An Optical MIM Pressure Sensor Based on a Double Square Ring Resonator

Abstract

In this paper, we have proposed a metal-insulator-metal (MIM) pressure sensor which consists of two plasmonic waveguides and a double square ring resonator. The two square rings are connected via a rectangular patch located between the two of them. The surface plasmon polaritons (SPPs) can be transferred from a square ring to the other through this patch. The finite-difference time-domain method (FDTD) has been used to simulate the device. Applying a pressure on the structure, it deforms, and a red shift of 103 nm in the resonance wavelength has been calculated. The deformation is linearly proportional to the wavelength shift in a wide range of wavelength. The proposed optical plasmonic pressure sensor has a sensitivity of 16.5 nm/MPa which makes it very suitable for using in biological and biomedical engineering.

Ultrahigh Sensitivity of a Plasmonic Pressure Sensor with a Compact Size

“…Note that resonance wavelength shift and sensitivity will increase with increasing b. The maximum ∆λ res and S(nm/MPa) in modes 1 can reach (254 nm, 30.23 nm/MPa) and show values 83.21% higher than those found in a previous study [55]. It implies that if we extend the length of the stub, it can anticipate a higher (∆λ res , S).…”

“…Pressure influence on the upper horizontal slot denotes deformation [37,52,54,55]. Figure 4a-d show the transmittance spectra of the designed structure with a variation of d from 0 to 10 nm with an interval of 2 nm in the wavelength of 700-3500 nm for modes 1-3, 1100-1300 nm for mode 3, 1300-1700 nm for mode 2, and 2500-3000 nm for mode 1, respectively.…”

“…In contrast, the |H| and |E| fields are hardly trapped in the horizontal slot and bottom stubs at off-resonance modes due to the destructive interference between bus WG and resonator. Pressure influence on the upper horizontal slot denotes deformation [37,52,54,55]. Figure 4a-d show the transmittance spectra of the designed structure with a variation of d from 0 to 10 nm with an interval of 2 nm in the wavelength of 700-3500 nm for modes 1-3, 1100-1300 nm for mode 3, 1300-1700 nm for mode 2, and 2500-3000 nm for mode 1, respectively.…”

“…The thickness of the Ag layer above the horizontal slot is h, and the gap distance between the bus WG and the resonator is g. In Figure 1, the golden and white parts stand for Ag and air. If an applied pressure F is exerted on the top of the Ag layer, it will bend downwards with deformation of d (see Figure 1b), which is stated according to [37,52,54,55]. A TM-polarized incident light couples with the fundamental SPP mode [56][57][58] into the bus WG's input port, and the transmission power reaches the output port [59,60].…”

Theoretical modelling of a deformation based concave square ring-square disc (SR-SD) silver structure for pressure sensing

“…As shown in figure 1 (inset), when a pressure P is applied on Pact, it bends down into the insulator cavity by a vertical displacement of d nm pursuant to the standard relation of beam bending. Considering Pact as a rectangular slab of length L= 350 nm and thickness WI =50 nm, the extent of deformation (d) as a result of the pressure applied (P) is expressed as [16] 𝑑 = 𝑃𝐿 4 2𝑌(𝑊 𝑠𝑟 ) 3 (1)…”