Optimized Design And Stability Analysis Of Dual-parameter Sensing Model Based On Photonic Crystal Nanobeam Cavities

With the development of science and technology,photonic crystal(PC)have attracted more and more attention of researchers,because of the advantages of small size and strong ability for controlling light.Compared with traditional sensing technology,PC sensing technology is used for the detection of physical,chemical and biological parameters because of its small size,easy integration and detecting without label.In recent years,sensors have gradually developed towards high integration and multi-parameter sensing simultaneously.Based on the existing PC sensors,this paper mainly studies the PC temperature sensor,the anti-external interference dual-parameter sensor and multifunctional dual-parameter sensor.The main research results of this paper can be summarized as follows:Firstly,the thermo-optic(TO)coefficient of silicon makes it difficult to improve the temperature sensitivity of PC sensors.Since SU-8 cladding has the advantage of large negative TO coefficient,the PC sensor is covered with SU-8 cladding to improve the temperature sensitivity.The one-dimensional(1D)photonic crystal nanobeam cavity sensor covered with SU-8 cladding is proposed,achieveing a temperature sensitivity of-108.9pm/K.The proposed sensor not only achieves a competitive temperature sensitivity,but also eliminates the influence of external ambient refractive index(RI)on sensing.Therefore,the proposed sensor is potentially a promising platform for future application of temperature sensing.Secondly,a 1D PC nanobeam cavity covered with SU-8 cladding and a 1D PC nanobeam cavity exposed to air directly are connected in parallel by a 1×2 power splitter.The 1D PC nanobeam cavities are based on elliptical stacks.The anti-external interference dual-parameter sensor based on PC nanobeam cavities is proposed,achieving the RI sensitivities of Onm/RIU and 354.6nm/RIU and temperature sensitivities of-107.9pm/K and 46.7pm/K.In addition,the concept of anti-external interference is proposed to describe the stability of dual-parameter sensor.The method is suitable for all dual-parameter sensors based on sensing matrix.After introducing some external interferences on the resonance wavelength,the aRI and aT of the dual-parameter sensor are derived under interferences such as the external interferences caused by the non-detected parameters and system errors.The smaller the aRI and aT,the stonger the anti-external interference ability of dual-parameter sensors and the better the stability.The proposed dual-parameter sensor not only has competitive RI sensitivities and temperature sensitivities,but also has strong stability after the calculation of aRI and aT.Finally,a 1D PC nanobeam air-mode cavity and a ID PC nanobeam dielectric-mode cavity are connected in parallel by a 1×2 power splitter and a 2×1 power combiner.The multifunctional dual-parameter sensor based on 1D PC nanobeam cavities is proposed.The multifunctional dual-parameter sensor can be used for simultaneous dctection of liquid concentration and temperature,as well as dual-parameter sensing of gas RI and temperature,and the proposed sensor can achieve similar resonant wavelengths and the Q-factors of sensor in the liquid or gas sensing process.In summary,a temperature sensor based on SU-8 cladding covered 1D PC nanobeam cavity is proposed.An anti-external interference dual-parameter sensor based on PC nanobeam cavities is proposed and the concept of anti-external interference is proposed to describe the stability of dual-parameter sensor.A multifunctional dual-parameter sensor based on PC nanobeam cavities is designed.The research may provide innovative ideas for the design of dual-parameter sensors in the future.