However, a high amplitude region appeared at the middle due to the shorter lengths of fins in the center region of the hyperlens. Additionally, the emitted wavefields from each fin experienced a time delay due to the unequal fin lengths. Therefore, the processing of results may account for this much time delay.

[0098] Nevertheless, the flat face hyper lens proved well-suited for practical inspections and held significant implications for achieving higher resolution ultrasonic imaging in industrial and biomedical applications. Ongoing efforts focused on refining the design to further enhance its effectiveness and performance.

[0099] Figure 9 illustrates exemplary experimental results showing comparison of frequency spectrums received with and without waveguide attachment to a transducer, in accordance with an embodiment of the present disclosure. In one example implementation, broadband reception is enabled through the use of a waveguide, which avoids limiting frequency range that the attached receiver or transducer may receive. Figure 9 shows the comparison of frequency spectrums received with and without waveguide and demonstrates the broadband reception of the waveguide receiver. Further, waves that interact with the waveguide propagate as the lowest symmetric Lamb mode, with displacements in the axial direction that may be captured by placing a suitably oriented longitudinal or shear transducer. For ease of implementation, a shear transducer may be considered, and a holder made of plexiglass may be designed and fabricated for mounting on it the waveguide. Since waveguides may conduct ultrasound over longer distances, this process allows remote reception. However, the length of the waveguide may be chosen so that the reverberations due to multiple reflections do not pollute the signal of interest. The signals may collect outside the rear edge of the hyperlens and the envelope of the maximum amplitudes may be obtained.

[00100] Figure 10 illustrate experimental results from 5X hyperlens showing the magnified image for defects separated by a subwavelength distance of 5 mm (A/3), with and without defects, in accordance with an embodiment of the present disclosure. The dotted lines show the expected locations of the defects in the magnified image. Experimental results for the cases with and without the presence of the defects, are shown in figure 10. The results show that the obtained peaks are well aligned with the expected locations of the defects or scatterers in the 5X magnified image, experimentally demonstrating for the first time, the cylindrical hyperlens concept for imaging defects under water immersion in the ultrasonic regime.

[00101] Figure 11 illustrates comparison of experimental results obtained using exemplary waveguide receiver and exemplary commercial transducer, in accordance with an embodiment of the present disclosure. To present the results on a normalized scale, the amplitudes of signals received in both cases are depicted, showing a nearly 20 dB difference for the same settings. The dotted lines indicate the expected locations of the defects in the magnified image.

[00102] The effectiveness of the waveguide receiver in spatially narrowband reception is demonstrated by comparing the results obtained with and without the waveguide attachment to the transducer, as shown in figure 11. Typically, the active diameter of bulk ultrasonic transducers is much larger than the dimensions of the fins of the hyperlens. Consequently, the transducer may capture scattered wavefields from an entire region of the hyperlens corresponding to this area, resulting in a received signal that represents an average value of the wavefields from all the fins within that region. Consequently, the information obtained from each fin in the hyperlens is not discretely captured, leading to imperfect resolution of the defects. [00103] Figure 12 depict a flow chart 1200 describing a method for providing ultrasonic far-field super resolution imaging, in accordance with an embodiment of the present disclosure.

[00104] As illustrated in figure 12, the method includes one or more blocks illustrating the method providing ultrasonic far-field super resolution imaging. The method is described within the general context of computer executable instructions. Computer executable instructions encompass various elements, including routines, programs, objects, components, data structures, procedures, modules, and functions.

[00105] The order in which the method is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method. Additionally, individual blocks may be deleted from the methods without departing from the scope of the subject matter described herein.

[00106] At block 1202, the method may describe transmitting, by the transmitter 102, a wavefield towards the object 106 under observation. The transmitted wavefield is scattered through the object 106.

[00107] At block 1204, the method may describe receiving, by the hyperlens 110, the scattered wavefield from the object 106. The scattered wavefield is received from the object 106 on an input side of the hyperlens 110 via a plurality of the fins.

[00108] At block 1206, the method may describe transforming, by the hyperlens 110, the scattered wavefield into a plurality of propagating waves. The scattered wavefield is transformed into the plurality of the propagating waves via the plurality of the fins of the hyperlens 110. The plurality of the propagating waves carries subwavelength information of the object 106. The plurality of the propagating waves is exited from an output side of the hyperlens via the plurality of the fins.

[00109] At block 1208, the method may describe receiving and transmitting, by the waveguide 112, the plurality of the propagating waves in a predefined direction. [00110] At block 1210, the method may describe receiving, by the receiver 114, the plurality of the propagating waves transmitted from the waveguide 112. The receiver 114 is operatively coupled to the waveguide 112. The method may further describe receiving the plurality of the propagating waves exiting from each of the plurality of the fins of the hyperlens 110, separately or discretely. Furthermore, the method may describe processing, by the processing unit 116, the plurality of the propagating waves received from the receiver 114 to generate a subwavelength image of the object 110.

[00111] While this invention has been described in detail with particular references to embodiments thereof, the embodiments described herein are not intended to be exhaustive or to limit the scope of the invention to the exact forms disclosed. Persons skilled in the art and technology to which this invention pertains will appreciate that alterations and changes in the described structures and methods of assembly and operation can be practiced without meaningfully departing from the principles, and scope of this invention. Further, as used herein, when a component is referred to as being "on" or "coupled to" another component, it can be directly on or attached to the other component or intervening components may be present therebetween.

[00112] The foregoing descriptions of specific embodiments of the present disclosure have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments may be chosen and described in order to best explain the principles of the present disclosure and its practical application, and to thereby enable others skilled in the art to best utilize the present disclosure and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the scope of the present disclosure. [00113] The invention offers significant technical advantages, revolutionizing ultrasonic imaging. Thorough numerical simulations optimize hyperlens designs, enhancing imaging performance and resolution. The innovative waveguide -based reception technique utilizes standard transducers, making hyperlenses more accessible and cost-effective. Additionally, the extension to flat face hyperlenses increases versatility, opening up new possibilities for practical applications. Demonstrated success with custom-fabricated metallic hyperlens showcases super -resolved imaging in the ultrasonic domain. Overall, the invention's advancements overcome existing limitations and promise higher resolution imaging in industrial and biomedical fields.

[00114] The primary objective of the invention is to design and implement a hyperlens concept, along with an effective signal reception technique, for achieving super-resolution in the far-field of the ultrasonic domain and imaging subwavelength features. Another important goal of the invention is to provide a system and method for imaging subwavelength separated defects/objects in the context of non-destructive evaluation and non- invasive diagnosis. Several other objectives of the invention are as follows:

• To develop a system and method for imaging sub-wavelength separated defects/objects in the context of non-destructive evaluation and non-invasive diagnosis.

• To offer flexibility in the shape of the hyperlens, which may be selected from various configurations, including cylindrical and spherical.

• To provide a planar hyperlens with flat inner and outer faces.

• To construct the hyperlens using radially alternating metal and fluid-filled fins.

• To arrange the fins of the hyperlens in different configurations, such as semi or full circle, semi or full cylinder, and hemi or full spherical.

• To allow variations in the shape of the inner and outer surfaces of the hyperlens, which can be either curved or planar.

• To provide flexibility in the shape of the waveguide, which may be selected from various configurations, including circular, cylindrical, tubular, elliptical, square, and a rectangular strip.

• To offer multiple forms for the waveguide, such as a wire, rod, sheet, plate, or a fiber. • To generate Longitudinal (L(m,n)), Torsional (T(m,n)), and Flexural (F(m,n)) wave modes with circular, cylindrical, tubular, and elliptical waveguides, where m denotes Symmetry and n denotes the number of modes.

• To generate Anti-Symmetric (A(n)), Symmetric (S(n)), or Shear Horizontal (SH(n)) modes with rectangular and square waveguides, where m denotes Symmetry and n denotes the number of modes.

• To allow attachment of the waveguide with a piezoelectric or electromagnetic transducer for effective signal transmission and reception.

Claims

The Claims:

1. A system for providing ultrasonic far-field super resolution imaging, comprising: a transmitter configured to transmit a wavefield towards an object under observation, wherein the transmitted wavefield is scattered through the object; a hyperlens configured to: receive the scattered wavefield from the object; and transform the scattered wavefield into a plurality of propagating waves; a waveguide configured to receive and transmit the plurality of the propagating waves in a predefined direction; and a receiver operatively coupled to the waveguide, wherein the receiver is configured to receive the plurality of the propagating waves transmitted from the waveguide.

2. The system as claimed in claim 1, wherein the receiver is further coupled to a processing unit, wherein the processing unit is configured to process the plurality of the propagating waves received from the receiver, to generate a subwavelength image of the object.

3. The system as claimed in claim 1, wherein the hyperlens is selected at least from a group of: cylindrical hyperlens, flat face hyperlens, or spherical hyperlens.

4. The system as claimed in claim 1, wherein the hyperlens comprises a plurality of fins, wherein each of the plurality of the fins is configured to transform the scattered wavefield into the plurality of the propagating waves.

5. The system as claimed in claim 1 , wherein the hyperlens comprises an input side and an output side, wherein the hyperlens is configured to: receive the scattered wavefield from the object on the input side via the plurality of the fins; transform the scattered wavefield into the plurality of the propagating waves, wherein the plurality of the propagating waves carries subwavelength information of the object; and exit the plurality of the propagating waves from the output side via the plurality of the fins.

6. The system as claimed in claim 1, wherein the waveguide has a shape selected from a group consisting of: circular strip, cylindrical strip, tubular strip, elliptical strip, square strip, or rectangular strip.

7. The system as claimed in claim 1, wherein the waveguide is provided in a form selected from at least one of: a wire, a rod, a sheet, a plate, or a fiber.

8. The system as claimed in claim 1, wherein the receiver is configured to receive the plurality of the propagating waves exiting from each of a plurality of fins of the hyperlens, separately.

9. A method for providing ultrasonic far-field super resolution imaging, comprising: transmitting, by a transmitter, a wavefield towards an object under observation, wherein the transmitted wavefield is scattered through the object; receiving, by a hyperlens, the scattered wavefield from the object; transforming, by the hyperlens, the scattered wavefield into a plurality of propagating waves; receiving and transmitting, by a waveguide, the plurality of the propagating waves in a predefined direction; and receiving, by a receiver, the plurality of the propagating waves transmitted from the waveguide, wherein the receiver is operatively coupled to the waveguide.

10. The method as claimed in claim 9, further comprising: processing the plurality of the propagating waves received from the receiver to generate a subwavelength image of the object.

11. The method as claimed in claim 9, comprising: transforming the scattered wavefield into the plurality of the propagating waves via a plurality of fins of the hyperlens.

12. The method as claimed in claim 9 and 11, comprising: receiving the scattered wavefield from the object on an input side of the hyperlens via the plurality of the fins; transforming the scattered wavefield into the plurality of the propagating waves, wherein the plurality of the propagating waves carries subwavelength information of the object; and exiting the plurality of the propagating waves from an output side of the hyperlens via the plurality of the fins. The method as claimed in claim 9, comprising: receiving the plurality of the propagating waves exiting from each of a plurality of fins of the hyperlens, separately.