Broadband solar energy absorber based on monolayer molybdenum disulfide using tungsten elliptical arrays

By means of critical coupling and impedance matching theory, we have numerically simulated the perfect absorption of monolayer graphene. Through the critical coupling effect and impedance matching, we studied a perfect single-band absorption of the monolayer graphene and obtained high quality factor (Q-factor = 664.2) absorption spectrum which has an absorbance close to 100% in the near infrared region. The position of the absorption spectrum can be adjusted by changing the ratio between the radii of the elliptic cylinder air hole and the structural period. The sensitivity of the absorber can be achieved S = 342.7 nm/RIU (RIU is the per refractive index unit) and FOM = 199.2 (FOM is the figure of merit), which has great potential for development on biosensors. We believe that our research will have good application prospects in graphene photonic devices and optoelectronic devices.

https://www.mdpi.com/2079-4991/10/1/95/pdf

High Quality Factor, High Sensitivity Metamaterial Graphene-Perfect Absorber Based on Critical Coupling Theory and Impedance Matching.

Surface plasmon resonance (SPR) infrared sensor based on D-shape photonic crystal fibers with ITO coatings

In this paper, we present a dual-band metamaterial absorber for graphene surface plasmon resonance at terahertz frequency. We use the finite difference time domain (FDTD) method to study the absorption characteristics of the homocentric graphene ring and disk nanostructure. These simulation results show that the change of the geometrical parameters and the substrate thickness of the nanostructure can change the absorption characteristics and the emergence of dual-band absorption peaks. Moreover, we study the field distribution of nanodisks with different radius in detail. By changing the Fermi level of graphene, the wavelength of their absorption peaks can be adjusted flexibly. In addition, the proposed dual-band absorber also shows a good angle tolerance for both TE and TM polarizations. By calculation the surface-filled water (n = 1.332) and 25% aqueous glucose solution (n = 1.372) for the metamaterial absorber, the sensitivities of mode I and mode II are 5.0 μm/RIU and 15.0 μm/RIU. These research results will have broad application prospects for sensing and spatial light modulators.

A dual-band metamaterial absorber for graphene surface plasmon resonance at terahertz frequency

In this paper, a triple-band perfect metamaterial absorber based on Cu-dielectric-Cu triple-layer nanostructure is reported. The top metal film structure consists of a ring and four pairs of capacitor plates, which has a frequency selection effect, allowing the absorber to resonate in the near infrared range. Theoretical study shows that the absorption of the three absorption peaks (872.54 nm, 1008.69 nm and 1138.62 nm) are 87.1%, 99.9% and 99.6%, respectively. The average absorption is 95.53%, including two perfect absorption peaks. Changing the structural parameters can affect its absorption peaks and resonant wavelengths. At the same time, due to the high symmetry of the absorber, it is not sensitive to the polarization angle and incident angle. Whether in the TE mode or the TM mode, the absorber at a wide incident angle (0-60°) also exhibits good operating angle polarization tolerance. Therefore, the perfect metamaterial absorber we designed can be widely used in sensing.

Triple-band perfect metamaterial absorber with good operating angle polarization tolerance based on split ring arrays

A U-shaped external photonic quasi-crystal fiber (PQF) sensor based on surface plasmon resonance is proposed for refractive index (RI) sensing. The advantages of sensing with metal/liquid surface plasmon polariton (SPP) mode are summarized. The gold/liquid SPP mode is excited and used for sensing in the U-shaped external PQF, which can detect a small variation of the analyte RI. The maximum sensitivity of the sensor is 33600 nm/RIU, and the average sensitivity is 21643.75 nm/RIU within the detection RI range of 1.420–1.436. The U-shaped PQF sensor will provide a new design idea for the RI sensor with high sensitivity.

https://iopscience.iop.org/article/10.7567/1882-0786/ab13bc/pdf

Qihui Liu

Papers

U-shaped photonic quasi-crystal fiber sensor with high sensitivity based on surface plasmon resonance