- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Metasurface for Constructing a Stable High- <i>Q</i> Plano-Planar Open Cavity
摘要： Traditional open cavities are constructed by planar or concave mirrors. A Fabry–Pérot (FP) cavity is convenient to integrate and fabricate, but highly sensitive to the parallelism of the end mirrors. In contrast, a concave cavity is more stable and possesses a lower leaky rate, but the curved geometry brings inconvenience. Here, it is suggested that a planar meta-cavity can simultaneously possess the advantages of both of the above open cavities by using a metasurface to create a planar meta-mirror that mimics the behavior of a concave mirror. For demonstration, a microwave meta-cavity is constructed, whose meta-mirror consists of subwavelength ceramic blocks on a metal substrate. Compared to an FP cavity, the meta-cavity is more robust against the alignment error of the end mirrors, and 15-fold enhancement of the quality factor is observed numerically. Experimental results are in good agreement with the simulated results. The suggested method may be extended to work in high frequency ranges. This work would support the planarization and miniaturization of an open cavity and may also increase the functionality.
关键词： open cavities,cavity stability,high quality factor,metasurfaces
更新于2025-09-23 15:23:52
-
Quality factor assessment of finite-size all-dielectric metasurfaces at the magnetic dipole resonance
摘要： Recently there has been a large interest in achieving metasurface resonances with large quality factors. In this article, we examine metasurfaces that comprised a finite number of magnetic dipoles oriented parallel or orthogonal to the plane of the metasurface and determine analytic formulas for their resonances’ quality factors. These conditions are experimentally achievable in finite-size metasurfaces made of dielectric cubic resonators at the magnetic dipole resonance. Our results show that finite metasurfaces made of parallel (to the plane) magnetic dipoles exhibit low quality factor resonances with a quality factor that is independent of the number of resonators. More importantly, finite metasurfaces made of orthogonal (to the plane) magnetic dipoles lead to resonances with large quality factors, which ultimately depend on the number of resonators comprising the metasurface. In particular, by properly modulating the array of dipole moments by having a distribution of resonator polarizabilities, one can potentially increase the quality factor of metasurface resonances even further. These results provide design guidelines to achieve a sought quality factor applicable to any resonator geometry for the development of new devices such as photodetectors, modulators, and sensors.
关键词： dipole approximation,Mie resonances,magnetic dipole resonance,finite-size metasurfaces,High quality factor
更新于2025-09-23 15:22:29
-
Engineering of high quality factor THz metasurfaces by femtosecond laser ablation
摘要： We report on the realization of high Q metasurfaces operating in the THz frequency range by femtosecond laser ablation applied to a nanometric metallic layer over a silicon substrate. Two different fabrication methods are used to develop periodic patterns whose basic elements are in form of an array of through-holes or metallic islands. The response of the resulting structures is characterized using a time-domain spectrometer in the frequency range 0.3–1.5 THz. The experimental findings are compared with the predictions of full wave electromagnetic simulations. The fairly good agreement between simulation predictions and experimental findings evidences that the proposed approach can offer a facile way to the elaboration of THz metasurfaces.
关键词： Femtosecond laser ablation,THz,High quality factor,Metasurfaces
更新于2025-09-23 15:21:01
-
Optimal Photonic Crystal Cavities for Coupling Nanoemitters to Photonic Integrated Circuits
摘要： Photonic integrated circuits that are manufactured with mature semiconductor technology hold great promise for realizing scalable quantum technology. Efficient interfaces between quantum emitters and nanophotonic devices are crucial building blocks for such implementations on silicon chips. These interfaces can be realized as nanobeam optical cavities with high quality factors and wavelength-scale mode volumes, thus providing enhanced coupling between nano-scale quantum emitters and nanophotonic circuits. Realizing such resonant structures is particularly challenging for the visible wavelength range, where many of the currently considered quantum emitters operate, and if compatibility with modern semiconductor nanofabrication processes is desired. Here, it is shown that photonic crystal nanobeam cavities for the visible spectrum can be designed and fabricated directly on-substrate with high quality factors and small mode volumes. Designs are compared based on deterministic and mode-matching methods and the latter is found advantageous for on-substrate realizations. The results pave the way for integrating quantum emitters with nanophotonic circuits for applications in quantum technology.
关键词： CMOS compatible,photonic crystal cavities,integrated photonics,high quality factor
更新于2025-09-19 17:13:59
-
[IEEE 2019 IEEE 2nd International Conference on Electronic Information and Communication Technology (ICEICT) - Harbin, China (2019.1.20-2019.1.22)] 2019 IEEE 2nd International Conference on Electronic Information and Communication Technology (ICEICT) - Hybrid Metamaterial Absorber based on the Combination of Plasmonic Structure and Magentic Absorber
摘要： This paper presents a thin-film wafer-level encapsulation process based on an epitaxial deposition seal that incorporates both narrow and wide lateral transduction gaps (0.7–50 μm), both in-plane and out-of-plane electrodes, and does not require release etch-holes in the device layer. Resonant structures fabricated in this process demonstrate high-quality factors ( f × Q products of up to 2.27e + 13 Hz) and exceptional stability (±18 ppb over one month) with no obvious aging trends. Studies on cavity pressure indicate that vacuum levels better than 0.1 Pa can be achieved after final encapsulation, thus reducing gas damping for high surface-to-volume devices. The vast diversity of functioning devices built in this process demonstrates the potential for combinations of high-performance MEMS devices in a single process and/or single chip.
关键词： high stability resonator,Wafer-level encapsulation,high quality factor,low pressure,hermetic encapsulation
更新于2025-09-16 10:30:52
-
Wideband Transition for Increased-Height Empty Substrate Integrated Waveguide
摘要： Recently, Empty Substrate Integrated Waveguide (ESIW) technology was proposed for embedding empty waveguides into planar substrates in order to improve their performance. A low-loss and narrow-band transition from microstrip to an increased height ESIW with 4 layers was presented in a previous work, and used to implement a very high-quality factor bandpass filter at Q-band. With such a narrow-band transition, based on a quarter-wavelength transformer, a very narrow-band filter response with resonators having a quality factor of 1000 was achieved. In this paper, in order to overcome the narrow-band and the 4-layers output restrictions, and extend the practical use of such increased height ESIWs beyond narrow-band filters, we present a novel wideband transition from microstrip to an increased height ESIW with an arbitrary number of layers. A full suite of wideband transitions to increased height ESIWs, built with different number of substrate layers ranging from 3 to 8, has been designed in this work to operate at Ka-band, though they can be easily transferred to other bands if the dimensions of the transition are properly scaled. To illustrate this, the original Ka-band transitions have been mapped to Ku-band, with excellent results. In order to test the proposed design method, a prototype of a 4-layer structure has been fabricated at Ka-band, achieving a good performance in the whole useful bandwidth of the ESIW.
关键词： Empty substrate integrated waveguide,multilayer,SIW,substrate integrated waveguide,substrate integrated circuit,microstrip transition,high quality factor,SIC,ESIW
更新于2025-09-11 14:15:04