Design Low Crosstalk Ring-Slot Array Structure for Label-Free Multiplexed Sensing

Abstract

We theoretically demonstrate a low crosstalk ring-slot array structure used for label-free multiplexed sensing. The proposed sensors array is based on an array of three ring-slot and input/output line defect coupling waveguides. Each ring-slot cavity has slightly different cavity spacing and different resonant frequency. Results obtained using two dimensional finite-difference time-domain (2D-FDTD) simulation indicate that the resonant frequencies of each sensor unit in response to the refractive index variations are independent. The refractive index sensitivity is 134 ~ 145.5 nm/RIU (refractive index unit) and the Q factors more than 10 4 can be achieved. The calculated detect limit lower than 1.13 × 10 −4 RIU is obtained. In addition, an extremely small crosstalk lower than −25.8 dB is achieved among the array of three ring-slot cavities. The results demonstrate that this multiplexed sensor array is a promising platform for integrated optical devices and enables highly parallel label-free detection.

High sensitive photonic crystal multiplexed biosensor array using H0 sandwiched cavities

“…Based on Equation (1) the calculated detection limit of the proposed biosensor array is about 6.58x 10-6 RIU. These results are favorably comparable to the similar reported works [19,21]. …”

“…As it can be seen from this figure, the shift occurs only with the functionalized biosensors while the others remain completely unchanged. It can also be noted that the spectral position of the resonating peak detected at the end of output waveguides shifts towards longer wavelengths (red-shift) as the RI of the biosensor functionalized area is increased by 1.330, 1.335, 1.340, 1.345, 1.350, 1.355, 1.360, 1.365, 1.370, 1.377, respectively, which is in good agreement with the previous works [21], [25]. Fig.…”

“…The calculated Q factors of the three peaks are equal to 44360, 28710 and 25029 respectively. These values showed an improvement in respect to other reports [17][18][19]21]. …”

“…In this section, the crosstalk between each other adjacent detection unit is analyzed by performing a detailed simulation and by calculating the extinction ratio (ER) which is defined by the following equation: [21] ‫ܴܧ‬ = 10 ‫݈݃‬ ் ் (2) Fig. 11.…”

“…Simulation and experimental results showed a good agreement with RI sensitivity of 153nm/RIU. Recently, In order to reduce the crosstalk effect Huang et al [21] have proposed a label-free integrated ring-slot sensor array structure that exhibits a Q factor of 11.000 and a crosstalk value of less than -25.8 dB in water environment. This work aims to investigate a high sensitive PhC integrated biosensor array structure, which is potentially used for label-free multiplexed sensing in aqueous environment.…”