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High sensitivity and a large detection range with simple design are highly desirable to realize temperature sensor. A highly sensitive temperature sensor based on Fano resonances in metal-insulator-metal (MIM) waveguide with Nano-wall side-coupled to oval resonator is proposed in this work. The Fano resonance is originated from the coherent coupling and interference between the discrete and the continua state. It shows a different profile, which is typically asymmetric and sharp line, in comparison with the Lorentzian resonance profile. The transmission properties are numerically simulated by finite-difference time-domain method. Structural parameters have a key role in the sensor's sensitivity and transmission spectrum that are studied to systematically analyze the sensing characteristics of such structure. The results of our study indicate that there exist Four-fano resonance peaks in the transmission spectrum. All of which has a linear relationship with the refractive index of the analyte under sensing. Through the optimization of structural parameters, sensitivity of 2.463 nm∕ • C is achieved, indicating the designed sensor can pave the way in the nano-integrated plasmonic devices for high-accurate temperature detection.

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In this work, we design a new pressure sensor based on two-dimensional photonic crystal waveguide coupled to a point-defect resonant microcavity. The mechanism of sensing is based on the change of the germanium refractive index as function of the hydrostatic pressure P . The resonant wavelength will shift when pressure variation induces change in the refractive indexes of the structure. The pressure variation causes the shifting of defect modes. The properties of the refractive index sensor are simulated using the finite-difference time-domain algorithm and the plane wave expansion method. These kinds of sensors have many advantages in compactness, high sensitivity, and various choices of materials.

In this paper, a plasmonic sensor based on a metal-insulator-metal (MIM) waveguide with a slotted side-coupled racetrack cavity is proposed. The transmission characteristics of the cavity are analyzed theoretically, and the improvements of performance for the racetrack cavity structure compared to a single disk cavity are studied. The influence of structural parameters on the transmission spectra and sensing performances is investigated thoroughly. The achieved sensitivity for the first mode was S = 959 nm/RIU and S = 2380 nm/RIU for the second one. Its corresponding sensing resolution is 1.04 × 10 −5 RIU for mode 1 and 4.20 × 10 −6 RIU for mode 2, respectively, and high transmissions are achieved at the two resonant wavelengths of 898.8 nm and 1857.1 nm. The proposed plasmonic sensor is a good candidate for designing novel devices and applications, in the field of chemical and biological sensing, and also in the field of plasmonic filters, switches, etc.