Design And Implementation Of Terahertz Metamaterial Refractive Index Sensor

The information age has promoted the development of all walks of life.Optical technology is no exception,especially the development needs of emerging technologies such as terahertz technology and optical storage,and the application needs of some unique or complex environments.Thus,it urgently needs some high-performance,miniaturized,integrated devices to replace traditional devices.In sensing and detection,devices based on micro-nano photonics technology can meet the above requirements,so many scientific researchers favor this.The emergence and application of metamaterials in sensing have promoted the revolution because it has physical properties that natural materials do not have.It can make a couple of light and electromagnetic radiation to sub-wavelength scales and break the diffraction limit,and it Make transmission-sensing performance has dramatically increased.When combined with terahertz technology,the application in biochemical testing and other aspects has good development prospects.In this paper,we first analyzed the resonance characteristics of terahertz metamaterials and summarized the advantages and disadvantages of existing metamaterials.Then,designs two metamaterial refractive index sensors,and a series of simulation studies or experimental studies have been carried out on its transmission characteristics and sensing performance.The main contents are as follows:To overcome the influence of the thickness of the traditional planar metamaterial sensor's analyte and single-wavelength sensing limitation.Here,an ultra-sensitive stereo metamaterial sensor with dual resonance frequencies based on coupled resonance is designed.The electromagnetic analysis shows that the double resonant coupling caused by the three-dimensional double-layer structure can significantly improve the sensor's sensitivity at terahertz frequencies.The results show that each resonant frequency can be adjusted independently in the range of 0.5-1.8 THz by changing the structure's size.The maximum refractive index sensitivity is 930.4 GHz/RIU,the quality factor Q is 23.7,and the analyte thickness that can be affected is 50?m.The sensor has relatively excellent sensing performance,which is of great significance for detecting samples at different frequency points and the excellent application potential in the detection and differentiation of biomolecules.General three-dimensional metamaterials have problems such as complex structure,difficulty to process or to demand processing conditions,and low precision of processed products.In the current design of planar sensors,most of the optimizations of sensing performance have trade-offs in terms of sensitivity,Q value,transmittance,and ease of processing,or only propose a better solution for one of the performances.Therefore,based on the above problems,we studied the transparent phenomenon of electromagnetic induction and metamaterial structure design and then designed a transparent metamaterial-like refractive index sensor with high sensitivity,high Q factor,and easy processing of electromagnetic induction.The refractive index sensor uses two metal cutting lines as the bright mode,and a linear similar to "H" is placed in the middle of the two cutting lines to act as a dark mode.The whole structure is composed of a linear structure,making processing much easy and using the coupled Lorentz harmonic oscillator model for coupling analysis.In terms of sensing performance,when the asymmetry is 6?m,the highest sensor sensitivity can reach330GHz/RIU,the quality factor Q is 24,and the peak value of the transparent peak exceeds 80%.Finally,through experimental verification,the experimental results are consistent with the simulation results.In the drug analysis experiment,it finds that the sensor can distinguish different concentrations of drugs.Therefore,the device has robust applications in the terahertz range and has a better sensing effect from the total point of view of various performance parameters.This structure can also provide specific guidelines for designing devices of the same type,provide a way of thinking for the design of sensors,and have individual application potential in drug discrimination and detection or medicine.