High numerical aperture and large focusing efficiency metalens based on multilayer transmitarray elements

Liu, Yongqiang; Sun, Jianning; Shu, Yingchao; Wu, Li; Lu, Linfeng; Qi, Kainan; Che, Yongxing; Li, Liangsheng; Yin, Hongcheng

doi:10.1016/j.optlaseng.2021.106734

Cited by 27 publications

(11 citation statements)

References 36 publications

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“…Because the phase change material GSSe has low loss, the focusing efficiency is about 59% and 48% under the excitation of the RCP wave and LCP wave. Such a double-layer structure may also add more metasurface layers or change the dielectric thickness to achieve higher NA and larger focusing efficiency [54]. This enables the idea of the continuous zoom metalens to be validated in the mid-infrared, while the proposed polarization-dependent continuous varifocal metalens also has potential applications in biological and medical instruments, optical imaging systems, and compact optical devices.…”

Section: Polarization-dependent Continuous Varifocal Metalensmentioning

confidence: 99%

Mid-Infrared Continuous Varifocal Metalens with Adjustable Intensity Based on Phase Change Materials

et al. 2022

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Metalenses can greatly reduce the complexity of imaging systems due to their small size and light weight and also provide a platform for the realization of multifunctional imaging devices. Achieving dynamic focus length tunability is highly important for metalens research. In this paper, based on single-crystal Ge and a new low-loss phase change material Ge2Sb2Se5 (GSSe), a tunable metalens formed by a double-layer metasurface composite was realized in the mid-infrared band. The first-layer metasurface formed by Ge nanopillars combines propagation and the geometric phase (equivalent to a half-wave plate function) to produce single- or multiple-polarization-dependent foci. The second-layer metasurface formed by GSSe nanopillars provides a tunable propagation phase, and the double-layer metalens can achieve the tunability of the focus length depending on the different crystalline fractions of GSSe. The focal length varies from 62.91 to 67.13 μm under right circularly polarized light incidence and from 33.84 to 36.66 μm under left circularly polarized light incidence. Despite the difference in the crystallographic fraction, the metalens’s focusing efficiency is maintained basically around 59% and 48% when zooming under RCP and LCP wave excitation. Meanwhile, the incident wave’s ellipticity can be changed to alter the relative intensity ratios of the bifocals from 0.03 to 4.26. This continuous varifocal metalens with adjustable intensity may have potential in practical applications such as optical tomography, multiple imaging, and systems of optical communication.

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Section: Polarization-dependent Continuous Varifocal Metalensmentioning

confidence: 99%

Mid-Infrared Continuous Varifocal Metalens with Adjustable Intensity Based on Phase Change Materials

et al. 2022

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“…10 This novel design method can overcome the disadvantages of traditional lenses, such as bulk, heavyweight, and difficulty of realization. 11,12 However, the miniaturization of metalens relies on the high effective permittivity of the unit cells. Achieving high permittivity at a larger unit cell thickness remains a key research target.…”

Section: Introductionmentioning

confidence: 99%

“…These metamaterial unit cells are easily fabricated with insulated substrate and etched metal 10 . This novel design method can overcome the disadvantages of traditional lenses, such as bulk, heavyweight, and difficulty of realization 11,12 . However, the miniaturization of meta‐lens relies on the high effective permittivity of the unit cells.…”

Section: Introductionmentioning

confidence: 99%

Beam shaping for magnetoelectric transverse electromagnetic horn by using gradient refractive index lens

Yang

Zhang

Song

et al. 2023

Micro & Optical Tech Letters

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This paper presents a new type of flat gradient index lens used for the beam shaping of a miniaturized magnetoelectric transverse electromagnetic (ME-TEM) horn antenna. Novel metamaterial unit cells with variable sizes are proposed to achieve high refractive index distribution. After applying the novel meta-lens to the modified transverse electromagnetic horn, the inherent E-plane beam squint of the low-profile ME-TEM horn is corrected. The radiation patterns in E-plane and H-plane are focused and the peak gain at 4 GHz is improved to 17.3 dBi. The −10 dB matching bandwidth of 0.4-4 GHz is achieved while the measured S 11 is a little poor at 0.8 GHz. The length of the total antenna is still shorter than half of the largest wavelength. The application potential of the gradient index meta-lens in the low-frequency band is verified.

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“…In the aspect of terahertz system design, Yin et al proposed an active meta‐lens composed of two concentric sets of complementary split‐ring resonator arrays that could dynamically switch the coaxial focus on three statuses 34 . In the same year, multilayer high transmission gradient metasurfaces are employed by Liu et al to design both high NA and large focusing efficiency metalenses in the low spectrums 35 . Tamminen et al studied the design, simulation, and characterization of a quasioptical system for submillimeter‐wave quantification for corneal to observe the dynamic changes in artificial tear‐film, thickness, and water content 36 .…”

Section: Introductionmentioning

confidence: 99%

“…34 In the same year, multilayer high transmission gradient metasurfaces are employed by Liu et al to design both high NA and large focusing efficiency metalenses in the low spectrums. 35 Tamminen et al studied the design, simulation, and characterization of a quasioptical system for submillimeter-wave quantification for corneal to observe the dynamic changes in artificial tear-film, thickness, and water content. 36 In fact, most of the researches about terahertz system are for terahertz imaging and detection, while few terahertz system designs for terahertz radiation are reported.…”

Section: Introductionmentioning

confidence: 99%

Design and energy research of terahertz optical systems for cell stimulation

Guan

Liu

et al. 2022

Micro & Optical Tech Letters

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Terahertz technology has its unique advantages in the field of biomedicine and is increasingly used in modern medical applications. In this study, to research the responding of biological tissues (cells or nerve nuclei) to various terahertz energy stimulation, an automatic terahertz energy control optical system is designed. The ray tracing simulation of the selfdesigned optical lens model is conducted and the results show that the system can achieve the focusing arrangement within 90 mm and control the strength of terahertz energy on image plane. In addition, an automatic control system with nanometer-level precision is designed using a stepper motor subdivision scheme to coordinate with the image plane (target point) energy and morphology adjustment. Then biomedical experiments based on this system are carried out. Through adjusting the system, terahertz intensity on cells is changed, so that the cells show various cell viabilities. The optimized experimental results show that the terahertz energy automatic control optical system designed in this study is qualified for terahertz energy irradiation research with biological cells.

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High numerical aperture and large focusing efficiency metalens based on multilayer transmitarray elements

Cited by 27 publications

References 36 publications

Mid-Infrared Continuous Varifocal Metalens with Adjustable Intensity Based on Phase Change Materials

Mid-Infrared Continuous Varifocal Metalens with Adjustable Intensity Based on Phase Change Materials

Beam shaping for magnetoelectric transverse electromagnetic horn by using gradient refractive index lens

Design and energy research of terahertz optical systems for cell stimulation

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