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SiCxOybeaded carbon fibers were successfully fabricated for the first time using a facile and stable electrospinning and temperature process. The resulting fibers showcase a unique micro-nanocomposite structure, in which β-SiC beads with a silica-enriched surface are strung together with defect carbon fibers, as confirmed by XRD, XPS, and HRTEM investigation. The SiCxOybeaded carbon fibers display efficient microwave absorption performance, with a minimum reflection loss of −58.53 dB and an effective absorption bandwidth of 5.92 GHz. A modified Drude–Lorentz model was developed for SiCxOybeaded carbon fibers to reveal the double-peaked feature of the permittivity of these fibers, which is in good agreement with experimental measurements. Moreover, simulations were performed to extract polarized electric fields and microwave energy volume losses within a typical distribution of SiCxOybeaded carbon fibers. It is concluded that the dipole relaxation and hopping migration of localized electrons give a superior contribution to the overall decay of the microwave energy. This study indicates that SiCxOybeaded carbon fibers with a unique micro-nanocomposite structure hold great promise for microwave absorption applications. Additionally, this fabrication strategy offers a unique approach to producing micro-nanocomposite structures and highlights their potential applications.

Maintaining the dynamical microwave synchronization between a target and its background is the key to electromagnetical invisibility in real environment. Herein, we introduce an archetypical paradigm for ultraelastic films of graphene-functionalized ionic gel with tunable microwave-absorbing behaviors. Inspired by the local structural changes during the wing-spreading process of vespertilionids, the experimental and finite element simulations have revealed that proper shape changing of 3D wrinkled structure containing ridge walls with moderate impedance is the effective way to minimize reflected wave and promote energy attenuation. An optimal RL value of −43.6 dB and valid regulatory amplitude of 41.5 dB, covering a microwave-absorbing to shielding state, could be reached with only 0.2% weight fraction of the active ingredient RGO filler. The significant regulatory performance is attributed to the competitive effect between intrinsic dielectric attenuation of silicon nitride modified reduced graphene oxide (RGO-SiN), multiscattering of a 3D wrinkled structure, and evolution of the oriented RGO-SiN.

Integration of photonic nanostructures with optoelectrical semiconductors offers great potential of developing high sensitivity and multifunctional photodetectors enabled by enhanced light–matter interactions. Split ring resonator (SRR) array which resonates at different resonant modes, including fundamental magnetic mode (m0), high order magnetic mode (m1), and electric (e) mode has been investigated because of the high potential for different applications. In this work, we study photodetection enhancement of these resonant modes of U-shape SRR arrays in the mid-infrared (2–5 μm) range and report, for the first time, the strong enhancement of photodetection by superimposition of m1and e modes in an integrated photodetector consisting of a U-shape SRR array and an InAsSb-based heterojunction photodiode. We observe that the m1mode in the SRR array shows the strongest enhancement of photocurrent, sequentially followed by the e and m0modes. Using superimposed m1and e modes, about an order of enhancement in room temperature detectivity (to about 2.0 × 1010Jones) is achieved under zero-power-supply without sacrificing the response speed. In addition, polarization-resolved photoresponse between m1and e modes and tunable enhancement of photoresponse are also demonstrated. The remarkable enhancement makes mid-infrared photodetection possible to operate at room temperature.

Half-wave plate (HWP) is one of the key polarization controlling devices in optical systems. The conventional HWPs based on birefringent crystals are inherently bulky and difficult to be monolithically integrated with other optical components. In this work, metasurface-based HWPs with high compactness are demonstrated on a 12-inch silicon complementary metal-oxide-semiconductor platform. Three-dimensional finite difference time domain simulation is used to design the nanostructure and investigate the impact of fabrication process variation on the device performance. In addition, the cross- and co-polarization transmittance (Tcrossand Tco) of the HWPs located at different wafer locations are characterized experimentally. The peak Tcrossand valley Tcovalues of 0.69 ± 0.053 and 0.032 ± 0.005 are realized at the wavelength around 1.7 μm, respectively. This corresponds to a polarization conversion efficiency of 95.6% ± 0.8%.

A sub-terahertz photodetector based on the narrow-gap semiconductor In0.53Ga0.47As is designed, fabricated, and characterized. The detector exhibits a responsivity up to 515 V/W, a noise equivalent power lower than 20 pW/Hz0.5, a detectivity up to 7.2 × 108cm·Hz0.5/W, and a response time of 4.1 µs in the sub-terahertz waveband for room-temperature operation. The achieved excellent performance, together with a relatively large detector feature size, simple structure, and easy manufacturing, provide a promising approach to the development of sensitive terahertz room-temperature detectors.