Chromatic-aberration-corrected diffractive lenses for ultra-broadband focusing

Wang, Peng; Mohammad, Nabil; Menon, Rajesh

doi:10.1038/srep21545

Cited by 183 publications

(143 citation statements)

References 30 publications

Supporting

Mentioning

142

Contrasting

Order By: Relevance

“…For the present design, the FWHM/ wavelength is a decaying function of wavelength, reaching the minimum value at the resonance wavelength (λ res = 4.56 µm) of the nanostructure and becomes less than 1, subwavelength concentration, for higher wavelengths, as shown in Figure 2a. [46,47] Figure 2b shows the predicted efficiency of the flat lens as a function of period P for a fixed differential diameter ΔD = 100 nm. These aberrations are much smaller compared with other reported flat lenses.…”

Section: Wwwadvopticalmatdementioning

confidence: 99%

High‐Efficiency Broadband Mid‐Infrared Flat Lens

Safaei

Vázquez‐Guardado

Franklin

et al. 2018

Advanced Optical Materials

View full text Add to dashboard Cite

wavelength of incoming light to accumulate 0 to π phase shifts. That means subwavelength compact planar geometry is not possible in conventional lenses making optical systems bulky. Furthermore, conventional lenses are limited by optical aberrations (e.g., spherical and chromatic) and diffraction limit. [1] The Abbe-Rayleigh diffraction limit is a natural obstacle in conventional optical lenses due to the far-field interference and absence of near-field. [2] Various planar lenses have been demonstrated following the diffractive optics concept of phase control based on dielectric scatterers on a 2D plane. [3][4][5][6][7][8][9] However, in the mid-infrared wavelength range (3-16 µm), such engineered dielectric surfaces are elusive due to the low spectral bandwidth [8,9] and high thermal noise in long wavelengths. [10,11] In contrast, plasmonic nanoantennas [12][13][14][15][16][17] enable abrupt change in phase, amplitude, and polarization of the incident light using subwavelength optical scatterers on a planar surface. Such control of phase according to the Huygens principle [18] allows the formation of arbitrary wavefront shapes enabling subwavelength focusing. [3][4][5] Spatially distributed plasmonic nanoantennas suppress higher diffraction orders and concentrate the incident light beam beyond the Abbe-Rayleigh diffraction limited focal point. [19][20][21][22] In addition, possibility of the optical impedance matching with the free space by the patterned plasmonic interface reduces back scattering, leading to higher transmission efficiency. [5,23] Going beyond the Abbe-Rayleigh diffraction limit requires the involvement of evanescent fields with large spatial frequency components which is possible by plasmonic nanoantennas, enabling subwavelength resolution capability going beyond the current imaging technologies. [2,14,22,24,25] Here, we propose and experimentally demonstrate an ultrathin flat lens working in the mid-IR spectral range with geometrically tunable focal length and subwavelength focusing ability. The transmission efficiency of this flat lens is substantially higher compared with other reported plasmonic lenses due to the low metallic fill-fraction and the geometry. [14][15][16]26,27] The biggest limitation of dielectric as well as metallic flat lenses is the bandwidth of operation due to the inherent narrowband resonance. [8,9] Previously, reported plasmonic flat lenses were limited to λ ≈ 1.0-1.9 µm, [15] ≈5.2-9.9 µm, [16] and λ ≈ 5-10 µm, [14] operation bandwidths in the infrared spectral range. None of these works reported the most critical lens Integrated photonic circuits and infrared imaging systems demand compact optical components. Dielectric diffractive optics enables miniaturization of the curved refractive optics into planar structure by encoding phase over a 2D plane. However, in the mid-infrared wavelength range, such engineered dielectric surfaces are not efficient, because optically transparent dielectric scatterers with high index contrast in the mid-infrared spectral range suffer f...

show abstract

Section: Wwwadvopticalmatdementioning

confidence: 99%

High‐Efficiency Broadband Mid‐Infrared Flat Lens

Safaei

Vázquez‐Guardado

Franklin

et al. 2018

Advanced Optical Materials

View full text Add to dashboard Cite

show abstract

“…While this may be the case for truncated waveguide and geometric phase type metalenses (depending on the NA of the lens, since for a diffractive element the aspect ratio increases for larger NA), the Huygens type metalens presented in this paper is based on nanoantennas with low aspect ratios. As mentioned above, the highest aspect ratio of our metalens is about 0.7, whereas the diffractive lenses discussed in (30,31) report an aspect ratio of about 1. To summarize, in our opinion surface relief diffractive elements and the various types of metasurface diffractive elements each have their advantages and disadvantages.…”

Section: Discussionmentioning

confidence: 62%

Near-IR Wide Field-of-View Huygens Metalens for Outdoor Imaging Applications

Engelberg

Zhou

Mazurski

et al. 2019

Conference on Lasers and Electro-Optics

View full text Add to dashboard Cite

The ongoing effort to implement compact and cheap optical systems is the main driving force for the recent flourishing research in the field of optical metalenses. Metalenses are a type of metasurface, used for focusing and imaging applications, and are implemented based on the nanopatterning of an optical surface. The challenge faced by metalens research is to reach high levels of performance, using simple fabrication methods suitable for massproduction. In this paper we present a Huygens nanoantenna based metalens, designed for outdoor photographic/surveillance applications in the near-infra-red. We show that good imaging quality can be obtained over a field-of-view (FOV) as large as ±15˚. This first successful implementation of metalenses for outdoor imaging applications is expected to provide insight and inspiration for future metalens imaging applications. MAIN TEXT

show abstract

“…Although our flat lens is not aberration-free, there are strategies to reduce comatic [18,19] and chromatic aberrations [20][21][22][23][24][25] of flat lenses. We envision that our flat lenses will complement or replace various conventional optical components in systems for IR imaging, ranging, and detection, as well as for beam shaping of IR lasers and beacons.…”

Section: Discussionmentioning

confidence: 99%

High efficiency near diffraction-limited mid-infrared flat lenses based on metasurface reflectarrays

Zhang¹,

Kim²,

Aieta³

et al. 2016

Opt. Express

119

View full text Add to dashboard Cite

A limiting factor in the development of mid-infrared optics is the lack of abundant materials that are transparent, low cost, lightweight, and easy to machine. In this paper, we demonstrate a metasurface device that circumvents these limitations. A flat lens based on antenna reflectarrays was designed to achieve near diffraction-limited focusing with a high efficiency (experiment: 80%; simulation: 83%) at 45 o incidence angle at λ = 4.6 μm. This geometry considerably simplifies the experimental arrangement compared to the common geometry of normal incidence which requires beam splitters. Simulations show that the effect of comatic aberrations is small compared to parabolic mirrors. The use of single-step photolithography allows large scale fabrication.

show abstract

Chromatic-aberration-corrected diffractive lenses for ultra-broadband focusing

Cited by 183 publications

References 30 publications

High‐Efficiency Broadband Mid‐Infrared Flat Lens

High‐Efficiency Broadband Mid‐Infrared Flat Lens

Near-IR Wide Field-of-View Huygens Metalens for Outdoor Imaging Applications

High efficiency near diffraction-limited mid-infrared flat lenses based on metasurface reflectarrays

Contact Info

Product

Resources

About