Abstract:the concept of superoscillation, [13,14] there has been growing interest in developing optical super-resolution devices for far-field operation without evanescent waves. [15,16] According to this concept, an arbitrary small point-spread function (PSF) can be achieved by engineering the wave front of the incident wave through a properly designed amplitude-phase mask. [17] This opens an alternative way toward far-field optical super-resolution. In the past several years, various types of superoscillatory lenses … Show more
“…Recently, there has been a growing interest in developing far‐field super‐resolution optical devices, which can achieve point‐spread‐function (PSF) of size smaller than the Abbe DL without evanescent waves [ 6 ] at a distance far beyond the near‐field regime. [ 7,8 ] Based on the concept of superoscillation, [ 9–11 ] a variety of sub‐diffraction or super‐resolution optical devices have been demonstrated either theoretically or experimentally, including scalar super‐resolution metalenses [ 12–22 ] and vector super‐resolution metalenses. [ 23–33 ] Such super‐resolution devices have been successfully shown great potential in label‐free super‐resolution microscopy [ 13,21,34,35 ] and super‐resolution telescope.…”
THz focusing and imaging include bulky dielectric refractive lenses and parabolic mirrors. Due to the diffraction effect, the resolution of conventional optics is limited by the Abbe diffraction limit (DL) of 0.5λ/NA, [5] where λ and NA are working wavelength and numerical aperture (NA), respectively. Recently, there has been a growing interest in developing far-field super-resolution optical devices, which can achieve point-spread-function (PSF) of size smaller than the Abbe DL without evanescent waves [6] at a distance far beyond the near-field regime. [7,8] Based on the concept of superoscillation, [9-11] a variety of sub-diffraction or super-resolution optical devices have been demonstrated either theoretically or experimentally, including scalar super-resolution metalenses [12-22] and vector super-resolution metalenses. [23-33] Such super-resolution devices have been successfully shown great potential in labelfree super-resolution microscopy [13,21,34,35] and super-resolution telescope. [36] However, most previously reported super-resolution metalenses only work at one single wavelength [37] or several designed discrete wavelengths, [38,39] while broadband achromatic metalenses working in the visible [40-42] and nearinfrared spectrum [43-46] as well as THz regime [47] are restricted by the Abbe DL. To achieve a broadband super-resolution imaging, recently, a broadband super-resolution scheme was proposed and experimentally demonstrated by adopting the combination of a super-oscillatory binary phase filter and a conventional bulk achromatic refractive convex lens. [48] Up to now, it is still a great challenge to realize a sub-diffraction achromatic metalens with a continuous broad bandwidth. To achieve broadband achromatic super-resolution focusing, similar to the conventional optics, dispersion compensation is required to ensure that the wave of different wavelengths is focused at the same focal point. In addition, wave front engineering is also required to achieve the super-resolution PSF. Recent fast development of metasurfaces [49-54] provides effective ways to manipulate the amplitude, [55,56] phase, [57-61] polarization [30,33,62-66] and dispersion properties [67,68] of light waves. To achieve wave front shaping without influences on dispersion, one possible way is to realize broadband achromatic super-resolution by adopting amplitude modulation. Conventionally, pupil filters [69-78] can be used to achieve super-resolution in traditional optical systems. Recently, there are growing interests in developing super-resolution metalenses for applications of focusing and imaging. On one hand, various sub-diffraction metalenses have been demonstrated; however, most of them only work at a single wavelength or multiple discrete wavelengths. On the other hand, the previously reported broadband achromatic metalenses are diffraction-limited, or their focal spots are larger than the corresponding Abbe diffraction limit, 0.5λ/NA, where λ and NA are the lens working wavelength and numerical aperture. In the present wo...
“…Recently, there has been a growing interest in developing far‐field super‐resolution optical devices, which can achieve point‐spread‐function (PSF) of size smaller than the Abbe DL without evanescent waves [ 6 ] at a distance far beyond the near‐field regime. [ 7,8 ] Based on the concept of superoscillation, [ 9–11 ] a variety of sub‐diffraction or super‐resolution optical devices have been demonstrated either theoretically or experimentally, including scalar super‐resolution metalenses [ 12–22 ] and vector super‐resolution metalenses. [ 23–33 ] Such super‐resolution devices have been successfully shown great potential in label‐free super‐resolution microscopy [ 13,21,34,35 ] and super‐resolution telescope.…”
THz focusing and imaging include bulky dielectric refractive lenses and parabolic mirrors. Due to the diffraction effect, the resolution of conventional optics is limited by the Abbe diffraction limit (DL) of 0.5λ/NA, [5] where λ and NA are working wavelength and numerical aperture (NA), respectively. Recently, there has been a growing interest in developing far-field super-resolution optical devices, which can achieve point-spread-function (PSF) of size smaller than the Abbe DL without evanescent waves [6] at a distance far beyond the near-field regime. [7,8] Based on the concept of superoscillation, [9-11] a variety of sub-diffraction or super-resolution optical devices have been demonstrated either theoretically or experimentally, including scalar super-resolution metalenses [12-22] and vector super-resolution metalenses. [23-33] Such super-resolution devices have been successfully shown great potential in labelfree super-resolution microscopy [13,21,34,35] and super-resolution telescope. [36] However, most previously reported super-resolution metalenses only work at one single wavelength [37] or several designed discrete wavelengths, [38,39] while broadband achromatic metalenses working in the visible [40-42] and nearinfrared spectrum [43-46] as well as THz regime [47] are restricted by the Abbe DL. To achieve a broadband super-resolution imaging, recently, a broadband super-resolution scheme was proposed and experimentally demonstrated by adopting the combination of a super-oscillatory binary phase filter and a conventional bulk achromatic refractive convex lens. [48] Up to now, it is still a great challenge to realize a sub-diffraction achromatic metalens with a continuous broad bandwidth. To achieve broadband achromatic super-resolution focusing, similar to the conventional optics, dispersion compensation is required to ensure that the wave of different wavelengths is focused at the same focal point. In addition, wave front engineering is also required to achieve the super-resolution PSF. Recent fast development of metasurfaces [49-54] provides effective ways to manipulate the amplitude, [55,56] phase, [57-61] polarization [30,33,62-66] and dispersion properties [67,68] of light waves. To achieve wave front shaping without influences on dispersion, one possible way is to realize broadband achromatic super-resolution by adopting amplitude modulation. Conventionally, pupil filters [69-78] can be used to achieve super-resolution in traditional optical systems. Recently, there are growing interests in developing super-resolution metalenses for applications of focusing and imaging. On one hand, various sub-diffraction metalenses have been demonstrated; however, most of them only work at a single wavelength or multiple discrete wavelengths. On the other hand, the previously reported broadband achromatic metalenses are diffraction-limited, or their focal spots are larger than the corresponding Abbe diffraction limit, 0.5λ/NA, where λ and NA are the lens working wavelength and numerical aperture. In the present wo...
“…However, the on-axis resolution is compromised due to the broad spectra going beyond the effect space. Although the resolution can be increased with designs such as an aplanatic superoscillatory metalens, the focusing efficiency is limited by the sidelobe 74 . Fig.…”
Section: Progress and Challenges For Typical Performancesmentioning
confidence: 99%
“…Although the resolution can be increased with designs such as an aplanatic superoscillatory metalens, the focusing efficiency is limited by the sidelobe 74 .…”
Section: Compromise Between High-na and High Fovmentioning
Lightweight, miniaturized optical imaging systems are vastly anticipated in these fields of aerospace exploration, industrial vision, consumer electronics, and medical imaging. However, conventional optical techniques are intricate to downscale as refractive lenses mostly rely on phase accumulation. Metalens, composed of subwavelength nanostructures that locally control light waves, offers a disruptive path for small-scale imaging systems. Recent advances in the design and nanofabrication of dielectric metalenses have led to some high-performance practical optical systems. This review outlines the exciting developments in the aforementioned area whilst highlighting the challenges of using dielectric metalenses to replace conventional optics in miniature optical systems. After a brief introduction to the fundamental physics of dielectric metalenses, the progress and challenges in terms of the typical performances are introduced. The supplementary discussion on the common challenges hindering further development is also presented, including the limitations of the conventional design methods, difficulties in scaling up, and device integration. Furthermore, the potential approaches to address the existing challenges are also deliberated.
“…Due to their flexibility in manipulating the amplitude, phase, and polarization in the subwavelength scale, optical metasurfaces provide powerful building blocks for realizing a complicated superoscillatory metalens. Birefringent metasurfaces have been reported for integrating the functions of polarization conversing and super-resolution focusing vectorial optical fields. − Geometric phase or Pancharatnam–Berry (PB) phase metasurfaces allow continuous phase variation with a spatial resolution up to 0.38λ, which is critical for realizing the deep superoscillation focusing transversely polarized wave, suppressing the sidelobes, and correcting off-axis aberration . SOLs have also shown promising potential in label-free far-field super-resolution microscopy. ,, …”
mentioning
confidence: 99%
“…34−36 Geometric phase or Pancharatnam−Berry (PB) phase 37 metasurfaces allow continuous phase variation with a spatial resolution up to 0.38λ, 38 which is critical for realizing the deep superoscillation focusing transversely polarized wave, suppressing the sidelobes, 39 and correcting off-axis aberration. 40 SOLs have also shown promising potential in label-free far-field superresolution microscopy. 18,38,41 Although conventional SOLs can work in a broadband wavelength range, achromatic operation is highly desirable in many practical applications.…”
Optical
super-resolution diffractive metalenses have been promising
candidates for realizing optical imaging and a microscope beyond the
Abbe diffraction limit. An achromatic super-resolution metalens is
particularly important for practical applications; however, it remains
challenging to achieve high-numerical-aperture achromatic super-resolution
metalens for subwavelength focusing. Herein, a holographic approach
of realizing a multiwavelength achromatic subwavelength super-resolution
focusing is proposed. Through wavefront engineering and holographic
synthesis, a high-numerical-aperture achromatic super-resolution metalens
is demonstrated for subwavelength super-resolution focusing at five
different wavelengths of 520, 555, 632.8, 660, and 690 nm. Broadband
achromatic performance is also expected. Generally, there is no theoretical
limit on the number of achromatic wavelengths. The proposed method
could be useful in super-resolution related applications, including
imaging, microscopy, and data storage.
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