基于四峰超材料THz传感器的B族维生素检测

Identification of Vitamin B Using a Quad-Peak Terahertz Metamaterials Sensor

水溶性B族维生素是维持人体正常生理功能必需的营养成分,摄取适量有益于生长、代谢和发育,摄入过量严重危害身体。因此,维生素检测方法的研究受到质量监控部门和国内外学者的重视。传统测量维生素的光谱法、化学法和高效液相色谱法存在操作繁琐、样品处理复杂、成本高等问题,迫切需要开发操作简单快速准确的B族维生素检测技术。太赫兹波的特殊性使其广泛用于物质的检测,超材料奇异的电磁特性和对表面介质的敏感性,促进太赫兹波段内的超材料传感器在检测领域发展和应用。提出了一种利用四峰太赫兹超材料传感器进行同浓度水溶性B族维生素检测的方法。利用有限积分法设计了一种由不对称开口的正六边形和圆环组成的四峰超材料结构,四峰的频率分别为0.46,0.57,0.66和0.90 THz。通过表面电流研究四谐振峰的形成机理和传感性能,四个谐振峰对入射的太赫兹波响应特性不同,导致了其不同的传感灵敏度。实验过程中,将同浓度(0.5 mg·μL^-1)不同类型B族维生素B1,B3,B5和B6水溶液滴于超材料传感器表面,利用太赫兹时域系统测量透射谱,得到了四个谐振峰在测四种维生素时的频率偏移量。实验结果验证了由正六边形外环和内圆环组成的不对称开口环结构传感器的传感特性。结果表明,由内外环耦合形成的传感器灵敏度明显大于仅由外环或内环的电偶极子振荡形成的传感器灵敏度。该太赫兹超材料传感器的四个峰均可用于物质传感,其中内外环耦合形成的谐振峰传感灵敏度最高。不对称的双开口环具有优越的传感性能,可用于生物医学等领域样品传感检测。

Water-soluble B vitamins are necessary nutrients to maintain the normal physiological function of the human body.Ingestion of proper amount is beneficial to growth,metabolism and development,but excessive intake is seriously harmful to the body.Therefore,the research of vitamin detection methods has attracted the attention of quality control departments and scholars at home and abroad.Traditional microbial,chemical and high performance liquid chromatography(HPLC)methods for vitamin determination have some problems,such as complicated operation,complex sample processing,high cost and so on.It is urgent to develop a B-vitamin detection technology that is simple,fast,and accurate.Special characteristics of terahertz wave make it widely used in the detection of materials.The singular electromagnetic properties of metamaterials and the sensitivity to surface media promote the development and application of terahertz metamaterials in the field of detection.We present an identification method of water-soluble Vitamins B using quad-peak terahertz metamaterials.The sensor consists of an outside aluminum hexagon ring and an inner aluminum circle on high resistance silicon substrate,and are asymmetrically split at the same position deviating from the center of the unit cell.Firstly,the formation mechanism of four peaks and the sensing performance are revealed by using the finite-difference time-domain(FDTD)method,and the frequencies of the four peaks are 0.46,0.57,0.66 and 0.90 THz,respectively.During the experiment,the different types of vitamin B(B1,B3,B5 and B6)aqueous solution were dripped on the surface of the metamaterial sensor with the same concentration(0.5 mg·μL^-1).The transmission spectra were measured by the THz time domain spectroscopy(TDS)system,and the frequency offsets of four resonance peaks were obtained.The simulation and experimental results show that the sensitivity of the sensor formed by the coupling of inner and outer rings are significantly higher than that of the sensor formed by the oscillation of the electric dipoles of the single outer or inner ring.The four peaks of the sensor can be used for sensing detection,and the sensing sensitivity of the resonance peaks formed by the coupling of inner and outer rings is relatively higher.The asymmetric double-open rings have excellent sensing properties and can be used for sample sensing in biomedicine and other fields.