Nanohole-based phase gradient metasurfaces for light manipulation

Yilmaz, Nazmi; Özer, Ahmet; Özdemir, Aytekin; Kurt, Hamza

doi:10.1088/1361-6463/ab0c70

Cited by 14 publications

(10 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Regardless, nanohole structures proved to have distinct advantages compared to nanopillars. First, nanoholes offer higher transmission as expected [29]. Equally important, nanoholes reduced fabrication difficulties making subwavelength structures with higher aspect ratios accessible for operation with visible light.…”

Section: Discussionmentioning

confidence: 90%

“…The two TEs, the phase plate (bottom) and nanoholes (top), are merged into a single structure which forms the unit cell of the hybrid metalens as shown in Figure 1(a). The nanohole structure is chosen due to its higher transmission than the nanopillar [29] and advantages for fabrication. Specifically, the nanohole architecture prevents pattern distortion and collapse that can accompany high aspect ratio pillars.…”

Section: Theory and Structurementioning

confidence: 99%

See 1 more Smart Citation

An ultrabroadband 3D achromatic metalens

et al. 2021

Self Cite

View full text Add to dashboard Cite

We design and fabricate ultra-broadband achromatic metalenses operating from the visible into the short-wave infrared, 450–1700 nm, with diffraction-limited performance. A hybrid 3D architecture, which combines nanoholes with a phase plate, allows realization in low refractive index materials. As a result, two-photon lithography can be used for prototyping while molding can be used for mass production. Experimentally, a 0.27 numerical aperture (NA) metalens exhibits 60% average focusing efficiency and 6% maximum focal length error over the entire bandwidth. In addition, a 200 μm diameter, 0.04 NA metalens was used to demonstrate achromatic imaging over the same broad spectral range. These results show that 3D metalens architectures yield excellent performance even using low-refractive index materials, and that two-photon lithography can produce metalenses operating at visible wavelengths.

show abstract

Section: Discussionmentioning

confidence: 90%

Section: Theory and Structurementioning

confidence: 99%

An ultrabroadband 3D achromatic metalens

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…To further analyze the focusing performance of AMDL within the frequency region of 10 GHz -14 GHz numerical aperture (NA) and focusing efficiency values are calculated. A common approach for calculation of focusing efficiency, which is taking the proportion of the collected light on the focal plane (exactly on the focal spot location) with a radius defined as three times that of the FWHM of a spot size, is used [37,38].…”

Section: Design Methodology and Numerical Results Of Amdlmentioning

confidence: 99%

“…5(c), measured FWHM values are varying from 0.68λ to 0.89λ which still show strong focusing effect of the proposed AMDL. It is difficult to directly measure the focusing efficiency of the AMDL structure through our microwave experimental setup, thus we used an indirect method which resembles the numerical calculations [37,38] to calculate the focusing efficiency of fabricated lens to provide comparable data. Here, the transmission value falling into a circular aperture with a radius equal to three times the FWHM centered at focal point is proportioned the transmission value falling into whole focal plane (200 mm × 200 mm).…”

Section: Experimental Analysis Of Achromatic Focusing Effectmentioning

confidence: 99%

Ultra-compact, high-numerical-aperture achromatic multilevel diffractive lens via metaheuristic approach

2021

Self Cite

View full text Add to dashboard Cite

Recently, the multilevel diffractive lenses (MDLs) have attracted considerable attention mainly due to their superior wave focusing performance; however, efforts to correct the chromatic aberration are still in progress. Here, we demonstrate the numerical design and experimental demonstration of high-numerical aperture (NA) (~0.99), diffraction-limited achromatic multilevel diffractive lens (AMDL) operating in microwave range 10 GHz-14 GHz. A multi-objective differential evolution (MO-DE) algorithm is incorporated with the three-dimensional finite-difference time-domain (3D FDTD) method to optimize both the heights and widths of each concentric ring (zone) of the AMDL structure. In this study, the desired focal distance ( d F  ) is treated as an optimization parameter in addition to the structural parameters of the zones for the first time. In other words, MO-DE diminishes the necessity of predetermined focal distance and center wavelength by also providing an alternative method for phase profile tailoring. The proposed AMDL can be considered as an ultra-compact, the radius is 3.7 c  where c  is the center wavelength (i.e., 12 GHz frequency), and flat lens which has a thickness of . c The numerically calculated full-width at half-maximum (FWHM) values are below 0.554λ and focusing efficiency values are varying between 28% and 45.5%. To experimentally demonstrate the functionality of the optimized lens, the AMDL composing of polylactic acid material (PLA) polymer is fabricated via 3D-printing technology. The numerical and experimental results are compared, discussed in detail and a good agreement between them is observed. Moreover, the verified AMDL in microwave regime is scaled down to the visible wavelengths to observe achromatic and diffraction-limited focusing behavior between 380 nm -620 nm wavelengths.

show abstract

“…In addition, material filling ratios (material volume to unit cell ratio) are a maximum of 0.6 and a minimum of 0.01. Due to the use of less dielectric material, which reduces the effective index variation, the chromatic aberration is expected to decrease …”

Section: Sampling Inhomogeneous Medium With Bruggeman Effective Mediu...mentioning

confidence: 99%

A Broad-Band Achromatic Polarization-Insensitive In-Plane Lens with High Focusing Efficiency

et al. 2021

Self Cite

View full text Add to dashboard Cite

Until now, many pioneering studies have been conducted on multiwavelength achromatic lens designs that can eliminate chromatic aberrations at various wavelengths. In these studies, the working bandwidth is still not wide enough for practical applications, and an effective achromatic design is achieved with a long design cycle that determines critical elements of the unit cell. To solve the limitations of the unit cell method, we use inverse design to simultaneously explore structures with broad bandwidth and high efficiency. In this study, we show that it is possible to obtain an achromatic cylindrical lens that can focus transverse electric and transverse magnetic polarization between 1300 and 1750 nm using the objective-first algorithm. We implement the generalized Bruggeman effective medium theory to binarize the lens with randomly varying index profiles while maintaining the optical performance of the cylindrical inverse-designed lens. The binarized lens is produced via three-dimensional printing and tested in a microwave regime, exhibiting high bandwidth operation and high focusing efficiency (average 62%).

show abstract

Nanohole-based phase gradient metasurfaces for light manipulation

Cited by 14 publications

References 29 publications

An ultrabroadband 3D achromatic metalens

An ultrabroadband 3D achromatic metalens

Ultra-compact, high-numerical-aperture achromatic multilevel diffractive lens via metaheuristic approach

A Broad-Band Achromatic Polarization-Insensitive In-Plane Lens with High Focusing Efficiency

Contact Info

Product

Resources

About