Efficient Silicon Metasurfaces for Visible Light

Zhou, Zhenpeng; Li, Juntao; Su, Rongbin; Yao, Beimeng; Fang, Hanlin; Li, Kezheng; Zhou, Lidan; Liu, Jin; Stellinga, Daan; Reardon, Christopher; Krauss, Thomas F.; Wang, Xuehua

doi:10.1021/acsphotonics.6b00740

Cited by 238 publications

(194 citation statements)

References 47 publications

Supporting

Mentioning

192

Contrasting

Order By: Relevance

“…In recent years, multiple groups have demonstrated highefficiency high-NA lenses using the HCA platform [66,67,69,72,124,128]. Figure 2g, shows one of the early demonstrations where lenses with NAs ranging from ∼0.5 to above 0.95 were demonstrated, with measured absolute focusing efficiencies from 82% to 42% depending on the NA, while keeping a close to diffraction limited spot.…”

Section: New Capabilities For Controlling Light Enabled By Metasmentioning

confidence: 99%

A review of dielectric optical metasurfaces for wavefront control

et al. 2018

View full text Add to dashboard Cite

During the past few years, metasurfaces have been used to demonstrate optical elements and systems with capabilities that surpass those of conventional diffractive optics. Here we review some of these recent developments with a focus on dielectric structures for shaping optical wavefronts. We discuss the mechanisms for achieving steep phase gradients with high efficiency, simultaneous polarization and phase control, controlling the chromatic dispersion, and controlling the angular response. Then we review applications in imaging, conformal optics, tunable devices, and optical systems. We conclude with an outlook on future potentials and challenges that need to be overcome. A. High-efficiency high-gradient phase controlSince high-contrast transmitarrays (HCA) are central to the most of the discussions of this section, we first briefly discuss their operation. We are primarily interested in the two-dimensional HCAs, and therefore we consider their case here, although much of the discussions are also valid for the one-dimensional case. In general, these devices are based on high-refractive-index dielectric nano-scatterers surrounded by low-index media [13, 38, 65, 67, 70-72, 76, 78]. The structure can be symmetric (i.e., with the substrate and capping layers having the same refractive indexes) [36] or asymmetric [66,67,76,78]. Depending on the materials and the required phase coverage, the thickness of the high-index layer is usually between 0.5λ 0 and λ 0 , where λ 0 is the free space wavelength. Typically, these structures are designed to be compatible with conventional microfabrication techniques;

show abstract

Section: New Capabilities For Controlling Light Enabled By Metasmentioning

confidence: 99%

A review of dielectric optical metasurfaces for wavefront control

et al. 2018

View full text Add to dashboard Cite

show abstract

“…As discussed in ref. [35,36], the loss of c-Si at wavelengths longer than 500 nm is not negligible only if the geometry of each nano-brick is carefully designed.…”

Section: Design Of the C-si Based Metalensmentioning

confidence: 99%

Ultrahigh Numerical Aperture Metalens at Visible Wavelengths

et al. 2018

Self Cite

View full text Add to dashboard Cite

Subwavelength imaging requires the use of high numerical aperture (NA) lenses together with immersion liquids in order to achieve the highest possible resolution. Following exciting recent developments in metasurfaces that have achieved efficient focusing and novel beam-shaping, the race is on to demonstrate ultra-high NA metalenses. The highest NA that has been demonstrated so far is NA=1.1, achieved with a TiO2 metalens and back-immersion. Here, we introduce and demonstrate a metalens with high NA and high transmission in the visible range, based on crystalline silicon (c-Si). The higher refractive index of silicon compared to TiO2 allows 2 us to push the NA further. The design uses the geometric phase approach also known as the Pancharatnam-Berry phase and we determine the arrangement of nano-bricks using a hybrid optimization algorithm (HOA). We demonstrate a metalens with NA = 0.98 in air, a bandwidth (FWHM) of 274 nm and a focusing efficiency of 67% at 532 nm wavelength, which is close to the transmission performance of a TiO2 metalens. Moreover, and uniquely so, our metalens can be front-immersed into immersion oil and achieve an ultra-high NA of 1.48 experimentally and 1.73 theoretically, thereby demonstrating the highest NA of any metalens in the visible regime reported to the best of our knowledge. The fabricating process is fully compatible with CMOS technology and therefore scalable. We envision the front-immersion design to be beneficial for achieving ultra-high NA metalenses as well as immersion metalens doublets, thereby pushing metasurfaces into practical applications such as high resolution, low-cost confocal microscopy and achromatic lenses.Metasurfaces are artificial sheet materials of sub-wavelength thickness that modulate electromagnetic waves mainly through photonic resonances [1][2][3]. Their properties are based on the ability to control the phase and/or polarisation of light with subwavelength-scale dielectric or metallic nano-resonators [4,5]. Correspondingly, metasurfaces are able to alter every aspect of transmitting or reflecting beams, achieving various extraordinary optical phenomena including deflection [6 -8], retro-reflection [9, 10], polarization conversion [4, 11 -14], focusing [15 -17] and beam-shaping [18], with a nanostructured thin film alone. Focusing metasurfaces -namely metalenses -are amongst the most promising optical elements for practical applications [19,20], e.g. for cell phone camera lenses [21,22] or ultrathin microscope objectives [23,24], since their subwavelength nanostructures are able to provide more precise and efficient phase control compared to binary amplitude and phase Fresnel zone plates .

show abstract

“…Higher resolution has been achieved by using aberration-correcting planar gratings [16], however an external spherical mirror makes the device bulky.Dielectric metasurfaces, a new category of diffractive optical elements with enhanced functionalities, have attracted a great deal of interest in recent years [19][20][21][22]. Overcoming many of the material and fundamental limitations of plasmonic metasurfaces [23], dielectric metasurfaces have proven capable of implementing several conventional [19,[24][25][26][27][28][29][30][31][32][33][34] and new optical devices [35][36][37][38][39] with high efficiencies. They enable control of phase with subwavelength resolution and high gradients and simultaneous control of phase and polarization [35].…”

mentioning

confidence: 99%

Compact folded metasurface spectrometer

et al. 2018

View full text Add to dashboard Cite

An optical design space that can highly benefit from the recent developments in metasurfaces is the folded optics architecture where light is confined between reflective surfaces, and the wavefront is controlled at the reflective interfaces. In this manuscript, we introduce the concept of folded metasurface optics by demonstrating a compact spectrometer made from a 1-mm-thick glass slab with a volume of 7 cubic millimeters. The spectrometer has a resolution of ~1.2 nm, resolving more than 80 spectral points from 760 to 860 nm. The device is composed of three reflective dielectric metasurfaces, all fabricated in a single lithographic step on one side of a substrate, which simultaneously acts as the propagation space for light. The folded metasystem design can be applied to many optical systems, such as optical signal processors, interferometers, hyperspectral imagers, and computational optical systems, significantly reducing their sizes and increasing their mechanical robustness and potential for integration.

show abstract

Efficient Silicon Metasurfaces for Visible Light

Cited by 238 publications

References 47 publications

A review of dielectric optical metasurfaces for wavefront control

A review of dielectric optical metasurfaces for wavefront control

Ultrahigh Numerical Aperture Metalens at Visible Wavelengths

Compact folded metasurface spectrometer

Contact Info

Product

Resources

About