Research On Multi-Resonant Pattern Metasurface Infrared Detector Based On FBAR

Infrared detectors are widely used in military,agriculture,industry and other fields because of their excellent performance in imaging,substance identification,temperature measurement and industrial diagnosis.The performance of traditional infrared thermal detectors mainly depends on the inherent characteristics of infrared absorbing materials,so the absorption band is single,and the absorption rate of infrared light is low,which greatly limits the application of infrared detectors in high-precision,wide-spectrum and other fields.The infrared metasurface absorber,as a new type of absorption structure that can change the electromagnetic characteristics through structural design and material selection,can theoretically even achieve perfect absorption of any waveband.Compared with traditional absorbing materials,it not only realizes the controllable absorption band and greatly improves the absorption rate,but also the infrared metasurface absorber has the advantages of small size and easy integration,which can better fit the development trend of integration and miniaturization.Based on the theory of surface plasmons,this paper studies the design rules of metasurface absorbers,and proposes a design method of single/multi-resonant pattern metasurface absorbers.By integrating the broadband/multi-frequency metasurface absorber with the thin film bulk acoustic resonator(FBAR),the detection of infrared light is realized,which opens up a new research field for infrared detectors based on acoustic devices.The article mainly introduces the theory of surface plasmon and its electromagnetic response characteristics,and analyzes the problems of MIM structure(metal-dielectric layer-metal)metasurface absorber with high absorption rate but single working wavelength and narrow absorption band.And the method of integrating multiple resonant patterns in a single basic period unit is adopted to realize the broadening of the absorption spectrum of the metasurface absorber and the design of multiple resonant absorption peaks.The main work is as follows:(1)Based on the MIM structure of the metasurface absorber,the FDTD simulation software is used to design the structure of the metasurface absorber.By studying the influence of various physical parameters of the metasurface structure on the absorption wavelength and absorption rate of the absorber,provide design directions for the follow-up study of broad-spectrum and multi-peak metasurface absorbers.(2)In this paper,the periodic subwavelength array structure of the metasurface is designed and studied.By integrating multiple resonant patterns with similar sizes in a single-period unit,the absorption peaks under the multiple resonant patterns are superimposed,and the absorption spectrum is broadened.(3)This paper also integrates multi-resonant patterns with large differences in size in a single-period unit.Through the superposition of multi-absorption spectra with large absorption wavelength differences,the multi-absorption peak design of the metasurface absorber is realized,so that the absorber is no longer limited to detect a fixed infrared light.(4)In this paper,the designed broadband and multi-frequency infrared metasurface absorber is processed and integrated into the surface of the film bulk acoustic resonator(FBAR)to form an infrared detector.The FBAR-based metasurface infrared detector was tested on the experimental platform built by myself,and good infrared test results were obtained.