Research Of Electrically Triggered Tunable Terahertz Multiband-pass Filter Based On Metamaterials

Terahertz filter is a frequency selecting device working in terahertz frequency band,which can provide signal output in passband and attenuation in stopband,and can effectively eliminate noise interference and improve signal-to-noise ratio.Terahertz filter is a very important terahertz functional device,which greatly promotes the development of terahertz technology.The tunable terahertz filter has become a research hotspot in the terahertz field because of its strong dynamic modulation performance.This dissertation is based on the study of electrically triggered tunable terahertz multiband pass filter based on metamaterials,and analyzes the static filtering characteristics and the physical mechanism of dynamic modulation response of tunable terahertz multiband pass filter.The specific work contents are as follows:（1）We demonstrate an electrically triggered dual-band tunable terahertz band-pass filter based on Si₃N₄-VO₂-Si₃N₄sandwich-structured composited metamaterials by numerical simulation and experimental test at the same time.The maximum transmissions at the central frequencies of two passbands,i.e.,0.56THz and 0.91THz,are 68.2%and70.4%,respectively.Under the current of 0.225A,terahertz wave intensity modulation depths at the central frequencies are 81.7%and 81.3%,respectively.The full width at half maximum（FWHM）of the first passband and the second passband were 0.29THz and0.2THz,respectively.This novel design enables dynamically electric–thermo–optic modulation in the terahertz region,and has great potential applications in the fields of terahertz dual-band communications,imaging,sensing,and astronomy exploration.（2）We design a polarization insensitive thermo-controlled tunable terahertz tri-band bandpass filter based on metamaterials.The maximum transmissions at the central frequencies of three passbands,i.e.,0.64THz,1.16THz and 1.37THz,are 86.7%,75.6%and 68.5%,respectively.The full width at half maximum of the three passbands were0.37THz,0.2THz,and 0.09THz,respectively.Terahertz wave intensity modulation depths at the central frequencies of the three passbands are close to 100%.On this basis,the polarization stability and the incident angle stability of the terahertz filter are analyzed.Because of its good static filtering characteristics and thermo-controlled modulation performances,the filter provides an idea for the design of terahertz tunable multiband devices and has a wide application prospect in the fields of multiband terahertz communication technology and high speed local area network.