Multiplexed terahertz multifocal metalens based on stretchable single-, dual-, and quad-axis synthetic rectangular optical sparse aperture

Materials & Design, Год журнала: 2024, Номер 237, С. 112631 - 112631

Опубликована: Янв. 1, 2024

As ultrathin optical elements with subwavelength structures densely arranged, planar lens or called metalens can effectively focus incident wave. Due to the compact design and wide operating frequency of metalens, it becomes promising in applications like information encryption, imaging, wireless communication fields. However, fabrication large-aperture is still time-consuming costly while focusing performances are commonly tuned by introducing active materials requiring extra stimuli, such as laser electrical pulses. In this study, five designs metalenses synthetic rectangular aperture proposed demonstrated excellent performances. By reconfiguring aperture, properties lengths, full width at half maximum values, modulation transfer function be great flexibility. With a polarization-dependent phase-shifting structure, shows different wave under transverse magnetic field electric modes. utilizing spatial multiplexing, terahertz variable foci based on stretchable single-, dual- quad-axis sparse investigated achieve tunable multifocal These provide novel strategy that reconfigure substrate make multifunction tunability, which show space telescope areas.

Язык: Английский

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Electrically Active Terahertz Liquid‐Crystal Metasurface for Polarization Vortex Beam Switching

Laser & Photonics Review, Год журнала: 2024, Номер 18(7)

Опубликована: Март 12, 2024

Abstract Polarized vortex waves have attracted widespread attention in investigations of light–matter interactions and the augmentation information capacity owing to their distinctive characteristics. Nevertheless, reconfigurable generation vector beams, especially at terahertz (THz) frequencies, remains challenging. In this study, a tunable THz polarization beam generator based on liquid‐crystal metasurface is proposed. A unit cell featuring linear selectivity developed. general methodology for designing metasurfaces generate customized patterns introduced. Furthermore, electrically polarized cylinder beams experimentally demonstrated. The findings study can open up opportunities wireless communication super‐resolution imaging applications.

Язык: Английский

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Color coded metadevices toward programmed terahertz switching

Light Science & Applications, Год журнала: 2024, Номер 13(1)

Опубликована: Июнь 25, 2024

Abstract Terahertz modulators play a critical role in high-speed wireless communication, non-destructive imaging, and so on, which have attracted large amount of research interest. Nevertheless, all-optical terahertz modulation, an ultrafast dynamical control approach, remains to be limited terms encoding multifunction. Here we experimentally demonstrated optical-programmed switching realized by combining optical metasurfaces with the metasurface, resulting 2-bit dual-channel encoding. The made up semiconductor islands artificial microstructures, enables effective programming providing multiple frequency channels modulation at nanosecond level. Meanwhile, covered metasurface alter spatial light field distribution obtain color code. According time-domain coupled mode theory analysis, energy dissipation modes can independently controlled excitation, explains principle well. This work establishes platform for programmed metadevices may further advance application composite manipulation.

Язык: Английский

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Recent Advances in Terahertz Manipulations Using C‐Shape‐Split‐Ring‐Resonator Metasurfaces (Review)

Advanced Optical Materials, Год журнала: 2024, Номер unknown

Опубликована: Янв. 20, 2024

Abstract Metasurfaces have garnered significant interest owing to their inherent advantages over traditional optical components in manipulating electromagnetic waves unconventionally. Among the fundamental building blocks of metasurfaces, C‐shaped‐split‐ring resonators (CSRRs) emerged as a highly promising option, enabling strong resonances and precise control various characteristics waves, such phase, amplitude, polarization. This review aims showcase recent advancements CSRR metasurfaces for THz particularly focusing on both passive active methods employed controlling using single‐layer multi‐layer metasurfaces. Moreover, this will provide valuable insights into potential research directions rapidly evolving field.

Язык: Английский

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Liquid Crystal Metasurface for On‐Demand Terahertz Beam Forming Over 110° Field‐Of‐View

Laser & Photonics Review, Год журнала: 2024, Номер 18(9)

Опубликована: Апрель 15, 2024

Abstract The terahertz spectral region, which bridges between electronics and optics, is poised to play an important role in the development of transformative wireless communication imaging systems with unprecedented functionality. Currently, a major challenge technology develop high‐performance beam‐forming devices that can dynamically shape radiation flexible manner. Existing have limited coding bits, field‐of‐view, beam gain. Here, reconfigurable liquid crystal‐integrated metasurface experimentally demonstrated, each unit cell being independently addressable. has 260° continuous phase tuning range crystal layer thickness only 1% free‐space wavelength. wave diffracted from be steered toward wide directions shown, covering record‐large 110° field‐of‐view peak gain 25 dBi. also features low power consumption sub‐second switching time. Furthermore, formation multiple beams direction ratio adjustable on demand. proposed possesses compelling prospects for future applications.

Язык: Английский

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Broadband long-wave infrared metamaterial absorbers based on germanium resonators

Results in Physics, Год журнала: 2023, Номер 51, С. 106660 - 106660

Опубликована: Июнь 22, 2023

The broadband metamaterial perfect absorbers over various incident angles are highly significant in long-wave infrared (LWIR) detection. Previous research on LWIR has mainly focused metallic resonators. Here, we propose two that use dielectric resonators instead. germanium (Ge) the top layer excite resonance modes control equivalent impedance of structure, which acts high-lossy Si3N4-Ti reflecting to assume absorption. Firstly, designed a three-layer structure Ge-Si3N4-Ti, achieved absorption with an average absorptivity 93.1 % 8–12 μm range. ratio metal can be effectively reduced by replacing metal. Then, further enhance absorptivity, inserted Si3N4 into Ge layer, increasing 90 bandwidth 7.96–14.16 and 8–14 96.5 %. Compared based resonators, large feature size make fabricating easier. Our proposed absorber provides ultra-wideband covering In addition, it is insensitive angle, making potential candidate for thermal imaging emission applications.

Язык: Английский

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Vortex‐Vector Beam Conversion and Chiral Field Manipulation based on Terahertz Liquid Crystal Cascaded Metadevice

Laser & Photonics Review, Год журнала: 2024, Номер unknown

Опубликована: Июнь 4, 2024

Abstract Vortex‐vector beam generators can effectively improve the channel capacity and communication accuracy, but they face problems of narrow operating frequency band, low efficiency, fixed function. Here, a terahertz liquid crystal cascaded metadevice is demonstrated, including layer, an asymmetric metasurface helical phase layer. The combination crystal's anisotropy structural from realizes dynamic chirality construction. Then, tunable chiral fields are coupled with geometric last layer to realize active control between symmetric spin‐orbit angular momentum coupling, leading two types generation conversion: 1) spin‐dependent conversion energy distribution vortex beams ±2 topological charges; 2) conversions 2‐order cylindrical vector beam. experimental results show that excitation efficiency reach over 92.1%, intensity modulation depth different more than 72.4%. This THz mechanism device scheme increase degree freedom have potential applications in multi‐channel wireless communication, polarization multiplexing imaging, spectrum detection.

Язык: Английский

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Liquid Crystal Integrated Dynamic Terahertz Metalenses

Laser & Photonics Review, Год журнала: 2024, Номер unknown

Опубликована: Июль 24, 2024

Abstract Metasurfaces can freely manipulate the wavefront of electromagnetic waves with merits minimization and integration. Dynamic metadevices have continued to be urgently pursued realize on‐demand functionalities. Among them, dynamic metalenses attracted particular attention due their widespread applications, especially in promising terahertz region. Here, a liquid crystal integrated metalens focusing properties is proposed. Subwavelength silicon columns are specifically designed set same lens phase profile for orthogonal linear polarizations, while rotation additionally introduces spin‐selective conjugated geometric phase. A photopatterned layer added compensate phase; therefore, polarization‐independent single focus achieved. With saturated bias applied crystal, compensation vanishes; bifocal function realized. When polarization grating profiles encoded separately, longitudinal lateral spin‐dependent separations demonstrated. The electrically switched between single‐focus functions. utilized depth‐of‐field imaging telecom port selection. design endows various existing

Язык: Английский

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Hydrogel‐Waveguiding On‐Chip Meta‐Optics for Dynamic Multicolor Holography

Advanced Functional Materials, Год журнала: 2024, Номер unknown

Опубликована: Сен. 16, 2024

Abstract On‐chip integrated meta‐optics hold tremendous potential for optical imaging and display applications compatible with photonic devices. Despite recent endeavors in multi‐dimensional image display, it remains a challenge to realize dynamic holography on‐chip integration scheme facile accessible tuning approach. Herein, an hydrogel‐waveguiding platform single‐step fabrication is demonstrated colorful holography. By exploiting the tunable property of waveguiding hydrogel, hydrogel metasurface enables concealment ON/OFF dual‐channel holographic switch within 310 ms through simple exhalation process. Furthermore, utilizing dispersion correlation between extraction efficiency relative humidity, color‐mixed encrypted successfully exhibited at specific humidity condition. Beyond conventional static monochromatic holography, such enjoys satisfactory humidity‐responsivity, high capability, full‐color potential, zero‐order diffraction interference‐free, which suggests active information concealment/encryption, next‐generation wearable AR

Язык: Английский

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When Structured Light Encounters Liquid Crystals

Advanced Functional Materials, Год журнала: 2024, Номер unknown

Опубликована: Май 13, 2024

Abstract Structured light refers to the field tailored by various degrees of freedom including intensity, phase, and polarization states in both spatial temporal domains, which may greatly vitalize technologies optics, such as next‐generation optical communication well subwavelength imaging materials science fabrication characterization. The structured characteristics structure need also with properties that can generate or manipulate a straightforward way, be satisfied liquid crystals, soft mater self‐assemble into tunable ordered structures through external stimuli. This review summarizes research progress crystal‐based devices used generations modulations, well‐established techniques market, like modulator, q‐plate crystal integrated metasurfaces. Especially, light‐matter interactions are discussed from topological view structures. Such perfect matching topology makes promising star together future optic photonic technologies.

Язык: Английский

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